JPS59176928A - Transistor driving circuit - Google Patents

Abstract

PURPOSE:To decrease the switching loss of a main transistor (TR) by applying a base current of pulse train form having an intermittent time of a period shorter than that of a storage time of the main TR to the main TR so as to drive switchingly a sub-TR. CONSTITUTION:A signal e1 having a period tau1 and a pulse width tau2 is impressed to a terminal A and a signal e2 having a period tau3 and a pulse period tau4 sufficiently smaller than the period tau1 is impressed to a terminal B respectively. A TRQ3 is conductive at the pulse width tau4 of the signal e2, and since windings W2, W1 of a winding W3 of a transformer T1 are of opposite characteristic, no current flows to the winding W2, the main power TRQ1 and the sub- TRQ2 are cut off and the magnetic energy is stored in the transformer T1. The TRQ3 is cut off after the time tau4 and the energy in the transformer T1 is dissipated via the winding W2 and a diode D5. The TRQ2 is turned on by the signal e1, the base current IB1 of the TRQ1 flows, a high voltage is generated in the winding W2, the TRQ1 is conductive rapidly and a load current Ic flows. When the TRQ3 is turned on again, after the excessive carrier of the TRQ1 is is dissipated via diodes D1-D3, the current Ic of the TRQ1 is cut off.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transistor 1 stable circuit, and particularly as a circuit for driving the opening and closing of a power transistor, it is a transistor opening/closing and driving circuit suitable for choppers, inverters, etc. that control opening and closing of large d forces at high frequency. It is related to.

-) A circuit that controls the opening and closing of power transistors to change gravity and l/l/1. In (j;, switching loss t loss and steady state loss (VoE (sa
In order to reduce t)', positive,
The base is big enough for Gyakuto! 111J 'iJ, it is necessary to flow the current at high speed, and what is more, is it necessary to control the power transistor? lql performance must be good.

Conventionally, this kind of transistor, one drive circuit, ii
'g The one shown in Figure 1 is known. FIG. 1 ω shows an example of a power transistor driving/auxiliary circuit.

In the circuit shown in FIG. 1(a), Ql is a main transistor, and a sub-transistor Q2 is connected in series from the emitter (jl) of the main transistor Qt.

A diode Dly is connected from the base of the main transistor Q1.
D2 sD3 is connected in series to the emitter of sub-transistor Q2. ;・It is strained. In this circuit, the main transistor Ql is turned on by forward biasing the main transistor Q0 and the sub-transistor Q simultaneously, and the main transistor Ql is turned off by
This is done by turning off the sub-transistor Q. To explain: First, when the sub-transistor Q1 turns off, the emitter of the main transistor Q is instantaneously opened, but the base of the main transistor Q0 remains saturated with excess carriers. , Therefore, the resistance between collector l and base is even low. As a result, the collector Ii current IB of the main transistor Q1 is connected to the diode DIs D! from the base of the main transistor Qt to the emitter of the sub-transistor Q. * Flows through DS. This one piece,
Rather than the flow, after erasing the excess carrier, the collector circulation IC is cut off. Therefore, main transistor Q1 is turned off.

This turn-off mechanism uses secondary transistors to enable high-speed switching of the power transistor without a large reverse bias power supply. Moreover, it is easy to increase the pressure of I' and %Un4.

However, since there is a contradictory relationship between the high surface voltage of the power transistor and the direct current increase rate hfe, the hfe of this type of power transistor is generally low. As the circuit becomes larger, the loss of II4, which disappears i and J+t in the 111 circuit, also becomes larger. Another example is the Fchi:111 circuit shown in Figure 1 Φ). 2;) In Figure 1 υ Show 111
In the power circuit, the operation of the power transistor ON signal 'r1! , Condition Energy::Ii:J1j I! ';
It is used in a closed manner and is capable of flowing large, high-speed base streams.

The transformer 'r1 is equipped with a return winding W1, so that once the main transistor Q1 is turned on, its base direct current acts in the direction maintained by the collector current, so that it is forced to turn on. do. 11 power supply requirements on the drive side can be reduced. However, this transformer feedback method supplies load 3'
It has the disadvantage that it cannot control gravity from 0 to 100%, and its control performance is confusing. To explain this in detail, when the transformer T2 attempts to maintain positive feedback by the feedback winding W1, it always resets one flux of the transformer RMTt, and the set period becomes 4. This is because this becomes an uncontrollable period, and 100% control (all 4 i++1 ) cannot be achieved in principle. Apart from this, there is also a method using the same transformer feedback method that improves controllability, but this time the reverse bias circuit is complicated and complicated.

The present invention has been made in order to eliminate the drawbacks of the conventional ones as described above. A transistor drive circuit consisting of a base ffi 1ijj circuit and a diode connected to the base of the main transistor and the emitter of the sub-transistor is provided, and the base drive circuit enables an intermittent cycle j9J that is shorter than the storage time of the main transistor. It has a configuration in which the main transistor is driven by supplying a base current of a pulse train having a time to the main transistor and opening/closing and driving the sub-transistor, and switching loss and steady-state loss of this main transistor. The purpose of the present invention is to provide a transistor 7% drive circuit in order to reduce the power consumption, downsize the base drive t'+iJ1 circuit, and improve control performance.

An embodiment of the present invention will be described below with reference to the drawings.

f! Figure 52 shows an example of a power transistor 11. I'4... 11th 1st heat 1k (11th V, 1st part equivalent to 1 is indicated using 1111-rF number, detailed explanation 11' will be omitted.

In the second j'21, the tertiary winding W3 of the main power transistor ON transformer T1 is connected 1' in series with the ON control transistor Q3 DC degree source 11, and this ON
An ON signal is input to the base of the resistor transistor Q3 via a resistor R1.

The secondary winding W2 of the transformer TI has a polarity opposite to the tertiary winding W3, and one terminal is connected to a rectifier diode D.

The base terminal of the main power transistor Q1 is connected to the fib terminal via =+I, and the fib terminal is connected to the emitter of the transistor Q2. The primary winding W1 of the transformer T1 is in a bipolar relationship with the secondary winding W2, and the main power transistor Q
1. The sub transistor Q2 and the load 3 are connected in series at 1%, and current is supplied from the main circuit side DC power supply 1. The auxiliary transistor Q2 is connected in series with the primary winding W1 of the transformer T1, the main power transistor Q, etc., and has a diode D, D2 connected from the base of the main power transistor Q1 to the emitter of the auxiliary transistor Q2. ．． D
, and mainly controls the turn-off of the main power transistor Q1. Figure S3 is an output waveform diagram of each part in the power transistor and ringing circuit shown in Figure 2.

Next, the operation of the power transistor drive circuit shown in FIG. 2, which is an embodiment of the present invention, will be explained with reference to FIG. 3.

First, assuming that the main power transistor Q1 is driven by 1 with a period τ1 and a conduction time τ2, this basic signal is assumed to be e shown in FIG. 3(a). This signal e1 is nothing1)
Regarding η, the pulse width τ is sufficiently small for 1Pi1 period τ1.
, to create a pulse train with a period of τ3, and this signal is expressed as shown in Figure 3 (
Let it be e2 shown in υ. Assuming that the above signal e4 is input to the A terminal in Fig. 2, and e2 is input to the B terminal, the transistor Q3
is ON for a period of time τ4 and OFF for a period of time τ3-74.
do.

As a result, when transistor Q is turned on, transformer T1
The voltage of each winding W1 p W2 ; W3 (navigation is the second
Since the memory capacity shown by the black dots in figure (a) becomes a positive voltage, 2
No current flows through the next winding W2, and the main power transistor Q1 is in a cut-off state. Therefore, the primary winding W0
What about the current? ! The r current flows only through the tertiary winding W3, and 1114 Rr7 Tl stores energy. When the transistor Q3 turns off after a time T4, the magnetoelectric energy l of the transformer T1 is tapped off via the secondary winding W2 and the rectifier diode l). At this time, the sub-transistor Q2 is in the ON state due to the signal e1, so the base of the main power transistor Q1 is
I flows. This base current rB+ begins to flow in the negative direction because the secondary winding W2 is in a state where a high temperature of 11° C. 1 F can occur due to the inductance of the winding. This causes the main power transistor Q1 to conduct ii+1 to negative 1f'.
f7"i"i: Since the flow Ic flows, the primary winding W1 is also loaded. ・1: The flow is the flow 'jt, and the primary winding W8 and the secondary winding W2 are in the relationship of a current transformer. , main power transistor Q
+ base current is maintained. However, metamorphosis k T1
The magnetic flux of
.

If the transformer Ri'i T1 tries to maintain the relationship of a current transformer as described above, the magnetic flux of this transformer T1 will eventually change from one to the other. −Saturates in the force direction. However, time τ3
-τ, later tIf and transistor Q3 is turned ON, the main power transistor Q1 is in the φ′f direction due to the rectification action of the rectifier diode D5. Before the power transistor Q1 reaches the cutoff state, the transformer T1
The magnetic flux of is reset, and this reset of the magnetic flux causes the current transformer relationship between the base-side primary winding W1 and the secondary winding W2 of the main power transistor Q to supply the r1 main current again. As long as the pulse train shown in FIG. 3 continues to be applied to the transistor Q3, the main power transistor Q1 continues to be conductive.

Next, as shown in FIG. 3, the signal e1 applied to the base of the sub-transistor Q at time T1 is cut off. Then, the sub-transistor Q becomes cut off, the base current of the main power transistor Q, which had been flowing until now, is also cut off, and the emitter of the main power transistor Q8 is also instantaneously opened. The base still remains saturated with excess carriers, so the collector-base resistance is down to low -P. Is that the lover of power transformer Q1?
[mInt is a diode D connected to the base of the main power transistor Qi and the emitter of the sub-transistor 02, I)2. D, flows through 110. This DC IB eliminates excess carriers and then reduces the collector current IC. Therefore, the main power transistor Q1 has a high i1! to turn off.

That is, since the storage time ts and the foreclosure time tf are very small, there is little loss.

At this time, naturally transistor Q3, all power transistors Q
Whether or not the base current IB8 of 1 is supplied is 19]
There is no one in charge. In other words, it has nothing to do with the sub-transistor Q2!
11. ! I made - [also good. Therefore, the number of base drive circuits is reduced to 17 (1).

Figure 2(b) shows the power MO5FE in the shaving transistor Q2.
TM2 is used, and FIG. 4 shows another embodiment of the present invention, in which the sub-transistor Q and the digit 1 of the primary winding W8 are used.
Although this is a different version of 11, the effect of the same move can be obtained.

As described above, according to the transistor drive circuit according to the present invention, the base drive circuit continues to supply the base current of the pulse train having the intermittent period shorter than the storage time of the power transistor to the power transistor, and By opening and closing the transistor, the power transistor is configured to operate by 11%, so the main transistor can be driven with less power per drive, and high-frequency switching and high voltage resistance are easy, with little power loss. This provides an excellent effect that enables a high-performance power transistor drive circuit to be realized.

[Brief explanation of the drawing]

Fig. 1 ω■ is a circuit diagram showing a conventional power transistor and drive, Fig. 2 (a) and (b) are circuit diagrams showing an embodiment of the present invention, and Fig. 3 (a) to c) are FIG. 2 is an output waveform diagram of each section divided into the circuits shown in FIG. 2, and FIG. 4 is a circuit diagram showing another embodiment of the present invention. (1) j+I11... [current current, (3)... load, Q4... main power transistor, Q,... sub transistor, Q3... transistor %T2... transformer, D,... Rectifier diode, D,,D. D3... For all diodes, the same reference numerals in Figure 1 indicate the relevant parts. 12

Claims (6)

[Claims] (1) A transistor drive circuit consisting of a main transistor, a sub-transistor connected to the emitter of the main transistor, and a base drive circuit connected to the emitter of the main transistor and the base transistor is 41i8
Furthermore, by supplying a base current of a pulse train having an intermittent period shorter than the accumulation time of the main transistor to the main transistor and opening and closing the sub transistor, the main transistor is pivoted by one turn. What is claimed is: 1. A transistor drive circuit characterized by having a configuration consisting of: (2) The transistor drive circuit according to claim 1, characterized in that a diode is connected in parallel with the base drive circuit connected to the pace of the main transistor and the emitter of the sub-transistor. (3) The transistor drive circuit according to claim 1 or 2, wherein the base current supplied from the base drive path is supplied or depleted via a transformer. (4) The transistor and drive circuit according to claim 3, wherein the K generator is provided with a feedback winding through which current flows between the collector and emitter of the main transistor. (5) Claims 1 and 2, characterized in that the sub-transistor is composed of a field effect transistor.
4. The transistor drive circuit according to claim 1, 3, or 4. (6) The transistor drive circuit according to claim 1, 2, 3, or 4, wherein the sub-transistor is a metal oxide film field effect transistor. .