CN113054975A - Low-side power switch integrated module and driving chip - Google Patents

Low-side power switch integrated module and driving chip Download PDF

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Publication number
CN113054975A
CN113054975A CN202110349747.8A CN202110349747A CN113054975A CN 113054975 A CN113054975 A CN 113054975A CN 202110349747 A CN202110349747 A CN 202110349747A CN 113054975 A CN113054975 A CN 113054975A
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circuit
current
power switch
drain
voltage
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CN113054975B (en
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高马利
蔡小五
郝宁
丁利强
夏瑞瑞
高悦欣
赵发展
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Institute of Microelectronics of CAS
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Institute of Microelectronics of CAS
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
    • H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors

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Abstract

The invention relates to the technical field of power switches, in particular to a low-side power switch integrated module and a driving chip. The low-side power switch integrated module comprises: the SenseFET current sampling circuit is used for acquiring sampling current corresponding to the access current of the power switch tube; the current-limiting protection circuit is used for pulling down the grid voltage of the power switch tube when the sampling current exceeds the threshold current, and reducing the access current of the power switch tube; the SenseFET voltage sampling circuit is used for acquiring sampling voltage corresponding to the drain voltage of the power switch tube; and the short-circuit protection circuit is used for switching off the power switch tube and switching off the whole circuit when the sampling voltage exceeds the threshold voltage. The invention realizes the sampling of current and voltage based on the SenseFET, can improve the sampling precision of the sampled current and sampled voltage, simultaneously reduces the influence of the sampling process on the output power of the power switch tube, and improves the reliability of the low-side power switch integrated module.

Description

Low-side power switch integrated module and driving chip
Technical Field
The invention relates to the technical field of power switches, in particular to a low-side power switch integrated module and a driving chip.
Background
The intelligent low-side power switch integrated module is an integrated circuit which integrates a power device, a protection circuit and a control circuit into the same chip, and has wide application in the fields of aviation electronic equipment, automotive electronics, industrial control and the like because of the advantages of high integration level, easy control and the like.
In practical application, an intelligent low-side power switch integrated module generally works in a severe environment, and faults such as overload and load short circuit caused by load fluctuation are more common.
Therefore, how to improve the reliability of the low-side power switch integrated module is a technical problem that needs to be solved at present.
Disclosure of Invention
The invention aims to provide a low-side power switch integrated module and a driving chip so as to improve the reliability of the low-side power switch integrated module.
In order to achieve the above object, the embodiments of the present invention provide the following solutions:
in a first aspect, an embodiment of the present invention provides a low-side power switch integrated module, including:
the SenseFET current sampling circuit is used for acquiring sampling current corresponding to the access current of the power switch tube;
the current-limiting protection circuit is used for pulling down the grid voltage of the power switch tube when the sampling current exceeds a threshold current, so as to reduce the access current of the power switch tube;
the SenseFET voltage sampling circuit is used for acquiring sampling voltage corresponding to the drain voltage of the power switch tube;
and the short-circuit protection circuit is used for switching off the power switch tube and switching off the SenseFET current sampling circuit, the current-limiting protection circuit, the SenseFET voltage sampling circuit and a current mirror device in the short-circuit protection circuit when the sampling voltage exceeds the threshold voltage.
In one possible embodiment, the power switch tube is an NMOS tube MN 1;
the SenseFET current sampling circuit comprises: an NMOS transistor MN2 and a resistor R1;
the drain electrode of MN1 is connected with the power supply end V of the power tube through a load resistor RLOPX(ii) a The source of MN1 is grounded via R1; the front gate of MN1 is respectively connected with the source of MN2 and the front gate of MN 2; the drain of the MN2 is connected with the drain of the MN 1; the back gate of MN1, the source of MN2, and the back gate of MN2 are all grounded.
In one possible embodiment, the current limiting protection circuit includes: PMOS transistors MP1 and MP2, and triodes Q1 and Q2;
the source of the MP1, the back gate of the MP1, the source of the MP2 and the back gate of the MP2 are all connected with the power supply end V of the current mirrorPWR(ii) a The front gate of the MP1 is connected with the front gate of the MP 2; the drain of the MP1 is respectively connected with the collector of the Q1, the base of the Q1 and the base of the Q2; the emitter of the Q1 is connected with the source of the MN 1; the drain of the MP2 is connected with the collector of the Q2; the emitter of Q2 is grounded.
In one possible embodiment, the SenseFET voltage sampling circuit includes: an NMOS transistor MN3, a resistor R2, and inverters INV1 and INV 2;
the drain of the MP2 is connected with the front gate of the MN3 through the INV1 and the INV2 in sequence; the input end of the INV1 is connected with the front gate of the MN 2; the drain of MN3 is connected to V via RLOPX(ii) a The source of MN3 is grounded via R2; the back gate of MN3 is grounded.
In one possible embodiment, the short-circuit protection circuit includes: a short circuit detection circuit and a turn-off control circuit;
the short circuit detection circuit includes: PMOS tubes MP3 and MP4, triodes Q3 and Q4, and a resistor R3;
the source of the MP3, the back gate of the MP3, the source of the MP4 and the back gate of the MP4 are all connected with VPWR(ii) a The front gate of MP3 and the front gate of MP4 are both connected with the front gate of MP 2; the drain of the MP3 is connected with the collector of the Q3; the emitter of the Q3 is connected with the source of the MN 3; the drain of MP4 is connected to the base of Q3, the base of Q4 and the collector of Q4; the emitter of Q4 is grounded through R3;
wherein the collector of Q3 is used to generate a short circuit detection signal when the voltage across R2 exceeds the threshold voltage; and the turn-off control circuit turns off the power switch tube and turns off the SenseFET current sampling circuit, the current-limiting protection circuit, the SenseFET voltage sampling circuit and a current mirror device in the short-circuit protection circuit under the trigger of the short-circuit detection signal.
In one possible embodiment, the shutdown control circuit includes: PMOS transistors MP5 and MP6, NMOS transistors MN4, MN5, MN6, MN7 and MN8, and an inverter INV 3;
the source of the MP5, the back gate of the MP5, the source of the MP6 and the back gate of the MP6 are all connected with VPWR(ii) a The front gate of MP5 is connected to the front gate of MP2 and the drain of MP 5; the front gate of MP6 is grounded; the drain of the MP5 is connected with the drain of the MN 4; the source of MN4 is connected with the drain of MN 5; the front gate of MN4 is connected with the front gate of MN6 through INV 3; drain of drain MP2 of MN 6; the source of MN6 is connected with the drain of MP6, the front gate of MN5, the drain of MN7, the front gate of MN7, the drain of MN8 and the gate of MN8 respectively; the front gate of MP6, the back gate of MN4, the back gate of MN5, the source of MN5, the back gate of MN6, the back gate of MN7, the source of MN7, the back gate of MN8 and the source of MN8 are all grounded.
In one possible embodiment, the short-circuit protection circuit further includes: a logic synthesis circuit;
the logic synthesis circuit comprises: inverters INV4 and INV5, and NAND circuits NAND1 and NAND 2;
the collector of Q3 is connected with the first input end of NAND1 through INV 4; the output end of the NAND1 is connected with the input end of the INV3 through the INV 5; a second input of the NAND1 terminates the output of the NAND 2; the first input of NAND2 terminates the output of NAND 1.
In one possible embodiment, the drain of MP2 is connected to the input of INV1 through resistor R4.
In one possible embodiment, the resistor types of R1, R2, R3, and R4 are well resistors or poly resistors.
In a second aspect, an embodiment of the present invention provides a driving chip, including: a low side power switch integrated module as claimed in any one of the first aspects.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the invention configures a SenseFET current sampling circuit, a current-limiting protection circuit, a SenseFET voltage sampling circuit and a short-circuit protection circuit for a power switch tube; when the sampling current exceeds the threshold current, the current-limiting protection circuit can pull down the grid voltage of the power switch tube and reduce the access current of the power switch tube; when the sampling voltage exceeds the threshold voltage, the short-circuit protection circuit can turn off the power switch tube, and turn off current mirror devices in the SenseFET current sampling circuit, the current-limiting protection circuit, the SenseFET voltage sampling circuit and the short-circuit protection circuit, so as to provide short-circuit protection for the power switch tube.
Compared with the traditional resistance sampling, the current and voltage sampling is realized based on the SenseFET, the sampling precision of the sampled current and sampled voltage can be improved, and the influence of the sampling process on the output power of the power switch tube is reduced, so that the reliability of the low-side power switch integrated module is improved.
Drawings
In order to more clearly illustrate the embodiments of the present specification or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present specification, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a low-side power switch integrated module according to an embodiment of the present invention;
fig. 2 is a connection diagram of a low-side power switch integrated module according to an embodiment of the invention;
fig. 3 is a connection diagram of a low-side power switch integrated module according to an embodiment of the invention;
fig. 4 is a diagram illustrating simulation results of the low-side power switch integrated module shown in fig. 3 according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by those skilled in the art based on the embodiments of the present invention belong to the scope of protection of the embodiments of the present invention.
In order to improve the reliability of the low-side power switch integrated module, the inventor of the present invention analyzes the existing power switch, and finds that the current limiting and short-circuit protection method of the existing power switch mainly compares the detected loop current with a preset protection value, and takes the comparison as a judgment condition for protection. This makes the existing power switch usually have only one function of current limiting and short circuit protection, and there is no power switch integrated module having two protection functions at the same time. Meanwhile, the sampling circuit part of the traditional current-limiting and short-circuit protection circuit uses external resistance sampling or on-resistance sampling of a power tube, so that the precision is low, and inaccurate sampling easily causes current-limiting and short-circuit protection failure. In addition, the signal processing part of the traditional current limiting and short-circuit protection circuit uses a voltage comparator circuit, a current comparator circuit and a threshold voltage generation circuit, so that the power consumption is high and the circuit complexity is high.
Through the analysis, the defects of the existing power switch in the following four aspects can be easily found out:
1. the traditional short-circuit protection has incomplete circuit protection function aiming at the abnormal condition of the load, and can not meet the requirement that the circuit still needs to work normally within a certain current range when the load is small (or overloaded);
2. the traditional short-circuit protection has incomplete circuit protection function aiming at the abnormal condition of the load, and can not meet the requirement that the circuit still needs to work normally within a certain current range when the load is small (or overloaded);
3. the sampling is not accurate, and the failure of a protection circuit is easily caused;
4. the common voltage and current comparator circuit and the threshold voltage generating circuit have the advantages of complex structure, large circuit area, high circuit complexity and large power consumption.
Therefore, the reliability of the conventional power switch is severely limited by the four defects. In order to improve the reliability of the low-side power switch integrated module, the following solutions are provided in the embodiments of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a low-side power switch integrated module according to an embodiment of the present invention, including: a Sense Field Effect Transistor (Sense fet) current sampling circuit, a current limiting protection circuit, a Sense fet voltage sampling circuit, and a short circuit protection circuit.
And the SenseFET current sampling circuit is used for acquiring sampling current corresponding to the access current of the power switch tube.
And the current-limiting protection circuit is used for pulling down the grid voltage of the power switch tube when the sampling current exceeds the threshold current, so that the access current of the power switch tube is reduced.
And the SenseFET voltage sampling circuit is used for acquiring sampling voltage corresponding to the drain voltage of the power switch tube.
And the short-circuit protection circuit is used for switching off the power switch tube and switching off current mirror devices in the SenseFET current sampling circuit, the current-limiting protection circuit, the SenseFET voltage sampling circuit and the short-circuit protection circuit when the sampling voltage exceeds the threshold voltage.
The SenseFET has a smaller device size than a conventional FET (Field Effect Transistor), and therefore, the power of the sampling circuit formed by the SenseFET is generally smaller, so that the influence on the output power of the power switching tube can be reduced, and the output efficiency and the output reliability of the power switching tube can be improved.
Here, the NMOS transistor MN1 is used as a power switch transistor to illustrate the operation process of the present embodiment.
Fig. 2 is a schematic connection diagram of a low-side power switch integrated module according to an embodiment of the present invention, in which an NMOS transistor MN1 is used as a power switch transistor, the NMOS transistor MN2 and a resistor R2 form a SenseFET current sampling circuit, and the NMOS transistor MN3 and a resistor R3 form a SenseFET voltage sampling circuit.
The low-side power switch integrated module samples the current of the output power tube through the SENSFET current sampling circuit in operation. And then the current-limiting protection circuit analyzes and processes the sampling current, and the current-limiting protection circuit completes current-limiting protection by utilizing the turn-on and turn-off of the triode and matching with the current mirror and the band gap structure.
When the sampling current is lower than the threshold value, the current-limiting protection circuit does not influence the grid voltage of the switching tube. When the current is higher than the threshold value, the current-limiting protection module pulls down the grid voltage of the switching tube, so that the current flowing through the switching tube is reduced and limited below the threshold current.
In the operation of the low-side power switch integrated module, the SENSFET voltage sampling circuit samples the drain voltage of the output power tube, the drain voltage is converted into the current flowing through the SENSFET voltage sampling circuit, and the current is converted into the sampling voltage through the sampling resistor R2. And then the short-circuit protection circuit analyzes and processes the sampling voltage, and the short-circuit protection circuit completes short-circuit protection by utilizing the on and off of the triode and matching with the current mirror and the band gap structure.
When the load RL is in the normal value range, the short-circuit protection circuit works normally, and the short-circuit protection circuit does not influence the work of the whole circuit. When the load RL short circuit, short-circuit protection module output signal2, power shutoff switch tube MN1 and whole circuit to guarantee that circuit and device are not damaged.
Fig. 3 is a connection diagram of a low-side power switch integrated module according to an embodiment of the invention, wherein the power switch is an NMOS transistor MN 1; a SenseFET current sampling circuit comprising: an NMOS transistor MN2 and a resistor R1; the drain electrode of MN1 is connected with the power supply end V of the power tube through a load resistor RLOPX(ii) a The source of MN1 is grounded via R1; the front gate of MN1 is respectively connected with the source of MN2 and the front gate of MN 2; the drain of the MN2 is connected with the drain of the MN 1; the back gate of MN1, the source of MN2, and the back gate of MN2 are all grounded.
In this embodiment, a SenseFET is used for current sampling: namely, the gate (arrow, back gate, how the source and drain are divided), the drain and the interconnection of the MN1 tube and the MN2 tube, the ratio of the width-to-length ratio of the MN1 tube to the width-to-length ratio of the MN2 tube is N:1 (usually, N >200), so the current flowing through the MN2 tube is small, the voltage drop of the sampling resistor R1 is small, so the source voltages of the MN1 tube and the MN2 tube are approximately equal, and then the current ratio of the MN1 tube to the MN2 tube is N:1, thereby realizing accurate sampling of the path current of the power switch tube MN 1.
A current limiting protection circuit comprising: PMOS transistors MP1 and MP2, and triodes Q1 and Q2; the source of the MP1, the back gate of the MP1, the source of the MP2 and the back gate of the MP2 are all connected with the power supply end V of the current mirrorPWR(ii) a The front gate of the MP1 is connected with the front gate of the MP 2; the drain of the MP1 is respectively connected with the collector of the Q1, the base of the Q1 and the base of the Q2; the emitter of the Q1 is connected with the source of the MN 1; the drain of the MP2 is connected with the collector of the Q2; the emitter of Q2 is grounded.
Specifically, the sampled current is converted to a voltage through a sampling resistor R1, and the voltage signal is provided to a current limiting protection circuit. In the current-limiting protection circuit, the MP6 tube, the MN8 tube and the MN5 tube form a current mirror), when the current-limiting protection circuit works, the MN4 tube is opened, the MN5 tube, the MP5 tube, the MP2 tube and the MP1 tube form a current mirror, and the Q1 tube and the Q2 form a current mirror. When the resistance value of the load RL is reduced to be lower than the threshold value, the current flowing through the power switch tube MN1 is increased to the current-limiting threshold current, the voltage across the current-limiting sampling resistor R1 is increased to the set threshold voltage, the voltage of the point a (the base of Q1) is increased, namely the base voltages of Q1 and Q2 are increased, the current of the current mirror formed by the transistors Q1 and Q2 is increased, the voltage of the point B (the drain of MP 2) is pulled low, namely the front gate voltage of the power switch tube is reduced, and the current flowing through the power switch tube is limited to the target limiting current.
In fig. 3, the drain of MP2 is connected to the input of INV1 through resistor R4, and resistor R4 is used to prevent the gate voltage from breaking down the device too much, and there is no voltage drop.
A SenseFET voltage sampling circuit comprising: an NMOS transistor MN3, a resistor R2, and inverters INV1 and INV 2; the drain of the MP2 is connected with the front gate of the MN3 through the INV1 and the INV2 in sequence; the input end of the INV1 is connected with the front gate of the MN 2; the input end of the INV1 is connected with the front gate of the MN 2; the drain of MN3 is connected to V via RLOPX(ii) a The source of MN3 is grounded via R2; the back gate of MN3 is grounded.
Specifically, the drain and the source of the MN1 transistor are interconnected with the drain and the source of the MN3 transistor, the front gate of the MN1 transistor is connected to the gate of the MN3 transistor through a two-stage inverter, and the ratio of the width-to-length ratio of the MN2 transistor to the MN3 transistor is M:1 (usually, M is equal to M:1>200) That is, the on and off states of the MN1 transistor and the MN3 transistor are the same, and meanwhile, when the MN1 transistor is turned on, the grid voltage of the MN3 transistor is fixed, and the drain electrode is opposite to the grid voltageThe voltage is sampled, and the current flowing through the MN3 tube is increased along with the increase of the drain voltage, so that the sampling of the drain voltage of the MN1 is realized. When short circuit occurs, the drain voltage of the power switch tube approaches the power supply voltage VPWRThat is, the value of the current flowing through the MN3 tube reaches the short circuit threshold current.
In the SenseFET voltage sampling circuit, the front gate of MP2 is connected with the front gate of voltage sampling tube MN3 through inverters INV1 and INV2, so that the SenseFET current sampling circuit and the SenseFET voltage sampling circuit are isolated from each other and do not affect each other, and therefore two functions of current limiting and short-circuit protection are realized under the same module.
The short-circuit protection circuit includes: a short circuit detection circuit and a turn-off control circuit.
A short detection circuit comprising: PMOS transistors MP3 and MP4, transistors Q3 and Q4, and a resistor R3.
The source of the MP3, the back gate of the MP3, the source of the MP4 and the back gate of the MP4 are all connected with VPWR(ii) a The front gate of MP3 and the front gate of MP4 are both connected with the front gate of MP 2; the drain of the MP3 is connected with the collector of the Q3; the emitter of the Q3 is connected with the source of the MN 3; the drain of MP4 is connected to the base of Q3, the base of Q4 and the collector of Q4; the emitter of Q4 is grounded via R3.
Wherein the collector of Q3 is used to generate a short circuit detection signal when the voltage across R2 exceeds the threshold voltage; and the turn-off control circuit turns off the power switch tube and turns off the SenseFET current sampling circuit, the current-limiting protection circuit, the SenseFET voltage sampling circuit and a current mirror device in the short-circuit protection circuit under the trigger of the short-circuit detection signal.
A shutdown control circuit comprising: PMOS transistors MP5 and MP6, NMOS transistors MN4, MN5, MN6, MN7 and MN8, and an inverter INV 3;
the source of the MP5, the back gate of the MP5, the source of the MP6 and the back gate of the MP6 are all connected with VPWR(ii) a The front gate of MP5 is connected to the front gate of MP2 and the drain of MP 5; the front gate of MP6 is grounded; the drain of the MP5 is connected with the drain of the MN 4; the source of MN4 is connected with the drain of MN 5; the front gate of MN4 is connected with the front gate of MN6 through INV 3; drain of drain MP2 of MN 6; the source of MN6 is connected to the drain of MP6, the front gate of MN5 and the drain of MN7Front gate of MN7, drain of MN8 and gate of MN 8; the front gate of MP6, the back gate of MN4, the back gate of MN5, the source of MN5, the back gate of MN6, the back gate of MN7, the source of MN7, the back gate of MN8 and the source of MN8 are all grounded.
The collector of Q3 can directly be connected with the input end of INV3 through an inverter, and in actual operation, sampling resistance R2 converts the electric current into voltage signal again, and MP6 pipe, MN8 pipe and MN5 pipe constitute the current mirror, and when short circuit detection circuit worked, MN4 pipe opened, and MN5 pipe, MP5 pipe, MP4 pipe and MP3 pipe constitute the current mirror at this moment. The base and collector of the Q4 transistor are interconnected and connected to the base of the Q3 transistor. The MP4 transistor, the Q4 triode and the R3 are composed of VPWRIn a path to GND, the base electrode and the collector electrode of the Q4 triode are interconnected, so that the path current is fixed, namely the voltage of a point C (the base electrode of Q3) is fixed, namely the voltage of the base electrode and the collector electrode of Q4 and the voltage of the base electrode of Q3 are both fixed, when the resistance value of a load RL is in a normal range, the voltage at two ends of a sampling resistor R2 is extremely small, the Q3 triode is turned on, and the voltage of a point D (the collector electrode of Q3) is at a low level. When short circuit occurs, the voltage at two ends of the sampling resistor R2 reaches threshold voltage, the Q3 triode is turned off, the voltage at the point D is high level, the signal is sent to the turn-off control circuit, the turn-off control circuit is triggered to turn off the power switch tube MN1 and other current mirror devices in the circuit, and the short circuit protection effect is achieved.
However, if the collector of Q3 is directly connected to the input terminal of INV3 through an inverter, when the collector voltage of Q3 fluctuates around the trigger voltage of the shutdown control circuit, the shutdown control circuit is triggered repeatedly to shut down the entire circuit, and the reliability of the shutdown control circuit is reduced.
Specifically, the logic synthesis circuit includes: inverters INV4 and INV5, and NAND circuits NAND1 and NAND 2; the collector of Q3 is connected with the first input end of NAND1 through INV 4; the output end of the NAND1 is connected with the input end of the INV3 through the INV 5; a second input of the NAND1 terminates the output of the NAND 2; the first input of NAND2 terminates the output of NAND 1.
When a short circuit occurs, the point D is at a high level, the INV5 inverter outputs a low level, that is, the voltage at the point OC _ C (the output end of the INV 5) is at a low level, and MN4 is turned off, so that all MOS transistor current mirrors are turned off. Meanwhile, since the INV3 outputs a high level, the MN6 is turned on, and the power switch MN1 is turned off at this time.
In particular, the resistor types of R1, R2, R3 and R4 are well resistors, poly resistors or other passive resistors compatible with semiconductor processes.
In the above embodiment, the power switch tube adopts an NMOS tube, which may be replaced by a PMOS tube, and the specific circuit connection needs to be adjusted according to the property of the PMOS tube, so as to implement the same or similar functions as those in the above embodiment, which is not described herein again.
Other switch tubes in the circuit may adopt devices with channel types opposite to those in the embodiments, and the connection of the circuit is correspondingly changed to realize the same or similar functions as those in the embodiments, which is not described herein again.
The switching tube used in this embodiment is a four-terminal MOS device, and may be replaced by other three-terminal devices or five-terminal devices, and the connection of the circuit may be changed accordingly to implement the same or similar functions as those in the above embodiments, which is not described herein again.
Fig. 4 is a diagram illustrating simulation results of the low-side power switch integrated module shown in fig. 3, and particularly, the low-side power switch integrated module is simulated through a cadence shunt, where M2/D is a current flowing through the power switch MN1, OC _ C is an output voltage of the logic synthesis circuit, and a low level indicates a short circuit condition. It can be seen that when the load resistance is lower than 7.5 Ω, the current flowing through the power switch tube is 2A, and the current limiting circuit limits the current to 2A. When the load short circuit occurs, the resistance value of the load is lower than 3 omega, the power switch tube and the whole circuit are switched off, and the current is zero.
Therefore, in the low-side power switch integrated module provided by the embodiment, the current and voltage of the power switch tube in the power integrated circuit are detected by using the SENSEFET, so that the detection accuracy is improved, the output capability of an output tube is effectively prevented from being reduced, and the efficiency of the power switch tube is improved.
In the low-side power switch integrated module provided by the embodiment, the current-limiting protection circuit and the short-circuit protection circuit are arranged at the same time, so that the circuit complexity is reduced while the circuit protection function is perfected, and the chip protection reliability is higher.
The current-limiting and short-circuit protection circuit in the low-side power switch integrated module, which is provided by the embodiment, is the sampling signal processing circuit and the circuit control module which are simple in local structure, so that the chip area occupied by current-limiting and short-circuit protection is saved, the power consumption is greatly reduced, the cost is reduced while the protection function is perfected, and the chip performance is improved.
Based on the same inventive concept as the method, the embodiment of the present invention further provides a driving chip, including: a low side power switch integrated module as claimed in any preceding claim.
The driving chip also comprises a driving power supply and a control circuit; the control end of the control circuit is used for controlling the on-off of the low-side power switch integrated module power switch tube so as to control the driving current and/or driving voltage provided by the driving power supply to the motor and other devices.
The technical scheme provided by the embodiment of the invention at least has the following technical effects or advantages:
the embodiment of the invention configures a SenseFET current sampling circuit, a current-limiting protection circuit, a SenseFET voltage sampling circuit and a short-circuit protection circuit for a power switch tube; when the sampling current exceeds the threshold current, the current-limiting protection circuit can pull down the grid voltage of the power switch tube and reduce the access current of the power switch tube; when the sampling voltage exceeds the threshold voltage, the short-circuit protection circuit can turn off the power switch tube, and turn off current mirror devices in the SenseFET current sampling circuit, the current-limiting protection circuit, the SenseFET voltage sampling circuit and the short-circuit protection circuit, so as to provide short-circuit protection for the power switch tube.
Compared with the traditional resistance sampling, the embodiment of the invention realizes the current and voltage sampling based on the SenseFET, can improve the sampling precision of the sampled current and the sampled voltage, and simultaneously reduces the influence of the sampling process on the output power of the power switch tube, thereby improving the reliability of the low-side power switch integrated module.

Claims (10)

1. A low-side power switch integrated module, comprising:
the SenseFET current sampling circuit is used for acquiring sampling current corresponding to the access current of the power switch tube;
the current-limiting protection circuit is used for pulling down the grid voltage of the power switch tube when the sampling current exceeds a threshold current, so as to reduce the access current of the power switch tube;
the SenseFET voltage sampling circuit is used for acquiring sampling voltage corresponding to the drain voltage of the power switch tube;
and the short-circuit protection circuit is used for switching off the power switch tube and switching off the SenseFET current sampling circuit, the current-limiting protection circuit, the SenseFET voltage sampling circuit and a current mirror device in the short-circuit protection circuit when the sampling voltage exceeds the threshold voltage.
2. The integrated module of claim 1, wherein the power switch is an NMOS transistor MN 1;
the SenseFET current sampling circuit comprises: an NMOS transistor MN2 and a resistor R1;
the drain electrode of MN1 is connected with the power supply end V of the power tube through a load resistor RLOPX(ii) a The source of MN1 is grounded via R1; the front gate of MN1 is respectively connected with the source of MN2 and the front gate of MN 2; the drain of the MN2 is connected with the drain of the MN 1; the back gate of MN1, the source of MN2, and the back gate of MN2 are all grounded.
3. The integrated module of claim 2, wherein the current limiting protection circuit comprises: PMOS transistors MP1 and MP2, and triodes Q1 and Q2;
source of MP1, back gate of MP1, source of MP2The pole and the back gate of the MP2 are both connected with the power supply end V of the current mirrorPWR(ii) a The front gate of the MP1 is connected with the front gate of the MP 2; the drain of the MP1 is respectively connected with the collector of the Q1, the base of the Q1 and the base of the Q2; the emitter of the Q1 is connected with the source of the MN 1; the drain of the MP2 is connected with the collector of the Q2; the emitter of Q2 is grounded.
4. The low-side power switch integrated module of claim 3, wherein the SenseFET voltage sampling circuit comprises: an NMOS transistor MN3, a resistor R2, and inverters INV1 and INV 2;
the drain of the MP2 is connected with the front gate of the MN3 through the INV1 and the INV2 in sequence; the input end of the INV1 is connected with the front gate of the MN 2; the drain of MN3 is connected to V via RLOPX(ii) a The source of MN3 is grounded via R2; the back gate of MN3 is grounded.
5. A low-side power switch integrated module as claimed in claim 4, wherein said short-circuit protection circuit comprises: a short circuit detection circuit and a turn-off control circuit;
the short circuit detection circuit includes: PMOS tubes MP3 and MP4, triodes Q3 and Q4, and a resistor R3;
the source of the MP3, the back gate of the MP3, the source of the MP4 and the back gate of the MP4 are all connected with VPWR(ii) a The front gate of MP3 and the front gate of MP4 are both connected with the front gate of MP 2; the drain of the MP3 is connected with the collector of the Q3; the emitter of the Q3 is connected with the source of the MN 3; the drain of MP4 is connected to the base of Q3, the base of Q4 and the collector of Q4; the emitter of Q4 is grounded through R3;
wherein the collector of Q3 is used to generate a short circuit detection signal when the voltage across R2 exceeds the threshold voltage; and the turn-off control circuit turns off the power switch tube and turns off the SenseFET current sampling circuit, the current-limiting protection circuit, the SenseFET voltage sampling circuit and a current mirror device in the short-circuit protection circuit under the trigger of the short-circuit detection signal.
6. The low-side power switch integrated module of claim 5, wherein the turn-off control circuit comprises: PMOS transistors MP5 and MP6, NMOS transistors MN4, MN5, MN6, MN7 and MN8, and an inverter INV 3;
the source of the MP5, the back gate of the MP5, the source of the MP6 and the back gate of the MP6 are all connected with VPWR(ii) a The front gate of MP5 is connected to the front gate of MP2 and the drain of MP 5; the front gate of MP6 is grounded; the drain of the MP5 is connected with the drain of the MN 4; the source of MN4 is connected with the drain of MN 5; the front gate of MN4 is connected with the front gate of MN6 through INV 3; drain of drain MP2 of MN 6; the source of MN6 is connected with the drain of MP6, the front gate of MN5, the drain of MN7, the front gate of MN7, the drain of MN8 and the gate of MN8 respectively; the front gate of MP6, the back gate of MN4, the back gate of MN5, the source of MN5, the back gate of MN6, the back gate of MN7, the source of MN7, the back gate of MN8 and the source of MN8 are all grounded.
7. The low-side power switch integrated module of claim 6, wherein the short-circuit protection circuit further comprises: a logic synthesis circuit;
the logic synthesis circuit comprises: inverters INV4 and INV5, and NAND circuits NAND1 and NAND 2;
the collector of Q3 is connected with the first input end of NAND1 through INV 4; the output end of the NAND1 is connected with the input end of the INV3 through the INV 5; a second input of the NAND1 terminates the output of the NAND 2; the first input of NAND2 terminates the output of NAND 1.
8. The integrated module of one of claims 1 to 7, wherein the drain of MP2 is connected to the input of INV1 through a resistor R4.
9. The low-side power switch integrated module of claim 8, wherein the resistor types of R1, R2, R3 and R4 are well resistors or poly resistors.
10. A driver chip, comprising: the low-side power switch integrated module of any one of claims 1 to 9.
CN202110349747.8A 2021-03-31 2021-03-31 Low-side power switch integrated module and driving chip Active CN113054975B (en)

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Citations (5)

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Publication number Priority date Publication date Assignee Title
CN102983554A (en) * 2012-12-31 2013-03-20 杭州士兰微电子股份有限公司 Sampling short-circuit protection circuit for high-power factor driving system and method
US20140078629A1 (en) * 2012-09-20 2014-03-20 Infineon Technologies Ag Semiconductor device including short-circuit protection
CN106774595A (en) * 2017-01-09 2017-05-31 电子科技大学 A kind of current foldback circuit for low pressure difference linear voltage regulator
CN206673557U (en) * 2017-04-10 2017-11-24 华立科技股份有限公司 A kind of electric instrument intelligent protection circuit
CN111342647A (en) * 2020-03-30 2020-06-26 西安电子科技大学 Current-limiting protection method and circuit for high-side power switch

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140078629A1 (en) * 2012-09-20 2014-03-20 Infineon Technologies Ag Semiconductor device including short-circuit protection
CN102983554A (en) * 2012-12-31 2013-03-20 杭州士兰微电子股份有限公司 Sampling short-circuit protection circuit for high-power factor driving system and method
CN106774595A (en) * 2017-01-09 2017-05-31 电子科技大学 A kind of current foldback circuit for low pressure difference linear voltage regulator
CN206673557U (en) * 2017-04-10 2017-11-24 华立科技股份有限公司 A kind of electric instrument intelligent protection circuit
CN111342647A (en) * 2020-03-30 2020-06-26 西安电子科技大学 Current-limiting protection method and circuit for high-side power switch

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