JPH1117232A - Peltier element driving circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive circuit used for a simple Peltier element driving circuit. SOLUTION: This circuit is provided with a switching circuit 8 for switching currents flowing from direct currents to the Peltier element of a load, by using forward and backward power switching elements. In this case, a drive circuit 20 for driving the power switching elements rectifies a voltage induced in a tertiary coil 5b provided at a transformer 5, and this circuit is provided with a bias power source connected serially with the switching circuit, first and second signal switching elements 23 and 24 which turn on when forward and backward drive command signals are inputted, and third and fourth signal switching elements 25 and 26 connected with the bias power source which turns on when the first and the second signal swirtching elements are turned on, and impress gate signals to forward and backward power switching elements 11 and 14 and 12 and 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Peltier device driving circuit for driving a Peltier device which generates or absorbs heat by supplying a power supply.

[0002]

2. Description of the Related Art A Peltier device is a device that generates or absorbs heat other than Joule heat at a junction by connecting two kinds of metals or a metal and a semiconductor and applying a current to the two.
Heat generation or absorption occurs by changing the current in a forward or reverse direction. FIGS. 2 and 3 show a configuration of an example of a Peltier device driving circuit for supplying a current to such a Peltier device.

In FIG. 2, 1 is a commercial power supply, 2 is an input-side rectifier for rectifying the commercial power supply 1, 3 is a capacitor for smoothing rectified DC, and 4 is high-frequency switching by a switching element having a built-in rectified and smoothed DC. A high-frequency converter that outputs high-frequency AC, 5 is a transformer that inputs high-frequency AC and transforms it to a desired voltage, 6 is an output rectifier that rectifies the transformed high-frequency AC, and 7 is rectified by the output rectifier 6. A reactor for smoothing direct current, 8 is a switching circuit for switching a direct current flowing through the Peltier element in a forward direction or a reverse direction, and 9 is a Peltier element of a load.

FIG. 3 is a schematic diagram of the switching circuit 8 and a driver circuit 50 of the switching circuit 8. The switching circuit 8 includes an IGBT connected in series to a DC output obtained by rectifying a high-frequency AC,
IGBTs, M connected in series with power switching elements 11 and 13 such as MOSFETs and power transistors
Power switching elements 12 and 14 such as OSFETs and power transistors;
It comprises diodes 15, 17, 16, 18 connected in anti-parallel with 13, 12, 14, respectively.

The driver circuit 50 includes a light emitting element 5 of photocouplers 51 and 57 connected in series to a DC bias power supply.
1a and 57a and the first signal switching 23 to which the forward drive command signal is input, and the light emitting elements 53a of the photocouplers 53 and 55 connected in series to a DC bias power supply.
, 55a and the second signal switching element 24 to which the reverse drive command signal is inputted, and the power switching elements 11, 12, 13, 1 receiving the drive signal.
4, photocouplers 51, 53, 55,
It is composed of 57 light receiving elements 51b, 53b, 55b, 57b. Here, 31, 32, 33 and 34 are current limiting resistors. 35, 36, 37, and 38 are overvoltage protection elements such as zener diodes for preventing an excessive voltage from being applied to the gates of the power switching elements 11, 12, 13, and 14. 61, 62, 63 and 64 are bias resistors.

Next, the operation will be described. The commercial power supply 1 is rectified by the input side rectifier 2, and the rectified DC is smoothed by the capacitor 3. The rectified and smoothed DC is converted into a high-frequency AC by a high-frequency converter 4, and the high-frequency AC is transformed into a desired voltage by a transformer 5. The transformed high-frequency AC is rectified by the output rectifier 6 and smoothed by the reactor 7. The rectified and smoothed DC is input to the switching circuit 8.

Now, when a forward drive command signal is input to the first signal switching element 23, the switching element 23 is turned on, and a current flows through the light emitting elements 51a and 57a to be turned on. The light emitting elements 51a and 57a are turned on, and a current flows through the light receiving elements 51b and 57b of the photocouplers 51 and 57,
A voltage is applied to the gates of the power switching elements 11 and 14, and the power switching elements 11 and 14 are turned on.
When the power switching elements 11 and 14 are turned on, a forward current flows through the power switching element 11, the load 9, and the power switching element 14, and the Peltier element of the load 9 generates heat.

Next, when the forward drive command signal is turned off and the reverse drive command signal is input to the second signal switching element 24, the second signal switching element 24 is turned off.
Turns on, and a current flows through the light emitting elements 53a and 55a to turn on. The light emitting elements 53a and 55a are turned on and the photocoupler 5
A current flows through the light-receiving elements 53b and 55b, and a voltage is applied to the gates of the power switching elements 12 and 13, and the power switching elements 12 and 13 are turned on. When the power switching elements 12 and 13 are turned on, a reverse current flows through the power switching element 12, the load 9, and the power switching element 13, and the Peltier element of the load 9 absorbs heat.

[0009]

However, in the above switching circuit, each of the power switching elements 11, 12, 1
Insulating photocouplers 51, 53, 5
5 and 57, and there is a problem that the drive circuit 50 becomes complicated, for example, a bias power supply must be separately provided.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems, and a Peltier device driving circuit of the present invention performs high-frequency switching of a rectified DC of an AC power supply and outputs a high-frequency AC. A high-frequency converter, a transformer for transforming the high-frequency alternating current, an output rectifier for rectifying the transformed high-frequency alternating current, and a power switching element for converting a current flowing from the DC output of the output rectifier to a Peltier element of the load using a power switching element. A drive circuit for driving the power switching element, wherein the drive circuit for driving the power switching element is provided in the transformer.
A first signal switching that rectifies a voltage induced in the next winding and turns on when a bias power supply connected in series with the switching circuit and a forward drive command signal and a reverse drive command signal are input. And the second signal switching element and the bias power supply, and are turned on when the first and second signal switching elements are turned on, respectively. A third signal switching element and a fourth switching element for applying a gate signal to the power switching element are provided.

The rectified DC of the AC power supply is subjected to high-frequency switching to obtain high-frequency AC, and the high-frequency AC is transformed into a desired voltage by a transformer. The transformed high-frequency AC is rectified by an output rectifier, and the rectified DC is input to the switching circuit 8. By turning on the forward power switching element incorporated in the switching circuit, a current flows in the Peltier element of the load in the forward direction, and the Peltier element generates heat.
When the reverse power switching element built in the switching circuit is turned on, a reverse current flows through the Peltier element of the load, and the Peltier element absorbs heat.

First, when a forward drive command signal is input to the first signal switching element, the first signal switching element is turned on. A third signal switching element connected to a bias power supply formed by rectifying an induced voltage induced in a tertiary winding provided in the transformer is turned on,
The output of the third signal switching element is applied to the gate of the forward power switching element of the switching circuit, and the forward power switching element is turned on. When the switching element for forward power is turned on, a forward current flows through the Peltier element.

On the other hand, when the reverse drive command signal is input to the second signal switching element, the second signal switching element is turned on and the fourth signal switching element is turned on. The output of the fourth signal switching element that is turned on is applied to the gate of the power switching element in the reverse direction of the switching circuit, the power switching element in the reverse direction is turned on, and a reverse current flows through the Peltier element.

[0014]

FIG. 1 is a schematic connection diagram of a switching circuit according to an embodiment of the present invention and a drive circuit of the switching circuit. In FIG. 1, those having the same reference numerals as those in FIG. 3 indicate those having the same functions. The difference between FIG. 1 and FIG.
A tertiary winding 5b for inducing a voltage as low as several volts, a diode 21 for rectifying the voltage generated in the tertiary winding 5b, and a smoothing capacitor 22.
Connected in series with each other and used as a bias power supply for the drive circuit, and connected to the bias power supply and turned on when a forward drive command signal is input to the first signal switching element 23, and turned on when the power switching element 11, A third signal switching element 2 for applying a gate signal to the gate 14
5, a fourth signal switching circuit which is connected to a bias power supply, is turned on when a reverse drive command signal is input to the second signal switching element 24, and applies a gate signal to the gates of the power switching circuits 12 and 13. The point is that the element 26 is provided. 27 and 28 are bias resistors.

If a forward drive command signal is input to the first signal switching element 23, the switching element 23 is turned on, the third signal switching element 25 is turned on, and the power switching elements 11, 14 are turned on. Gate voltage is applied to the gate of the power switching element 11,
14 turns on. When the power switching elements 11 and 14 are turned on, a forward current flows through the power switching element 11, the load 9, and the power switching element 14, and the Peltier element of the load 9 generates heat.

Next, when the forward drive command signal is turned off and the reverse drive command signal is input to the second signal switching element 24, the second signal switching element 24 is turned off.
Is turned on, the fourth signal switching element 26 is turned on, and a gate voltage is applied to the gates of the power switching elements 12 and 13 so that the power switching elements 12 and 13 are turned on.
Turns on. When the power switching elements 12 and 13 are turned on, a reverse current flows through the power switching element 12, the load 9, and the power switching element 13, and the Peltier element of the load 9 absorbs heat.

[0017]

According to the Peltier device driving device of the present invention, a tertiary winding for inducing a low voltage is provided in a transformer to form a bias power source. This eliminates the need to use a drive circuit and simplifies the drive circuit.

[Brief description of the drawings]

FIG. 1 is a connection diagram of an embodiment of a drive circuit used in a Peltier device driving device of the present invention.

FIG. 2 is a block diagram of a Peltier device driving device according to the present invention.

FIG. 3 is a connection diagram of a drive circuit used in a conventional Peltier device driving device.

[Explanation of symbols]

 Reference Signs List 2 input side rectifier 4 high frequency converter 5 transformer 5a tertiary winding 6 output side rectifier 8 switching circuit 11, 12, 13, 14 power switching element 20 drive circuit 21 diode 22 capacitor 23 (first) signal switching element 24 (second) signal switching element 25 (third) signal switching element 26 (fourth) signal switching element

Claims (1)

[Claims] 1. A high-frequency converter that performs high-frequency switching on a rectified DC of an AC power supply and outputs a high-frequency AC,
A transformer for transforming the high-frequency AC, an output rectifier for rectifying the transformed high-frequency AC, and a switching circuit for switching the current flowing from the DC output of the output rectifier to the Peltier element of the load using a power switching element. A drive circuit for driving the power switching element rectifies a voltage induced in a tertiary winding provided in the transformer, and provides a bias connected in series with the switching circuit. A first signal switching element and a second signal switching element that are respectively turned on when a power supply, a forward drive command signal and a reverse drive command signal are input, and connected to the bias power supply; And when the second signal switching element is turned on, the power switching element is turned on in the forward direction. Peltier element driving circuit, wherein the third signal switching element and the fourth switching element for applying a gate signal to the device and the reverse direction of the power switching element is provided.