JPS6289440A - Source circuit of electronic device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a power supply circuit for an electronic device, which includes a part to which power can be cut off and a part to which the power cannot be cut off.

[Background of the invention]

2. Description of the Related Art Electronic devices are used in a variety of fields, and among them, there are some that cause problems in subsequent operation if the power supply is cut off. For example, if a microcomputer is used as a child device, the microcomputer is equipped with RAM (Random Access Memory) for storing data during operation, but this RAM K is The data stored in the electronic device disappears when the power is cut off, and therefore, even if the power is turned on again, the data necessary for subsequent operation cannot be used, and the intended operation of the electronic device may not be possible. For this reason, in such electronic devices, a method is adopted to avoid this inconvenience by constantly turning on the power.However, this method consumes a large amount of power.
＜There is a possibility that the power supply will become unusable in a short period of time. For this reason, a method is used in which a separate power source is used to back up only the portion of the 1W child device that requires constant voltage application.

This will be explained with reference to FIG.

FIG. 4 is a block diagram of a conventional power electronic device.

In the figure, ] indicates an electronic device using a microcomputer. 1a is a component to which it is necessary to constantly apply power to the electronic device 1, and lb is a component to which power must always be applied (hereinafter, this will be referred to as R, A M
Let it be represented by ). 2 and 2' are power terminals of the electronic device 1, and 3 is a power switch. The component part 1a of the market unit M1 receives power from the power terminal 2.2'. 4
is a battery installed in the electronic device 1, and RAM1
It becomes the power source for b.

Note that the electronic device f1 also includes a power supply stabilization circuit (not disclosed) for the component 1a.

In such a configuration, when the power switch 3 is opened, the supply of power to the component 1a is stopped and the operation of the electronic device 1 is also stopped, but the RAM 1b is connected to the battery 4.
The power supply is continued from f, and the stored data is saved as is. Therefore, when the primary IIFM switch 3 is closed and the electronic device 1 is driven, the RAMI
The data stored in bK can be used without causing any trouble in driving the W child device l.

However, in the above-mentioned conventional power supply circuit, the battery 4 must be installed in the electronic device 1, and the battery 4 is used to operate the RAM 1b during the life of the electronic device ftx. I need something like that.

Separately preparing such a battery 4 is extremely uneconomical and costly.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the above-mentioned conventional techniques and to provide a power supply circuit for an electronic device that does not require a separate backup battery.

[Summary of the invention]

To achieve the above object, the present invention provides an electronic device including a component that requires backup and a component that does not require backup.

A power supply stabilizing circuit that applies a predetermined voltage is connected to these first and second component parts, and a cutoff means is provided that cuts off the supply of the predetermined voltage from the power supply stabilizing circuit to the second component part by a signal. It is characterized by having been established.

[Embodiments of the invention]

Hereinafter, two embodiments of the present invention will be explained based on illustrated embodiments.

FIG. 1 is a block diagram of an electronic device according to an embodiment of the present invention. In the figure, parts that are the same as those shown in FIG. 4 are given the same reference numerals, and description thereof will be omitted. 1' is the electronic device i of this embodiment.
&, 6 k′! A power supply stabilizing circuit (same structure W' as the wealth 1 source stabilizing circuit 5 shown in FIG. 4) constantly applies a predetermined voltage to the RAM 1b, and 7 applies a predetermined voltage to the component 1a that does not require backup. This is a power supply stabilization circuit that stably applies power. The power supply stabilizing circuits 6.7 have almost the same configuration as will be described later.

A switch 8 is inserted between the terminal 2' (ground terminal) and the source stabilizing circuit 7, and is closed when the power supply to the child device rWl is cut off. Here, the configuration of the source stabilization circuit will be explained with reference to FIG.

FIG. 2 is a circuit diagram showing a specific example of the power supply stabilizing circuit 7 shown in FIG. In Figure f, 10 is an input terminal connected to power supply terminal 2, 11 is an output terminal connected to component 1a and outputs a predetermined voltage, 12 is a ground terminal connected to power supply terminal 2', and 13 is connected to switch 8. This is the signal input terminal to be connected. 71, 74, 75, and 76 are resistors, 72 and 73 are transistors, and 77 is a Zener diode.

Next, the operation of the power supply stabilizing circuit 7 shown in FIG. 2 will be explained.

When the switch 8 is opened and the electronic device 1' is activated, the power supply voltage is input to the input terminal 10. Resistor 71 makes transistor 72 conductive. And Zener diode 7
7, a pipe current flows through a resistor 76. Also, a blind occurs at the emitter of transistor 72.

The voltage is divided by resistors 74 and 75, and when this voltage is applied to the base of transistor 73, transistor 73 becomes conductive. In this state, the emitter voltage of transistor 73 is kept constant by Zener diode 77.

Now, if the Zener voltages of the resistors 74, 75 and the Zener diode 77 are selected appropriately, the voltage input to the input terminal 1O increases, and when the voltage of the output terminal 11 increases, the base voltage of the transistor 730 increases to -F. Line up.

Its collector current increases. Therefore, the voltage drop across the resistor 71 becomes large, and the pace voltage of the transistor 72 decreases, causing its emitter voltage, that is, the increased output voltage of the output terminal 11 to decrease. When the voltage input to the input terminal 10 decreases and the voltage at the output terminal 11 decreases, the output voltage at the output terminal 11 increases by the operation opposite to the above. In this way.

Output terminal 11 remains empty regardless of fluctuations in power supply voltage.

A constant voltage is always output.

Next, when the switch 8 is closed to stop the operation of the single device 11, the pace of the transistor 72 is grounded through the signal input terminal 13 and the switch 8.

The transistor 72 is cut off, and the voltage at its emitter voltage, that is, the output terminal 11, becomes Ov. As a result, the supply of power to the component 1a of the electronic device 1 is cut off.

The configuration and operation of the source stabilization circuit 7 have been explained above.
The configuration of the power supply stabilizing circuit 6 is the same as the configuration of the power supply stabilizing circuit 7 except that the signal input terminal 13 in the configuration of the power supply stabilizing circuit 7 is removed. The operation is also the same as that of the power supply stabilizing circuit 7 when the switch 8 is open.

Here, the operation of the power supply circuit shown in FIG. 1 will be explained. evening,
During operation of the slave device 1', its component part 1a and RAM 1
A predetermined voltage is applied to b by power supply stabilizing circuits 7 and 6. Now, when the switch 8 is closed to stop the operation of the electronic device 1'.

As mentioned above, the power supply stabilizing circuit 7 becomes F day 10■, and the operation of the component part 1a stops. but.

1! Since there is no relation to the opening/closing of the i-source stabilizing circuit 6 & switch 8, a predetermined voltage is continuously output from its output terminal to RAM1b, and RA, Mlb
The stored data will never be lost.

In this way, in this embodiment, there are component parts of the W child device that do not require backup, and components of the R A child device that do not require backup.
Connect the power supply stabilizing circuit to M.

Only the power supply stabilizing circuit connected to the above components is equipped with a signal input terminal that inputs the signal of a switch that is temporarily closed (stopping the operation of electronic devices), and the output voltage is set to 0 when the item A is input.
Since the pressure is applied so that a backup n@ pond is not required, it is economical.

Also, it is important to back up your electronic devices. Since the VT source is supplied to components that do not have a VT source only when they are activated,
The capacity of the power supply can be reduced.

If we consider the electronic equipment of construction machinery, we get the following. That is, in a construction machine, a power generating device driven by an engine, which is the power of the machine, charges a battery mounted on the construction machine. By the way, the capacity of this battery is insufficient to constantly apply voltage to electronic devices, but it usually has sufficient capacity to constantly apply voltage to RAM. .

Therefore, if the above embodiment is applied, the electronic device of the construction machine can be sufficiently driven only by the on-board battery without using a backup battery.

Furthermore, since the switch of this embodiment only allows a control current to flow, a switch with a small capacity can be used.

Furthermore, since this switch is wired separately from the power supply wiring, its placement can be freely selected.

FIG. 3 is a block diagram of an electronic device according to another embodiment of the present invention. In the figure, parts that are the same as those shown in FIG. ]P' indicates the electronic device of this embodiment. In the example of the rabbit, electronic equipment ffi
Although the power supply stabilizing circuit was connected to both the component part 1a and the RAM 1b, in this embodiment, the power supply stabilizing circuit is provided in common to the component part 1a and the RAM 1b.

Its configuration is the same as the power supply stabilizing circuit 6 shown in FIG.

The output terminal is connected to the component part 1a and RAM1b.
connected to. 14 is a transistor interposed between the output terminal of the power supply stabilizing circuit 6 and the component 1a, its collector is connected to the output terminal of the power supply stabilizing circuit 6, the emitter is connected to the component 1a, and the base is connected to the switch 8. has been done. 15 is a resistor connected between the collector and base of the transistor 14.

When the switch 8 is opened to operate the electronic device Ii1'', the resistor 15 turns the transistor 14 conductive to L-.

A predetermined voltage output from the output terminal of the power supply stabilizing circuit 6 is applied to both the component 1a and the RAM 1b.

Next voltage, electronic installation] To stop the operation of the door (when the switch 8 is closed, the base of the transistor 14 is grounded via the switch 8, and from this K the transistor 14 is cut off. Therefore, the component 1a The power is cut off, and the operation of the electronic device 1 stops.On the other hand, power continues to be supplied to the RAM 1b1 even when the switch 8 is closed, so that the data that has been memorized will not be lost. .

As described above, in this embodiment, a common power supply stabilizing circuit is provided for the components of the electronic device that do not require backup and the RAM, and the connection circuit between the output terminal and the above-mentioned components is configured to be closed when the electronic device is stopped. Since the transistor operated by the filter switch is interposed, not only can the same effect as the locking embodiment be achieved, but also the number of power supply stabilizing circuits can be reduced.

In the above description of the embodiment, the RAM of a microcomputer was used as an example of a component that requires backup, but the invention is not limited to RAM (it is also applicable to other electronic circuits that require backup). In addition, the switch is not limited to a mechanical switch, and a reserved switch can also be used.Furthermore, the switch can be used at any point where the connection of power to components that do not require backup can be cut off. Furthermore, if a microcomputer is used in the electronic device, the above switching can be performed by the microcomputer itself using an external signal.

〔Effect of the invention〕

As described above, in the present invention, a power supply stabilizing circuit applies a predetermined voltage to components that require backup and components that do not require backup.
The application of the predetermined voltage is cut off only to component voltages that do not require backup by an external signal that stops the electronic device.

It is possible to eliminate the need for a backup battery.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electronic device according to an embodiment of the present invention;
@Figure 2 is a circuit diagram of the power supply stabilizing circuit shown in Figure 1, Figure 3 is a block diagram of an electronic device according to another embodiment of the present invention, and Figure 4 is a circuit diagram of the power supply stabilizing circuit shown in Figure 1.
The figure is a block diagram of a conventional electronic device. 1...Electronic device, la...Components requiring backup, lb...RAM, 2.2
'...Power terminal, 6,7...Power stabilization circuit, 8...Switch. 10...Input terminal, 11...Output terminal, 12...Ground terminal, 13...Signal input terminal, 14,72.73... ...Transistor, 77...Zena diode. 1st /' Figure 3, n

Claims (1)

[Scope of Claims] 1. In an electronic device including a first component that requires backup and a second component that does not require backup, a predetermined component is provided in the first component and the second component. 1. A power supply circuit for an electronic device, comprising: a power supply stabilizing circuit that supplies a voltage; and a cutoff means that cuts off the supply of a predetermined voltage from the power supply stabilizing circuit to the second component in response to an external signal. 2. In claim 1, the power stabilizing circuit includes a first power stabilizing circuit connected to the first component and a second power stabilizing circuit connecting to the second component. A power supply circuit for an electronic device, comprising: 3. The power supply circuit for an electronic device according to claim 2, wherein the second power supply stabilizing circuit is configured such that its output is cut off by the cutoff means. 4. In claim 1, the power supply stabilizing circuit includes a first connection circuit connected to the first component and a second connection circuit connected to the second component. A power supply circuit for an electronic device, comprising constant voltage output terminals connected together. 5. The power supply circuit for an electronic device according to claim 4, wherein the second connection circuit includes the cutoff means.