JPS63190551A - Voltage multiplying rectifier - Google Patents

Abstract

PURPOSE:To simplify a driving circuit and reduce loss, by employing MOSFET in a voltage multiplying rectifier. CONSTITUTION:A voltage multiplying rectifier consists of a DC power source 1, capacitors 2, 3, MOSFET 5a-8a, photocouplers 9a-12a and the like. When the polarity of an AC power source 22 is in a direction to impress a positive voltage on a resistor 21, light emission diodes 9b, 11b are lighted to put phototransistors 9a, 11a ON. According to this operation, the MOSFETs 5a, 7a are put ON and a capacitor 2 is charged to the voltage of the DC power source 1. When the polarity of the AC power source 22 is in a direction impress a negative voltage on the resistor 21, the capacitor 3 is charged in the same manner. As a result, a voltage about double of the voltage of the DC power source is impress.d on a DC load 4.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a voltage doubler circuit, and particularly relates to a voltage doubler rectifier that has low loss due to a small voltage drop during rectification, is suitable for low voltage rectification, and can be further miniaturized. .

[Conventional technology]

Conventionally, this type of voltage doubler rectifier circuit uses two transistors, a rectifier diode, and a capacitor, as shown in FIG. In Figure 3, 1 is a DC power supply, 2.3
is a capacitor, 4 is a DC load, 25.26 is a diode, and 27.28 is a transistor.

When a pace current is supplied to transistor 27.

The transistor 27 is turned on, and the capacitor 3 is charged through the diode 25 to the voltage of the DC power supply voltage 1. Similarly, when the base current is supplied to the transistor 28, the capacitor t2Vc is charged, and as a result, the DC load 4 has the sum of capacitors 2 and 3, ie.

A voltage approximately twice the DC power supply voltage is applied.

[Problem that the invention seeks to solve]

In the conventional circuit described above, the rectifier diode is used, so approximately 1
(2) Voltage drop occurs, resulting in large power loss.Also, when high-speed switching is pursued due to the use of transistors, the circuit becomes complicated due to pace bias, etc.

[Means for solving problems]

The voltage doubler rectifier circuit according to the present invention includes a DC power supply, two capacitors connected in series, two pairs of MOS FETs that alternately charge the capacitors, and the MO8FE.
It has a T drive circuit.

〔Example〕

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

FIG. 1 is a circuit diagram showing an embodiment of the present invention. In FIG. 1, 1 is a DC power supply, 2.3 is a capacitor, 4 is a DC load,
5a, 6a, 7a, 8a are MOSFETs, and the diodes are parasitic diodes of the MOS FETs.5 9
a * 9 b * 10 a @ 10 b * 11
a, 11b, 12a, 12b are phototransistors and light emitting diodes constituting a photocoupler; 13°14.15.
16.21 is a resistor, 17.18.19.20 is a DC power supply, and 22 is an AC power supply. Now, when the polarity of the AC power supply 22 is in the direction of applying a positive voltage to the resistor 22, the light emitting diodes 9b and llb are turned on, so the phototransistors 9a and lla are turned on. Therefore MO8FET5a
, 7a are turned on, and the capacitor 2 is charged to the voltage of the DC power supply 1. Similarly, the polarity of the AC power supply 22 is changed to the resistance 22.
When a negative voltage is applied to the capacitor 3, the capacitor 3 is charged, and as a result, the capacitors 2 and 3 are connected to the DC load 4.
A voltage approximately twice the DC power supply voltage is applied.

FIG. 2 is a circuit diagram showing another embodiment of the present invention, and the overall configuration is the same as that in FIG. 1. The second factor is one MOS
This figure shows a driving section paired with an FET. 23 in the figure
is a photodiode, 24 is a light emitting diode, and 6':)
The photodiodes 23 are connected in series so that a voltage equal to or higher than the minimum gate drive voltage of the gate of s M OS k h T 5 a is obtained. When the light emitting diode 24 emits light, each photodiode 23 generates a photovoltaic force and the MOS F
Since ET 5 a is turned on, the operation is similar to that shown in FIG. 1.

〔Effect of the invention〕

As explained above, the present invention uses MOS in the voltage doubler rectifier circuit.
The convenient use of FETs not only simplifies the drive circuit, reduces its voltage drop, reduces loss, and makes it more compact, but also provides the advantage of providing a voltage doubler rectifier circuit suitable for rectifying low voltages.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a circuit diagram showing another embodiment, and FIG. 3 is a circuit diagram showing a conventional example. In the figure, 1...DC power supply, 2.3...Capacitor, 4...Ei current negative load 5a, 6a, 'Ia, 13
m・・・・・MO8FET9aa9b, 10a, 10
b, 11amllb, 12a. 12b...Phototransistor and light emitting diode forming a photocoupler, 13.14.15.16...
... Resistor, 17.18.19.20 ... DC power supply, 21 ... Resistor, 22 ... AC power supply, 23 ... Photodiode, 24・・・・・・
- Light emitting diode, 25.26...diode, 27.28...transistor. Book

Claims (1)

[Claims] A first MOS FE whose drain is connected to one end of the first capacitor and whose source is connected to the positive electrode of the DC power supply.
T, a second MOS whose drain is connected to the other end of the capacitor, and whose source is connected to the negative electrode of the DC power supply.
FET, third and fourth MOS FETs connected in opposite directions to the first and second MOS FETs between the second capacitor and the DC power supply, M
1. A voltage doubler rectifier circuit comprising an OS FET and a third and fourth MOS FET in pairs, a drive circuit that turns on alternately, and the first and second capacitors are connected in series.