JPS6027916A - Power supply device - Google Patents

Abstract

PURPOSE:To improve the reliability of switching by switching a rectifying function automatically from double voltage rectification to nondouble voltage rectification or vice versa according to the switching of an input voltage. CONSTITUTION:When an input voltage applied between input terminals 2A and 2B is V2, the transistor TR40 of a voltage switching detecting circuit 34 becomes conductive because its base is held at a high potential, and the TR52 of a switching driving circuit 36 becomes non-conductive. Consequently, a triac 38 is controlled to a cut-off state and V20 which is a voltage non-multifying rectification output appears between output terminals 30A and 30B. Then, when the input voltage drops V2-V1, the TR40 of the circuit 34 turns off according to the voltage change, and the TR52 turns off. Namely, a trigger current is supplied to the gate of the triac 38 from an auxiliary power source circuit 60 through the TR52 to turn on the triac, and consequently a DC output 2V10 which is double appears between the terminals 30A and 30B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device, and more particularly to a power supply device that is capable of automatically switching between two types of rectification functions, voltage doubler rectification and non-voltage doubler rectification, in accordance with switching of AC input voltage. .

Generally, in various electronic devices, 100V or 220V
There are devices that operate in response to different AC input voltages such as V. This type of electronic equipment is required to always generate a constant DC output even when different AC voltages are applied to the power supply device. That is, this power supply device generates a rectified output based on a high AC input voltage,
When a low input voltage is supplied, methods such as increasing the voltage value of the rectified output by voltage double rectification are adopted.

When providing such two types of rectification functions, switching between them becomes a problem. If switching the AC input voltage is scheduled in advance, it is possible to switch the rectification function using a mechanical switch, but the power supply voltage may be switched arbitrarily due to the movement of electronic equipment or the convenience of the power supply side. In some cases, handling mechanical switches that require manual operation can be extremely cumbersome, especially in the presence of high AC input voltages, where voltage doubler rectification can provide high DC output to electronic equipment that is not intended for it. There is even a risk of damaging electronic equipment.

An object of the present invention is to provide a power supply device that automatically switches the rectifying function in response to switching of the power supply voltage and that improves the reliability of the switching.

This invention provides a rectifier circuit having both a voltage doubler rectification function and a non-voltage rectification function, a switching circuit that switches between the voltage doubler rectification function and the non-voltage rectifier function of this rectifier circuit, and an AC input voltage reference potential of the rectifier circuit. and a switching control circuit that controls the switching circuit based on voltage switching of the AC input.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 shows an embodiment of the power supply device of the present invention. In the figure, an AC power supply 4 is supplied between input terminals 2A and 2B, and the input voltage varies from low voltage V1 to high voltage V2 (=2V
I), or from high pressure ■2 to low pressure V. A capacitor 6 for eliminating high-frequency ripples is connected between the power lines where the input terminals 2A and 2B are formed, and a rectifier circuit 8 having both a voltage doubler rectifier function and a non-voltage doubler rectifier function is connected. The rectifier circuit 8 includes a switching circuit I for switching the rectification function.
O is installed. That is, diode 12.14.1
6.18, a capacitor 22.24 and a resistor 26.28 are connected between the output terminals of the bridge rectifier circuit 20, and an output terminal 30A for taking out the rectified output;
30B is formed. And capacitor 22.2
4 and the non-power supply side terminals of the resistors 26 and 28 are connected in common, and this connection point and the bridge rectifier circuit 20
The switching circuit 10 is connected between the cathode and anode of the diodes 14 and 18.

This switching circuit 10 includes a switching control circuit 32
Switching control is performed at That is, this switching control circuit 32 includes a voltage switching detection circuit 34 that detects switching between input voltages (1) and (2), and this detection circuit 3.
The switching drive circuit 36 drives the switching circuit 10 in response to the detection output of No. 4. The voltage detection reference point of the voltage switching detection circuit 34 in the switching control circuit 32 is set to the power line on the AC input side where the potential does not change even when the function of the rectifier circuit 8 is switched.

With the above configuration, when the input voltage from the AC power supply 4 is switched from V to V2, the voltage increase is detected by the voltage switching detection circuit 34, and the switching drive circuit 36 responds to the detected output. controls the switching circuit 10 to open. In this case, a capacitor 2 with a resistor 26 connected in parallel is connected between the output terminals of the bridge rectifier circuit 20.
2 and a capacitor 24 connected in parallel with a resistor 28 are inserted in series, and a rectified output V20 of voltage 2 is taken out between the output terminals 30A and 30B.

Further, when the input voltage decreases from V2 to V section, the voltage change is similarly detected by the voltage switching detection circuit 34,
Based on the detection output, the switching drive circuit 36 controls the switching circuit 1o to be in a closed state. In this case, a capacitor 22 with a resistor 26 and a capacitor 24 with a resistor 28 are individually inserted into the output of the bridge rectifier circuit 2o, and each capacitor 22.
Since VIO, which is a rectified output of the voltage V, is generated at the terminal 24, a DC output 2 which is twice as large is generated between the output terminals 30A and 30B.
V1 o (-V2 o ) will be extracted.

The rectification function is automatically switched in response to such switching of the input voltages v, , v2, and when the voltage 7fold and ■2 are in the relationship of V2 = 2VI, the output terminal 30A
, 30B can always generate a constant DC output regardless of input voltage switching. In particular, since the detection point of the voltage switching detection circuit 34 is set on the AC input side, a stable reference voltage can be generated regardless of switching of the rectification function, so switching of the input voltage can be detected without malfunction. can.

FIG. 2 shows a specific example of the circuit configuration of the power supply device of the present invention, and the same parts as those in the power supply device shown in FIG. 1 are given the same reference numerals. In the figure, the switching circuit 10 includes a bidirectional control rectifier (hereinafter referred to as a TRIAC) 38.
is used.

The voltage switching detection circuit 34 includes a transistor 40, a diode 42, a Zener diode 44, a capacitor 46, and a resistor 48.50.

That is, a diode 42 for rectifying AC input is connected to the power line where the input terminal 2A is formed, and a "+"? A capacitor 46 is connected, as well as a resistor 48, a Zener diode 44, and a resistor 50.The voltage detected by the resistor 50 is applied to the base of a transistor 40, and the emitter of this transistor 40 is a detection reference point. The collectors of transistors 1 to 40 are connected to a switching drive circuit 36.

The switching drive circuit 36 includes a 1-transistor 52 and resistors 54, 56, and 58, and the base of the transistor 52 is connected to the collector of the transistor 40. An auxiliary power supply circuit 6 is connected to the collector of the transistor 52.
DC input is applied from 0, and the gate of a triac 38 is connected to the emitter, and a resistor 54 is inserted between this gate and the power supply line. Further, a resistor 56 is inserted between the collector of the transistor 52 and the anode of the Zener diode 44, and a resistor 58 is connected between the collector of the transistor 52 and the collector of the transistor 40.

In the auxiliary power supply circuit 60, an AC power supply 62 of the same type or different from the AC power supply 4 is provided between input terminals 64A and 64B. That is, after the input voltage is lowered by the transformer 66, the AC output is rectified by the diode 68, smoothed by the capacitor 70, and then applied to the switching drive circuit 36 and the voltage switching detection circuit 34.

The operation will be explained based on the above configuration.

Now, when the input voltage applied between the input terminals 2A and 2B is 2, the transistor 40 of the voltage switching detection circuit 34 becomes conductive because its base becomes high potential, and the switching drive circuit 36 The transistor 52 becomes non-conductive. Therefore, the triac 38 is controlled to be non-conductive, and V2O, which is a non-voltage rectified output, is output to the output terminals 30A and 30B.

Next, when the input voltage decreases from 2 to V, the transistor 40 of the voltage switching detection circuit 34 becomes non-conductive according to the voltage change, and as a result, the transistor 5
2 becomes conductive. That is, a trigger current is applied to the gate of the triac 38 from the auxiliary power supply circuit 60 through the collector-emitter of the transistor 52, and the triac 38 becomes conductive. As a result, the rectifier circuit 8 is configured as a voltage doubler rectifier circuit, and in this case, the voltage V1 is voltage double rectified and the voltage V1 is doubled between the output terminals 30A and 30B.
DC output of VIO is obtained.

With the above configuration, the rectification function is automatically changed from voltage doubler rectification to non-voltage rectification, or from non-voltage doubler rectification to voltage doubler rectification, in response to switching of the AC input voltage applied to the input terminals 2A and 2B. It can be switched automatically and the rectified output can be taken out as quickly as possible in response to changes in input voltage. Further, in this embodiment, since the gate current to be applied from the switching drive circuit 36 to the gate of the triac 38 is obtained by the auxiliary power supply circuit 60, the voltage is quickly established, which improves controllability. can. In particular, the power loss in the main power system applied between the input terminals 2A and 2B can be reduced, and the efficiency of the main power system can be improved.

In the above embodiment, voltage doubler rectification is explained as an output twice the input, but the present invention can be similarly implemented in the case of an N-times voltage doubler rectifier circuit that increases the output by N times.
The present invention can be configured as a power supply circuit with at least two types of voltage switching, and is not limited to the circuit of the embodiment.

As explained above, according to the present invention, the rectification function can be automatically switched from voltage doubler rectification to non-voltage rectification, or from non-voltage doubler rectification to voltage doubler rectification, as the input voltage is switched. DC output can be extracted in response to switching.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the power supply device of the present invention, and FIG. 2 is a circuit diagram showing a specific example of the circuit configuration of the power supply device of the present invention. 4... AC power supply, 8... Rectifier circuit, 10... Switching circuit, 32... Switching control circuit.

Claims (1)

[Claims] A rectifier circuit that has both a voltage doubler rectification function and a non-voltage rectification function, a switching circuit that switches between the voltage doubler rectification function and the non-voltage rectifier function of this rectifier circuit, and a switching circuit that sets the AC input voltage reference potential point of the rectifier circuit. A power supply device comprising: a switching control circuit that controls the switching circuit based on voltage switching of AC input.