KR930003002B1 - High power transistor driving circuit - Google Patents

Abstract

The circuit providing the stability, reliability and downsizing by using MOSFET comprises: a section (1) supplying the stabilized power; a rectification circuit (2) for supplying the full-wave rectified alternating current of power supply section (1) to the driving circuit (4); a section (3), which drives the circuit (4) through the transistors (Q3,Q4) receiving the control signal from the control circuit using the optical fiber; a configuration circuit outputting the ON side current and the OFF side current to the base of passive driving high power transistor.

Description

High power transistor drive circuit

1 is a circuit diagram showing an embodiment of a conventional transistor driving circuit.

2 is a circuit diagram showing an embodiment of a transistor driving circuit of the present invention.

* Explanation of symbols for main parts of the drawings

1: power supply 2: rectifier circuit

3: control signal receiving unit 4: driving circuit unit

T1: saturable trans T1 ', T2: trans

OP: Optical transmitter Q1, Q2: Switching transistor for AC output

R1: Starting resistor of power supply R2: For current limiting of T1

Q3, Q4: Q7, Q8 control transistor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large power transistor driving circuit, and more particularly, to a large power transistor driving circuit adapted to be suitable for the safe operation of a large power transistor by increasing the driving speed of a driven transistor by using a MOS FET in the driving circuit.

In the prior art, Korean Patent Application No. 86-2054, "Transistor Drive Circuit," is a switching mode power supply device and a single-seat forward switching method that supply power to a base drive circuit using a single-seat forward switching method on the primary side of a transformer. A device that detects the current flowing in the primary side and makes the output of the secondary side electric transformer constant current, and an inverted circuit and a smoothing reactor are installed in the ON side current to make the output of the inverted circuit dedicated to OFF base current. As a smoothing reactor, it is comprised with the structure provided with the apparatus which reduces the ripple of the whole output current.

Referring to the accompanying drawings of the prior art operation described with reference to Figure 1 T1 is a transformer of a one-seat forward switching power supply, Q1 is a switching element. Here, Q1 switches at a high speed to generate an output current of a frequency faster than the operating speed of a driven transistor on the secondary side of the transformer, and detects a primary current flowing in R2 and compares the reference value of R1 with a voltage comparator. The secondary output is made constant current by driving the base of T2 constitutes an inverted-circuit circuit using the main current flowing to Q2, which drives Q3 and is used for OFF base energization of the driven device Q5. Q3 energizes when Q2 turns off, and speeds up the current rise time when the Q2 turns on.

As described above, the prior art has a disadvantage in that the device is complicated and the ripple of the output current is increased by supplying power of the transistor driving circuit using a single-seat forward switching method. In addition, the transistors Q2 and Q3 are bipolar transistors, which have a large power loss, a long switching time, and a larger size than the MOS FET devices at the same rating.

Accordingly, an object of the present invention is to provide a power supply to the drive circuit in a two-transformed route method in order to solve the problems of the prior art, and compared to the conventional one-seat forward method, and to reduce the ripple of the output current to drive a large power transistor drive circuit To provide high reliability to the furnace.

Another object of the present invention is to use the MOS FETs Q7 and Q8 instead of the bipolar transistors Q2 and Q3 in the prior art to miniaturize the driving circuit, shorten the switching time and drive the high power transistor at a higher frequency. It is.

The configuration and operation of the large power transistor driving circuit of the present invention will be described with reference to FIG. The present invention provides a power supply unit (1) for supplying power by using a two-transmitter type of power required for the drive circuit, and a rectifier circuit unit for full-wave rectifying the AC power supplied from the power supply unit to supply the drive circuit unit (4). (2) and from the control signal receiver 3, which receives the control signal from the control circuit (not shown) to the OPTICAL FIBER and drives the drive circuit through the transistors Q3 and Q4. The driving circuit unit 4 receives the control signal through the transistor Q4 and amplifies and outputs the current required to supply the ON side current and the OFF side current to the base B of the driven large-power transistor. Looking at the operation process of the large power transistor driving circuit of the present invention made up of the configuration, the switching unit of the power supply unit 1 by switching to 20KHz or more faster than the operating speed of the driven transistor ( Q1 and Q2 alternately operate) When AC power is outputted, full-wave rectification is performed in the rectifying circuit 2 of T2 to supply stable power to the driving circuit 4.

On the other hand, the driving circuit section 4 receives the stable power supply from the rectifier circuit 2 and the control signal from the control signal receiving section 3 to operate Q7 and Q8 alternately. First, when the high level signal is received from Q4, Q7 is turned on. Therefore, the base B current required for the driven large power transistor is driven by the current signal input from the rectifier circuit 2 through the RO. At this time, Ro (non-inductive metal craft resistor) serves to determine the base B of the driven large-power transistor to make a constant current, and CO accelerates the rise of the base B drive current when the ON control signal is supplied. In addition, the high level signal of Q4 drives the base of Q6, which results in the gate voltage of Q8 being bypassed to Q6 and Q8 is turned off.

On the other hand, upon receiving a low level signal from Q4, Q7 is turned off, which causes Q5 to turn on, allowing Q7 to turn off faster. In addition, when Q6 is turned off by receiving a low-level signal from Q4, a voltage is applied to the gate of Q8 to turn on Q8, so that a reverse current flows through the driven large power transistor, thereby turning off the driven large power transistor.

As described above, the high-power transistor driving circuit of the present invention can secure stability and reliability by supplying power to the driving circuit in a two-transformer-role method, and by using MOS FETs Q7 and Q8 in the driving circuit, There is an advantage that it can be miniaturized and improves the switching speed so that it can be driven by the power transistor at a high frequency.

Claims (3)

In the high power transistor driving circuit, a power supply unit (1) for supplying a stable power supply in a two-transistor type loir method, and a rectifier circuit unit for full-wave rectifying and supplying AC power supplied from the power supply unit to the driving circuit unit (4). (2) and a control signal receiver (3) for receiving the control signal from the control circuit to the OPTICAL FIBER and driving the driving circuit through the transistors (Q3, Q4), and the control signal receiver (3) from the transistor (Q4). The driving circuit of the high power transistor, comprising: a driving circuit unit 4 which receives the control signal and amplifies and outputs the current necessary to supply the ON side current and the OFF side current to the base B of the driven large power transistor; in. 2. The apparatus according to claim 1, wherein RO is provided in the drive circuit section 4 to make the ON-side current constant, and Co is provided to speed up the base drive current when supplying the ON control signal. Power transistor driving circuit. 2. The MOS FETs (Q7, Q8) are used in the driving circuit section (4) receiving the control signal, Q5 is installed to speed up the turn-off, and Q6 is used to turn off the Q8. A high power transistor driving circuit, characterized in that.

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