JPS5816649B2 - transistor switch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transistor switch device, and more particularly to a transistor switch device constituting a chopper device or the like.

Conventionally, in transistor switch devices used for this purpose, sufficient base current flows through the transistor while the transistor is on, but the collector current is limited due to insufficient base current. It was designed not to.

For this reason, it is common practice to provide a circuit that supplies a constant base current corresponding to the maximum load current, or to configure the transistor as a Goulington circuit, and if necessary, to configure a multi-stage Goulington circuit. there were.

However, in many cases, the load of a transistor switch device includes a reactance component, or a back electromotive force is included in the load as in the case of a motor as a load, and the value of the back electromotive force changes, so the transistor switch Flows into the device's transistor.

Collector current varies over a wide range.

A drawback of conventional transistor switch devices is that they always flow a base current corresponding to the maximum collector current, even though the collector current varies over a wide range.

In other words, unnecessary power consumption will occur,
Furthermore, since the Goulington circuit is constructed with this structure, the device becomes larger and its reliability decreases.

The above-mentioned drawbacks of the conventional transistor switch device are as follows: A current transformer is used, and the current of the second transistor is passed through the primary side of the current transformer, and both ends of the secondary winding are connected to the base and emitter of the transistor. This was improved by passing a base current through the transistor that is proportional to the current flowing to the side.

However, when the collector current of the transistor changes over a wide range, the so-called current amplification factor hfe0 value also changes, so in order to supply a base current according to the collector current, the current transformation ratio (hereinafter abbreviated as HFE) of the current transformer must also be changed. Not fixed, but automatic in response to hfe.

It is desirable that the situation changes.

An object of the present invention is to provide a transistor switch device that uses a current transformer to flow a base current proportional to the collector current of a transistor, in which HFE is automatically changed in response to changes in hFE.

This purpose is achieved by providing a plurality of transistor base current circuits and appropriately selecting the voltage applied to each base current circuit and the voltage-current characteristics of the diode inserted in the circuit. can.

Examples of the present invention will be described in detail below with reference to the drawings.
The same reference numerals represent the same or equivalent parts throughout the drawings, and redundant explanations of the reference numerals that have already been explained in other drawings will be omitted.

Fig. 1 is a wiring diagram showing one embodiment of the present invention, and Fig. 2 is a wiring diagram showing an embodiment of the present invention.
FIG. 3 is a waveform diagram showing the voltage or current waveforms of the main parts of the circuit, and FIG. 3 is a graph showing the magnetic hysteresis phenomenon of the current transformer core used in the present invention.

In FIG. 1, 10 is a DC power supply, 11 is a load, 12 is a main transistor 10, and 11.12 are connected in series.

A block 2 surrounded by a dotted line is a current transformer, and one end of its primary winding 21 is connected to the emitter of the transistor 12, and the other end is connected to the ground terminal of the power supply 10.

In the embodiment shown, the current transformer 2 has a first secondary winding 22 and a second secondary winding 23, the first secondary winding 22 having at least one intermediate terminal 54. shall have the following.

Further, the diode 13 is connected in parallel to the load 11 and with a polarity opposite to the conduction direction of the main transistor 12.

One end 53 of the first secondary winding 22 is connected to the emitter of the main transistor 12, and the other end 51 is connected to the resistor 50 and the diode 4.
The intermediate terminal 54 is connected to the base of the main transistor 120 through a series circuit to form a first base current circuit of the main transistor, and the intermediate terminal 54 is connected to the base of the main transistor 12 via a diode 44 to form the first base current circuit of the main transistor.
This constitutes a second base current circuit.

Generally speaking, the first secondary winding 22 is connected to the intermediate terminal 54.
It also has intermediate terminals in addition to the third . 4th degree...
Needless to say, it is possible to configure the base current circuit of 3., but in normal cases, the necessary HFE characteristics can be obtained using only the first base current circuit and the second base current circuit, and 3. The operation of the fourth base current circuit can be easily inferred from the operation of the second base current circuit, so in the embodiment shown in Fig. 1, there is only one intermediate terminal. Only one person shall be provided.

, the second secondary winding 23 is short-circuited by the thyristor 19, and a trigger pulse is applied to the gate of the thyristor 19 from the terminal 17 via the resistor 18 to form a thyristor switch device, and the second secondary winding 23 is short-circuited. Since a short circuit effectively shorts the first secondary winding 22, in this installation, a circuit that provides a similar effect, including this thyristor switch device, is used to short circuit the current transformer secondary voltage. Let's call it a circuit.

Block 3 surrounded by a dotted line is a transformer, and the primary winding 3
1 and a secondary winding 32, the primary winding 31 is connected in series between the power supply 10 and the auxiliary transistor 14, and a diode 43 having a polarity opposite to that of the power supply is connected in parallel to the winding 31. be done.

One end of the secondary winding 32 is connected to the base of the main transistor 12 via a diode 42, and the other end is connected to a connection point 52 between the diode 41 and the resistor 50.

The secondary winding 32 of the transformer 3 is for the purpose of generating a pulse voltage and applying it to the first base circuit of the main transistor 12, and the circuit for this purpose is referred to as a pulse voltage generation source in this specification. Make it.

°The operation of the circuit shown in Figure 1 will be explained with reference to Figure 2.
First, terminal 54, diode 44, main transistor 12
The operation will be described assuming that the second base current circuit of the main transistor, which is composed of the base of the main transistor 12, the emitter of the main transistor 12, and the terminal 53, is in an off state.

The black circles attached to the current transformer and transformer windings indicate the relative polarity of the induced voltage.

At time 11 (see Figure 2), the main transistor 12 is in the off state, and the pulse voltage shown by waveform P16 is applied to terminal 1.
6 to the base of the auxiliary transistor 14 via the resistor 15, the auxiliary transistor 14 is turned on, and a pulse voltage is generated in the secondary winding 32 of the transformer 3. Emitter of main transistor 12 → resistor 50 of winding 22 → winding 32
The base current of the main transistor 12 flows through the circuit, turning the main transistor 12 on.

Since the connection point 53 between the main transistor 12 and the winding 22 is equal to the potential of the solenoid ground, the terminal of the winding 32 connected to the diode 42 has the potential of the solenoid ground. The potential at the other end, that is, the connection point 52 becomes a negative pulse voltage as shown by the waveform V5□ in FIG. flows.

Assuming that the ampere turns of current transformer 2 is 0 before time t1 (see Figure 3, ampere turns are denoted as AT) and its magnetic flux φ is at point A, a voltage shown in waveform v, 2 causes a voltage across winding 22 to The ampere-turn of the flowing current once becomes a negative value and becomes 0 again at time t2, so the magnetic flux of the current transformer φ
is a value equivalent to point E.

That is, the magnetic flux of the current transformer 3 is reset.

Main transistor 12 is turned on at point t1.

However, due to the reactance of the load 11, the load current Ill gradually increases as shown in the waveform Ill of FIG.

The number of turns of the primary winding 210 of current transformer 2 is N1, and the current flowing through the primary is .

(>■ in the section t1 to t3 in Figure 2).

= 111), the number of turns of the first secondary winding 220 is N2, and the current flowing through the secondary is 3.

Since the ampere turns caused by 18 are generated to balance the excitation ampere turns necessary to maintain the induced voltage by canceling the ampere turns caused by

IB proportional to flows. ■As o increases, the excitation ampere-turns also increase, and at time t3, the value shown by N2 is reached, and φ becomes a value corresponding to point F (see Figure 3). Therefore, the current transformer 2 ceases to function, but whether or not the magnetic flux has reached point F in the current transformer 2 can be easily detected by the loss of the secondary induced voltage, so this point is set as t3.
This is detected and a pulse shown in FIG. 2 pta is applied to the terminal 16 to turn on the transistor 14.

Then, the indicated polarity voltage is induced in the secondary winding 32 of the transformer 3, and current 3 flows from the transformer through the path of winding 32 → diode 42 → transistor 12 → winding 22 → resistor 50 → winding 32. .

This current becomes the base current of the transistor 12, and it satisfies the equal ampere turn law between them.
A relationship of 1 is established.

In other words, even while the current transformer core is being reset, the transistor 12 remains on, and the space current at that time has a value proportional to the load current, and while the magnetic flux of the current transformer core is repeatedly set and reset, the transistor 12 continues to Can be kept on.

When the magnetic flux of the current transformer magnetic core reaches point 6 from point F through B and A while transistor 14 is on, the secondary induced voltage is lost, and it can be seen that the magnetic core saturates in the opposite direction to the above. t4, it is preferable to turn off the transistor 14 at the time t4.

Thereafter, the base current of the transistor 12 flows again along the path of the transistor 12 -> the winding 22 -> the resistor 50 -> the diode 41 -> the transistor 12, and operates in the same manner as at the beginning of this description.

When the P1□ pulse is applied to the gate 17 at point t7, the thyristor 19 turns on and shorts the winding 23, causing the point 51 to turn on.
The voltage becomes zero, the main transistor 12 is turned off, and the load current Ill is commutated to the diode 13 and gradually attenuates as seen in the section t7→t9 of the waveform 11□ in FIG.

Next, the operation of the second base current circuit will be explained.

The diode 44 can be selected from a variety of characteristics depending on the desired HFE characteristics.In the embodiment shown in the force ζ diagram, a diode 44 with characteristics that turns on only when the forward voltage exceeds a predetermined value is used. If the value of Ill in FIG. 2 is still small, the voltage at the terminal 54 is low and the diode 44
remains off, and the ampere turn balance is approximately N1■o.

Medium N2■8.

When Ill increases and the voltage at terminal 54 exceeds a predetermined value, current begins to flow through diode 44.

If the current flowing through the diode 41 is IB2, the current flowing through the diode 44 is IB2, then the base current IB of the main transistor 12 is IB-IB1+IB□, and the balance of the ampere turns is still from terminal 53 to terminal 54 of the winding 22.
If the number of turns up to N3 is approximately N, Io=N2■B1
+N31B2 (IB1+■8□-IB) becomes ■8□=
It will be easily understood that the effective current transformation ratio HFE (HFE=■o/■B) changes compared to the ampere-turn balance N1■o=N2■8 when the current is 0.

FIG. 4 is a graph showing how HFE of the circuit shown in FIG. Changes in values are also shown.

By appropriately selecting the characteristics of the diode 44 and the position of the intermediate terminal 54 within the winding 22, an HFE with characteristics corresponding to hfe can be obtained.

Furthermore, not only one intermediate terminal but also a plurality of intermediate terminals can be provided, and accordingly, in addition to the second base current circuit, a third
．． A fourth base current circuit is provided for hfe and H.
Needless to say, the similarity with FE can be further improved.

The embodiment shown in Fig. 1 shows an example in which specific circuits are used for the current transformer secondary voltage short circuit and the pulse voltage generation source, but various changes may be made to these circuits other than the embodiment shown in Fig. 1. Needless to say, similar designs are possible.

FIG. 5 is a wiring diagram showing another embodiment of the present invention.
In the embodiment shown, the power supply for the pulse voltage generation source is DC power supply 1.
Using a DC power supply 60 separate from 0, the current transformer secondary voltage short circuit consists of a thyristor 19 connected directly between the ends 5L 53 of the first secondary winding 22.

FIG. 6 is a wiring diagram showing another embodiment of the present invention, in which the pulse voltage generation source is mainly the auxiliary transistor 1.
4 and a diode 45, the diode 45 being connected between the emitter of the main transistor 12 and the terminal 53.

When the auxiliary transistor 14 is turned on, the current flows from the positive terminal of the DC power supply 10 → the auxiliary transistor 14 → the winding 23 →
The flow flows from the resistor 50 to the diode 41 to the base of the main transistor 12 to the emitter of the main transistor 12 to the negative terminal of the DC power supply 10, turning on the main transistor 12 and resetting the magnetic flux of the current transformer 2 at the same time.

FIG. 1 is a wiring diagram showing still another embodiment of the present invention, in which the current transformer 2 is replaced by the main transistor
An example is shown in which the device is inserted into the collector side of No. 2.

FIG. 8 is a wiring diagram showing still another embodiment of the present invention, which is different from the embodiment shown in FIG. is thyristor 19
The difference is that the circuit configuration is short-circuited.

As is clear from the above description, according to the present invention, when the current amplification ratio hfe of the transistor changes depending on its collector current, the effective current transformation ratio HFE of the current transformer is automatically changed accordingly, and the collector current of the transistor is A transistor switch device is obtained in which an appropriate base current can always flow through the transistor.

[Brief explanation of drawings]

Fig. 1 is a wiring diagram showing one embodiment of the present invention, and Fig. 2 is a wiring diagram showing an embodiment of the present invention.
Figure 3 is a waveform diagram showing the voltage or current waveforms of the main parts of the circuit; Figure 3 is a graph showing the magnetic hysteresis phenomenon of the current transformer core used in the present invention; is a graph showing changes in the effective current transformation ratio of the current transformer in the circuit of FIG. 1; FIG. 5 is a wiring diagram showing another embodiment of the invention, FIG. 6 is a wiring diagram showing still another embodiment of the invention, and FIG. 7 is a wiring diagram showing still another embodiment of the invention. FIG. 8 is a wiring diagram showing another embodiment of the present invention. In the figure, 2 is a current transformer, 21 is the primary winding of the current transformer, 22
is the first secondary winding of the current transformer, 23 is the second secondary winding of the current transformer, 3 is the transformer, 31 is the primary winding of the transformer, 32 is the secondary winding of the transformer , 10 is a DC power supply, 11 is a load, 12 is a main transistor, 13 is a diode, 14 is an auxiliary transistor, 19 is a thyristor, 4L 42, 43, 44
゜45 is a diode, 50 is a resistor, 51゜53
are both terminals of the winding 22, 54 is an intermediate terminal of the winding 22, and 52 is a contact point between the resistor 50 and the diode 41. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A series circuit of a DC power supply, a load, a main transistor, and a primary winding of a current transformer, and a series circuit of a resistor and a diode connected to both ends of the first secondary winding of the current transformer. A first base current circuit of the main transistor configured by connecting the base of the main transistor to the emitter through the base of the main transistor through a diode from at least one intermediate terminal of the first secondary winding. or a second base current circuit of the main transistor connected to the emitter,
a pulse voltage generation source connected in parallel to the first base current circuit of the main transistor and applying a pulse voltage to the series circuit of the first secondary winding and the base of the main transistor; A transistor switch device characterized in that it is equipped with a current transformer secondary voltage short circuit that effectively shorts the voltage at both ends of the winding. 2. The transistor switch device according to claim 1, wherein the current transformer secondary voltage short circuit comprises a thyristor switch device that shorts the second secondary winding of the current transformer. , 3 The current transformer secondary voltage short circuit is the first voltage short circuit of the current transformer.
2. The transistor switch device according to claim 1, further comprising a thyristor switch device for short-circuiting a secondary winding of the transistor switch device. 4. One output terminal of the pulse voltage generation source is connected to the base of the Doi main transistor via a diode node, and the other output terminal is connected to the connection point between the resistor and the diode of the first base current circuit of the main transistor. A transistor switch device according to claim 1, characterized in that: 55 The pulse voltage generation source has an auxiliary transistor whose collector is connected to the positive terminal of the DC power supply, and the emitter of the main transistor is connected to one terminal of the first secondary winding and the emitter of the auxiliary transistor via a diode. Claim 1 characterized in that the first claim is connected to the connection point with
Transistor switch device as described in . 6 One output terminal of the pulse voltage generation source is connected to one terminal of the first secondary winding through a diode, and the other output terminal is connected to the resistance of the first base current circuit of the main transistor 1. Claim 1, characterized in that the first secondary winding is connected to a connection point with a diode, and the other terminal of the first secondary winding is connected to the base of the main transistor.
Transistor switch device as described in .