JPS62207023A - Semiconductor switch - Google Patents

Abstract

PURPOSE:To detect properly the on/off state of a main current even when a main current switch is in any operating potential to a control power supply by detecting the on/off state of the main current by a current flowing respectively into the 1st detection terminal or not of the 2nd detection termonal. CONSTITUTION:When a PNPN switch 1 is in the on-state and a potential of an anode terminal A is higher than an earth potential of the control side, the 1st detection transistor (TR) Q4 is active and the on-detection current flows from the 1st detection terminal C1. When a potential of a cathode terminal K is lower than the control power supply V2, the 2nd detection TR Q5 is active and the ON-detection current flows to the 2nd detection terminal C2. The flowing current from the 1st and 2nd detection terminals C1, C2 acts like flowing itself to the sensing resistor R3 and the on/off state of the PNPN switch 1 is detected depending on the presence of the current flowing to the sensing resistor R3.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a semiconductor switch including a main current switch such as a PNPN switch, and particularly to a semiconductor switch including a main current switch such as a PNPN switch. This invention relates to a semiconductor switch that can accurately detect on/off states.

[Background of the invention]

Traditionally, semiconductor switches such as PNPN switches have advantages over transistor switches, such as being able to obtain high breakdown voltage in both directions, lower on-resistance, and lower on-voltage even when a large current is applied. However, since it has a self-holding function, it also has the disadvantage that when used as an on/off switch, the off control is relatively distant. In order to turn off such a PNPN switch without changing the load current, there are two methods: temporarily shorting the gate and cand to temporarily increase the holding current and making it impossible to hold the load current, and applying a reverse current to the gate. There are two methods for turning off the power supply, and the method to use depends on the current cutting ability and external circuit conditions.

In an on/off switch including a main current switch such as a PNPN switch configured using the above method, it may be necessary to detect the on/off state of the main current switch. For example, when a current selection switch is configured with two on/off switches using PNPN switches, first one switch is turned off in a pulsed manner, and then the other switch is turned on in a pulsed manner. When trying to switch the load current, there are cases where the switch that has been driven off does not completely turn off before the other switch turns on, and two switches remain on at the same time. This is a malfunction phenomenon caused by the self-holding function of the PNPN switch and the fact that the turn-off time is generally longer than the turn-on time.1. In order to prevent this, it is necessary to provide the switch with an on/off state detection function and synchronize it with the off drive. In addition, in order to reduce power consumption, there are cases where a function is required to stop the OFF drive after the switch is turned off, but in this case, if the switch is not reliably turned OFF and the OFF drive is not stopped, the ON state will be stopped. Not satisfied with off function.

A conventional method for detecting the on/off state of this type of PNPN switch is to detect the inflow current of a detection NPN transistor connected in parallel with the NPN section of the PNPN switch, as shown in Japanese Patent Application Laid-open No. 59-17861. A method is known in which the on/off state is detected based on the presence or absence.

However, this conventional method is effective only when the operating potential of the switch is lower than the control power supply, and when the operating potential is higher, the detection transistor cannot operate and the detection function is not satisfied.

[Purpose of the invention]

An object of the present invention is to provide a semiconductor switch that can accurately detect the on/off state of the main current no matter what operating potential the main current switch has with respect to the control power supply.

[Summary of the invention]

In order to achieve the above object, the present invention provides a main current switch circuit including a main current switch such as a PNPN switch with a current outflow type first main current on/off detection means and its detection terminal, and a current inflow type first main current on/off detection means and its detection terminal. This semiconductor switch is equipped with a second main current on/off detection means and its detection terminal, and is configured to be able to accurately detect the on/off state of the main current regardless of the operating potential of the main current switch.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a circuit diagram showing a first embodiment of a semiconductor switch according to the present invention. In Figure 1, 1 is PNPN
A switch (main current switch), 2 is a turn-off switch circuit, and 3 is a main current switch circuit. Ql and C2 are PNP transistors and NPN transistors of the PNP section and NPN section that equivalently constitute the 4-terminal PNPN switch 1, and C3 is the NPN transistor that constitutes the turn-off switch circuit 2.
PN transistors C4 and C5 constitute the main current switch circuit 3. The second on/off detection transistor R1 is a resistor for preventing malfunction due to the dtt/dt effect of the PNPN switch 1. Vl and R2 are respectively a load power supply and a resistor, DI and D2 are reverse current prevention diodes, C6 is a current conversion transistor, and V2. R3 is a control power supply and a detection resistor, respectively. Also, A and C have an anode terminal and a cathode terminal, respectively, G has a gate terminal, and CI
, C2 is the first. The second detection terminal B is an off control terminal.

The semiconductor switch in Fig. 1 has an anode terminal A and a cathode terminal for the main electrodes of a PNPN switch (main current switch) 1, a gate terminal G for on control, and a current outflow type first main current on/off detection terminal. means (in this case, the detection transistor Q4) and the first detection terminal C1, and a current inflow type second main current on/off detection means (in this case, the detection transistor Q5) and the second detection terminal C2.
The turn-off switch circuit 2 is connected between the gate terminal G and the cathode terminal of the main current switch circuit 3 and has a turn-off control terminal B. )1
The on/off state of the above 1. Second detection terminal (1,
The configuration is such that the detection resistor R3 detects the current flowing in and out from C2. Moreover, the main current switch circuit 3 is PNPN.
Switch 1 and PNP transistors Q1 and N of the PNP part and NPN part that equivalently constitute this PNPN switch 1
The first . consisting of a second detection transistor; The collectors of the second detection transistors are respectively connected to the first and second detection transistors. Second detection terminal C
The turn-off switch circuit 2 consists of an NPN transistor Q3, which is connected to I and C2.
The base of transistor Q3 is connected to the off control terminal B.

In this circuit configuration, first, P of the main current switch circuit 3
Turn-on control of the NPN switch (main current switch) 1 is performed by supplying an on-drive current from the gate terminal G, and at this time, equivalently, the transistors Q1. The PNPN switch 1 constituted by Q2 is turned on, and the main current determined by the load 111tV1 of the external circuit and the resistor R2 flows from the anode terminal A to the cathode terminal. At the same time, transistor Q1 of PNPN switch 1. The emitter and base of Q2 are connected to the first . Second detection transistor Q4. Is Q5 also in the on state depending on the operating potential of PNPN switch 1? A current flows out or flows in from PJ1 or the second detection terminal C1 or C2, and the diode D1D2. An on-detection signal current determined by the control power supply v2 and the resistor R3 flows through the detection resistor R3 via the transistor Q6. Next, off control is performed by flowing an off drive current into the off control terminal B, and at this time, the transistor Q3 of the turn-off switch circuit 2 is turned on, and the voltage between the gate terminal G and the cathode terminal of the PNPN switch 1 is turned on. That is, by short-circuiting the base and emitter of the transistor Q2, the holding current value of the PNPN switch 1 is increased, and the main current flowing from the anode terminal A to the cathode terminal K is turned off. At the same time, the first. Since the second detection transistor Q41Q5 is also turned off, the first detection transistor Q41Q5 is also turned off. The on-detection signal current flowing through the detection resistor R3 is also turned off due to the outflow or inflow current from the second detection terminal C1 or C2.

Here, the on/off state detection of the main current is performed using the main current P.
The first . Second detection transistor Q41Q5
This is determined by the presence or absence of the collector current. First, PNPN
When switch 1 is in the on state, the potential of anode terminal A is approximately 2 × VEI (
(base-emitter voltage), the first detection transistor Q4 becomes active, and an on-detection current flows out from the first detection terminal C1 connected to its collector. Further, when the potential at the cathode terminal is lower than approximately 3×N'BK with respect to the control power supply v2, the second detection transistor Q5 becomes active and the second detection terminal C2 connected to its collector becomes active. Heon detection current flows. The first of these. Second detection terminal CI.

Both the currents flowing in and out of C2 act to flow the current into the detection resistor R3, and the current flows into the detection resistor R3. The on/off operation of the second detection transistors Q4 and C5 is performed by the PNPN switch 1.
Since the detection resistor R3 is synchronized with the on/off operation of
The on/off state of the PNPN switch 1 can be detected by the presence or absence of current flowing through the switch. And number one. One or both of the second detection transistors Q4tQ5 becomes active depending on the operating potential of the PNPN switch 1, and they operate to complement each other, so it is recommended to connect the reverse current prevention diodes DI and D2. First. There is no adverse effect due to reverse current to the second detection terminal C1C2, and no matter what operating potential the PNPN switch (main current switch) 1 has with respect to the control power supply v2, the on/off state of the main current can be controlled. Can be detected accurately.

FIG. 2 is a circuit diagram showing a second embodiment of the semiconductor switch according to the present invention. In FIG. 2, the same reference numerals or symbols indicate the same or corresponding parts throughout the drawings, and C7 is P that constitutes the turn-off switch circuit 2.
NP transistor, B2 is the second off control terminal, G2
is the second gate terminal of the main current switch circuit 3. The semiconductor switch shown in FIG. 2 has a PNP transistor Q7 having a second off control terminal B2 added to the turn-off switch circuit 2 of the circuit mt shown in FIG. This is an embodiment in which a gate terminal) G2 is provided to enable on/off operation even when the PNPN switch (main current switch) 1 is in the completely positive direction with respect to the control power supply v2, and the main current switch circuit 3 connects the cathode gate terminal and anode gate terminal of the PNPN switch 1 to the first . The turn-off switch circuit 2 includes an NPN transistor Q3 and a PNP transistor Q.
7 parallel circuits, two transistors Q3tQ7
The base terminals of are the first and second off control terminals B, respectively.
1, B2.

Note that external circuits similar to those in FIG. 1 are omitted.

In this circuit configuration, its operation is almost the same as that shown in FIG. The PNPN switch 1 can be controlled to be turned on by drawing an on-drive current from the terminal (terminal) G2, and can be controlled to be turned off by drawing an off-drive current from the second off-control terminal B2. 1゜The operation of the second detection transistor Q' + Qs is the same as that shown in Fig. 1, and no matter what operating potential the PNPN switch 1 is at, it seamlessly detects the on/off state of its main current. can. Note that it is also possible to configure a 1-AC on/off switch by connecting the semiconductor switches shown in FIG. 2 in antiparallel.

FIG. 3 is a circuit configuration showing a third embodiment of a semiconductor switch according to the present invention. In FIG. 6, C8tQ9 is the first current shunt. This is the second transistor. The cow conductor switch shown in FIG. 3 has a main current switch circuit 3 having the circuit configuration shown in FIG. Second transistor Q a
t Q9 is added to further increase the current cutting ability as a semiconductor switch, and the main current switch circuit 3 is a PNPN switch (main current switch).
1, a first and second transistor Q8 for current shunting,
Q9 and 1st. Second detection transistor Q4. Q5, one main electrode of the PNPN switch 1 is the first
is connected to the emitter of the current shunting transistor Q8,
The other main electrode is connected to the base of the second current dividing transistor Q9, and the base and collector of the first current dividing transistor Q8 are respectively connected to the collector and emitter of the second current dividing transistor. .

In this circuit configuration, on-control is performed by supplying an on-drive current from the gate terminal G, as in FIG. The main current flows from A to the cathode terminal. At the same time, the first. Second detection transistor Q4. Since Q5 is also in the on state, the first. A current (ON detection current) flows through the second detection terminal C1 or C2. Next, OFF control is performed by flowing an OFF drive current from the OFF control terminal B in the same way as in FIG. Transistor Q8. Q9 turns off, turning off the main current flowing from the anode terminal A to the cathode terminal. In the embodiment shown in FIG. 3, the main current is divided into the PNPN switch 1 and the current shunting transistors Q8tQ9, so that the semiconductor switch has a greater current cutting ability than that shown in FIG. In addition, the first switch is capable of detecting the on/off state regardless of the operating potential of the PNPN switch 1.
It is similar to the figure. However, especially regarding the time for detecting the off state, there is a tendency for an error to occur in the turn-off time by the current shunting transistor Q81Q9. The following embodiment shown in FIG. 4 improves this point.

FIG. 4 is a circuit diagram showing a fourth embodiment of the semiconductor switch according to the present invention. In FIG. 4, Q10. Ql
1.l constitutes the main current switch circuit 3. This is a second on/off detection transistor. The cow conductor switch of FIG. 4 is the first conductor switch of the main current switch circuit 3 of FIG. Second detection transistor Q4. Change the connection point of Q5 and connect it to the 1st. The first current shunting transistors Q8 and Q9 are connected in parallel with each other. Second detection transistor Q10. Ql
This is an embodiment in which the main current switch circuit 3 is connected to
is a PNPN switch 1 and a first . A second transistor Q8tQ9 and a first transistor Q8tQ9 that detects the on/off state of the main current. Second detection transistor Q10jQ11
, one of the above-mentioned PNPN switches 1.

The main electrode of is connected to the emitter of the first current shunting transistor Q8, the other main electrode is connected to the base of the second current shunting transistor Q9, and the base of the first current shunting transistor Q8, The collectors are connected to the collector and emitter of the second current shunting transistor Q9, respectively, and the collectors are connected to the collector and emitter of the second current shunting transistor Q9, and the first detection transistor Q1
The emitter and base of Q0 are connected to the emitter and base of the first current shunting transistor Q8, respectively, and the emitter and base of the
The emitter and base of the detection transistor Q11 are connected to the emitter and base of the second current shunting transistor Q9, respectively, and the first and second detection transistors Q11 are connected to the emitter and base of the second current shunting transistor Q9, respectively. Second detection transistor Q10. The collectors of Qil are connected to first and second detection terminals CI and C2, respectively.

In this circuit configuration, the operation is almost the same as that in FIG. 3, but the detection of the on/off state of the main current is performed by the current shunting transistor Q8, which is finally turned off during off control. Q
9 emitters and paces, and their emitters and bases are connected in common. Second detection transistor Q10
The first question is whether there is current flowing into or out of the collector of 9Qll.
Since the detection is performed using the second detection terminals CI and C2, the on/off state of the main current can be detected more accurately. Further, no matter what operating potential the PNPN switch 1 is at, the on/off state can be accurately detected in the same way, and the current cutting ability is also increased.

In addition, in the above embodiment, the PNPN switch (main current switch) 1 of the main current switch circuit 3 is not limited to a PNPN switch. It goes without saying that improvements could be made, such as connecting resistors to the emitters of the detection transistors Q4t, Q5, QiO, Qll, etc. to prevent the current hogging phenomenon.

〔Effect of the invention〕

As explained above, according to the present invention, the main current switch circuit including a main current switch such as a PNPN switch includes a current sending/outflow type first detection means and a detection terminal and a current inflow type second detection means. By detecting the on/off state of the main current from the detection means and detection terminal, we have created a semiconductor switch with excellent on/off detection characteristics that can accurately detect whatever operating potential the main current switch is at. Can be provided.

[Brief explanation of drawings]

1, 2, 5, and 4 respectively show a first embodiment of a semiconductor switch according to the present invention. 21 is a circuit configuration diagram showing third and fourth embodiments; FIG. 1...PNPN switch (main current switch), 2...
- Turn-off switch circuit, 3... Main current switch circuit, Ql, Q2... PNPN switch configuration transistor, Q3. Q7...Turn-off transistor,
Q4. Q5. Q10. Qll...Detection transistor (detection means), Q8, Q9...Current shunting transistor, A...Main +, 11/Representative Patent Attorney Katsuo Ogawa Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. An anode terminal and a cathode terminal for the main electrode of the main current switch, a gate terminal for on control, a current drain type first main current on/off detection means and its detection terminal; , a main current switch circuit including a current inflow type second main current on/off detection means and its detection terminal, and a main current switch circuit connected between the on control gate terminal and the cathode terminal of the main current switch circuit and off control. and a turn-off switch circuit equipped with a terminal for detection, and configured to detect the on/off state of the main current by the current flowing out or flowing in from the first detection terminal or the second detection terminal, respectively. A semiconductor switch featuring: 2. The main current switch circuit mentioned above is P which forms the main current switch.
It consists of an NPN switch, and first and second detection transistors whose emitters and bases are connected to the emitters and bases of the PNP and NPN parts, respectively, which equivalently constitute the PNPN switch. The collectors of the detection transistors are connected to the first and second detection terminals, and the turn-off switch circuit is composed of an NPN transistor, and the base of the NPN transistor is connected to the OFF control terminal. A semiconductor switch according to claim 1. 3. The PNPN switch of the main current switch circuit has a cathode gate and an anode gate as the on-control terminal and the second on-control terminal, respectively, and the turn-off switch circuit has a PNP transistor in parallel with the NPN transistor. 3. The semiconductor switch according to claim 2, further comprising a base terminal of the PNP transistor serving as a second off control terminal. 4. The main current switch circuit has two main current switch circuits, a first and a second switch for current shunting.
one main electrode of the PNPN switch is connected to the emitter of the first transistor, the other main electrode is connected to the base of the second transistor, and the base of the first transistor is connected to the base of the first transistor. ,
3. The semiconductor switch according to claim 2, wherein the collector is connected to the collector and emitter of the second transistor, respectively. 5. The main current switch circuit mentioned above is P which forms the main current switch.
It consists of an NPN switch, a first and second transistor for current shunting, and second and third detection transistors, one main electrode of the PNPN switch is connected to the emitter of the first transistor, and the other main electrode is connected to the emitter of the first transistor. The main electrode is connected to the base of the second transistor, and the main electrode is connected to the base of the second transistor.
The base and collector of the transistor are respectively
The emitter and base of the first detection transistor are connected to the emitter and base of the first transistor, respectively, and the emitter and base of the second detection transistor are connected to the emitter and base of the first transistor, respectively. The semiconductor according to claim 1, wherein the semiconductor is connected to the emitter and base of the second transistor, and the collectors of the first and second detection transistors are connected to the first and second detection terminals, respectively. switch.