JP2000278953A - Power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption while stabilizing the operation by constituting a circuit for controlling operation/non-operation of a phototriac which controls a triac for switching between a full-wave rectifier circuit and a voltage doubler rectifier circuit selectively based on the power supply voltage of a transistor circuit performing thyristor operation. SOLUTION: When AC power supply VAC is 100 V system, a triac TR1 is turned on to form a voltage doubler rectifier circuit and when AC power supply VAC is 200 V system, the triac TR1 is not operated and a full-wave rectifier circuit is formed. The control circuit for the photodiode of a phototriac PC1 controlling trigger of the triac TR1 is provided with a switching transistor Q3 performing thyristor operation by supplying a base current when the switching transistor Q2 is turned on. Power consumption can be reduced by decreasing the base current for turning the switching transistor Q2 on and switching operation of the rectifier circuit can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called world wide input power supply which can be applied to a plurality of types of commercial AC power supplies having different voltages by switching a full-wave rectifier circuit and a voltage doubler rectifier circuit by a triac. The present invention relates to a switching regulator power supply used.

Further, the present invention provides a switching regulator power supply which can be applied to a plurality of types of commercial AC power supplies having different voltages by switching between a full-wave rectifier circuit and a voltage doubler rectifier circuit by a triac. The present invention relates to a power supply device characterized by a circuit that switches and controls the rectifier circuit according to the voltage of an AC power supply.

[0003]

2. Description of the Related Art Conventionally, a triac has been used in a switching power supply device which can be applied to a 100V-system commercial AC power supply and a 200V-system commercial AC power supply by switching between a full-wave rectifier circuit and a voltage doubler rectifier circuit by a triac. Because the gate drive power (trigger signal) of the gate was obtained from the commercial AC power supply (input power supply), the drive voltage was high (140
V), so that the heat loss is very large, and there is a problem that it is difficult to apply to a low power consumption type personal computer or the like.

Therefore, by controlling the triac gate with a gate drive power supply lower than the power supply voltage which is separated from the commercial AC power supply, the heat loss of the triac drive is reduced, and the triac drive can be easily applied to a low power consumption type personal computer or the like. Thus, a switching regulator power supply device has been realized.

[0005] A conventional circuit in a world wide input power supply, in which a full-wave rectifier circuit and a voltage doubler rectifier circuit are switched by a triac so that they can be applied to a plurality of types of commercial AC power supplies having different voltages. The configuration is shown in FIG.

Here, it is assumed that a 100 V system and a 200 V system are used as the world wide input power supply (commercial AC power supply), and the 100 V system / 200 V system is controlled by on / off control of the triac.
The input of the 200 V system is switched.

In the switching regulator power supply having the circuit configuration shown in FIG. 2, a commercial AC power supply (input power supply) AC is rectified by a rectifier circuit composed of diodes D1 to D4 and smoothed by electrolytic capacitors C1 and C2. . The rectified and smoothed DC power supply voltage is charged to the electrolytic capacitor C3 via the resistor R1.

When the voltage of the capacitor C3 rises to a certain constant voltage, an integrated circuit IC1 for controlling a switching power supply for turning on / off the switching transistor Q1 operates, and the photodiode of the phototriac (optical coupling element) PC1 operates. Electric current flows.

When a certain current or more flows through the photodiode of the phototriac PC1, the phototriac PC1 is turned on, and the triac TR1 is turned on.

Here, the input commercial AC power is AC2
In the case of the 00V system, the switching transistor Q2 is turned on, the operation current is not supplied to the photodiode of the phototriac PC1, the phototriac PC1 is turned off, and the triac TR1 is prohibited from being turned on. Thereby, a full-wave rectifier circuit is formed.

The commercial AC power source to be input is AC10
In the case of the 0 V system, the switching transistor Q2 is turned off, and an operating current is supplied to the photodiode of the phototriac PC1, whereby the phototriac PC1 is turned on and the triac TR1 is turned on. Thus, a voltage doubler rectifier circuit using the capacitors C1 and C2 connected in series is formed.

Thus, the input commercial AC power is A
In the case of the C100V system, the triac TR1 is turned on to form a voltage doubler rectifier circuit. In the case of the AC200V system, since the triac TR1 is not turned on, a full-wave rectifier circuit is formed and the input power supply voltage (100V system / 200V system) Automatically switches and controls the rectifier circuit.

However, in the above-described conventional circuit configuration, as shown in FIG. 2, the driving power of the switching transistor Q2 for controlling the on / off of the triac TR1 (trigger control) is supplied to the input commercial AC power supply. Therefore, there is a problem in that the driving voltage is high, and therefore a large current flows through the resistor R2, resulting in a large heat loss.

FIG. 4 shows the relationship between the input power supply voltage VAC of the circuit shown in FIG. 2 (the voltage of the commercial AC power supply supplied from the outside) and the smoothed voltage VN of the capacitors C1 and C2. Here, the upper limit of voltage doubled rectification is VACH, the lower limit of full wave rectification is VACL, and the difference is ΔVAC. Capacitor C
When converted to a voltage of 4, the voltage becomes 1.4ΔV _AC . AC100
V system is double voltage rectification below 138V, AC200V system is 1
The full-wave rectification operation must be performed reliably at 80 V or more.
Therefore, ΔVAC needs to be about 20 V or less in consideration of variations. Let the collector currents Ic and hfe of the switching transistor Q2 be Ic = 0.1 A and hf, respectively.
Assuming that e = 100, R2 <hfe / Ic * 1.4ΔV
AC = 28KΩ, and at the time of AC240V input, R2 = 2
Assuming 7 KΩ, the loss of R2 is (240 * 1.4) ² /
27 * 1000 = 4.2 W, which is a large value.

As described above, in the circuit configuration shown in FIG. 2, there is a problem that a large current flows through the resistor R2 and heat loss is large.

At a voltage between VACL and VACH, the state of the switching transistor Q2 is not constant (this unstable voltage region is shown by a broken line in FIG. 4), so that there is a possibility that ON / OFF is repeated. Each time, the triac TR1 may be turned on to perform voltage doubler rectification, or may be turned off to perform full-wave rectification, resulting in an unstable operation state, which has a problem in reliability.

As described above, in the conventional circuit configuration, the driving power of the switching transistor Q2 for controlling the on / off of the triac TR1 (trigger control) is obtained from the commercial AC power input through the resistor R2. Therefore, there is a problem that the driving voltage is high, a large current flows through the resistor R2, and the heat loss is large. Further, there is a problem that a normal operation cannot be ensured because an input voltage region where the ON / OFF state of the switching transistor Q2 is not constant (stabilized) is created.

[0018]

As described above, FIG.
In the conventional circuit configuration shown in FIG.
Since the driving power of the switching transistor Q2 for controlling ON / OFF of the switching transistor is obtained from the input commercial AC power supply, there is a problem that the driving voltage is high and the heat loss of the resistor R2 is large. Further, there is a problem that a normal operation cannot be ensured because an input voltage region where the on / off state of the switching transistor Q2 is not constant is formed.

The present invention has been made in view of the above circumstances,
A full-wave rectifier circuit and a voltage doubler rectifier circuit are switched by a triac to drive a switching transistor that controls on / off of the triac in a switching regulator power supply that can be applied to multiple types of commercial AC power supplies with different voltages. Provided is a power supply device capable of reducing a heat loss of a resistor for supplying power, and maintaining a stable and highly reliable operation by eliminating an input voltage region where the ON / OFF states of the switching transistor and the triac are not constant. The purpose is to:

[0020]

According to the present invention, there is provided a phototriac for trigger-controlling a triac for switching between a full-wave rectifier circuit and a voltage doubler rectifier circuit. A circuit for selectively controlling operation / non-operation is realized by a transistor circuit which operates in the same manner as a thyristor.

That is, according to the present invention, a full-wave rectifier circuit and a voltage doubler rectifier circuit are switched by a triac,
In a switching power supply adapted to be applied to a plurality of types of commercial AC power supplies having different voltages, such as a 0 V system and a 200 V system, a photo triac that triggers the triac and a photo triac that operates through a photodiode of the photo triac. A switching power supply control IC to which power is supplied, a first switching transistor for selectively suppressing the operation of a photodiode provided in the phototriac by a voltage value of the commercial AC power supply, and a transistor similar to a thyristor And a control circuit including a second switching transistor that operates.

Further, according to the present invention, the full-wave rectifier circuit and the voltage doubler rectifier circuit are switched by a triac, for example, by switching between
In a switching power supply unit that can be applied to a plurality of types of commercial AC power supplies having different voltages, such as a 00V system and a 200V system, a voltage value lower than the power supply voltage separated from the commercial AC power supply at the gate of the triac. A drive circuit comprising a resistor and a phototriac that allows a trigger current to flow, a switching power supply control IC in which an operation power supply is supplied to the operation circuit of the photodiode provided in the phototriac via the photodiode, A first switching transistor for forming a bypass circuit that selectively inhibits the operation of the photodiode according to the input voltage value of the commercial AC power supply;
And a control circuit including a second switching transistor that is turned on when the transistor is turned on, causes a base current to flow through the transistor, and controls the transistor to be turned on by a thyristor operation. The operation of the photodiode of the phototriac is controlled by a thyristor operation by a transistor, and the triac is trigger-controlled by the phototriac to switch between full-wave rectification and voltage doubler rectification.

As shown in FIG. 1, for example, the control circuit of the photodiode includes switching transistors Q2 and Q3 that perform on / off operation, a resistor R6 for bias, a capacitor C6 for removing high-frequency noise, and the like. As a result, the transistor Q3 is turned on and a base current flows through the transistor Q2, thereby realizing a switching circuit that operates similarly to a so-called thyristor. This circuit is connected in parallel to the photodiode of the phototriac PC1, and functions as a photodiode bypass circuit. The circuit has an input power supply voltage (A
A monitoring voltage obtained by a diode D3 for rectifying the C input) and resistors R2 and R3 for dividing the voltage is input, and when the voltage exceeds a certain value, the switch is turned on to switch the anode-cathode of the photodiode. Between them, and the lighting drive of the photodiode is prohibited. Here, the resistance R when the 200 V system AC power is input
The switch is turned on at the monitoring voltage determined by the voltage 2 and the divided voltage value of the resistor R5.

The phototriac is controlled by the photodiode control circuit having the transistor configuration that operates as a thyristor, and the triac is controlled by the phototriac. Thus, the driving power is supplied to the switching transistor that controls on / off of the triac. In addition, the heat loss of the resistor (R2 shown in FIG. 1) that supplies the triac can be significantly reduced, and the on / off control of the switching transistor can be always performed in a stable state, thereby eliminating the input voltage region where the on / off state of the triac is not constant. Stable and reliable operation can be maintained. That is, in FIG. 1, the heat loss of the resistor R2 can be greatly reduced, and the VAC shown in FIG.
An automatic switching technology of a rectifier circuit based on an input power supply voltage (AC voltage) can be realized in which the triac TR1 can always operate stably without the indeterminate state of turning on and off the transistor Q2 between L and VACH.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention. The same parts as those in FIG. 2 described above are denoted by the same reference numerals and description thereof will be omitted.

The circuit configuration shown in FIG. 1 is particularly different from the circuit configuration shown in FIG.
1 in that a switching transistor Q3 for supplying a base current to the transistor Q2 and operating the transistor Q2 in the same manner as a thyristor when the transistor Q2 is turned on is provided in the switching transistor Q2 for controlling one photodiode. is there.

Here, the cathode of the photodiode is
NPN type switching transistor Q between anodes
2, PNP switching transistor Q3, resistor R
6. A photodiode control circuit comprising a capacitor C6 and the like is connected in parallel, and the transistors Q2 and Q3 are switched based on a monitoring voltage of an AC input power supply rectified by a diode D3 and divided by resistors R2 and R3. Operate. That is, when the monitoring voltage of the AC200 system input power supply is received, the switching transistor Q2 is turned on to generate a potential difference between the base and the emitter of the transistor Q3 to which the resistor R6 is connected, and the base voltage of the transistor Q3 becomes the collector potential. When approaching, the transistor Q3 is turned on. When the transistor Q3 is turned on, a base current sufficient to turn on the transistor Q2 flows through the transistor Q2 via the transistor Q3. As a result, the current flowing through the resistor R2 is significantly reduced.

[0029] Figure 3 is an illustration and (commercial voltage of the AC power supplied from the outside) V _AC AC input power supply voltage shown in FIG. 1, the relationship between the smoothed voltage VN of the capacitor C1, C2, in FIG. 4 It is shown in comparison with the operation explanatory diagram of the related art shown.

In the configuration shown in FIG. 1, commercial AC power (AC input power) supplied from the outside is rectified by diodes D1 to D4, and electrolytic capacitors C1 and C2 are supplied.
Is smoothed. The rectified and smoothed DC power supply voltage charges the electrolytic capacitor C3 via the resistor R1.

When the voltage of the capacitor C3 rises to a certain constant voltage, the switching power supply control integrated circuit IC1 for controlling the switching transistor Q1 to be turned on / off operates, and a current flows through the photodiode of the phototriac PC1.

When a certain current or more flows through the photodiode of the phototriac PC1, the phototriac PC1 is turned on, and accordingly, the triac TR1 is turned on.

Here, when the commercial AC power supplied from the outside is an AC 100 V system, the monitoring voltage of the AC input power rectified by the diode D3 and divided by the resistors R2 and R3 is set to a value that turns on the switching transistor Q2. Thus, the switching transistor Q2 is in the off state, and the operating current is supplied to the photodiode of the phototriac PC1, so that the phototriac PC1 is turned on and the triac TR1 is turned on. Thereby, the capacitors C1 and C2 connected in series
Is formed.

When the commercial AC power supplied from the outside is an AC 200 V system, the monitoring voltage of the AC input power rectified by the diode D3 and divided by the resistors R2 and R3 reaches a value for turning on the switching transistor Q2. When the switching transistor Q2 is turned on, the operating current is not supplied to the photodiode of the phototriac PC1, so that the phototriac PC1 is turned off and the triac TR1 is prohibited from being turned on. Thereby, a full-wave rectifier circuit is formed.

At this time, in the embodiment shown in FIG.
Between the cathode and the anode of the photodiode provided in the phototriac PC1, the switching transistor Q2 and a photodiode control circuit including the switching transistor Q3 that operates the transistor Q2 in the same manner as a thyristor are connected in parallel. When the switching transistor Q2 is turned on, a bypass current path is formed between the cathode and the anode of the photodiode, so that no operating current flows through the photodiode, and the triac TR1 is turned off.
Switch to full-wave rectification. That is, here, the cathode of the photodiode provided in the phototriac PC1 is connected.
NPN type switching transistor Q between anodes
2, PNP switching transistor Q3, resistor R
6. A photodiode control circuit composed of a capacitor C6 and the like is connected in parallel.
When the monitoring voltage of the 0 system is input via the resistor R2, the switching transistor Q2 is turned on, and a potential difference is generated between the base and the emitter of the transistor Q3 to which the resistor R6 is connected, and the base voltage of the transistor Q3 is reduced. The transistor Q3 is turned on when approaching the collector potential. When the transistor Q3 is turned on, a base current sufficient to turn on the transistor Q2 flows through the transistor Q2 via the transistor Q3, and the transistor Q2 is turned on by the transistor Q3 in the same manner as the thyristor. As a result, in a state where the current flowing through the resistor R2 is significantly reduced, the transistor Q2
Maintain the switch-on state.

Accordingly, the base current for turning on the switching transistor Q2 may be a small value (small current value), and the unstable voltage region in which the on / off state is not constant, which is indicated by a broken line in FIG. 4, is eliminated. A stable switching operation is performed at a certain constant voltage VACN shown in FIG. Here, the loss of the resistor R2 can be suppressed to about 0.1 W.
Further, the smoothing capacitor C4 for input detection shown in FIG. 2 is not required.

As described above, the input commercial AC power is
In the case of the C100V system, the triac TR1 is turned on to form a voltage doubler rectifier circuit. In the case of the AC200V system, since the triac TR1 is not turned on, a full-wave rectifier circuit is formed and the input power supply voltage (100V system / 200V system) Automatically switches and controls the rectifier circuit.

As described above, according to the embodiment of the present invention, when the switching transistor Q2 is turned on, the transistor Q2 is turned on by the transistor Q3 in the same manner as the thyristor, so that the base for turning on the switching transistor Q2 is turned on. The current may be a small value (small current value), so that the loss of the resistor R2 can be significantly reduced. Here, the loss of the resistor R2 can be suppressed to about 0.1 W.

Further, since the unstable voltage region where the ON and OFF states are not constant, which is indicated by the broken line in FIG. 4, is eliminated.
A stable switching operation of the triac TR1 can be performed at a certain constant voltage VACN shown in FIG. Further, the smoothing capacitor C4 for input detection shown in FIG. 2 is not required.

The circuit configuration of the present invention is not limited to the above-described embodiment. For example, the photodiode of the phototriac PC1 is not interposed in the operating current path of the integrated circuit IC1 for controlling the switching power supply, and the photodiode of the phototriac PC1 is not used. Various modifications can be made without departing from the gist of the present invention, for example, by making the current path of FIG. 1 and the current path of the integrated circuit IC1 for switching power supply control independent.

[0041]

As described above in detail, according to the present invention, a full-wave rectifier circuit and a voltage doubler rectifier circuit are switched by a triac so as to be applicable to a plurality of types of commercial AC power supplies having different voltages. In the power supply, it is possible to reduce the heat loss of the resistor that supplies the driving power to the switching transistor that controls the on / off of the triac, and to stabilize the switching transistor and the input voltage region where the on / off state of the triac is not constant. A power supply device capable of maintaining a highly reliable operation can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a circuit configuration of a main part in an embodiment of the present invention.

FIG. 2 is a diagram showing a circuit configuration of a switching power supply device according to the related art.

FIG. 3 is an operation explanatory diagram of the embodiment.

FIG. 4 is an operation explanatory diagram of a switching power supply device according to the related art.

[Explanation of symbols]

 TR1 Triac PC1 Phototriac (optical coupling element) Q1, Q2, Q3 Switching transistor D1, D2, D3, D4, D5 Diode C1, C2, C3, C4, C5, C6 Capacitor R1, R2, R3 R4, R5, R6: Resistor IC1: Switching power supply control integrated circuit AC: Commercial AC power supply (input power supply) T1: Transformer

Claims (3)

[Claims] 1. A switching power supply device in which a full-wave rectifier circuit and a voltage doubler rectifier circuit are switched by a triac so as to be applicable to a plurality of types of commercial AC power supplies having different voltages. A triac, a first switching transistor that selectively inhibits the operation of a photodiode provided in the phototriac by a voltage value of the commercial AC power supply, and a second switching transistor that causes the transistor to perform a thyristor operation. A power supply device comprising: 2. A switching power supply device in which a full-wave rectifier circuit and a voltage doubler rectifier circuit are switched by a triac so as to be applicable to a plurality of types of commercial AC power supplies having different voltages. A drive circuit composed of a resistor and a phototriac that allows a trigger current having a voltage value lower than the power supply voltage to be separated from the commercial AC power supply, and a photodiode provided in the phototriac; A bypass circuit comprising: a first switching transistor that is selectively turned on / off according to a voltage value; and a second switching transistor that is turned on when the transistor is turned on, causes a base current to flow through the transistor, and causes the transistor to perform a thyristor operation. Provided in the bypass circuit The thyristor operation of the first and second switching transistors controls the operation of the photodiode of the photo triac, and the photo triac triggers the triac to switch between full-wave rectification and voltage doubler rectification. Power supply. 3. The power supply device according to claim 1, wherein the photodiode is interposed in a current path for supplying an operation power supply to the switching power supply control integrated circuit.