CN111831027A - A kind of outdoor electronic equipment and its system circuit - Google Patents

Abstract

The application discloses a system circuit, including a voltage regulator circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a heating element and a first switch connected in series; the first end of the first switch is used as the input of the constant power heating circuit The terminal is connected to the input terminal of the voltage regulator circuit for receiving the wide voltage input signal; the voltage regulator circuit is used to stabilize the wide voltage input signal so as to supply power to the main circuit; the heating control output terminal of the main circuit is connected to the constant power heating The control end of the circuit is connected to output a heating control signal; the first switch switches based on the on-off control signal of the power switch in the voltage stabilizing circuit to ensure that the heating element performs constant power heating under the action of the heating control signal. The present application reduces the demand for output power of the voltage regulator circuit, thereby reducing the circuit cost and power loss of the voltage regulator circuit, and improving the product benefit and applicability. The present application also discloses an outdoor electronic device, which also has the above beneficial effects.

Description

A kind of outdoor electronic equipment and its system circuit

technical field

The present application relates to the technical field of circuit design, in particular to an outdoor electronic device and a system circuit thereof.

Background technique

In order to ensure normal operation in a low temperature environment, a constant power heating circuit is often set in outdoor electronic equipment such as outdoor monitoring equipment. Generally, a constant power heating circuit includes a heating element and a switch for controlling the operation of the heating element to start and stop. The on-off of the switch is controlled by the main circuit of the outdoor electronic equipment according to the needs of the actual application scenario. In the prior art, both the constant power heating circuit and the main circuit are powered by the constant voltage output by the voltage stabilizing circuit after stabilizing the wide voltage input signal. In this way, when the heating power required by the system increases, the output power demand of the voltage stabilizer circuit also increases accordingly, so the related components in the voltage stabilizer circuit need to adopt higher specifications, thereby increasing the circuit cost and power consumption. In view of this, it is urgently needed by those skilled in the art to provide a solution for solving the above technical problems.

SUMMARY OF THE INVENTION

The purpose of the present application is to provide an outdoor electronic device and a system circuit thereof, so as to effectively reduce the power demand for the voltage stabilizer circuit under the condition that constant power heating can be realized, thereby reducing the circuit cost and power loss of the voltage stabilizer circuit.

In order to solve the above technical problems, in a first aspect, the present application discloses a system circuit, including a voltage regulator circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a series-connected heating element and a first switch;

The first end of the first switch is used as the input end of the constant power heating circuit, and is connected to the input end of the voltage regulator circuit for receiving a wide voltage input signal; the voltage regulator circuit is used for the wide voltage input signal. The voltage input signal is regulated so as to supply power to the main circuit; the heating control output end of the main circuit is connected to the control end of the constant power heating circuit for outputting heating control signals;

The first switch performs a switching action based on the on-off control signal of the power switch in the voltage regulator circuit, so as to ensure that the heating element performs constant power heating under the action of the heating control signal.

Optionally, the constant power heating circuit further includes an AND gate;

The first input end of the AND gate is used as the control end of the constant power heating circuit to receive the heating control signal; the second input end of the AND gate is connected to the power switch in the voltage regulator circuit The control terminal of the AND gate is connected to the control terminal of the first switch; the output terminal of the AND gate is connected to the control terminal of the first switch;

The first end of the heating element is connected to the second end of the first switch, and the second end of the heating element is grounded.

Optionally, the constant power heating circuit further includes a second switch connected in series with the heating element and the first switch;

The first switch is connected in parallel with the power switch in the voltage regulator circuit; the heating control signal is used to control the on-off of the second switch.

Optionally, the second switch is a triode;

The first end of the heating element is connected to the second end of the first switch, the second end of the heating element is connected to the first end of the second switch; the second end of the second switch is grounded , the base of the second switch is used as the control terminal of the constant power heating circuit to receive the heating control signal.

Optionally, the second switch is an NPN transistor, a first end of the second switch is a collector, and a second end of the second switch is an emitter.

Optionally, the second switch is a MOS tube; the constant power heating circuit further includes a pull-up resistor and a driving transistor;

The first end of the heating element is connected to the second end of the first switch, the second end of the heating element is connected to the first end of the second switch; the gates of the second switch are respectively connected to The first end of the pull-up resistor is connected to the first end of the driving transistor; the second end of the pull-up resistor is connected to the output end of the voltage regulator circuit; the base of the driving transistor is used as the The control terminal of the constant power heating circuit is used for receiving the heating control signal; the second terminal of the driving transistor and the second terminal of the second switch are both grounded.

Optionally, the second switch is an NMOS transistor, the first end of the second switch is a drain, and the second end of the second switch is a source;

The driving triode is an NPN triode, the first end of the driving triode is the collector, and the second end of the driving triode is the emitter.

Optionally, the constant power heating circuit further includes a Zener diode and a first protection resistor;

The cathode of the zener diode and the first end of the first protection resistor are both connected to the gate of the second switch, and the anode of the zener diode and the second end of the first protection resistor are both grounded .

Optionally, the constant power heating circuit further includes a protection capacitor and a second protection resistor;

The first end of the protection capacitor and the first end of the second protection resistor are both connected to the base of the driving transistor, and the second end of the protection capacitor and the second end of the second protection resistor are both connected to the base. ground.

Optionally, the first switch is a MOS transistor.

Optionally, the voltage regulator circuit includes a buck step-down circuit or a forward forward circuit.

In a second aspect, the present application also provides an outdoor electronic device, including any of the above-mentioned system circuits.

The system circuit provided by this application includes a voltage regulator circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a heating element and a first switch connected in series; the first end of the first switch serves as the constant power The input end of the heating circuit is connected to the input end of the voltage stabilizing circuit for receiving a wide voltage input signal; the voltage stabilizing circuit is used for stabilizing the wide voltage input signal so as to supply power to the main circuit ; The heating control output end of the main circuit is connected to the control end of the constant power heating circuit for outputting a heating control signal; the first switch is based on the on-off control signal of the power switch in the voltage regulator circuit. The switch action is used to ensure that the heating element performs constant power heating under the action of the heating control signal.

It can be seen that, compared with the prior art, the present application directly uses the wide voltage input signal to provide input power for the constant power heating circuit, and controls the power access control of the constant power heating circuit based on the on-off control signal of the power switch in the voltage stabilizing circuit. The switch, that is, the first switch, performs the switching action, which can ensure that the average voltage input from the first switch to the heating element remains stable when the main circuit starts the constant power heating circuit through the heating control signal to perform heating work, thereby realizing constant power heating. Since the heating power is directly provided by the wide-voltage input signal instead of the voltage-stabilizing circuit, the present application effectively reduces the output power demand for the voltage-stabilizing circuit, thereby reducing the circuit cost and power loss of the voltage-stabilizing circuit, and improving the applicability of the system circuit. performance and product benefits. The outdoor electronic equipment provided by the present application includes the above-mentioned system circuit, and also has the above-mentioned beneficial effects.

Description of drawings

In order to more clearly illustrate the prior art and the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings to be used in the description of the prior art and the embodiments of the present application. Of course, the following drawings related to the embodiments of the present application describe only a part of the embodiments of the present application. For those of ordinary skill in the art, without any creative effort, they can also obtain other embodiments according to the provided drawings. The accompanying drawings and other drawings obtained also belong to the protection scope of the present application.

1 is a schematic structural diagram of a system circuit disclosed in the application;

2 is a schematic structural diagram of a specific system circuit disclosed in the application;

FIG. 3 is a logic control signal diagram of the constant power heating circuit in FIG. 2 disclosed in the application;

4 is a schematic structural diagram of another specific system circuit disclosed in the application;

FIG. 5 is a specific circuit structure diagram of the system circuit in FIG. 4 disclosed in the application;

FIG. 6 is another specific circuit structure diagram of the system circuit in FIG. 4 disclosed by the application;

FIG. 7 is another specific circuit structure diagram of the system circuit in FIG. 4 disclosed by the application;

8 is a circuit structure diagram of a specific voltage regulator circuit disclosed in the application;

FIG. 9 is a circuit structure diagram of another specific voltage stabilizing circuit disclosed in this application.

Detailed ways

The core of the present application is to provide an outdoor electronic device and a system circuit thereof, so as to effectively reduce the power demand for the voltage stabilizer circuit under the condition that constant power heating can be realized, thereby reducing the circuit cost and power loss of the voltage stabilizer circuit.

In order to describe the technical solutions in the embodiments of the present application more clearly and completely, the technical solutions in the embodiments of the present application will be introduced below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

The current outdoor electronic equipment is generally equipped with a constant power heating circuit in order to ensure that it can work normally in a low temperature environment. Constant power heating circuit, as the name implies, can continue to heat with constant power. Different from the main circuit used to realize the main functions of outdoor electronic equipment, the constant power heating circuit is an additional circuit dedicated to heating, which generally includes heating elements and switches that can control the on-off of the heating circuit. In the prior art, similar to the main circuit, the input power of the constant-power heating circuit is also provided by the voltage-stabilizing circuit, so as to ensure the constant heating power based on the stable supply voltage output by the voltage-stabilizing circuit. However, this increases the power output requirement of the voltage regulator circuit, thereby increasing the circuit cost and power loss of the voltage regulator circuit. To this end, the present application provides a system circuit, which can effectively reduce the power demand for the voltage stabilizer circuit under the condition that constant power heating can be realized, thereby reducing the circuit cost and power loss of the voltage stabilizer circuit.

Referring to FIG. 1 , an embodiment of the present application discloses a system circuit, including a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a heating element R and a first switch K1 connected in series;

The first end of the first switch K1 is used as the input end of the constant power heating circuit, and is connected to the input end of the voltage stabilizer circuit for receiving a wide voltage input signal Vin; the voltage stabilizer circuit is used to The wide voltage input signal Vin is regulated so as to supply power to the main circuit; the heating control output end of the main circuit is connected to the control end of the constant power heating circuit for outputting the heating control signal CTRL; A switch K1 performs a switching action based on the on-off control signal of the power switch G in the voltage regulator circuit, so as to ensure that the heating element R performs constant power heating under the action of the heating control signal CTRL.

It should be pointed out that the constant power heating circuit in this embodiment is not directly connected to the output end of the voltage stabilizing circuit, that is, the input power is not provided by the voltage stabilizing circuit, but the first switch K1 in the constant power heating circuit is used. It is directly connected to the input end of the voltage regulator circuit to receive the wide voltage input signal Vin, and the input power is directly provided by the input signal of the entire system circuit, that is, the wide voltage input signal Vin.

It is easy to understand that the input signal of the system circuit, that is, the wide-voltage input signal Vin, is a signal whose amplitude fluctuates and is unstable. Therefore, the voltage stabilization circuit is used in the system circuit to stabilize the voltage to obtain a constant power supply. voltage Vo. The application does not limit the specific type of the voltage stabilizing circuit, for example, the voltage stabilizing circuit may specifically be a buck step-down circuit or a forward forward circuit.

In this embodiment, the first end of the first switch K1 in the constant power heating circuit is used as the input end of the constant power heating circuit to receive the input wide voltage input signal Vin. Therefore, the first switch K1 is used for constant power heating The power access control switch of the circuit. When the first switch K1 is closed, the wide voltage input signal Vin is connected to the constant power heating circuit to provide a heating energy source; when the first switch K1 is opened, the wide voltage input signal Vin is disconnected from the constant power heating circuit. When the turn-on frequency of the first switch K1 is relatively fast, the duty cycle of the on-off control signal of the first switch K1 will determine the magnitude of the average voltage U input to the constant power heating circuit.

The above process is similar to the working principle of the voltage regulator circuit. In fact, the voltage regulator circuit generally includes a power switch G for controlling the output voltage. According to the size of the feedback voltage, the on-off control signal of the power switch G based on the PWM (Pulse Width Modulation, pulse width modulation) technology is the PWM wave. By adjusting the duty cycle of the voltage stabilizer, the size of the power supply voltage Vo output by the voltage stabilizer circuit can be adjusted, thereby realizing the function of voltage stabilizer.

It can be seen that the key to maintaining the stability of the power supply voltage Vo output by the voltage regulator circuit lies in the on-off control signal of the power switch G. Similarly, in this embodiment, the constant power heating circuit inputs a wide voltage input signal Vin with a fluctuating voltage amplitude through the first switch K1, then the on-off control signal of the first switch K1 determines the input signal to the constant power heating circuit. The size of the average voltage U.

Therefore, in order to achieve constant power heating, that is, to ensure that the average voltage U input to the heating element R remains stable, the first switch K1 in this embodiment specifically performs the switching action based on the on-off control signal of the power switch G in the voltage regulator circuit. . Specifically, the on-off control signal of the power switch G can be used to directly control the on-off of the first switch K1, and the processing signal obtained based on the on-off control signal of the power switch G and the heating control signal CTRL can also be used to control the first switch K1. on and off. Therefore, when the heating control signal CTRL output by the main circuit is in an effective state for starting the heating element for heating, it can effectively ensure that the average voltage U input by the first switch K1 is the same as the power supply voltage Vo output by the voltage stabilizer circuit, That is, it is also a constant stable voltage, which can ensure the realization of constant power heating.

Among them, since the first switch K1 is a controllable switch that performs switching operations based on the on-off control signal of the power switch G, and considering the high turn-on frequency requirement of the power switch G, as a preferred embodiment, the first switch K1 is a MOS Tube.

Since the power input to the constant-power heating circuit is directly provided by the wide-voltage input signal Vin, rather than from the voltage-stabilizing circuit, the change in the heating power requirement has nothing to do with the voltage-stabilizing circuit, even when the system circuit needs to output a larger heating power When the voltage regulator circuit is used, there is no need to change and improve the voltage regulator circuit, so the present application effectively reduces the power output requirement for the voltage regulator circuit, and improves the flexibility and applicability of the system circuit.

In addition, it should be noted that the heating control signal CTRL is a start-stop control signal output by the main circuit and used to control the heating element R to perform the heating operation. In practical applications, the control module in the main circuit can determine whether constant power heating is required according to the current temperature detected by the temperature sensor. If necessary, it can output the corresponding heating control signal CTRL, such as a high-level signal, to start constant power heating. The circuit is running; if it is not needed, the corresponding heating control signal CTRL, such as a low level signal, can be output to stop the operation of the constant power heating circuit.

Wherein, the heating control signal CTRL can act on the first switch K1 to realize the heating start-stop control function, and can also act on other switches in the constant power heating circuit to realize the heating start-stop control function, which is not limited in this application. Those skilled in the art can choose and set by themselves according to actual application requirements.

In addition, the heating element R in the constant power heating circuit can be specifically an electric heating wire, a heating resistor, an electric heating film, etc. Those skilled in the art can choose and set a suitable heating element R according to the actual application scenario requirements. For example, the lens, cover glass, etc. of outdoor electronic equipment can be heated by the electric heating film made into a thin film.

The system circuit provided by the embodiment of the present application includes a voltage regulator circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a heating element R and a first switch K1 connected in series; the first end of the first switch K1 As the input end of the constant power heating circuit, it is connected to the input end of the voltage stabilizer circuit for receiving the wide voltage input signal Vin; the voltage stabilizer circuit is used to stabilize the voltage of the wide voltage input signal Vin, in order to supply power to the main circuit; the heating control output end of the main circuit is connected to the control end of the constant power heating circuit for outputting the heating control signal CTRL; the first switch K1 is based on the The on-off control signal of the power switch G performs a switching action to ensure that the heating element R performs constant power heating under the action of the heating control signal CTRL. It can be seen that the application directly uses the wide voltage input signal Vin to provide input power for the constant power heating circuit, and based on the on-off control signal of the power switch G in the voltage regulator circuit, the power access control switch of the constant power heating circuit is controlled, namely the first switch. The switching action of K1 can ensure that the average voltage U input from the first switch K1 to the heating element R remains stable when the main circuit starts the constant power heating circuit through the heating control signal CTRL for heating operation, thereby realizing constant power heating. Since the heating power is directly provided by the wide-voltage input signal Vin instead of the voltage-stabilizing circuit, the present application effectively reduces the output power demand for the voltage-stabilizing circuit, thereby reducing the circuit cost and power loss of the voltage-stabilizing circuit, and improving the performance of the system circuit. Applicability and Product Benefits.

Referring to FIG. 2 , an embodiment of the present application discloses a specific system circuit, including a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a heating element R and a first switch K1 connected in series; The constant power heating circuit further includes an AND gate;

The first end of the first switch K1 is used as the input end of the constant power heating circuit, and is connected to the input end of the voltage stabilizer circuit for receiving a wide voltage input signal Vin; the voltage stabilizer circuit is used to The wide voltage input signal Vin is regulated so as to supply power to the main circuit; the first input end of the AND gate is used as the control end of the constant power heating circuit, and is connected to the heating control output end of the main circuit, Used to receive the heating control signal CTRL; the second input end of the AND gate is connected to the control end of the power switch G in the voltage regulator circuit; the output end of the AND gate is connected to the control end of the first switch K1 Connection; the first end of the heating element R is connected to the second end of the first switch K1, and the second end of the heating element R is grounded.

It should be pointed out that, in this embodiment, the heating control signal CTRL output by the main circuit and the on-off control signal of the power switch G in the voltage stabilization circuit act together on the first switch K1, that is, the first switch K1 is not only used as a constant power The power of the heating circuit is connected to the control switch, and it is also used as the heating start-stop control switch of the constant power heating circuit. Therefore, in this embodiment, the number of switches required for the constant power heating circuit can be at least one, which further effectively simplifies the circuit structure and cost, and facilitates implementation.

Specifically, the heating control signal CTRL and the on-off control signal of the power switch G are AND logic processed through the AND gate, and the output terminal of the AND gate is directly connected to the control terminal of the first switch K1 for controlling the on-off of the first switch K1 break. Taking high-level driving as an example, only when the heating control signal CTRL and the on-off control signal of the power switch G are high-level at the same time, the output signal DRIVER of the AND gate will be high-level, and the first switch K1 will be turned on. Then make the heating element R start heating; when any one of the heating control signal CTRL and the on-off control signal of the power switch G is at a low level, the output signal DRIVER of the AND gate is at a low level, the first switch K1 is disconnected, and then Stop heating element R.

Referring to FIG. 3 , an embodiment of the present application discloses a logic control signal of the constant power heating circuit in FIG. 2 .

The on-off control signal of the power switch G is a periodic signal with a relatively high frequency, which can be as high as 100 Hz or kHz; the duration of the action of the heating control signal CTRL depends on the heating requirements of the electronic equipment in practical applications. Using the output signal DRIVER of the AND gate, the first switch K1 can be made to switch based on the on-off control signal of the power switch G and the heating control signal CTRL, thereby ensuring that the heating element R is in the heating control Constant power heating is performed under the action of the signal CTRL.

Referring to FIG. 4 , the embodiment of the present application discloses another specific system circuit, including a voltage regulator circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a series-connected heating element R and a first switch K1 ; The constant power heating circuit also includes a second switch K2 connected in series with the heating element R and the first switch K1;

The first end of the first switch K1 is used as the input end of the constant power heating circuit, and is connected to the input end of the voltage stabilizer circuit for receiving a wide voltage input signal Vin; the voltage stabilizer circuit is used to The wide voltage input signal Vin is regulated to supply power to the main circuit; the heating control output end of the main circuit is connected to the control end of the constant power heating circuit for outputting a heating control signal CTRL, the heating The control signal CTRL is used to control the on-off of the second switch K2; the first switch K1 is connected in parallel with the power switch G in the voltage regulator circuit to ensure that the heating element R is in the heating control signal CTRL Under the action of constant power heating.

It should be noted that, in this embodiment, the first switch K1 is connected in parallel with the power switch G of the voltage regulator circuit, which specifically means that each terminal of the first switch K1 is connected to the corresponding terminal of the power switch G, including the control terminals of both. Therefore, the first switch K1 is turned on and off synchronously with the power switch G of the voltage regulator circuit, and the average voltage U input from the first switch K1 to the constant power heating circuit is equal to the power supply voltage Vo output by the voltage regulator circuit.

It can be seen that in this embodiment, the on-off control signal of the power switch G directly acts on the first switch K1 to control the on-off of the first switch K1; the heating control signal CTRL directly acts on the second switch K2 to control the first switch K1. The on-off of the second switch K2. Therefore, in this embodiment, the first switch K1 is used as the power access control switch of the constant power heating circuit to maintain the stability of the average voltage U; the second switch K2 is used as the heating start-stop control switch of the constant power heating circuit, which is used It is used to control the start and stop of the heating element R. Since the first switch K1, the second switch K2 and the heating element R are all connected in series in the same heating circuit, the heating element R will start heating only when the first switch K1 and the second switch K2 are closed at the same time. , so as to ensure that the heating element R performs constant power heating under the action of the heating control signal CTRL.

Referring to FIG. 5 , the embodiment of the present application discloses a specific circuit structure of the system circuit in FIG. 4 , including a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a series-connected heating element R and a first switch K1; the constant power heating circuit further includes a second switch K2 connected in series with the heating element R and the first switch K1, and the second switch K2 is a triode;

The first end of the first switch K1 is used as the input end of the constant power heating circuit, and is connected to the input end of the voltage stabilizer circuit for receiving a wide voltage input signal Vin; the voltage stabilizer circuit is used to The wide voltage input signal Vin is regulated so as to supply power to the main circuit; the first end of the heating element R is connected to the second end of the first switch K1, and the second end of the heating element R is connected to the second end of the first switch K1. The first end of the second switch K2 is connected; the second end of the second switch K2 is grounded, and the base of the second switch K2 is used as the control end of the constant power heating circuit, and is connected with the main circuit. The heating control output end is connected to receive the heating control signal CTRL; the first switch K1 is connected in parallel with the power switch G in the voltage regulator circuit to ensure that the heating element R acts on the heating control signal CTRL Under constant power heating.

It should be pointed out that the second switch K2 in this embodiment is specifically a triode. In addition, as a specific implementation manner, a high-level active driving scheme is adopted, the second switch K2 is an NPN transistor, the first end of the second switch K2 is a collector, and the second switch K2 terminal is the emitter. Specifically, when the heating control signal CTRL is at a high level, the second switch K2 is turned on, thereby enabling the heating element R to perform heating.

Of course, those skilled in the art can also choose a PNP transistor as the second switch K2, and change the driving scheme accordingly, which is not limited in this application.

Referring to FIG. 6 , another specific circuit structure of the system circuit in FIG. 4 is disclosed in the embodiment of the present application, including a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a series-connected heating element R and the first switch K1; the constant power heating circuit also includes a second switch K2 connected in series with the heating element R and the first switch K1; the second switch K2 is a MOS tube; the constant power heating The circuit also includes a pull-up resistor Rt and a drive transistor Q;

The first end of the first switch K1 is used as the input end of the constant power heating circuit, and is connected to the input end of the voltage stabilizer circuit for receiving a wide voltage input signal Vin; the voltage stabilizer circuit is used to The wide voltage input signal Vin is regulated so as to supply power to the main circuit; the first end of the heating element R is connected to the second end of the first switch K1, and the second end of the heating element R is connected to the second end of the first switch K1. The first end of the second switch K2 is connected; the gate of the second switch K2 is respectively connected to the first end of the pull-up resistor Rt and the first end of the driving transistor Q; the pull-up resistor The second end of Rt is connected to the output end of the voltage regulator circuit; the base electrode of the driving transistor Q is used as the control end of the constant power heating circuit, and is connected to the heating control output end of the main circuit for receiving heating control signal CTRL; the second end of the driving transistor Q and the second end of the second switch K2 are both grounded; the first switch K1 is connected in parallel with the power switch G in the voltage regulator circuit to ensure that The heating element R performs constant power heating under the action of the heating control signal CTRL.

It should be pointed out that the second switch K2 in this embodiment is specifically a MOS transistor. Since the driving current of the main circuit is limited for the MOS transistor, a pull-up resistor Rt and a driving transistor Q are provided in this embodiment. The second end of the pull-up resistor Rt is connected to the output end of the voltage-stabilizing circuit, and the power supply voltage Vo output by the voltage-stabilizing circuit is used as the pull-up power supply. The base of the driving transistor Q is connected to the heating control output end of the main circuit, and the base voltage depends on the heating control signal CTRL output by the main circuit. When the driving transistor Q is turned on, the gate of the second switch K2 is grounded; when the driving transistor Q is turned off, the gate of the second switch K2 is limited to a high level by the pull-up power supply. Therefore, by using the circuit structure of the driving transistor Q and the pull-up resistor Rt, the on-off control of the second switch K2 by the heating control signal CTRL can be realized.

In addition, as a specific implementation manner, an active low-level driving scheme is adopted, the second switch K2 is an NMOS transistor, the first end of the second switch K2 is a drain, and the second switch K2 is a drain. The terminal is the source; the driving transistor Q is an NPN transistor, the first terminal of the driving transistor Q is the collector, and the second terminal of the driving transistor Q is the emitter.

Therefore, when the system circuit is powered on, the gate of the second switch K2 is at a high level, and the second switch K2 is turned on. When the heating control signal CTRL output from the main circuit is at a high level, the driving transistor Q is turned on, the gate of the second switch K2 is grounded and becomes a low level, and the second switch K2 is turned off; when the heating control signal CTRL becomes a low level Normally, the driving transistor Q is turned off, the gate of the second switch K2 is again limited to a high level by the pull-up power supply, and the second switch K2 is turned on. Thus, the on-off control of the second switch K2 by the heating control signal CTRL is realized.

Of course, those skilled in the art can also choose a PMOS transistor as the second switch K2, and correspondingly replace the relevant components and connection methods for driving the second switch K2, which are not limited in this application.

Referring to FIG. 7 , another specific circuit structure of the system circuit in FIG. 4 is disclosed in the embodiment of the present application, including a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant power heating circuit includes a heating element R connected in series and the first switch K1; the constant power heating circuit also includes a second switch K2 connected in series with the heating element R and the first switch K1; the second switch K2 is an NMOS tube; the constant power heating The circuit also includes a pull-up resistor Rt, a driving transistor Q, a Zener diode Z, a first protection resistor Rs1, a protection capacitor Cs and a second protection resistor Rs2, and the driving transistor Q is an NPN transistor;

The first end of the first switch K1 is used as the input end of the constant power heating circuit, and is connected to the input end of the voltage stabilizer circuit for receiving a wide voltage input signal Vin; the voltage stabilizer circuit is used to The wide voltage input signal Vin is regulated so as to supply power to the main circuit; the first end of the heating element R is connected to the second end of the first switch K1, and the second end of the heating element R is connected to the second end of the first switch K1. The drain of the second switch K2 is connected; the gate of the second switch K2 is respectively connected to the first end of the pull-up resistor Rt and the collector end of the driving transistor Q; the pull-up resistor Rt The second end of the voltage regulator circuit is connected to the output end of the voltage regulator circuit; the base of the driving transistor Q is used as the control end of the constant power heating circuit, and is connected to the heating control output end of the main circuit for receiving heating control signal CTRL; the emitter of the driving transistor Q and the source of the second switch K2 are grounded; the first switch K1 is connected in parallel with the power switch G in the voltage regulator circuit to ensure the heating The element R performs constant power heating under the action of the heating control signal CTRL;

The cathode of the Zener diode Z and the first end of the first protection resistor Rs1 are all connected to the gate of the second switch K2, the anode of the Zener diode Z and the first terminal of the first protection resistor Rs1. The second ends are both grounded; the first end of the protection capacitor Cs and the first end of the second protection resistor Rs2 are both connected to the base of the driving transistor Q, and the second end of the protection capacitor Cs, the first end of the second protection resistor Rs2 The second ends of the second protection resistor Rs2 are all grounded.

It should be noted that, in this embodiment, a zener diode Z and a first protection resistor Rs1 are set to protect the second switch K2. Both the Zener diode Z and the first protection resistor Rs1 are connected in parallel between the gate and the source of the second switch K2 to prevent the second switch K2 from being damaged due to excessive gate voltage.

Similarly, in this embodiment, in order to protect the driving transistor Q, a protection capacitor Cs and a second protection resistor Rs2 are set. Both the protection capacitor Cs and the second protection resistor Rs2 are connected in parallel between the base and the emitter of the driving transistor Q to prevent the base current from being too large and have a certain filtering function.

For other specific related contents in this embodiment, reference may be made to the foregoing embodiments, which will not be repeated here.

Referring to FIG. 8 , the embodiment of the present application also discloses a specific circuit structure of a voltage stabilizer circuit. The voltage stabilizer circuit is a buck step-down circuit, including a power switch G, a ground switch S, a first inductor L1 and a first A capacitor C1;

The first end of the power switch G serves as the input end of the voltage regulator circuit, the second end of the power switch G, the first end of the grounding switch S, and the first end of the first inductor L1 are all connected, the second end of the first inductor L1 is connected to the first end of the first capacitor C1 and used as the output end of the voltage regulator circuit; the second end of the grounding switch S is connected to the first end of the first capacitor C1. Both the second terminals of the capacitor C1 are grounded.

As mentioned above, due to high turn-on frequency requirements, most of the power switches G are MOS transistors; of course, they can also be triodes in low-demand applications. The ground switch S is used to form a freewheeling loop with the first inductor L1 and the first capacitor C1 when the power switch G is turned off. In a specific implementation manner, the grounding switch S can be a freewheeling diode, the first terminal of the grounding switch S is a cathode, and the second terminal of the grounding switch S is an anode. In another specific embodiment, the grounding switch S and the first switch K1 may both be MOS transistors. In this case, the power switch G may be referred to as a high-side driving MOS transistor, and the grounding switch S may be referred to as a low-side driving MOS transistor.

It should be noted that those skilled in the art can use the voltage stabilizing circuit provided by this embodiment on the basis of any of the foregoing embodiments, and the relevant content may refer to the foregoing embodiments, which will not be repeated here.

In fact, when the heating control signal CTRL is in an active state, that is, a state in which the heating element R is controlled to start heating, the constant power heating circuit in any of the foregoing embodiments can be simplified as a first power switch G that is turned on and off synchronously Switch K1 and heating element R in series with it. If the duty cycle of the on-off control signal of the power switch G is D, then in the ideal state ignoring the parasitic parameters of the circuit, when the heating control signal CTRL is in the active state, the duty cycle of the first switch K1 is also D. The average voltage U input by the first switch K1 to the constant power heating circuit is U=Vin·D; according to the calculation formula of heating power P=U ² /R, the heating power of the heating element R can be obtained as:

P=D ² ·Vin ² /R.

For a buck step-down circuit, if Vo represents the output power supply voltage and Vin represents the input wide voltage input signal, under the ideal state of ignoring circuit parasitics, the duty cycle of the on-off control signal of the power switch G is specifically D =Vo/Vin. Substituting into the calculation formula of the heating power can be obtained, the heating power corresponding to this embodiment is:

P=(Vo/Vin) ² ·Vin ² /R=Vo ² /R.

As for the prior art, since the constant power heating circuit is powered by the power supply voltage Vo output by the voltage stabilization circuit, the heating power in the prior art is specifically P'=Vo ² /R. It can be seen that the heating power of the system circuit provided in this embodiment is equal to the heating power in the prior art.

Referring to FIG. 9 , the embodiment of the present application also discloses another specific circuit structure of a voltage stabilizer circuit. The voltage stabilizer circuit is a forward excitation circuit, including a transformer, a power switch G, a first diode D1, a second diode D2, a second inductor L2 and a second capacitor C2;

The first end of the primary winding of the transformer is used as the input end of the voltage regulator circuit, and the primary winding is coupled to the power switch G; the first end of the secondary winding of the transformer is grounded, and the secondary winding is grounded. The second end of the diode is connected to the anode of the first diode D1, the cathode of the first diode D1, the cathode of the second diode D2, and the first end of the second inductor L2 are all connected to each other, the second end of the second inductor L2 is connected to the first end of the second capacitor C2, and serves as the output end of the voltage regulator circuit, the anode of the second diode D2 and the Both the second ends of the second capacitor C2 are grounded.

It should be noted that those skilled in the art can use the voltage stabilizing circuit provided by this embodiment on the basis of any of the foregoing embodiments, and the relevant content may refer to the foregoing embodiments, which will not be repeated here.

Similarly, when the heating control signal CTRL is in an active state, that is, a state in which the heating element R is controlled to start heating, the constant power heating circuit in any of the foregoing embodiments can be simplified into a first power switch G that is turned on and off synchronously. Switch K1 and heating element R in series with it. If the duty cycle of the on-off control signal of the power switch G is D, then in the ideal state ignoring the parasitic parameters of the circuit, when the heating control signal CTRL is in the active state, the duty cycle of the first switch K1 is also D. The average voltage U input by the first switch K1 to the constant power heating circuit is U=Vin·D; according to the calculation formula of heating power P=U ² /R, the heating power of the heating element R can be obtained as:

P=D ² ·Vin ² /R.

For the forward forward circuit, if Vo represents the output power supply voltage, Vin represents the input wide voltage input signal, Np represents the number of turns of the primary winding, and Ns represents the number of turns of the secondary winding, then the parasitic parameters of the circuit are ignored. In an ideal state, Vo=Vin·D·Ns/Np, and the duty ratio can be obtained as D=(Vo/Vin)·(Np/Ns). Denote n=Np/Ns, then there are:

D=n·Vo/Vin.

Substituting into the calculation formula of the heating power can be obtained, the heating power corresponding to this embodiment is:

P=(n·Vo/Vin) ² ·Vin ² /R=n ² ·Vo ² /R.

As mentioned above, for the prior art, since the constant power heating circuit is powered by the power supply voltage Vo output by the voltage stabilization circuit, the heating power in the prior art is specifically P'=Vo ² /R. It can be seen that the heating power of the system circuit provided in this embodiment is n ² times that of the heating power in the prior art.

Further, the present application also discloses an outdoor electronic device, including the system circuit disclosed in any of the above embodiments.

For the specific content of the system circuit, reference may be made to the corresponding content disclosed in the foregoing embodiments, which will not be repeated here.

The various embodiments in this application are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments may be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

It should also be noted that, in this application document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require Or imply that there is any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The technical solutions provided by the present application have been introduced in detail above. Specific examples are used herein to illustrate the principles and implementations of the present application, and the descriptions of the above embodiments are only used to help understand the methods and core ideas of the present application. It should be pointed out that for those skilled in the art, without departing from the principles of the present application, several improvements and modifications can also be made to the present application, and these improvements and modifications also fall within the protection scope of the present application.

Claims (10)

1. A system circuit is characterized by comprising a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant power heating circuit comprises a heating element and a first switch which are connected in series;

the first end of the first switch is used as the input end of the constant power heating circuit, is connected with the input end of the voltage stabilizing circuit and is used for receiving a wide voltage input signal; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal so as to supply power to the main circuit; the heating control output end of the main circuit is connected with the control end of the constant-power heating circuit and used for outputting a heating control signal;

the first switch performs switching action based on an on-off control signal of a power switch in the voltage stabilizing circuit and is used for ensuring that the heating element performs constant-power heating under the action of the heating control signal.

2. The system circuit of claim 1, wherein the constant power heating circuit further comprises an and gate;

the first input end of the AND gate is used as the control end of the constant power heating circuit and is used for receiving the heating control signal; the second input end of the AND gate is connected with the control end of the power switch in the voltage stabilizing circuit; the output end of the AND gate is connected with the control end of the first switch;

the first end of the heating element is connected with the second end of the first switch, and the second end of the heating element is grounded.

3. The system circuit of claim 1, wherein the constant power heating circuit further comprises a second switch in series with both the heating element and the first switch;

the first switch is connected in parallel with the power switch in the voltage stabilizing circuit; the heating control signal is used for controlling the on-off of the second switch.

4. The system circuit of claim 3, wherein the second switch is a triode;

the first end of the heating element is connected with the second end of the first switch, and the second end of the heating element is connected with the first end of the second switch; the second end of the second switch is grounded, and the base of the second switch is used as the control end of the constant-power heating circuit and is used for receiving the heating control signal.

5. The system circuit of claim 4, wherein the second switch is an NPN transistor, a first terminal of the second switch is a collector, and a second terminal of the second switch is an emitter.

6. The system circuit of claim 3, wherein the second switch is a MOS transistor; the constant-power heating circuit also comprises a pull-up resistor and a driving triode;

the first end of the heating element is connected with the second end of the first switch, and the second end of the heating element is connected with the first end of the second switch; the grid electrode of the second switch is respectively connected with the first end of the pull-up resistor and the first end of the driving triode; the second end of the pull-up resistor is connected with the output end of the voltage stabilizing circuit; the base electrode of the driving triode is used as the control end of the constant-power heating circuit and is used for receiving the heating control signal; and the second end of the driving triode and the second end of the second switch are both grounded.

7. The system circuit of claim 6, wherein the second switch is an NMOS transistor, a first terminal of the second switch is a drain, and a second terminal of the second switch is a source;

the driving triode is an NPN triode, a collector is arranged at the first end of the driving triode, and an emitter is arranged at the second end of the driving triode.

8. The system circuit of claim 7, wherein the constant power heating circuit further comprises a zener diode and a first protection resistor;

the cathode of the voltage stabilizing diode and the first end of the first protection resistor are connected with the grid of the second switch, and the anode of the voltage stabilizing diode and the second end of the first protection resistor are grounded.

9. The system circuit according to any one of claims 6 to 8, wherein the constant power heating circuit further comprises a protection capacitor and a second protection resistor;

the first end of the protection capacitor and the first end of the second protection resistor are both connected with the base electrode of the driving triode, and the second end of the protection capacitor and the second end of the second protection resistor are both grounded.

10. An outdoor electronic device, characterized in that it comprises a system circuit according to any one of claims 1 to 9.

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