JPS61154311A - Base circuit - Google Patents

Abstract

PURPOSE:To decrease the turn-on and turn-off time and the switching loss by applying an excess voltage at the turn-on and turn-off of a self-extinction semiconductor element only. CONSTITUTION:When an amplifier 8 outputs an on-command, a PTR 3 is in the off-state, an output of a comparator 13 is logical '0' and an output of an NOT circuit 14 is logical '1'. Then the output of an AND circuit 15 is logical '1', an output of AND circuits 16-18 is logical '0' and a transistor (TR) 19 is turned on and an excess voltage is fed to a lead of the base. Thus, the base current rises rapidly, a collector current of the PTR 3 increases quickly and the turn-on time is shortened. When the collector-emitter voltage is decreased than the detected voltage level, the TR 19 is turned off and the excess voltage is shut off. Similarly, the turn-off time is decreased. Through the operation above, the switching time is decreased and the switching loss is also decreased.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a base circuit of a self-extinguishing semiconductor device,
Particularly related to a base circuit with a function of shortening the switching time of the element in a circuit with a large base lead inductance.

[Technical background of the invention and its problems]

Self-extinguishing elements, such as large capacity transistors (hereinafter referred to as PT)
It is written as R. ) or gate turn-off thyristor (G
The circuit shown in FIG. 4 is used as the base drive circuit for the TO) or electrostatic induction type SIRISK (8IT). (For example, IEEJ Technical Report (Part ■) No. 162
No. ``False power converters: Technological trends in the application of self-arc-extinguishing elements in power converters'' (1980, 1'), Institute of Electrical Engineers of Japan, p. 11) Figure 4 shows power supply 1.2 and self-arc-extinguishing elements (for example, PTR). 3,
Transistor 4.5, on-current/off-current limiting resistor 6,
7 current amplification amplifier 8, its cam, base lead resistance 9.10, and inductance 11 and 12.

When the capacity of the self-extinguishing element that is the load of the base circuit becomes large, the distance between the base circuit and the self-extinguishing element increases due to heat radiation, etc., and the base lead (base lead in the case of PTR) becomes longer. Therefore, the influence of the resistance and inductance of the base lead cannot be ignored when switching the element. In other words, the rise and fall times of the base current become longer, leading to a delay in the switching time of the self-extinguishing semiconductor element and an increase in element loss.

The operation shown in FIG. 4 will be explained using FIG. 5. In Fig. 4 1, when an off signal is input to the input of the amplifier 8, the transistor 5 is in the off state, and a voltage e is applied to the self-extinguishing element, here GTR3, so it is in the off state. .

At times t and 12 in FIG. 4, when an on signal is input to the amplifier 8, the transistor 4 is turned on and the transistor 5 is turned off. In this case, a voltage e is applied to the base circuit side of the base lead.

However, if the lead is long and the inductance is large, GT
The Ta2 base-emitter voltage Vill is small at first, the rise of the base current iII is rounded, and it takes time until a sufficient base current value is obtained. Therefore, it takes time for the collector current io to rise and the collector-emitter voltage to fall, resulting in an increase in turn-on time and turn-on loss.

Similarly, at time t, when an off signal is input to the amplifier 8, the transistor 4 is turned off and the transistor 5 is turned on. At this time, a voltage e is applied to the base circuit side of the base lead. However, the inductance of the base lead blunts the fall of the reverse bias current of the transistor, leading to an increase in turn-off time and turn-off loss. Also, by increasing the power supply 1.2, it is possible to reduce the rise and fall times of the base current, but increasing the on-voltage will reduce the accumulation time and the loss of the base limiting resistance due to the increase in the base current. Increasing the off-state voltage is expected to increase the off-state voltage.
This may exceed the withstand voltage between the emitters and lead to destruction of the device.

[Purpose of the invention]

Therefore, the present invention has been made in view of the above-mentioned points, and an object of the present invention is to reduce the turn-on-turn-off time by applying an excessive voltage only at the time of turn-on and turn-off of a self-extinguishing semiconductor element. and to provide a base circuit that reduces switching loss6.
There are two.

[Summary of the invention]

In order to achieve this object, the present invention detects the voltage between the anode and cathode of a self-extinguishing element to control excessive voltage from being applied to the base lead only during turn-on and turn-off. This is what I did.

[Embodiments of the invention]

Hereinafter, two embodiments C of the present invention will be explained. FIG. 1 shows an embodiment of the present invention.

A comparator circuit 13 that detects the collector voltage of the DC buses P, N, and PTR3 to which a voltage higher than the voltage of the power supply 1.2 is applied, and outputs 0 or 1 depending on the value. This circuit detects the difference in the switching characteristics of the PTR3. Therefore, it may be necessary to provide hysteresis or a delay circuit.

A NOT circuit 14 that inverts the output of this comparator, and an AN that takes the AND of the comparator output and the on and off signals.
D circuit 15, 16, 17, 18, transistor 1
9 and 20 and current limiting resistors 21 and 22. In FIG. 1, the same reference numerals as in FIG. s4 represent the same elements.

Next, we will explain the effect.

The operation shown in FIG. 1 will be explained using FIG. 2. In FIG. 1, when an off command is input to amplifier 8, transistor 4 is off, transistor 5 is off, and PTR
3 is in the off state. When the amplifier 8 outputs an ON command at time t0 in FIG. 2, at this time, PTR3 is still
is in the off state, and the output of the comparator 13 is Q, NO
The output of the T circuit 14 is 1. Therefore, AND circuit 1
The output of ND circuit 16, 17, 18 becomes 0, transistor 19 is turned on, and an excess voltage is applied to the base lead (2). Therefore, the base current increases with a steep rise, and the output of PTR3 becomes 0. Collector current 1
° increases quickly and the turn-on time becomes shorter.

Here, the collector-emitter voltage 'ION is at time t.

When the odor falls below the detection voltage level, the output of the comparator 3 changes from 0 to l+, the output of the AND circuit 5 changes to 0, and the output of the AND circuit 17 changes to 1.

Therefore, transistor 19 is turned off, the excess voltage is cut off, transistor 4 is turned on, and PTTa2 is kept in the off state.

Similarly, when the amplifier 8 outputs an off command at time t,
Since PTFL3 is still on, the AND circuit 16 outputs 1 due to the AND with the comparator 13 which outputs 1.
, AND circuits 15, 17, and 18 output 0, transistor 4 is turned off 12, and transistor 20 is turned on. Therefore, a negative excess voltage is applied to the base lead, the base current falls rapidly, and PrB6 turns off.
Turn-off time is reduced.

When the collector-emitter voltage v (1m) exceeds the detection level at time -, the output of the comparator 13 changes from 1 to O, transistor 4 turns off and transistor 5 turns on, so the negative excess voltage is applied to the base:2 The voltage from the power source 2 is applied to the base (== applied and the off state is maintained).

The above operation reduces switching time and switching loss.

Other embodiments of the present invention will be described. FIG. 3 shows another embodiment of the invention. The difference from the circuit in FIG. 1 is that instead of switching the transistor 4C transistor 19, transistor 5, and transistor 20, only the transistor 19 and the transistor addition are added to the conventional circuit, and the comparator 1
3 to turn it on and off. Even in this circuit, the functions of the present invention are fully fulfilled.

The present invention can also be applied by replacing the PrB6 part with GTO or 8IT, even if its features are impaired.

〔Effect of the invention〕

As described above, according to the present invention 62, in a self-arc-extinguishing element having a large inductance and resistance in the base lead, by detecting the anode voltage and controlling the application of excessive voltage using the signal, the self-arc-extinguishing element It is possible to provide a base circuit that maintains high-speed performance and has low switching loss.

[Brief explanation of drawings]

FIG. 1 is a connection diagram showing one embodiment of the base circuit according to the present invention, FIG. 2 is a time chart of FIG. 1, FIG. 3 is a connection diagram showing another embodiment of the present invention, and FIG. The figure shows a conventional base circuit, and FIG. 5 is a time chart of FIG. 4. 1.2. P, N...Power supply 3...Large capacity transistor 4, 5.19.20...Transistor 6
, 7 $9 tlo, 21.22...Resistance 11.1
2...Inductance 13...Comparator 1
4...NOT circuit 8...Amplifier 15.16
．． 17.18...AND circuit (7317) Agent Patent attorney Kenichi Chika (and 1 other person) Figure 1 Colt c21J Otsu 4 Figure 3 P Figure 4 Figure 5

Claims (1)

[Claims] In a base circuit for making a self-extinguishing semiconductor element conductive or non-conductive, the voltage between the anode and cathode of the element is detected, and depending on the presence or absence of this voltage, the base voltage applied to the control pole of the element is determined only during switching. A base circuit characterized by switching and adjusting.