JPH0445433Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) The invention relates to a switching regulator,
In particular, the present invention relates to a switching regulator that supplies or cuts off power to a set load such as a color television receiver using a remote control.

(Prior Art) A conventional switching regulator of this type will be explained with reference to FIG.

In the figure, AC is an alternating current power supply, and SW1 is a power switch. A regulator circuit 2 is connected to the output side of the rectifier circuit 1 which is connected to the alternating current power supply AC. A primary winding of converter transformer T1 is connected to the output side of regulator circuit 2, and a secondary winding of converter transformer T1 is connected to rectifier circuit 3. And the rectifier circuit 3
Set load 4 such as color television receiver etc.
is connected. Further, the regulator circuit 2 is connected to a set load 4 via a flyback transformer T2.

On the other hand, a light receiving section 6 that detects a signal from the remote control gun 5 is connected to a control circuit 7 for remote control. This control circuit 7 includes the set load 4 and a switching circuit to be described later.
Give a control signal to SW2.

The primary winding of a remote control transformer T3 is connected to the alternating current power supply AC. The secondary winding of this transformer T3 is connected to a rectifier circuit 8, and the output side of the rectifier circuit 8 is connected to a regulator circuit 9. This regulator circuit 9 supplies power to a power relay RY interposed between the alternating current power supply AC and the rectifier circuit 1, the light receiving section 6, and the control circuit 7. The opening and closing of the power relay RY is controlled by a switching circuit SW2.

Next, the operation of the switching regulator described above will be explained.

When the power switch SW1 is closed, the remote control power supply consisting of the transformer T3, the rectifier circuit 8 and the regulator circuit 9 is activated.
The regulator circuit 9 applies a constant voltage to the light receiving section 6 and the control circuit 7. When the remote control is turned on in this state, the control circuit 7 that receives the detection signal from the light receiving section 6 switches the switching circuit SW.
A control signal is given to 2 to close it. As a result, the power relay RY closes, and AC voltage is applied to the main power supply section composed of the control circuit 1 and the regulator circuit 2. The output voltage of the regulator circuit 2 is transformed by the converter transformer T1,
Further, by smoothing in the rectifier circuit 3, a predetermined constant voltage is applied to the set load 4, and the set load 4 is driven. When the set load 4 is driven, a flyback pulse having the same frequency as the horizontal scanning frequency is fed back from the set load 4 to the regulator circuit 2 via the flyback transformer T2. separately excited oscillation at the same switching frequency as
Supplies power to the set load.

However, the conventional switching regulator with such a configuration includes a remote control transformer T2 for standby for remote control, separate from the converter transformer in the main power supply section, and a transformer T2 for controlling the main power supply section. Since it is necessary to include the power relay RY, the shape of the switching regulator becomes larger and the manufacturing cost of the switching regulator increases.

(Purpose of the invention) The present invention was made in view of the above circumstances, and is a switch that can reduce the size of the switching regulator and reduce its manufacturing cost. The purpose is to provide an angular regulator.

(Structure of the invention) In order to achieve the above purpose, the invention has the following features:
It has the following characteristics.

That is, the switching regulator according to the present invention includes a first rectifier circuit connected to an AC power source, a regulator circuit to which a smoothing input is given from the first rectifier circuit, and a primary side winding in the regulator circuit. A converter transformer to which the line is connected, and a second rectifier circuit connected to the secondary winding of the converter transformer, and the power is supplied from the second rectifier circuit to the set load by remote control. A switching regulator for supplying and cutting off electric power, the switching circuit being interposed between the second rectifier circuit and the set load and operating to open and close in order to control the supply and cut off of power to the set load. , a detection means that is supplied with power from the second rectifier circuit and detects input of a remote control signal; and a detection means that is supplied with power from the second rectification circuit and detects input of a remote control signal from the detection means. Control that controls opening and closing of the switching circuit so that when the detection input is not applied, the switching circuit is opened and placed in a remote control standby state, and when the detection input is applied, the switching circuit is closed and placed in the remote control on state. The regulator circuit includes a switching transistor having a collector connected to the primary winding of the converter transformer, and a switching transistor connected to a drive winding of the converter transformer, and a switching transistor connected to the drive winding of the converter transformer. and a drive circuit that drives the switching transistor in response to the induced voltage, and when the switching circuit is opened in the remote control standby state and the power supply to the set load is cut off. When the switching transistor, the primary winding, the drive winding, and the drive circuit form a self-oscillating feedback loop, the remote control is turned on and the switching circuit is closed and set. When power is being supplied to the load, the switching transistor is turned on and off by the application of pulses from the set load, thereby forming a feedback loop for separately excited oscillation.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings. FIG. 1 is a block diagram schematically showing the configuration of a switching regulator according to an embodiment of the present invention.

In this figure, the same parts as in FIG. 4 are indicated by the same reference numerals. For example, the first rectifier circuit 1 composed of a rectifier diode bridge and a smoothing capacitor connects an AC power source to an AC power source via a power switch SW1.
It is connected to the. A regulator circuit 2 is connected to the output side of the rectifier circuit 1, and the output side of the regulator circuit 2 is connected to the primary winding of the converter transformer T1. The secondary winding of converter transformer T1 is connected to a second rectifier circuit 3 composed of a rectifier diode and a smoothing capacitor. A switching circuit SW2 for supplying or cutting off power from the rectifier circuit 3 to the set load 4 is interposed between the rectifier circuit 3 and a set load 4 such as a color television receiver. Further, the regulator circuit 2 is connected to a set load 4 via a flyback transformer T2.

On the other hand, the light receiving section 6 as a detection means for detecting the signal from the remote control gun 5 is connected to the rectifier circuit 3.
Electric power is supplied from the controller, and its output is given to a control circuit 7 for remote control. This control circuit 7
is supplied with electric power from the control circuit 3, and the switching circuit SW2 is switched to the switching circuit SW2 based on the output of the light receiving section 6 as a detection means.
Gives a control signal to control the opening and closing of SW2.

FIG. 2 is a block diagram showing the details of the configuration of the main power supply section including the rectifier circuit 1, regulator circuit 2, etc. The regulator circuit 2 includes an NPN power transistor TR that performs a switching operation,
The collector of this transistor TR is connected to one end of the primary winding NP of the converter transformer T1, and its emitter is grounded. transistor tr
The base of is connected to the rectifier circuit 1 via the start circuit 21.
connected to the output side of the This start circuit 2
1 is composed of a voltage dividing resistor and a capacitor connected in series with the resistor. Further, a drive circuit 21 and a control section 22 are connected to the base, and one end of a flyback transformer T2 is connected via a diode D.

The drive circuit 21 is composed of a capacitor and a resistor connected in series to a drive winding ND provided separately to the converter transformer T1, and one end of the resistor is connected to the base of the transistor TR. . On the other hand, the control section 22 controls the drive circuit 21 based on the signal from the detection section 22.
The transistor TR's switching operation is controlled by sucking the current supplied from the transistor TR's base to the transistor TR's base. The detection unit 23 is connected to a detection winding Nd provided in the converter transformer T1, and when the terminal voltage of the winding Nd (indirectly, the output voltage Vo on the secondary side of the converter transformer T1) exceeds a certain value. This is to cause the control section 22 to perform a current sucking operation when the current is exhausted.

Next, the operation of the switching regulator having the above-described configuration will be explained.

When the power switch SW1 is closed, the smoothed voltage of the rectifier circuit 1 is divided by the start circuit 21 and applied to the base of the transistor TR. This causes transistor TR to become active,
A current flows through the primary winding NP of the converter transformer T1, and a voltage is induced in the drive winding ND.
A current based on this voltage is positively fed back to the base of the transistor TR via the drive circuit 21, so that the transistor TR momentarily shifts to the saturation region, and as a result, the output voltage Vo on the secondary side suddenly increases. stand up.

When the output voltage Vo exceeds a certain value, the detection section 23 detects this from the terminal voltage of the detection winding ND, and provides a detection signal to the control section 22. the result,
The control unit 22 sucks the current from the drive circuit 21, and the transistor TR enters the cutoff state. Then, when the output voltage Vo becomes below a certain value, the control unit 2
2 stops sucking current, and the transistor TR shifts from the cutoff region to the saturation region again, and the output voltage decreases.
Increase Vo. By repeating such operations, the output voltage is maintained at a constant value.

In addition, in the remote control standby state, the secondary rectifier circuit 3 of the converter transformer T1
Power is being supplied to the control circuit 7 for remote control and the light receiving section 6 from the control circuit 7, but since the light receiving section 6 is not detecting the signal from the remote control gun 5, the switching circuit SW2 is open. Therefore, the set load is in a stopped state and no flyback pulse is fed back from the set load 4 to the regulator circuit 2, so that the switching regulator self-oscillates in the remote control standby state. Note that FIG. 3A shows the waveform of the collector-emitter voltage of the transistor TR in a self-oscillation state.

Next, when the remote control is turned on, that is, when the light receiving unit 6 receives a remote control signal corresponding to power on from the remote control gun 5, the light receiving unit 6 sends the corresponding output to the remote control signal. It is given to the control circuit 7. As a result, the control circuit 7 provides a control signal to the switching circuit SW2 to close the switching circuit SW2. As a result, the rectifier circuit 3
Electric power is supplied from the set load 4 to the set load 4, and the set load 4 is driven. At this time, the flyback pulse is fed back to the regulator circuit 2 via the flyback transformer T2 of the color television receiver, which is a set load, so that the switching frequency of the transistor TR included in the circuit is locked to the horizontal scanning frequency. be done. That is, when the remote control is turned on, this switching regulator enters a so-called separately excited oscillation state and supplies power to the secondary side. In addition, FIG. 3B shows the transistor TR in the separately excited oscillation state.
The waveform of the collector-emitter voltage is shown.

The switching regulator of this embodiment performs self-excited oscillation when the remote control is on standby, and separately-excited oscillation when the remote control is turned on. It is advantageous in this respect. That is, when the set load is a color television receiver, the switching frequency of the switching power transistor can be locked to the horizontal scanning frequency. Thereby, the noise during switching can be made to appear during the blanking period, so that disturbances in the screen caused by the noise can be reduced.

Furthermore, in a switching regulator that self-oscillates when the remote control is turned on, as the AC power supply voltage increases, the switching frequency also increases. This may cause problems such as radiation, but in this example,
Since separately excited oscillation is performed as described above, such a problem does not occur.

In addition, in this embodiment, separately excited oscillation is performed when the remote control is turned on, so the configuration of the drive circuit included in the switching regulator can be simplified, which is also advantageous in terms of manufacturing costs. .

In the above embodiment, the set load is described as being a color television receiver, but the present invention is not limited to this, and can be used in other electrical equipment.

(Effects of the invention) As described above, the switching regulator according to the invention can control the power supply of the detection unit for remote control (the light receiving unit in the embodiment) and its control circuit.
Since it is installed on the secondary side of the converter transformer, there is no need for a remote control transformer or power relay, which were required in conventional devices. Therefore, according to the present invention, it is possible to downsize the switching regulator and reduce manufacturing costs.

Furthermore, the switching regulator according to the present invention performs self-excited oscillation when the remote control is on standby, and performs externally-excited oscillation when the remote control is turned on. It is advantageous in the following points. That is, when the set load is a color television receiver, the switching frequency of the switching power transistor can be locked to the horizontal scanning frequency. Thereby, the noise during switching can be made to appear during the blanking period, so that disturbances in the screen caused by the noise can be reduced.

Furthermore, in a switching regulator that self-oscillates when the remote control is on, as the AC power supply voltage increases, the switching frequency also increases, so the high frequency of switching can cause screen distortion and unnecessary switching on color television receivers. Problems such as radiation occur, but in the present invention, such problems do not occur because separately excited oscillation is performed as described above.

Further, in the present invention, since separately excited oscillation is performed when the remote control is turned on, the configuration of the drive circuit included in the switching regulator can be simplified, which is advantageous in terms of manufacturing costs.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the outline of the configuration of an embodiment of the present invention, Figure 2 is a block diagram showing details of the configuration of the main power supply section of the embodiment shown in Figure 1, and Figure 3 is a regulator. FIG. 4 is an explanatory diagram of the voltage waveform between the collector and emitter of the power transistor TR included in the circuit 2, and FIG. 4 is an explanatory diagram of a conventional switching regulator. DESCRIPTION OF SYMBOLS 1...First rectifier circuit, 2...Regulator circuit, 3...Second rectifier circuit, 4...Set load,
6... Light receiving section, 7... Control circuit, T1... Converter transformer, T2... Flyback transformer.

Claims (1)

[Claims for Utility Model Registration] A first rectifier circuit 1 connected to an AC power source, a regulator circuit 2 to which a smoothing input is applied from the first rectifier circuit 1, and a primary winding in the regulator circuit 2. NP is connected to the converter transformer T1, and a second rectifier circuit 3 is connected to the secondary winding of the converter transformer T1. A switch regulator that supplies and cuts off power to the load 4, and is interposed between the second rectifier circuit 3 and the set load 4 to control the supply and cut off of power to the set load 4. Switching circuit SW that opens and closes
2, a detection means 6 which is supplied with power from the second rectifier circuit 3 and detects input of a remote control signal; and a detection means 6 which is supplied with power from the second rectification circuit 3 and which detects the input of a remote control signal. When the detection input of the remote control signal from 6 is not applied, the switching circuit SW2 is opened and the remote control standby state is established, and when the detection input of the remote control signal is applied, the switching circuit SW2 is closed and the remote control state is established. The regulator circuit 2 includes a switching transistor TR whose collector is connected to the primary winding NP of the converter transformer T1, and a control circuit 7 that controls opening and closing of the switching circuit SW2. The drive circuit 21 is connected to the drive winding ND and drives the switching transistor TR in response to the voltage induced in the drive winding ND, and the switching transistor TR is connected to the drive winding ND and drives the switching transistor TR in response to the voltage induced in the drive winding ND. When the circuit SW2 is opened and the power supply to the set load 4 is cut off, the switching transistor TR, the primary winding NP, the drive winding ND, and the drive circuit 21 are in a self-operating state. A feedback loop for excitation oscillation is formed, and when the remote control is turned on and the switching circuit SW2 is closed, the set load 4 is turned on.
When power is being supplied to the set load 4, the switching transistor TR is turned on and off by the application of a pulse from the set load 4, thereby forming a feedback loop for separately excited oscillation. Yureta.