DE102014109142B4 - Circuit with efficient switch - Google Patents

Abstract

Comprising circuit
a series connection comprising a p-type semiconductor switch (T1) and a further component (D1),
- A control circuit (T2, R7, R1, R3-R6), wherein the control circuit of a voltage which drops at the series circuit (T1, D1), supplied and is arranged such that the p-type semiconductor switch (T1) in remains in standby mode until a current through the p-type semiconductor (T1) reaches and / or exceeds a predetermined threshold,
- Wherein the p-type semiconductor switch in a standby mode is conductive, and
- The p-type semiconductor switch (T1) remains self-locking off after the current through the p-type semiconductor (T1) has reached and / or exceeded the predetermined threshold.

Description

The invention relates to a circuit with an efficient switch, an electronic switch for a terminal circuit in a motor vehicle and a motor vehicle with at least one such switch.

DE102010000161A1 relates to an overvoltage protection circuit.

It is known to power semiconductors, in particular transistors, e.g. IGBTs, MOSFETs, JFETs, etc. for switching loads (loads), e.g. in a vehicle electrical system. For example, such power semiconductors are used as so-called high-side switches in a current-carrying connection to a load.

However, in the automotive sector, a connection or disconnection of the terminal 30 (ie positive lead directly from the battery) by means of a relay. The use of the relay in this case basically has the disadvantage of mechanical stress and thus the compared to a power semiconductor significantly reduced life. Also, it comes in the switching operations of the relay to noise and the control of the relay leads to switching losses.

If a normally open relay (also referred to as normally open relay) is used, the relay is closed in the active state (ie when current flows through the coil of the relay). In this case, the closed relay in active operation does not lead to the discharge of the battery of a motor vehicle, because it is recharged via the generator of the motor vehicle.

If, however, the generator is not active, because the motor vehicle has been turned off (standby state) and the engine is not running, it is problematic to provide consumers of the motor vehicle with energy by means of a working current relay, because in this case, the working current relay itself permanently electric Consumes energy and thus discharges the battery. Increasingly, however, even in the standby state of the motor vehicle different consumers (at least temporarily), e.g. an access system for keyless access to the motor vehicle or for a radio key or an electric parking brake to be powered.

The object of the invention is to avoid the above-mentioned disadvantages and in particular to provide a possibility according to which a (semiconductor) switch should be activatable without requiring a (significant) drive current. Furthermore, it is an object to provide an overcurrent shutdown to protect the semiconductor switch and to protect a line, this overcurrent shutdown does not need (significant) drive current.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims.

• - eine Reihenschaltung umfassend einen p-Typ Halbleiter und ein weiteres Bauelement,
• - eine Regelschaltung, wobei sich die Regelschaltung aus einer Spannung, die an der Reihenschaltung abfällt, versorgt.

To solve the problem, a circuit is proposed comprising

• a series circuit comprising a p-type semiconductor and another component,
• - A control circuit, wherein the control circuit of a voltage which drops at the series circuit supplied.

Due to the p-type semiconductor, the present circuit makes it possible for it to remain switched on (almost) without loss by means of the control circuit and is therefore particularly suitable for supplying electrical power to connected consumers. On the other hand, the control circuit makes it possible to automatically switch off this p-type semiconductor when the current of the p-type semiconductor increases by a predetermined threshold. Thus, the p-type semiconductor is suitable for a power-efficient supply to consumers, while also ensuring that in an overload situation (current exceeds threshold), the p-type semiconductor is protected from damage.

In particular, the control circuit has at least one input, by means of which the p-type semiconductor can be switched to be conductive or non-conductive. Such inputs may be used, for example, by a control circuit (e.g., in the form of a microcontroller).

A further development is that the control circuit is set up such that the p-type semiconductor remains switched on in a standby mode until a current through the p-type semiconductor leads to and / or exceeds a predetermined threshold value.

Another development is that the control circuit is set up in such a way that the p-type semiconductor remains switched off in a self-locking manner after the current through the p-type semiconductor has reached and / or exceeded the predetermined threshold.

• - eine Diode,
• - eine Schottky-Diode,
• - eine Zener-Diode,
• - einen ohmschen Widerstand.

In particular, it is a development that the further component comprises at least one of the following:

• - a diode,
• a Schottky diode,
• a Zener diode,
• - an ohmic resistance.

It is also a development that the series connection on the side of the p-type semiconductor is connected to a power line.

The power line is, for example, a line to a positive pole (positive line) of a power supply, such as a generator or a battery (eg a terminal 30 a motor vehicle).

Furthermore, it is a further development that the series connection on the side of the further component is connected to a line to a consumer.

The consumer may be any consumer, e.g. of a motor vehicle, e.g. during a standby mode has a reduced power requirement.

• - einen Halbleiterschalter,
• - einen Leistungshalbleiterschalter,
• - einen Transistor,
• - einen MOSFET,
• - einen PMOS,
• - einen IGBT,
• - einen JFET.

In an additional development, the p-type semiconductor comprises at least one of the following semiconductors:

• a semiconductor switch,
• a power semiconductor switch,
• a transistor,
• a MOSFET,
• a PMOS,
• - an IGBT,
• - a JFET.

A next development is that the control circuit is arranged parallel to the series circuit of p-type semiconductor and further component.

An embodiment is that the control circuit has a semiconductor switch whose operating point can be set via a resistance network comprising at least one resistor.

An alternative embodiment is that the semiconductor switch is a transistor, in particular a bipolar transistor, e.g. a pnp transistor, wherein the resistor network is dimensioned such that the semiconductor switch becomes conductive when the voltage drop across the series circuit of p-type semiconductor and further device is greater than a predetermined threshold, as a result, the p-type semiconductor is controlled so that it turns off self-holding.

A next embodiment is that the control circuit comprises a temperature compensation circuit.

The temperature compensation circuit may be e.g. a resistor network comprising at least one temperature-dependent resistor. The temperature compensation circuit may be e.g. be arranged between the base and emitter (or between the source and gate or between the gate and emitter) of the semiconductor switch. As a result, in particular the temperature dependence of the voltage drop is at least partially compensated.

It is also an embodiment that the circuit comprises a detection circuit which is arranged parallel to the series circuit of p-type semiconductor and further component.

By means of the detection circuit, it is possible to detect when a current through the p-type semiconductor reaches or exceeds a predetermined threshold value. In this case, the detection circuit may provide a trigger signal by which, for example, a control circuit (e.g., a microcontroller) is activated that activates a power switch having a high current carrying capacity.

• - der p-Typ-Halbleiterschalter selbsthemmend abschaltet (im Fall der Regelschaltung, indem der Halbleiterschalter der Regelschaltung den p-Typ-Halbleiter entsprechend ansteuert) oder
• - ein entsprechendes Triggersignal (im Fall der Detektionsschaltung) z.B. dem Mikrocontroller bereitgestellt wird.

The detection circuit may be constructed similarly to the control circuit. Also, the detection circuit may include a temperature compensation circuit. By suitable dimensioning of the resistance network for the control circuit or the detection circuit can be ensured that from certain current values through the p-type semiconductor switch

• - The p-type semiconductor switch switches off self-locking (in the case of the control circuit by the semiconductor switch of the control circuit drives the p-type semiconductor accordingly) or
• - A corresponding trigger signal (in the case of the detection circuit), for example, the microcontroller is provided.

Advantageously, different current values are used for switching off the p-type semiconductor on the one hand and for the trigger signal on the other hand.

Optionally, a plurality of detection circuits can also be provided, which, depending on the current value (for example, determined by the wiring of a respective semiconductor switch), have differently dimensioned resistor networks.

A further development consists in that the circuit has a control circuit, by means of which the circuit can be controlled, so that the p-type semiconductor is switched either conductive or non-conductive.

The control circuit may have, for example, at least one microcontroller.

An additional embodiment is that the p-type semiconductor is conductive in a standby mode.

Another embodiment is that the standby mode is a standby mode of a system having multiple consumers, the circuit providing electrical power to at least one of the consumers in standby mode of the system.

Also, it is a possibility that the system includes an electric system in a motor vehicle.

The above object is also achieved by an electronic switch for a terminal circuit in a motor vehicle comprising at least one circuit as described herein.

Furthermore, the above object is achieved by means of a motor vehicle with at least one electronic switch according to the present embodiments.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following schematic description of exemplary embodiments which will be described in detail in conjunction with the drawings. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

• 1 ein schematisches Blockschaltbild zur Realisierung ruhestromfreier elektronischer Schalter für eine Klemmenschaltung in einem Kraftfahrzeug;
• 2 einen beispielhaften schematischen Aufbau des Schalters für einen Verbraucher umfassend einen p-Typ Halbleiter mit einer in Reihe geschalteten Schottky Diode, wobei parallel zu dieser Reihenschaltung eine Regelschaltung umfassend einen pnp-Transistor angeordnet ist;
• 3 eine Ergänzung der in 2 gezeigten Schaltungsanordnung zusätzlich umfassend einen weiteren pnp-Transistor zum Detektieren eines zusätzlichen Stromwerts durch den p-Typ Halbleiter.

Show it:

• 1 a schematic block diagram for the realization of quiescent-free electronic switch for a terminal circuit in a motor vehicle;
• 2 an exemplary schematic structure of the switch for a consumer comprising a p-type semiconductor with a Schottky diode connected in series, wherein parallel to this series circuit, a control circuit comprising a pnp transistor is arranged;
• 3 an addition to the 2 additionally comprising a further pnp transistor for detecting an additional current value by the p-type semiconductor.

The approach proposed herein uses, for example, a p-type semiconductor, for the driving of which no charge pump is required and which can thus be driven without power or current. In particular, an overcurrent shutdown for the protection of the semiconductor and a possibly connected line is proposed, which does not require a (significant) quiescent current.

The p-type semiconductor is, for example, a semiconductor switch, in particular a power semiconductor switch, a transistor, a MOSFET, an IGBT, a JFET or the like. In particular, a circuit arrangement may be provided which comprises at least one of the aforementioned components.

1 shows a schematic block diagram for implementing quiescent-free electronic switch for a terminal circuit in a motor vehicle.

the clamp 30 (Connection with the plus line of the battery of the motor vehicle) is via a semiconductor switch 101 with a consumer 102 , via a semiconductor switch 103 with a consumer 104 and via a semiconductor switch 105 with a consumer 106 connected.

The semiconductor switches 101 . 103 and 105 are preferably designed as low-resistance semiconductor switches (eg as field-effect transistors (FETs) or FET stages) and are designed for high currents (eg 50 A in the case of an electronic parking brake as a consumer).

If the motor vehicle is put into a standby mode, the semiconductor switches 101 . 103 and 105 switched off, since they have a relatively high operating current or drive current and otherwise permanently load and unload the battery. The standby mode may, for example, be a mode in which the motor and / or the generator of the motor vehicle is not active. Also, the standby mode may be active as soon as a predetermined period of time has elapsed after the motor vehicle has been parked. In principle, it is possible to adopt the standby mode when the motor vehicle is parked for an unforeseeable duration and / or when no electrical energy source is connected or active except for the battery of the motor vehicle.

In standby mode, a switch will appear 107 activated. The desk 107 is preferably designed so that it is normally switched on (ie in the case in which it requires no or only a very small drive current) (also referred to as "normally-on"). The desk 107 is from the terminal 30 supplied with electrical energy and supplies in the activated state electrical energy to the consumer 102 . 104 and 106 ,

Exemplary is the switch 107 in 1 each via a diode 108 to 110 with the consumers 102 . 104 and 106 connected, so that consumers 102 . 104 and 106 over the diodes 108 to 110 decoupled can be supplied individually with electrical energy.

It should be mentioned that at least one consumer via the switch 107 can be supplied.

There is also a microcontroller 111 provided the semiconductor switch 101 . 103 and 105 controls (see the dedicated control lines 112 to 114 ). The microcontroller 111 in particular, the semiconductor switch 101 . 103 and 105 eg when entering standby mode and switch on when leaving standby mode.

Furthermore, optional (at least) one control line 115 provided by which the microcontroller 111 the switch 107 (eg depending on the standby mode) activated or deactivated.

2 shows an exemplary schematic structure of the switch 107 with one of the diodes 108 to 110 , wherein the diode in 2 exemplified as a Schottky diode D1 is shown. The switch in 2 has a single output, eg at a node 204 that has a line resistance R8 with a load R10 is coupled. Weight R10 for example, corresponds to one of the consumers 102 . 104 or 106 and the power resistance R8 corresponds to the resistance of a line to this consumer.

A connection 201 is with the clamp 30 connected. The connection 201 is connected to the source terminal of a p-channel MOSFET T1 connected. The connection 201 is connected to the emitter of a pnp transistor T2. The emitter of the transistor T2 is via a series circuit of resistors R5 and R6 connected to its base. Parallel to the series connection of the resistors R5 and R6 is a resistance R4 arranged.

The gate terminal of the MOSFET T1 is about a resistance R3 connected to ground. Furthermore, the gate terminal of the MOSFET T1 about a resistance R2 with a connection 202 connected. Also, the gate terminal of the MOSFET T1 about a resistance R1 with the collector of the transistor T2 connected.

The drain terminal of the MOSFET T1 is via the Schottky diode D1 with the node 204 connected, wherein the cathode of the diode D1 in the direction of the knot 204 shows. The knot 204 is about the resistance R8 (Line resistance) with the load R10 connected. The knot 204 is still over a resistance R7 with the base of the transistor T2 connected. The base of the transistor T2 is about a resistance R9 with a connection 203 connected.

The connection 202 is connected to a control line, by means of which the switch 107 (in particular the MOSFET T1 ) can be activated (by applying a logic "0" signal (eg 0V) to the control line). The connection 203 is connected to a control line, by means of which the switch 107 (in particular the MOSFET T1 ) can be switched off (by placing a logic "0" signal (eg 0V) on the control line). Based on the connections 202 and 203 can thus the switch 107 be switched on or off. This can for example be based on the microcontroller 111 done (in 1 indicated schematically by the control line 115 , this control line can also have several control lines).

The MOSFET T1 is with the Schottky diode D1 connected in series. The Schottky diode D1 serves on the one hand as a reverse polarity protection and on the other hand to decouple several outputs of the switch 107 (in 2 is exemplary based on the node 204 a single output of the switch 107 shown).

A voltage drop across the MOSFET T1 and over the diode D1 becomes the emitter base of the transistor T2 fed. For example, if the voltage dropped there is more than 0.7V (temperature dependent), then the base is 0.7V more negative than the emitter of the transistor T2 so the transistor turns on T2 through and as a result the MOSFET T1 self-holding off.

Locks, however, the transistor T2 so is on the mosfet T1 the gate voltage U _G smaller than the source voltage U _S and the MOSFET T1 is conductive.

Optionally, the resistors can be used for temperature compensation R4 to R6 be provided, the resistance R5 can be designed as an NTC resistor. Thus, the temperature dependence of the MOSFET T1 as well as the diode D1 decreasing voltage (at least partially) can be compensated.

The transistor T2 along with the resistance R7 and the operating point circuit (including, for example, the resistors R4 to R6 ) of the transistor T2 So form an analog control circuit for overcurrent limiting. This is adjustable from which current the transistor T2 turns on and in succession the MOSFET T1 locks.

3 shows a supplement of in 2 circuit shown additionally comprising a pnp transistor T3 whose emitter is connected to the terminal 201 connected is. The emitter of the transistor T3 is via a series circuit of resistors R13 and R14 connected to its base. Parallel to the series connection of the resistors R13 and R14 is a resistance R12 arranged. The base of the transistor T3 is about a resistance R15 with the node 204 connected. The collector of the transistor T3 is about a resistance R11 with a connection 301 connected. The connection 301 provides, for example, a trigger signal for the microcontroller 111 (see 1 ), by means of which the microcontroller can be woken up.

For temperature compensation, the resistors R12 to R14 provided, the resistance R13 can be designed as an NTC resistor. Thus, the temperature dependence of the control loop comprising the transistor T3 (at least partially) be compensated.

The control loop can be controlled by means of the resistor R15 and the operating point circuit comprising the resistors R12 to R14 be set such that when a threshold value of a current through the MOSFET T1 a signal at the port 301 by means of which (eg, at a current load of 1A) the microcontroller is provided 111 can be woken up, then the semiconductor switch 101 . 103 and 105 too active and possibly the switch 107 over with the connection 203 disable connected control line. Thus, it can be detected automatically if the connected consumer has a high power consumption, via one of the semiconductor switches 101 . 103 and 105 should be provided.

Accordingly, for example, when stopping the motor vehicle, the microcontroller 111 the semiconductor switches 101 . 103 and 105 turn off (lock) and the switch 107 by means of the connection 202 Activate connected control line. In standby mode, the switch is required 107 no (significant) current and the (power) semiconductor switch 101 . 103 and 105 are disabled, so that the load on the battery, for example, when a parked motor vehicle, is significantly reduced.

The following is an example of a dimensioning of in 2 and 3 R1 = 1kOhm, R2 = 5kOhm, R3 = 95kOhm, R4 = 14kOhm, R5 = 27kOhm (NTC), R6 = 47kOhm, R7 = 20kOhm, R8 = 1mOhm, R9 = 1kOhm, R10 = 0,5Ohm, R11 = 1kOhm, R12 = 14kOhm, R13 = 27kOhm (NTC), R14 = 87kOhm, R15 = 20kOhm.

In particular, it is an advantage of the solution presented here that there are no heavy, expensive and large bistable relays for connecting the terminal 30 needed. Instead, an efficient electronic overload switch with overcurrent protection is used, which has no (significant) quiescent power requirement.

While the invention has been further illustrated and described in detail by the at least one embodiment shown, the invention is not so limited and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

101

Semiconductor switches

102

consumer

103

Semiconductor switches

104

consumer

105

Semiconductor switches

106

consumer

107

switch

108

diode

109

diode

110

diode

111

microcontroller

112

control line

113

control line

114

control line

115

control line

201

Connection (eg connected with terminal 30 )

202

connection

203

connection

204

node

301

Connection (trigger signal)

T1

p-channel MOSFET

T2

PNP transistor

T3

PNP transistor

D1

Schottky diode

R1-R15

resistance

Claims (14)

Comprising circuit a series connection comprising a p-type semiconductor switch (T1) and a further component (D1), - A control circuit (T2, R7, R1, R3-R6), wherein the control circuit of a voltage which drops at the series circuit (T1, D1), supplied and is arranged such that the p-type semiconductor switch (T1) in remains in standby mode until a current through the p-type semiconductor (T1) reaches and / or exceeds a predetermined threshold, - Wherein the p-type semiconductor switch in a standby mode is conductive, and - The p-type semiconductor switch (T1) remains self-locking off after the current through the p-type semiconductor (T1) has reached and / or exceeded the predetermined threshold. Switching to Claim 1 in which the further component comprises at least one of the following: a diode, a Schottky diode, a Zener diode, an ohmic resistance. A circuit as claimed in any one of the preceding claims, wherein the series circuit on the side of the p-type semiconductor switch is connected to a power line. Circuit according to one of the preceding claims, in which the series circuit on the side of the further component is connected to a line (R8) to a load (R10). A circuit as claimed in any one of the preceding claims, wherein the p-type semiconductor switch comprises at least one of the following semiconductors: a semiconductor switch, a power semiconductor switch, a transistor, a MOSFET, a PMOS, - an IGBT, - a JFET. A circuit according to any one of the preceding claims, wherein the control circuit (T2, R7, R1, R3-R6) is arranged in parallel with the series circuit of p-type semiconductor switch and further device. Switching to Claim 6 in which the control circuit has a semiconductor switch (T2) whose operating point can be set via a resistance network comprising at least one resistor. Switching to Claim 7 in which the semiconductor switch (T2) is a transistor, in particular a bipolar transistor, wherein the resistor network is dimensioned such that the semiconductor switch becomes conductive when the voltage drop across the series circuit of p-type semiconductor switch and further component is greater than a predetermined threshold value, as a result, the p-type semiconductor switch is driven so that it turns off self-holding. Switching to one of the Claims 6 to 8th in which the control circuit has a temperature compensation circuit (R4-R6). A circuit according to any one of the preceding claims, comprising a detection circuit (T3, R11-R15) arranged in parallel with the series circuit of p-type semiconductor switch and further device. Circuit according to one of the preceding claims, comprising a control circuit by means of which the circuit can be controlled, so that the p-type semiconductor switch is connected either conductive or non-conductive. Switching to Claim 11 comprising a power switch (101, 103, 105), which is arranged parallel to the series circuit of p-type semiconductor switch and further component, wherein the power switch on the basis of the control circuit (111) is controllable. A circuit as claimed in any one of the preceding claims, wherein the standby mode is a standby mode of a system having a plurality of consumers, the circuit providing electrical power to at least one of the consumers in standby mode of the system. Switching to Claim 13 in which the system comprises an electrical system in a motor vehicle.

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