JPS6359728A - Automatic switching circuit for ac input source - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a power supply circuit using a voltage doubler rectifier circuit, and in particular automatically determines whether the input power source is, for example, general commercial, single-phase AC 100V or AC 200V. This invention relates to an automatic switching circuit for alternating current input power supply that can detect both types and use either one.

[Conventional technology]

Conventionally, in a power supply circuit using this type of voltage doubler rectifier circuit, there is a configuration shown in FIG. 2 when switching between AClooV and AC 200V power supplies.

In other words, this is a switch type circuit with a built-in autotransformer, and includes diodes 1, 2) and capacitor 3.
．． In a power supply circuit using a voltage doubler rectifier circuit 5 consisting of 4,
As shown in Figure 2, an autotransformer 6 and a two-pole switch 7 are incorporated, and a single-phase AC input power source 8
The user switches this two-pole switch 7 depending on whether the voltage is C200V or not.

In this way, conventionally, an autotransformer 6 is installed in the input section, a switch 7 is switched to step down the input voltage, and the input power is supplied to the voltage doubler rectifier circuit 5. Separately designed devices were used for the phase AC100V input voltage or for the AC200V input voltage.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional method of inserting an autotransformer 6 into the input section, switching the switch 7 to step down the input voltage, and supplying the input power to the voltage doubler rectifier circuit 5 does not allow the user to switch the switch incorrectly. Capacitors 3 and 4 of voltage rectifier circuit 5
There is a drawback that there is an accident of damage due to overvoltage being applied to the device, and if the power supply is dedicated to single-phase AC 100V or Ae 200V, the factory management will be doubled and costs will increase.

The present invention aims to eliminate such inconveniences, and aims to enable automatic switching and use of AC input power sources of different voltages.

[Means for solving problems]

The AC input power automatic switching circuit of the present invention is a power supply circuit using a voltage doubler rectifier circuit, and includes a parallel circuit consisting of a diode inserted in the front stage of the voltage doubler rectifier circuit and a switch connected in parallel with the diode. , a control means for detecting the magnitude of AC input to the power supply circuit and controlling the switch of the parallel circuit according to the AC input.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a circuit diagram of an embodiment of the present invention. In this embodiment, AClooV and AC
This is an example where 200V is used.

As shown in FIG. 1, the power supply circuit includes, in addition to a voltage doubler rectifier circuit 5, a diode 9, a solid state relay 10 as a switch capable of on/off control, and a rectifier smoothing circuit 1.
1 and a voltage detection circuit 12.

The diode 9 is inserted before the voltage doubler rectifier circuit 5. In the case shown, diode 1 of voltage doubler rectifier circuit 5
．． 2 and one end of the single-phase AC input power source 8 with the polarity shown. A solid state relay 10 is connected in parallel with such a diode 9.

When the single-phase AC input power supply 8 is connected to the power supply circuit, the rectification smoothing circuit 11 and the voltage detection circuit 12 detect the magnitude of the AC input and output the single-phase AC input power supply 8.
It is detected whether the voltage is AClooV or AC200V, and the solid state relay 10 is controlled to be turned on or off depending on the type.

The rectifying and smoothing circuit 11 includes a diode rectifying stack 13 that rectifies the supplied AC input, and a smoothing capacitor 14. This rectifying and smoothing circuit 11 takes out an output of approximately 140 V DC when the AC input is AClooV, and an output of approximately 280 V DC when the AC input is 200 V AC. The voltage detection circuit 12 includes a Zener diode 15, a comparator 16, and resistors 17-21. A series circuit of a resistor 17 of this voltage detection circuit 12 and a Zener diode 15 is connected to the output end of the rectifying and smoothing circuit 11, and the Zener voltage is connected to a resistor 20.2.
The voltage obtained by dividing the voltage by 1 is applied to the comparator 16 as a reference voltage. The resistor 18 and the resistor 19 constitute a voltage dividing circuit that divides the rectified and smoothed voltage obtained according to the magnitude of the AC input, and the divided voltage is used as the voltage to be compared with the reference voltage by the comparator 16. can be added to.

Here, regarding the resistance values of these resistors 18 and 19,
When AClooV is connected as the single-phase AC input power source 8, its resistance value is selected in advance so that the voltage obtained from the voltage dividing point is lower than the above-mentioned reference voltage.

The output from the comparator 16 is supplied to the solid state relay 10 as an output signal of the voltage detection circuit 12.

In this way, the AC input power automatic switching circuit shown in FIG.
AC input with diode rectifier stack 13 and capacitor 1
4, the rectified and smoothed voltage is rectified and smoothed by a rectification and smoothing circuit 11 consisting of resistors 17 to 21, a Zener diode 15, and a comparator 16.
, and the output signal of the voltage detection circuit 12 is applied to the input section of the solid state relay 10.

Next, the operation of the circuit of this embodiment will be explained.

When the single-phase AC input power source 8 is a single-phase AC 100V, the rectifier and smoothing circuit 11 rectifies and smoothes the AClooV to a DC voltage of about 140V. The rectified and smoothed voltage is supplied to the Zener diode 15 through a resistor 17 as an operating power source and a reference power source for the voltage detection circuit 12. Zener diode 15 supplies a stable voltage to comparator 16 and solid state relay 10. The reference voltage of the comparator 16 is the Zener voltage connected to the resistor 20 as described above.
．． This is the voltage divided by 21. This reference voltage and the voltage obtained by rectifying and smoothing in the rectifying and smoothing circuit 11 are connected to the resistor 18.1.
A comparator 16 compares the voltage divided by 9.

The resistors 18 and 19 are connected to the single-phase AC input power source 8.
When the voltage is V, the resistance value is set so that the divided voltage is smaller than the reference voltage, so in this case, the comparator 16 detects that it is smaller than the reference voltage.

When the comparator 16 detects this voltage being less than the reference voltage, its output signal is sent to the input of the solid state relay, and the solid state relay 10 is activated.

As a result, the current of the single-phase AC input power supply 8 is
, 4 is in a positive half cycle, the capacitor 4
．． Diode 1. It passes through the solid state relay 10 and returns to its original state, and the capacitor 4 is charged with approximately DC140V.
For the next half cycle, the current of the single-phase AC input power supply 8 flows through the diode 9. Diode 2. The voltage returns through the capacitor 3, charges the capacitor 3, and outputs a doubled voltage of approximately 280 V DC to the output terminal.

Next, if the single-phase AC input power supply 8 is a single-phase AC 200V, approximately DC 280V is output from the rectifier and smoothing circuit 11,
Since the voltage detection circuit 12 detects that the voltage divided by the resistors 18 and 19 becomes higher than the reference voltage, the solid state relay 10 will not be driven in this case. Therefore, the current of the single-phase AC input power supply 8 flows through the diode 9 for only half a cycle. Diode 2. The voltage returns to the source through the capacitor 3, and the capacitor 3 is charged with a voltage, and about 280 V DC is output to the output terminal. In this way, the same voltage is obtained in both cases.

As explained above, input power supply voltage AC100V or A
Automatically switches to C200V and operates normally no matter which power source is connected.

(Effects of the Invention) As explained above, the present invention is lighter than the conventional autotransformer and connects by switching a switch depending on the input voltage because it automatically switches. Mistakes can be prevented, and therefore there is an effect that overvoltage will not be applied to the capacitor of the voltage doubler rectifier circuit due to a switching mistake by the user.

In addition, for example, input power supply AC100V only or AC200■
Compared to having to use a special product,
There are also benefits such as factory management and expenses being reduced to 172 yen.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a power supply circuit equipped with an automatic alternating current input power supply switching circuit according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional switching type circuit with a built-in autotransformer. 1, 2. 9... Diode 3.4.14... Capacitor 5... Voltage doubler rectifier circuit 8... Single phase AC input power supply 10... Solid state relay 11... Rectifier smoothing circuit 12... Voltage Detection circuit 13...Diode rectifier stack 15...Zener diode 16...Comparators 17-21...Resistor patent attorney Yoshiyuki Iwasa Figure 1

Claims (2)

[Claims] (1) In a power supply circuit that uses a voltage doubler rectifier circuit, a parallel circuit consisting of a diode inserted before the voltage doubler rectifier circuit and a switch connected in parallel with this diode, and the magnitude of AC input to the power supply circuit are detected. and a control means for controlling the switch of the parallel circuit according to the AC input. (2) In the AC input power automatic switching circuit according to claim 1, the switch of the parallel circuit is a solid state relay, and the control means includes a diode rectifier stack and a capacitor that rectify and smooth the AC input. and a voltage detection circuit having a Zener diode and a comparator that uses the voltage obtained by using the Zener diode as a reference voltage and the voltage obtained from the rectified and smoothed output as the voltage to be compared. , An AC input power supply automatic switching circuit characterized in that the output of the comparator of this voltage detection circuit is applied to the solid state relay.