JPH08186983A - Power circuit - Google Patents

Abstract

PURPOSE: To construct a small power circuit at low cost that produces less heat and offers relatively favorable efficiency. CONSTITUTION: The gate of a SCR 10 to which a.c. voltage VAC is applied, is connected to a gate trigger signal generating section 12 to which a.c. voltage VAC is applied also. The gate trigger signal generating section 12 consists of a delay circuit 9 and a diode 10. The cathode of the SCR 10 that outputs discrete rectified voltage VR, is connected to a voltage stabilizing circuit 13. The voltage stabilizing circuit 13 comprises a transistor 14, a Zener diode 15, and a resistor 16. A capacitor 18 is connected to the voltage stabilizing circuit 13. The charging voltage VDC with which the capacitor 18 is charged, is prevented from being discharged within the power circuit by a transistor 14 that is turned on/off by the discrete rectified voltage VR.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit, and more particularly to a power supply circuit for obtaining a DC voltage for driving a small-scale electronic device such as a sanitary equipment cleaning device from a commercial AC power supply.

[0002]

2. Description of the Related Art Conventionally, various power supply circuits have been used for such small-scale electronic devices.
For example, as shown in FIG. 3, there is a transformer power supply circuit 34 including a step-down transformer 31, a bridge rectifier circuit 32, and a smoothing capacitor 33. Also, as shown in FIG.
There is a resistor drop circuit 45 including a resistor 41 that steps down the commercial AC voltage VAC, a bridge rectifier circuit 42, a stabilizing circuit 43, a smoothing capacitor 44, and the like. Furthermore, DC
-There is a switching power supply circuit configured by a DC converter or the like. The transformer power supply circuit is easy to handle, strong in noise, and relatively good in efficiency, because the AC voltage of the power supply is separated by the transformer. Also, the resistance drop circuit is inexpensive and the switching power supply circuit is highly efficient.

[0003]

However, when each of the power supply circuits described above is used in a small-scale electronic device such as a cleaning device for sanitary equipment, the following problems arise. First,
In the transformer power supply circuit 34, the transformer 31 for stepping down the commercial AC voltage is large, so that the entire transformer is large and relatively expensive. In addition, the resistance drop circuit 45 generates a large amount of heat due to the voltage drop across the resistance 41 and has a low efficiency.
Further, the switching power supply circuit is large and expensive because the circuit configuration is complicated.

The present invention has been made to solve the above problems, and an object thereof is to provide a power supply circuit which is small in size, generates little heat, has relatively good efficiency, and can be constructed at low cost. It is in.

[0005]

In order to solve the above problems, the invention according to claim 1 is a power supply AC voltage, and a timing signal generator for generating a timing signal synchronized with the power supply AC voltage. A smoothed DC voltage is generated by smoothing the phase-controlled rectifier element that generates a discrete rectified voltage that is phase-controlled and rectified based on a timing signal from the voltage and the discrete rectified voltage that the phase-controlled rectifier element outputs. And a smoothing DC voltage generator.

According to a second aspect of the present invention, in the first aspect of the invention, the timing signal generating section includes a delay signal generating section for generating a delay signal obtained by delaying the AC power supply voltage, and a delay signal. A diode that outputs a timing signal to the phase control rectifier is used.

According to a third aspect of the present invention, in the invention according to the first or second aspect, the smoothing DC voltage generating section is configured to generate a stabilized voltage that stabilizes the discrete rectified voltage. The charging unit includes a charging unit, a capacitor that charges and stabilizes the stabilizing voltage, and a discharge blocking unit that blocks discharging of the charging voltage of the capacitor.

According to a fourth aspect of the invention, in the invention according to any one of the first to third aspects, the phase control rectifying element is a silicon control rectifier.

[0009]

Therefore, according to the first aspect of the invention, the phase control rectifying element is phase-controlled and rectified from the power supply AC voltage by the timing signal synchronized with the power supply AC voltage generated by the timing signal generating section. To generate a discrete rectified voltage. This discrete rectified voltage is converted into a smoothed DC voltage by the smoothed DC voltage generator. As a result, a smoothed DC voltage having a voltage value lower than the maximum voltage value is generated from the power supply AC voltage.

According to the invention described in claim 2, in addition to the operation of the invention described in claim 1, a delay signal is generated from the power supply AC voltage in the delay signal generator, and the delay signal is generated by the diode. Is output as a timing signal to the phase control rectifier.

Further, according to the invention described in claim 3, in addition to the operation of the invention described in claim 1 or 2, the discrete rectified voltage is stabilized in the voltage stabilizing unit and then stored in the capacitor. It is charged and smoothed. Further, the voltage charged in the capacitor is prevented from being discharged inside the circuit by the discharge preventing means.

According to the invention described in claim 4, in addition to the function of the invention described in any one of claims 1 to 3,
A discrete rectified voltage that is phase-controlled and rectified is generated by a silicon rectifier.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a power supply circuit for obtaining a DC voltage of about 12 V from a commercial power supply (100 V) will be described below with reference to FIGS.

As shown in FIG. 1, a DIAC 4 is connected in parallel via a fuse 3 between terminals 2 to which the AC voltage VAC of the power supply circuit 1 is connected. This diac 4
Is a surge absorber for preventing overvoltage. The variable resistor 5, the resistor 6, and the capacitor 7 are serially connected in this order to one end of the diac 4, and the other end of the capacitor 7 is grounded via the resistor 8. In the present embodiment, the variable resistor 5, the resistor 6 and the capacitor 7 constitute a delay circuit 9 as a delay signal generator.

Further, one end of the diac 4 has an SCR (Silicon Controlled Recti) as a phase control rectifying element.
The anode of the fier) 10 is connected, and the cathode thereof is connected between the capacitor 7 and the resistor 8. further,
The gate of the SCR 10 is connected between the resistor 6 and the capacitor 7 via a diode 11. In the present embodiment, the delay circuit 9 and the diode 11 constitute a gate / trigger signal generator 12 as a timing signal generator. Therefore, the delay circuit 9 receives the input AC voltage VAC
The delayed voltage is output to the anode of the diode 11. The diode 11 outputs the delayed voltage to the gate of the SCR 10 as a timing signal. Therefore, this timing signal becomes a discrete intermittent voltage. SCR
10 turns on when the input timing signal becomes equal to the gate trigger voltage, and turns off when the current flowing due to the input AC voltage VAC becomes less than the holding current. Therefore, SC
R10 conducts the AC voltage VAC only while it is on. As a result, the voltage VR output from the SCR 10 becomes a discrete intermittent voltage. In the present embodiment, the timing at which the SCR 10 is turned on by the timing signal is set to a timing in which the phase is largely delayed by 90 ° or more with respect to the AC voltage VAC. That is, as shown in FIG. 2, the voltage VR is set so that the voltage value of the latter half of the positive side portion of the AC voltage VAC is sufficiently low.

A voltage stabilizing circuit section 13 as a voltage stabilizing section is connected to both ends of the resistor 8. The voltage stabilizing circuit unit 13 is composed of an NPN transistor (hereinafter, simply referred to as a transistor) 14 as a discharge blocking unit, a Zener diode 15 and a resistor 16. The collector of the transistor 14 is connected to the cathode of the SCR 10, and the base is grounded via the Zener diode 15. A resistor 16 is connected between the collector and the base of the transistor 14. In this embodiment, the rated voltage of the Zener diode 15 is set to 12V. Therefore, the voltage stabilizing circuit unit 13 sets the voltage VR to the rated voltage of the Zener diode 15 (that is, about 12V).
It stabilizes and outputs.

The emitter of the transistor 14 is connected to one end of a smoothing capacitor 18 via a resistor 17, and the other end of the capacitor 18 is grounded. This resistor 17 is an overcurrent protection resistor. In the present embodiment, the voltage stabilizing circuit section 13 and the capacitor 18 constitute a smoothing circuit section 19 as a smoothing DC voltage generating section.
Therefore, when the voltage VR is input, the voltage stabilization circuit unit 13 turns on the transistor 14 and the capacitor 18 receives the voltage V
Outputs a voltage that stabilizes R. The capacitor 18 charges and smoothes the input voltage and holds it as a charging voltage VDC of about 12V. Also, the transistor 14 is turned off when the voltage VR becomes 0, and the capacitor 18 and the SC
The output side of R10 is shut off.

Terminals 20 are provided at both ends of the capacitor 18. A load circuit 21 is connected to both terminals 20. Therefore, the charging voltage VDC of the capacitor 18 is applied to the load circuit 21 connected to the terminal 20.

Next, the operation of the power supply circuit configured as described above will be described. When the AC voltage VAC of 100 V is applied to the terminals, the phase of the AC voltage VAC is greatly delayed by the delay circuit 9. The delayed AC voltage VAC is input to the gate of the SCR 10 as a timing signal via the diode 11. Therefore, the SCR 10 has the AC voltage V
It is turned on at the timing when the phase is greatly delayed by 90 ° or more with respect to the AC, and turned off at the timing when the current flowing by the AC voltage VAC becomes equal to or less than the holding current. As a result, as shown in FIG. 2, the SCR 10 outputs a discrete voltage VR consisting of a low voltage value region in the latter half of the positive side of the AC voltage VAC.

When the discrete intermittent voltage VR is input to the voltage stabilizing circuit 13, the transistor 14 is repeatedly turned on and off. Then, while the transistor 14 is turned on, a voltage in which the voltage VR is stabilized to the rated voltage of the Zener diode 15 is output and the capacitor 18 is charged. Further, while the transistor 14 is off, discharge of the voltage VDC charged in the capacitor 18 inside the power supply circuit is blocked. As a result of repeating this process, the capacitor 18 is charged to the voltage VDC which is approximately smoothed by the rated voltage of the Zener diode to about 12V. This charging voltage VDC is applied to the load circuit 21 via the terminal 20.

As described in detail above, according to the power supply circuit of this embodiment, the timing signal of the SCR 10 synchronized with the AC voltage VAC is generated from the AC voltage VAC of 100 V, and the SCR 10 is turned on by this gate trigger voltage. Thus, the low voltage portion of the AC voltage VAC (that is, the voltage VR
) Was taken out. Then, the discrete voltage VR is stabilized and smoothed by the power supply stabilizing circuit 13 and the capacitor 18 to obtain a smoothed DC voltage VDC of about 12V. Therefore, the power supply circuit 1 can be configured only with small and inexpensive parts without using a transformer for stepping down the AC voltage VAC, so that the power supply circuit 1 can be downsized and configured at low cost. be able to. Further, since the AC voltage VAC is not dropped by the resistance, the heat generation is small and the efficiency of the transformer can be achieved. Furthermore, like a switching power supply, DC-
Since a complicated circuit such as a DC converter is not included, the size can be reduced and the cost can be reduced.

The present invention is not limited to the above embodiment, but may be configured as follows. (1) In the above embodiment, the rated voltage of the Zener diode 15 is set to approximately 12 V, so that the capacitor 1
Although the voltage VDC charged to 8 is set to approximately 12V, the rated voltage may be changed to a voltage VDC other than 12V.

By increasing the breakdown voltage of the SCR 10 and the transistor 14, the smoothed DC voltage VDC can be obtained from the AC voltage VAC in the range of about 85 to 270V. (2) The configuration of the voltage stabilizing circuit 13 may be changed.
For example, transistor 14 is connected so that its collector is connected to the cathode of SCR 10 and its emitter is grounded. Then, a Zener diode 15 is connected between the collector and the base of the transistor 14,
1 between the collector and the collector and the cathode of the SCR10
6 may be connected.

(3) The gate / trigger signal generator 12 is composed of the resistors 5 and 6 and the capacitor 7 and the delay circuit 9
It may be configured with a circuit configuration other than the combination of the diode 11 and the diode 11. For example, UJT (Unijunction Tr
ansistor) or PUT (Programable Unijunction Tran
A gate trigger circuit using a sistor) is configured, and an AC voltage DAC is applied to the gate trigger circuit so that a trigger pulse synchronized with the AC voltage VAC is obtained. Then, the SCR 10 is turned on by this trigger pulse.

(4) The voltage stabilizing circuit unit 13 is, for example, the voltage stabilizing circuit unit 1 which does not include the transistor 14 constituted by only the Zener diode 15 and the resistor 16.
Set to 3. A diode may be provided between the cathode of the SCR 10 and the high potential side of the capacitor 18 to prevent discharge of the charging voltage of the capacitor 18 inside the power supply circuit.

(5) The power supply circuit may not be provided with the fuse 3 or the diac 4 as the surge absorber. The technical ideas other than the claims that can be understood from the above-described embodiments will be described below along with their effects.

(1) In the power supply circuit according to a third aspect of the present invention, the voltage stabilizing unit 13 includes a transistor 14, a Zener diode 15 connected between the base of the transistor 14 and the ground, and a base-collector of the transistor 14. The resistor 16 is connected to. According to this configuration, the transistor 14 as the discharge blocking means can be provided inside the voltage stabilizing circuit 13.

[0028]

As described in detail above, the first, third, and fourth aspects are provided.
According to the invention described in (1), it is possible to provide a small size, low heat generation, relatively good efficiency, and low cost.

According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the timing signal generator can be configured without using a semiconductor element such as UJT.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a power supply circuit.

FIG. 2 is a timing chart of an AC voltage and each processing signal.

FIG. 3 is a circuit diagram of a conventional power supply circuit.

FIG. 4 is a circuit diagram of a power supply circuit.

[Explanation of symbols]

9 ... Delay circuit as delay signal generator, 10 ... SCR as phase control rectifier, 11 ... Diode, 12 ... Gate / trigger signal generator as timing signal generator, 13 ... Voltage stabilization as voltage stabilizer Circuit section, 1
4 ... Transistor as discharge preventing means, 18 ... Capacitor, 19 ... Smoothing circuit section as smoothing DC voltage generating section, VAC ... AC voltage, VDC ... Charging voltage, VR ... Discrete rectified voltage.

Claims (4)

[Claims] 1. A timing signal generator (12) for generating a timing signal synchronized with a power source alternating voltage (VAC) from the power source alternating voltage (VAC) and a phase based on the timing signal from the power source alternating voltage (VAC). Controlled and rectified discrete rectified voltage (VR
And a discrete rectification voltage (V) output by the phase control rectifier element (10).
R) is smoothed to generate a smoothed DC voltage (VDC) and a smoothed DC voltage generator (19). 2. A timing signal generator (12) is a delay signal generator (9) for generating a delay signal by delaying a power supply AC voltage (VAC), and a phase control rectifier (10) using the delay signal as a timing signal. ) Output diode (1
The power supply circuit according to claim 1, which is 1). 3. A smoothing DC voltage generator (19) is a voltage stabilizer (13) that generates a stabilized voltage that stabilizes a discrete rectified voltage (VR), and charges and smooths the stabilized voltage. Capacitor (18) and capacitor (1
The discharge preventing means (14) provided between the phase control rectifying element (8) and the phase control rectifying element (10) for preventing discharge of the charging voltage (VDC) of the capacitor (18). Power supply circuit. 4. The power supply circuit according to claim 1, wherein the phase control rectifier element (10) is a silicon control rectifier.