JPH048703Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a circuit device for a television receiver (hereinafter referred to as TV) having a remote control (hereinafter referred to as remote control) receiving circuit. relates to a circuit device that can simplify the power supply.

[Summary of the idea]

The TV circuit device of the present invention does not have a dedicated power supply circuit for the remote control receiving circuit, and the TV circuit device connects the remote control receiving circuit to the TV.
It has a voltage stabilizing power supply circuit that is shared with the circuit.
The auxiliary power switch controlled by the remote control receiving circuit is provided at a later stage than the voltage stabilizing power supply circuit.
When this is off, it disables at least the horizontal deflection circuit. By omitting a power supply circuit dedicated to the remote control receiving circuit, the TV circuit device can be simplified and reduced in cost.

[Conventional technology]

A conventional power supply circuit for a TV equipped with a remote control receiving circuit has been achieved as shown in FIG. In this figure, 1 is a power supply terminal, 2 is a main power switch, 3 is a sub power switch, 4 is a TV voltage stabilizing power supply circuit, 5 is a TV circuit, 6 is a remote control receiving circuit,
7 is a remote control power supply circuit.

If the main power switch 2 of the TV power circuit device configured in this way is kept on, the remote control receiving circuit 6 responds to a remote control transmitter (not shown).
The auxiliary power switch 3 can be controlled to be turned on or off by this operation. When the sub power switch 3 is turned off, the power supply to the TV voltage stabilizing power supply circuit 4 is cut off, and the TV circuit 5 becomes inactive.

[Problem that the invention attempts to solve]

By the way, in the TV circuit device shown in FIG. 3, both the remote control power supply circuit 7 and the TV voltage stabilizing power supply circuit 4 must be provided, which inevitably increases the size and cost of the TV power supply circuit.

Therefore, an object of the present invention is to provide a circuit device that can easily supply stable power to a remote control receiving circuit and a TV circuit.

[Means for Solving the Problems] The present invention for achieving the above object includes: a main power switch of a television receiver; a rectifier circuit connected to an AC power source via the main power switch; a switching transistor connected between a pair of output terminals of a rectifier circuit via a primary winding of a transformer; one or more secondary windings of the transformer; and a base of the rectifier circuit and the switching transistor. a starting resistor connected between
a tertiary winding electromagnetically coupled to the primary winding and the secondary winding and connected between the base and emitter of the switching transistor for feedback control of the switching transistor; a voltage control transistor connected in parallel between the base and emitter of the television; a remote control receiving circuit that receives power through the secondary winding; and a television that receives power through the secondary winding. a voltage control circuit that controls the voltage control transistor so as to control the base current of the switching transistor with the voltage control transistor to keep the power supply voltage of the television receiver circuit constant; , configured to be on/off controlled by the remote control receiving circuit,
and an auxiliary power switch disposed to put at least a horizontal deflection circuit included in the television receiver circuit into an inoperable state when turned off, and a base of the horizontal deflection circuit and the switching transistor. and a trigger circuit connected between the horizontal deflection circuit and the trigger circuit to flow a trigger current for turning on the switching transistor in response to the horizontal deflection signal of the horizontal deflection circuit, the on-time width of the switching transistor being equal to the horizontal deflection signal. The present invention relates to a circuit device for a television receiver characterized in that the period is set to be shorter than the period of a signal.

[Effect]

When both the main power switch and the sub power switch in the TV circuit device according to the present invention are kept on, the TV becomes operational. On the other hand, if the main power switch is kept on and the sub power switch is turned off, at least the horizontal deflection circuit in the TV circuit becomes inoperable, but the remote control receiving circuit remains operational. Therefore, by turning on the sub power switch using the remote control, the TV can be operated again. When the horizontal deflection circuit is in operation, a trigger current synchronized with the horizontal deflection signal flows through the switching transistor, turning the switching transistor on. after that,
The switching transistor turns off in a manner similar to a self-excited switching regulator.
When the horizontal deflection circuit is not operating, the switching transistor turns on and off on the principle of a self-excited switching regulator.

[Embodiment] Next, a TV circuit device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. In this device, a voltage stabilizing power supply circuit 4 is connected to an AC power supply terminal 1 via a main power switch 2, and a TV circuit 5 and a remote control receiving circuit 16 are connected to the output stage of this power supply circuit 4. The sub power switch 3 is
It is arranged after the power supply circuit 4.

To explain each part in detail, the power supply circuit 4 has a switching regulator configuration, and includes a rectifier circuit 8 connected to the AC power supply terminal 1 via a switch, and a primary winding 10 of a transformer 9 connected to the rectifier circuit 8. switching transistor 11 connected via
has. A rectifier circuit 15 including a diode 13 and a capacitor 14 is connected to the secondary winding 12 of the transformer 9 . Tertiary winding 1 of transformer 9
One end of the transistor 6 is connected to the base of the transistor 11 via a resistor 17, a capacitor 18, and a parallel circuit of a resistor 19 and a capacitor 19a. In this embodiment, the capacitor 18 is charged during the OFF period of the transistor 11, and this charged charge is transferred to the transistor 11 during the ON period of the transistor 11.
used to supply base current. Therefore, the first, second and third diodes 20, 2
1 and 22 are provided. 23 is a starting resistor, which connects the output line of the rectifier circuit 8 and the transistor 11.
is connected between the base of the Reference numeral 24 denotes a base current bypass transistor, which is connected between the base and emitter of the switching transistor 11. A voltage control circuit 26 is connected to the base of the base current bypass transistor 24 for detecting the voltage of the DC power supply line 25 of the output rectifier circuit 15 and controlling the output voltage to a constant voltage.

The TV circuit 5 includes various circuits other than the remote control receiving circuit 6, including a horizontal deflection circuit, a vertical deflection circuit, a high voltage circuit, a video receiving circuit, an audio receiving circuit, a picture tube circuit, and the like. However, in FIG. 1, only the horizontal deflection circuit is shown as the TV circuit 5. The horizontal deflection circuit includes a horizontal oscillator 27 connected to the DC power line 25 via the sub power switch 3, a transformer 28 provided at the output of the horizontal oscillator 27, and a DC power line 25.
a transistor 30 connected in series to the flyback transformer 29 and driven by the horizontal oscillation output transformer 28, and a diode 31 connected in antiparallel to the transistor 30. , a horizontal deflection coil 32 coupled to a flyback transformer 29.
It consists of 35 is a flyback transformer 2 for obtaining a trigger signal for the switching regulator.
9 is a winding electromagnetically coupled to a diode 34.
and the switching transistor 1 via the resistor 35.
It is connected to the base of 1.

(Operation) Next, the operation of the circuit shown in FIG. 1 will be explained with reference to FIG. When both the main power switch 2 and the sub power switch 3 are on, power is supplied to the horizontal oscillator 27, so a horizontal oscillation output V _H is obtained as shown before time t ₁ in FIG. 2A. Based on this, the transistor 30 is controlled to be turned on or off. Therefore, a 15.75 kHz trigger current I _T shown in FIG. 2B is supplied to the switching transistor 11 from the winding 33 which is electromagnetically coupled to the flyback transformer 29. Therefore, the transistor 11 has a trigger current I _T
It turns on in synchronization with , and then capacitor 1
A drive current is supplied from 8. Therefore, a base drive current I _B as shown in FIG. 2C is supplied to the transistor 11, and a collector current I _C as shown in FIG. 2D flows.

Since the primary winding 10 has inductance,
Collector current I _C increases with time. The base current I _B of the switching transistor 11 is
As shown in Figure C, since the trigger current remains almost constant after the trigger current, the switching transistor 11
The maximum collector current of is determined by the product of the base current _{IB and} the _current amplification factor _hFE . Collector current I _C is I _B h _FE
When the switching transistor 11 reaches saturation, it becomes impossible to maintain the saturation of the switching transistor 11, and the switching transistor 11 shifts to a non-saturated state, and the voltage between the collector and emitter increases.
Conversely, the voltage across the primary winding 10 decreases, the base current also decreases, and the switching transistor 11 is turned off. Thereafter, when the trigger current based on the horizontal oscillation output is applied again, the switching transistor 11 is forcibly turned on.

When the base current bypass (voltage control) transistor 24 is controlled according to the output voltage, the base current bypass amount changes, and the base current I _B of the switching transistor 11 changes. As a result, the maximum value, ie, the on-time width, of the collector current I _C shown in FIG. 2D changes, and the output voltage is controlled. The operation to keep the output voltage constant is horizontal oscillator 2.
This also occurs during the non-operating period of 7. In addition,
When no trigger current is applied by the horizontal oscillation output, the switching transistor 11 is turned on when the discharge of the stored energy of the transformer 9 is completed. That is, the well-known ringing
Operates as a converter (RCC).

On the other hand, after time _t1 in FIG. 2 when the main power switch 2 is on and the sub power switch 3 is off, the horizontal oscillator 27 becomes inactive, so the flyback transformer 29 also becomes inactive. In this state, no deflection is performed by the horizontal deflection coil 32, and the high voltage circuit coupled to the flyback transformer 29 is also kept inactive. That is,
The main part of the TV circuit 5 becomes inactive. Therefore, the supply of trigger current from the winding 33 is also stopped, and the switching regulator operates on and off asynchronously with the horizontal deflection. After this t ₁ point,
The load on the power supply circuit 4 is reduced to only the remote control receiving circuit 6 and other small loads. As a result, the base drive current of the switching transistor 11 becomes smaller, and the collector current saturates in a short time as shown after t ₁ in Figure 2D, making the switching regulator suitable for light loads. .

Next, the switching regulator shown in Figure 1 is
The principle of generating a nearly constant output voltage despite fluctuations in the DC input voltage E _IN will be explained. When transistor 11 is turned on, power supply voltage E _IN is applied to primary winding 10 , and a corresponding voltage is also induced in tertiary winding 16 . At this time, a closed circuit consisting of the tertiary winding 16, the resistor 17, and the first diode 20 is formed, and most of the voltage of the tertiary winding 16 is applied to both ends of the resistor 17, and is not applied to the base of the transistor 11. do not have. When transistor 11 turns off, diode 13 turns on and the energy stored in transformer 9 when on is released. Then, a substantially constant voltage is generated in the tertiary winding 16 that is independent of the power supply voltage E _IN . Since this voltage is opposite to the voltage when the transistor 11 is turned on, the second diode 21 is turned on, and the tertiary winding 16, the second diode 21, and the capacitor 1
8 and the third diode 22 is formed, and the capacitor 18 is charged. When the transistor 11 is turned on after the capacitor 18 is charged, the discharge current of the capacitor 18 flows through the closed circuit consisting of the capacitor 18, the resistor 19, the transistor 11, and the first diode 20.
A base current of transistor 11 is supplied. At this time, a positive current flowing through the first diode 20 based on the voltage of the tertiary winding 16 flows through the capacitor 18.
Since the reverse current is larger than the reverse current due to the discharge of , the diode 20 is kept on. In this circuit, when the AC power supply voltage changes from, for example, 100V to 220V, the voltage of the tertiary winding 16 also increases when the transistor 11 is turned on, but the voltage of the first diode 2
0 is turned on, the voltage of the tertiary winding 16 becomes independent of driving the switching transistor 11 and charging the capacitor 18. Therefore, the switching transistor 11 is controlled in the same way as when the AC power supply voltage is 100V, and a constant voltage is obtained on the DC power supply line 25 regardless of fluctuations in the input voltage.

As is clear from the above, this embodiment has the following effects.

(a) Since both the remote control receiving circuit 6 and the TV circuit 5 are connected to the common power supply circuit 4, a power supply circuit dedicated to the remote control is not required, and the device can be simplified.

(b) Since the sub power switch 3 is connected to the power line of the horizontal oscillator 27 through which a large current does not flow, the current capacity of the sub power switch 3 can be reduced.

(c) The switching regulator is the horizontal oscillator 2
When the horizontal oscillator 7 is in operation, it is driven in synchronization with the horizontal deflection signal, but when the horizontal oscillator 27 is inactive, it self-oscillates regardless of the horizontal deflection signal.
Since no trigger current flows during this self-oscillation period, loss is reduced by the amount of this trigger current, and efficiency is improved.

The present invention is not limited to the embodiments described above, but can be modified. For example, as shown in FIG. 4, a sub power switch 3 that responds to the remote control receiving circuit 6 is arranged between the power supply circuit 4 and the TV circuit 5, and all power supplies of the TV circuit 5 other than the remote control receiving circuit 6 are switched off. It may also be blocked. Further, the power supply circuit 4 can be a voltage stabilizing circuit other than the switching regulator shown in FIG. For example, the on/off time control of the switching transistor 11 may be performed based on the voltage of the tertiary winding 16 instead of based on the detection of the DC output voltage. In addition, the output transformer of the switching regulator is provided with separate windings for obtaining the voltage for the remote control receiving circuit 6 and for obtaining the voltage for the TV circuit 5, so that the DC output circuit is separate. You can.

[Effect of idea]

As is clear from the above, according to the present invention, the television receiver circuit operates even though the voltage stabilizing power supply circuit portion is configured as a relatively simple self-excited switching regulator. Sometimes, a trigger current based on the horizontal deflection signal forces the switching transistor to turn on, resulting in a stable operating condition at a constant frequency. On the other hand, when the television receiver circuit is not operating, the switching transistor turns on and off by self-excitation, so that power can be supplied to the remote control receiver circuit.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a part of a TV circuit device according to an embodiment of the present invention, Fig. 2 is a waveform diagram showing the states of each part in Fig. 1, and Fig. 3 shows a conventional TV circuit device. Block Diagram FIG. 4 is a block diagram showing a modified example of the TV circuit device according to the present invention. 1...Power terminal, 2...Main power switch, 3...
... Sub-power switch, 4... Voltage stabilization power supply circuit,
5...TV circuit, 6...Remote control receiving circuit.

Claims (1)

[Claims for Utility Model Registration] A main power switch of a television receiver, a rectifier circuit connected to an AC power source via the main power switch, and a primary transformer connected between a pair of output terminals of the rectifier circuit. a switching transistor connected via a winding; one or more secondary windings of the transformer; a starting resistor connected between the rectifier circuit and the base of the switching transistor; a tertiary winding electromagnetically coupled to the primary winding and the secondary winding and connected between the base and emitter of the switching transistor for feedback control of the transistor; a voltage control transistor connected in parallel between the emitters; a remote control receiving circuit receiving power through the secondary winding; and a television receiver receiving power through the secondary winding. a voltage control circuit that controls the voltage control transistor such that the base current of the switching transistor is controlled by the voltage control transistor to keep the power supply voltage of the television receiver circuit constant; and the remote control. The receiver is configured to be turned on and off by a control receiving circuit, and is arranged to put at least the horizontal deflection circuit included in the television receiver circuit into a non-operating state when turned off. a sub-power switch; and a trigger connected between the horizontal deflection circuit and the base of the switching transistor, which causes a trigger current to flow to turn on the switching transistor in response to a horizontal deflection signal of the horizontal deflection circuit. 1. A circuit device for a television receiver, comprising: a circuit, wherein an on-time width of the switching transistor is set to be shorter than a cycle of the horizontal deflection signal.