JPS5843935B2 - High power transistor switch device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a high-power transistor switch device in which the base is driven by a feedback current transformer, and in particular, when the power supply voltage of the base drive circuit fluctuates, the present invention immediately responds to the magnetic flux saturation of the feedback current transformer iron core. , relates to an improvement in the base drive circuit of a high power transistor switch device in which an auxiliary transistor cools off.

As is well known, a transistor is capable of arbitrarily switching large currents with a relatively small base signal, and its conduction period approximately corresponds to the supply period of the base signal.

Therefore, it is an attractive device as a control element for the power input switch 1, and various methods can be considered for driving the high-power device, which is generally called a power transistor. Especially in the large current range, A base drive method with a feedback current transformer is advantageous.

FIG. 1 shows a transistor switch device using a conventional feedback current transformation base and drive method. In FIG. 1, 1 is the main transistor for power control, and 2 is the iron core of the base drive feedback current transformer CT. , 3 is the primary winding of the feedback current transformer CT, and the conductor of the main power circuit connected to the collector or emitter of the main transistor 1 is used.

4 is the secondary winding of the feedback current transformer CT, and with this winding, 1
A current proportional to the collector current of the main transistor 1 flowing through the secondary winding 3 is supplied to the base electrode of the main transistor 1 through the diode 6.

5 is a tertiary winding of the feedback current transformer CT, and 8 connected to both ends of this tertiary winding is a switch such as a Cyrisk, and by igniting the Cyrisk 8, the above 3 The secondary winding 5 is short-circuited, the current in the secondary winding 4 is commutated to the tertiary winding 5, and the base current of the main transistor 1 is cut off.

Therefore, the collector current is cut off and the main transistor 1
becomes OFF.

Primary winding n1. Secondary winding n2.3 of the feedback current transformer CT
The next winding n3 has a relationship of nl<n2<n3, and in FIG. 1, the symbol * indicates the positive polarity of each winding.

Reference numeral 9 denotes an iron core of a pulse transformer PT used for supplying an initial base current for guiding the main transistor 1 from an OFF state to a conductive state and resetting the magnetic flux of the iron core 2 of the feedback current transformer CT through a diode T; ,11
．． 12 are the primary windings of the pulse transformer PT, respectively;
They are a secondary winding and a feedback winding, 13 is an auxiliary transistor for supplying initial base current and resetting the magnetic flux, and 14 is a surge voltage of the auxiliary transistor 13 which also serves to reset the magnetic flux of the iron core 9 of the pulse transformer PT. Absorption circuit, 15 is the base drive circuit power supply, 16 is a diode for rectifying the current of the feedback winding 12, 17 is the base resistance of the auxiliary transistor 13, 18 is for turning off the main transistor
19 is a reset pulse generator, 20 is an OFF pulse generator, and 21 is an ON pulse generator.

Next, the operation of the conventional high power transistor switch device will be explained with reference to the signal waveforms shown in FIGS. 2 and 5.

FIG. 2a shows an ON signal Pon that determines the conduction period of the main transistor 1, and FIG. 2 also shows an OFF signal Poff that determines the non-conduction period of the main transistor 1. , OFF signal generator 20, and the main transistor 1 is controlled according to these signals to transmit or cut off power from the X side to the Y side.

Now, time t. , the ON signal generator 21 turns ON
The signal Pon is generated, and the reset signal generator 19 and OFF
Activating signal generator 20 causes reset signal generator 19
, a reset signal Prese as shown in FIG.
t occurs, and at the same time, the OFF signal Pof from the OFF signal generator 20, which had been supplied to the gate electrode of the OFF transistor 18 and the thyrisk switch 8, is generated.
f disappears.

Therefore, the OFF transistor 18 and the risk switch 8 are in the OFF state (in an open state), and the reset signal Preset is supplied to the base electrode of the auxiliary transistor 13.

A reset signal Pr is applied to the base electrode of the auxiliary transistor 13.
By supplying eset, the auxiliary transistor 13
is conductive, and the voltage EDO of the base drive circuit power supply 15 is applied to the primary winding 10 of the pulse transformer PT.

The numbers of turns of the primary winding, secondary winding, and feedback winding of the pulse transformer PT are Wl, W2, respectively. When Wf, a voltage w2=5EDc appears in the secondary winding, and a voltage Vwf=WvEDc appears in the feedback winding fWl, with the polarity marked .Auxiliary transistor 13 is applied to these windings at time t1. Until it turns off, that is, for a period of tB,
A rectangular wave voltage as shown in FIG. 2f is applied.

As voltage ■w2 is generated in the secondary winding 11 of the pulse transformer PT, the base-emitter of the main transistor 1 is forward biased through the diode 7, and current begins to flow to the base electrode, so that the main transistor 1 It becomes conductive, and a collector current Ic as shown in FIG. 2j begins to flow.

At time t1, the auxiliary transistor 13 is turned off,
When the voltage in each winding of the pulse transformer PT (the voltage with the polarity marked ) disappears, tonight we will construct a feedback current transformer with conductor 3 at any point between X and Y shown in Figure 1 as the primary winding. Due to the action of the CT, a current proportional to the current flowing through the primary winding 3 (collector current Ic) is supplied to the base electrode of the main transistor 1 through the secondary winding 4 and the diode 6.

Completion of the reset period tl (at time t1) is performed as follows.

Time t.

When the reset signal Preset is supplied to the base electrode of the auxiliary transistor 13, the auxiliary transistor 13 becomes conductive, and a voltage appears in each winding of the pulse transformer PT.
As mentioned before, the main transistor 1 starts conducting,
After voltage appears in each winding of the pulse transformer PT, even if the reset signal Preset disappears, the voltage wf generated in the feedback winding 12 of the pulse transformer PT continues through the rectifier diode 16 and the base resistor 17. Since current is supplied to the base electrode of the auxiliary transistor 13, the auxiliary transistor 13 is subsequently in a conductive state, and voltage continues to be applied to each winding of the pulse transformer PT.

Therefore, the reset signal Preset may have a pulse width Δt as short as to make the auxiliary transistor conductive at the beginning of the reset period.

Voltage generated in the secondary winding 11 of the pulse transformer PT ■W
2 is applied through the diode 1 and the base-emitter electrodes of the main transistor 1 to the secondary winding 4 of the feedback current transformer CT, with a polarity opposite to that indicated by .

Figure 2g shows the secondary winding voltage v2 of the feedback current transformer CT,
This indicates that during the period tH, the reset voltage ■R is applied with the opposite polarity.

The reset voltage ■R is vR■W2 (VF D 2
+ V B E).

However, VFD2 is the forward voltage drop of the diode 7, and VBE is the voltage drop between the base and emitter electrodes of the main transistor 1.

FIG. 3 is a magnetization curve representing the magnetic characteristics of the iron core 2 of the feedback current transformer CT, and is expressed by the magnetic flux density B and the magnetizing force H.

Now, time t. Assume that the magnetic flux level of the iron core 2 of the feedback current transformer CT is at point 0 in FIG.

Time t. Thereafter, due to the conduction of the auxiliary transistor 13, a reset voltage of opposite polarity is applied to the secondary winding 4 of the feedback current transformer CT.
By applying R, the magnetic flux level at the 0 point becomes the third
It starts to change towards point a in the figure.

Then, at time 11+■ after tR time has elapsed, the negative saturation magnetic flux level Bam=''' tR at point a is reached 2A.

Here, A is the cross-sectional area of the iron core of the feedback current transformer CT.

When the magnetic flux level reaches the saturation point, there is no further change in the magnetic flux, so the secondary winding of the feedback current transformer CT does not lose impedance and is almost in a short circuit state.

Therefore, the current supplied from the pulse transformer PT to the base electrode of the main transistor begins to increase, and at the same time, the collector current IOI of the auxiliary transistor 13 also begins to increase as shown in FIG. 2g.

As the collector current of the auxiliary transistor 13 increases, the DC current amplification factor hFE decreases, and on the other hand, the base current of the auxiliary transistor 13 increases as the voltage of the feedback winding 12 w
Since the f-end EDc and the base resistance remain unchanged if they are in the same state, the base current will be insufficient with respect to the collector current.

In this way, the impedance of the auxiliary transistor 13 increases, so that the auxiliary transistor eventually becomes O
It enters the FF state and the reset is completed.

As mentioned above, after the reset of the iron core 2 of the feedback current transformer CT is completed at time t1, the base current continues to be supplied to the base electrode of the main transistor 1 by the action of the feedback current transformer CT. When the secondary winding 4 of the feedback current transformer CT
As shown in Figure 2g, the current voltage VC, with the polarity marked .
T=VFDt+VBE will be applied.

However, FD1 is the forward voltage drop of the diode 6.

Therefore, at time t1 after the reset is completed, the magnetic flux level that was at point a in FIG. 3 will begin to increase toward point b in FIG. 3 tonight, contrary to before.

Then, at time t2 before the magnetic flux level of the iron core 2 of the feedback current transformer CT reaches the positive saturation level, the reset signal Preset is generated again from the reset signal generator 19 as shown in FIG. 2C. Auxiliary transistor 13 is activated.

At this time, the magnetic flux level of the iron core 2 of the feedback current transformer CT is
reach the desired point.

That is, due to the current transformation voltage ■cT, the current transformation action period tcT
During this period, the magnetic flux level will change by ΔB as shown in Figure 3, so at time t, , t2-'BAn2, the current transformation action period tc'r between the tables becomes tcT --- Wawarashi. Ru.

At time t2, the auxiliary transistor 13 becomes conductive again, so that the base current is supplied from the pulse transformer PT to the main transistor 1, and the reset voltage R is again applied to the secondary winding of the feedback current transformer. That will happen.

At this time, a voltage is applied to the diode 6 in the opposite direction from the secondary winding 11 of the pulse transformer PT through the diode γ, so the diode 6 is turned off.

Therefore, a current as shown by the solid line in FIG. 2e flows through the diode 6 during the current transformation period tc'r, which is represented between times t1 and t2.

Note that the current of the diode 7, which is also the current of the secondary winding 11 of the pulse transformer PT, is maintained during the reset period tH, as shown by the broken line in FIG. 3e.

During this period, a current similar to the primary winding current of the auxiliary transistor 13 and the pulse transformer PT flows.

At time t3, the iron core 2 of the feedback current transformer CT is pulled back to the negative saturation magnetic flux level shown at point a in FIG. A current proportional to the current (collector current) in the winding 3 is supplied to the base electrode of the main transistor 1.

In this way, the reset action and current transformation action can be adjusted to an appropriate period TR.
By doing so, a current as shown in the second diagram can be supplied to the base electrode of the main transistor 1 for a long time without saturating the feedback current transformer CT.

Therefore, for example, if the electrode of the main transistor 1 is a DC power supply and the load is a resistive load with low inductance, a collector current c as shown in Fig. 2j flows through the collector of the main transistor 1. .

Furthermore, the base current IB of the main transistor 1 is almost similar to the collector current IC as shown in the second diagram, and its magnitude is determined by the number of turns n1 and 2 of the primary winding 3 of the feedback current transformer CT.
It is proportional to the ratio of the number of turns n2 of the next winding 4.

That is, the base current 1B==11c, and Ic
7■B-”2, so n2
If n is set to a small value, the DC current amplification factor of the main transistor 1 will decrease in a large current range, allowing the collector current to flow effectively even if it is very small.

Note that, as shown in FIG. 2f, a voltage with a polarity opposite to that of the reset period tR is applied to each winding of the pulse transformer PT during the current transformation period tc'r, so that the pulse transformer PT The iron core 9 of is never saturated.

In this way, the reverse polarity voltage applied to the winding of the pulse transformer PT absorbs the surge voltage generated due to the leakage inductance existing in the winding of the pulse transformer PT when the auxiliary transistor 13 is turned off. This occurs due to the action of the surge absorption circuit 14 provided to protect the auxiliary transistor 13.

At time t6, when the signal output from the ON signal generator 21 becomes "O", the OFF signal generator 20
As shown in FIG. 2, an OFF signal Poff is generated and energizes the thyrisk switch 8 and the OFF transistor 18.

Therefore, the thyrisk 8 is conductive and the tertiary winding 5 of the feedback current transformer CT is short-circuited.

The tertiary winding 5 is wound so that the number of turns is several times larger than that of the secondary winding 4, so the voltage 2 of the secondary winding 4 decreases and the current of the secondary winding 4 decreases. is all commutated to the tertiary winding 5, so the base current IB of the main transistor 1 is cut off at time t7, and since the OFF transistor 18 is in a conductive state, the feedback winding 1 of the pulse transformer PT
2, or even if a signal is generated from the reset signal generator 19, no current is supplied to the base electrode of the auxiliary transistor 13.

Therefore, the collector current of main transistor 1 is at time t6
It is completely cut off.

FIG. 2i shows the current in the tertiary winding 5 of the feedback current transformer CT.

At time t, the ON signal P is again output from the ON signal generator 21.
on occurs and the above-mentioned time t.

Return to state.

In this way, the high power transistor has a cycle of period T, and moreover, its conduction period Ton can be arbitrarily controlled.

Additionally, by using a feedback current transformer, you can relatively easily drive the base of a high-power transistor, especially in a high-current range where the DC current amplification factor of the high-power transistor decreases, and you can also reset the magnetic flux of the feedback current transformer. By doing
Base drive is possible in a wide frequency band from high frequency to direct current.

As mentioned above, driving the base of the main transistor using a feedback current transformer with a magnetic flux reset function is a very effective means, but when the voltage of the base drive circuit power supply 15 fluctuates, conventional The following drawbacks occur in the high power transistor switch device of 1.

First, consider a case where the voltage EDC of the base drive circuit power supply 15 is constant, that is, does not vary.

Assuming that the collector current IC is flowing through the main transistor 1, the base current IB is approximately 1 B 2 2 Ic due to the action of the feedback current transformer CT. Part 2 During the reset period TR, the base current IB is Auxiliary transistor 1
As described above, by the conduction of 3, the signal is supplied from the pulse transformer PT.

Therefore, the primary winding 10 of the pulse transformer PT or
During the reset period TR, a collector current 2c1 represented by 2cl''WlB flows through the auxiliary transistor 13, and its waveform becomes as shown by the dashed-dotted line in FIG. 4a.

In order to cause the auxiliary transistor 13 to flow a current with a magnitude of ICx2 or IB as shown by the dashed line in FIG. It is necessary to flow a base current IBt such that the collector-emitter voltage becomes a sufficiently small value cE2 (generally 2 to 3 V or less).

As mentioned above, this base input current 131 is supplied from the feedback winding 12 of the pulse transformer PT for most of the period, and its magnitude is approximately equal to As shown by the dashed line in Figure C, IB, =W
The voltage ED of the base drive circuit power supply 15 is expressed as i-EIXmeIRBt.
It remains constant as long as c remains unchanged.

The completion of the reset is shown in Fig. 4 when the iron core 2 of the feedback current transformer CT saturates to negative polarity at time t1, and the voltage of the secondary winding reaches a peak as shown by the dashed line in Fig. 4. It happens when you lose something.

That is, the feedback current transformer CT is activated at time t1 in FIG.
Since the impedance is lost, the secondary winding 11 of the pulse transformer PT becomes almost short-circuited.

Therefore, the primary winding current of the pulse transformer PT, that is, the collector current of the auxiliary transistor 13 increases to IO2 at time t1, as shown by the dashed line in FIG. , even though I82 or more is required in FIG. 5, it remains at IBL, so as shown in FIG. 5, the base current becomes insufficient and the base-emitter voltage VOE of the auxiliary transistor 13 increases. However, since the voltage ■cE [■] applied to the pulse transformer PT decreases, the base current becomes increasingly insufficient, and the auxiliary transistor 13 is finally turned off, completing the reset period.

Next, consider a case where the conditions of the high-power transistor switch device shown in FIG. 1 remain as described above, and only the voltage EDO of the base drive circuit power supply 15 is increased by α times.

The secondary winding voltage 2 VW2 of the pulse transformer PT becomes VW2 f,〒αEDC, and the reset voltage applied to the secondary winding 4 of the feedback current transformer CT during the reset period is Vrt'-Vw2-( VpD2+VcE)W
? It is expressed as αEDC-(VFD2+VOE), and is approximately α times thicker than before, as shown by the solid line in FIG. 4C.

Therefore, if the change in the magnetic flux level of the iron core 2 of the feedback current transformer CT is ΔB in Fig. 3 as described above, the completion of magnetic flux reset (saturation of the iron core 2 to negative polarity) is as shown in Fig. 4. As shown by the solid line, it occurs at time t', so the reset period tR'-Ay2■ ΔB-A-n2
VR-1-ya.

-1, and becomes shorter by the increase in reset voltage.

However, at this time, the value of the base current of the auxiliary transistor f 13 is I B 4 = W,
・αEDc・■RBl, and as shown by the solid line in FIG. 4C, it is α times larger than before, so at time 1. /, auxiliary transistor 1
3 is not turned off, and as shown in FIG. 5, when the collector current of the auxiliary transistor 13 reaches IC4 corresponding to the base current IB4 at this time, that is, at time 11' as shown by the solid line in FIG. 4a. It turns off at time t2' when ΔtR' has elapsed since then.

Since the base drive circuit must supply a predetermined base current to the main transistor even when its power supply voltage is the lowest expected, the conditions of the base drive circuit are determined at this lowest voltage.

Therefore, as mentioned above, if the power supply voltage of the base drive circuit increases for some reason or fluctuates in nature (for example, with lead-acid batteries, the maximum As the power supply voltage increases, the collector current of the auxiliary transistor 3 increases and the loss increases, so there is a risk that the auxiliary transistor may be destroyed.

Therefore, stable operation of the high power transistor switch device becomes impossible.

Furthermore, even if a high-rated auxiliary transistor is used, the reset time will be longer by △1/, resulting in loss during this period and when the auxiliary transistor turns off at the end of the reset period. Since the loss caused by the increase in collector current is large and the reset frequency fl2i cannot be increased, the base drive circuit cannot be downsized, which is uneconomical.

In addition, when the collector current of the auxiliary transistor increases, that is, the secondary winding current of the pulse transformer increases, the current of the secondary winding also increases, so the loss of the pulse transformer and the diode 7 and The main transistor base losses are increased, and in addition to the auxiliary transistor losses are increased, the efficiency of the device is reduced.

In addition, it is necessary to strengthen the cooling to suppress the rise in temperature of the device due to these losses.

This invention was made in view of the above points, and the base current of the auxiliary transistor supplied by the feedback winding of the pulse transformer for magnetic flux reset of the feedback current transformer is
The present invention provides a high-power transistor switch device that maintains a constant value regardless of fluctuations in base drive circuit power supply voltage.

Hereinafter, various embodiments of this invention will be questioned in detail based on FIGS. 6 to 8.

FIG. 6 is a circuit configuration diagram showing a partial block diagram of a high power transistor switch device according to the present invention, and the difference from the circuit of FIG. 1 is that the feedback winding 1 of the pulse transformer PT
2, the base current of the auxiliary transistor 3 supplied by the base drive circuit power supply 15 is
The constant current supply means 22 for maintaining a constant value is connected to the feedback winding 12.
and the connection point between the base of the auxiliary transistor 3 and the collector of the OFF transistor.

Next, the operation of the high power transistor switch device according to the present invention will be explained based on FIG.

The basic operation of the high-power transistor switch device according to the present invention is exactly the same as that of the conventional device already explained in FIGS. 1 and 2, so only the portion related to the constant current supply means 22 will be explained. do.

When the voltage of the base drive circuit power supply 15 fluctuates, the turn-off of the auxiliary transistor 13 is delayed with respect to the completion of the magnetic flux reset of the iron core of the feedback current transformer CT.
As mentioned above, the current in the primary winding 10) increases.
This is because the base current of the auxiliary transistor 13 supplied by the feedback winding of the pulse transformer PT fluctuates as the voltage of the base drive circuit power supply 15 fluctuates.

Therefore, if the constant current supply means 22 supplies a constant current to the base of the auxiliary transistor 13 regardless of the fluctuation in the voltage of the base 1 drive circuit power supply 15, the auxiliary transistor 13 will be as shown in FIG. 4d. In response to the magnetic flux saturation of the feedback current transformer core 2, time 1. / to turn off,
Moreover, the collector current of the auxiliary transistor 13 hardly increases and can be suppressed by the IC2.

Of course, the base current of the auxiliary transistor 13 at this time is a sufficient value for the collector current IC1 shown in FIG. 4d, as described above based on FIG. value (IBt in Figure 5)
must be selected.

FIG. 1 is an embodiment of a circuit specifically showing the constant current supply means 22 of FIG. 6, and in FIG. is an impedance element, for example, a resistor 23 and a constant current resistor 25 are connected in series, and these resistors 23 and 25
A constant voltage element, such as a Zener diode 24, is connected between the connection point A and ground.

The voltage appearing in the feedback winding 12 of the pulse transformer PT during the reset period is connected to the Zener diode 24 so as to keep the potential at the connection point A constant at all times, and is therefore connected to the constant current resistor 25 whose resistance value remains unchanged. Since a constant voltage is always applied, a constant current can be supplied to the base of the auxiliary transistor 13.

Note that the resistor 23 is provided to protect the Zener diode 24.

FIG. 8 shows another embodiment of a circuit specifically showing the constant current supply means 22 of FIG.
A semiconductor switch, e.g.
The collector of the transistor 29 is connected to the base of the auxiliary transistor 13, and the base of the transistor 28 is connected to the feedback winding 12 through the resistor 2γ and the diode 26.

The voltage appearing in the feedback winding 12 of the pulse transformer PT causes the diode 26 and the resistor 27 to act on the transistor 2.
When transistor 8 is made conductive, no current is supplied to the base of transistor 29, so transistor 29 is turned off.

Therefore, during the reset period, a constant current is supplied to the base of the auxiliary transistor 13 by the resistor 31 connected to the terminal 32 of the constant voltage power supply.

Except for the reset period, the feedback winding 1 of the pulse transformer PT
Since no voltage appears on 2, transistor 28 is OFF.
A current is supplied to the base of the transistor 29 from the terminal 32 of the constant voltage source through the resistor 30, and the transistor 29
9 is ONL, and no current flows through the base of the auxiliary transistor 13.

In this case, since the base energy of the auxiliary transistor 13 may be very small, it is possible to easily create a power source for supplying a stable voltage to the terminal 32 that is separate from the base drive circuit power source.

As is clear from the above description, the transistor switch device according to the present invention prevents the base current of the auxiliary transistor 13 from changing with respect to voltage fluctuations of the base drive circuit power supply during magnetic flux reset of the feedback current transformer. The following effects can be obtained by providing a constant current means.

(1) Even when the base drive circuit power supply voltage fluctuates, the auxiliary transistor can be turned off in response to the magnetic flux saturation of the feedback current transformer, thereby preventing an increase in the collector current of the auxiliary transistor and an associated increase in loss. can.

Therefore, destruction of the auxiliary transistor can be prevented and stable operation of the high power transistor switch device can be achieved.

(2) In addition, as mentioned above, since the collector current and loss of the auxiliary transistor can be reduced, a transistor with a relatively low rating can be used as an auxiliary transistor at high frequencies, so the iron core of pulse transformers, feedback current transformers, etc. It only needs to be small, the base drive circuit can be miniaturized, and it is economical.

(3) Since the losses of the base drive circuit including the auxiliary transistor can be reduced, a decrease in the efficiency of the device can be prevented, and furthermore, the increase in temperature change due to these losses can be reduced, making cooling easier.

[Brief explanation of the drawing]

Figure 1 is a circuit configuration diagram of a conventional high power transistor switch device, Figure 2 is a diagram for questioning the operation of Figure 1, Figure 3 is a diagram showing the magnetization characteristics of the feedback current transformer iron core, and Figure 4 is a diagram showing the magnetization characteristics of the feedback current transformer iron core. The figure is a diagram for explaining the operation of the feedback current transformer iron core during the magnetic flux reset period, Figure 5 is a diagram showing the VCE IC characteristics of a transistor, and Figure 6 is a simplified configuration diagram of a high power transistor switch device according to the present invention. , FIG. 7 is a circuit diagram showing an embodiment of constant current supply means used in the high power transistor switch device according to the present invention, and FIG. 8 is a circuit diagram showing a constant current supply means used in the high power transistor switch device according to the present invention. FIG. 3 is a circuit diagram showing another embodiment of the invention. In the figure, 1 is the main transistor, CT is the feedback current transformer, 2.3
, 4.5 are the iron core of the feedback current transformer, ■ secondary winding, secondary winding, tertiary winding, PT is the pulse transformer, 9, 10, 1
1 and 12 are the iron core and primary winding of the pulse transformer, respectively.
Secondary winding, feedback winding, 13 is an auxiliary transistor, 14 is a surge voltage absorption circuit, 15 is a base 1 drive circuit power supply, 1
9 is a reset pulse generator, 20 is an OFF pulse generator, 21 is an ON pulse generator, 22 is a constant current supply means, 2
3 is a resistor, 24 is a Zener diode, 25 is a constant current resistor, and 27, 30.31 are resistors. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A feedback current transformer as a base current supply means, a pulse transformer having a primary winding, a secondary winding and a feedback winding, and an auxiliary transistor as means for resetting the magnetic flux of the iron core of the feedback current transformer. In a high-power transistor switch device using A high-power transistor switch device characterized in that a reset means has a constant value that is independent of fluctuations in power supply voltage. 2. Claim No. 2 uses an impedance element connected in series between a feedback winding and an auxiliary transistor as a constant current supply means, and a constant voltage element connected between one end of this impedance element and ground. The high power transistor switch device according to item 1. 3. A first transistor driven by a voltage generated in a feedback winding as a constant current supply means, a second transistor energized by this first transistor, and a Claim 1 which uses resistors respectively connected to the collectors and a constant voltage power supply for supplying current to the bases of the auxiliary transistors through the actions of the first and second transistors. High power transistor switch device.