Overvoltage protection circuit, sensor assembly, controller assembly and vehicle

Abstract

The utility model relates to an overvoltage protection circuit, which is characterized in that the overvoltage protection circuit (1) comprises a first switch tube (M1) and a second switch tube (M2) which are connected in series back to back between an input end (IN) and an output end (OUT), and the potential of the control end of the second switch tube (M2) is controlled by a third switch tube (Q1). A switching path of the third switching tube (Q1) and the first resistor (R1) are connected in series between the power supply side and the grounding side, a series circuit formed by the second resistor (R2), the reverse bias voltage stabilizing diode (D1) and the third resistor (R3) is connected between the power supply side and the grounding side, and a control end of the third switching tube (Q1) is connected to a cathode of the voltage stabilizing diode (D1). In addition, the utility model designs a sensor assembly, a controller assembly and a vehicle.

Description

Technical Field

[0001] This utility model relates to an overvoltage protection circuit, a sensor assembly, a controller assembly, and a vehicle. Background Technology

[0002] In industrial settings or vehicles, electrical overstress (EOS) events can lead to sensor and / or controller failures. In particular, as vehicle electrical architectures become increasingly complex, EOS events are occurring more frequently in the vehicle's electrical network, especially in low-voltage systems. This can affect the operation of sensors and / or controllers connected to the vehicle's electrical network, and even cause electronic components, particularly chips, to burn out, thus impacting vehicle operation and potentially posing safety risks. Moreover, such EOS events are more common in new energy vehicles with attached high-voltage electrical networks.

[0003] Electrical overstress events take many forms and have various causes. On the one hand, the increasing number of electronic devices in vehicles, due to their high-frequency operation, severely degrades the overall vehicle electrical environment. Furthermore, the close proximity of various circuits within the vehicle's wiring harness means that electromagnetic waves generated by high-frequency devices and switching elements can induce pulse voltages, or transient voltages, in other circuits. On the other hand, misconnections, aging, damage, or water immersion in wiring can cause short circuits with other voltage networks, such as 24V or 48V networks, resulting in excessively high DC voltages on the lines. For these reasons, overvoltages occurring on sensors or controllers, particularly at their power input or signal output terminals, include both positive and negative voltages.

[0004] In response to the aforementioned electrical over-stress events, overvoltage withstand requirements have been introduced for sensors and controllers used in vehicles or industrial applications. However, the previously specified overvoltage withstand requirements, such as withstand 24V transient overvoltage, may be insufficient to prevent damage to sensors and controllers in modern vehicles, especially new energy vehicles.

[0005] Typically, the maximum voltage that a chip, especially an application-specific integrated circuit (ASIC) chip, can withstand is specified in its specifications, allowing for selection based on the application scenario. To meet overvoltage requirements, a capacitor can be connected in parallel between the power input and ground terminals of a sensor or controller, particularly its chip, to absorb transient overvoltages. However, such capacitors often have small capacitance values, capable of withstanding only limited voltages, such as 24V or 40V, and are ineffective against DC overvoltages.

[0006] In addition, transient voltage suppressors (TVS) can be used. However, transient voltage suppressors are only effective for transient overvoltages, cannot withstand DC overvoltages, and have limited control accuracy. Furthermore, when selecting one for overvoltage protection purposes, it is difficult to take into account the special voltage requirements of some chips during calibration or communication.

[0007] In view of the above-mentioned disadvantages of the prior art, there is an urgent need for an overvoltage protection circuit that should at least protect the connected load from the effects of transient overvoltage and DC overvoltage. Utility Model Content

[0008] The objective of this invention is to provide an overvoltage protection circuit, a sensor assembly, a controller assembly, and a vehicle that can withstand transient overvoltages and DC overvoltages, while also providing reverse polarity protection.

[0009] The first aspect of this utility model relates to an overvoltage protection circuit, which includes a first switch and a second switch connected back-to-back between the input and output terminals. The potential at the control terminal of the second switch is controlled by a third switch. The switching path of the third switch is connected in series with a first resistor between the power supply side and the ground side. A series circuit consisting of a second resistor, a reverse-biased Zener diode, and a third resistor is connected between the power supply side and the ground side. The control terminal of the third switch is connected to the cathode of the Zener diode.

[0010] According to this invention, the first and second switching transistors are connected back-to-back in series between the input and output terminals. Alternatively, switching paths of transistors of the same or different types can be connected in series on the power supply side between the input and output terminals. In particular, common-source or common-drain structures of PMOS (P-channel metal-oxide-semiconductor field-effect transistors) or NMOS (N-channel metal-oxide-semiconductor field-effect transistors) can be considered. In the overvoltage protection circuit according to this invention, the first and second switching transistors can respectively block reverse polarity voltages and overvoltages exceeding a threshold value, wherein the second switching transistor is controlled by a third switching transistor. The third switching transistor is triggered by a Zener diode: the reverse-biased Zener diode in the series circuit conducts when the power supply voltage exceeds its regulated voltage (or breakdown voltage or Zener voltage), thereby changing the potential of the control terminal of the third switching transistor, changing the state of the third switching transistor, and subsequently controlling the second switching transistor to turn off, thus preventing overvoltage from entering the load.

[0011] In the overvoltage protection circuit according to this invention, the Zener diode can precisely trigger the state change of the third switch and then precisely control the first switch to turn off when the input voltage exceeds its regulated voltage, regardless of whether the input voltage involves transient voltage or DC voltage.

[0012] Therefore, the overvoltage protection circuit according to this invention can be configured for the load to be protected, such as a sensor and / or controller, thereby accurately and reliably blocking transient overvoltages caused by electromagnetic interference and DC overvoltages caused by aging, damage, or water immersion from entering the load to be protected; it also provides reverse polarity protection, ensuring that in case of incorrect connection or short connection with other voltage networks, the reverse polarity power supply voltage is not input to the downstream connected load, such as the sensor and / or controller. Compared with the transient voltage suppressors used in the prior art, the overvoltage protection circuit according to this invention can not only achieve protection against DC overvoltages, but also more accurately set the voltage value of the overvoltage to be blocked through the Zener diode, while also taking into account the special voltage requirements during calibration or communication, allowing pulse signals higher than the operating voltage to pass through.

[0013] According to one embodiment of this utility model, the first switching transistor can provide reverse polarity protection when the power supply voltage is reversed. The critical value of the reversed power supply voltage can depend on the withstand voltage of the first switching transistor. Here, in order to minimize the voltage drop and power consumption on the overvoltage protection circuit, the first switching transistor is preferably configured as a MOSFET, especially a PMOS or NMOS transistor. However, it is not limited to this; other types of switching transistors can also be considered. For example, a PMOS transistor is used as the first switching transistor, with its drain connected to the input terminal of the overvoltage protection circuit, and its gate grounded through a resistor, an optional capacitor, and a reverse-biased diode. Thus, when the polarity of the power supply voltage at the input terminal is correct, the PMOS transistor is in the on state, and current can flow normally; while when the polarity of the power supply voltage at the input terminal is reversed, the PMOS transistor is in the off state, and current cannot flow, thereby achieving reverse polarity protection. Here, the critical value of the reversed power supply voltage depends on the withstand voltage of the first switching transistor, that is, the drain-source rated voltage or drain-source breakdown voltage that can be applied before avalanche breakdown occurs in the case of using a MOSFET. Therefore, by selecting the right first switching transistor, it is possible to effectively prevent reverse polarity power supply voltage from being input to the downstream connected load when the transistor is misconnected or short-circuited with other voltage networks.

[0014] According to one embodiment of this invention, the second switching transistor can provide overvoltage protection when an overvoltage occurs in the power supply voltage. The overvoltage threshold can be set by the Zener diode's regulated voltage. As previously described, the third switching transistor, triggered by the Zener diode, can correspondingly control the second switching transistor to turn off when the power supply voltage exceeds the Zener diode's regulated voltage, thereby achieving overvoltage protection when an overvoltage occurs in the power supply voltage, regardless of whether the overvoltage involves a transient overvoltage or a DC overvoltage. Here, by selecting the Zener diode's regulated voltage, the overvoltage threshold for triggering overvoltage protection can be precisely set.

[0015] According to one embodiment of this utility model, the Zener diode can have a Zener voltage of 12V, 24V, 36V, or 48V. Here, considering that the common voltage tolerance of sensor and controller chips is 24V, a Zener diode with a Zener voltage of 24V is particularly preferred to prevent power supply voltages exceeding 24V from being input to the sensor and controller.

[0016] According to one embodiment of this utility model, a first capacitor can be connected upstream of the series circuit between the power supply side and the ground side; and / or a second capacitor can be connected upstream of the first switching transistor between the power supply side and the ground side. Here, the first and second capacitors can achieve high-frequency decoupling, reduce high-frequency noise interference to the signal, and optimize EMC performance. Simultaneously, the first capacitor upstream of the series circuit where the Zener diode is located can mitigate the application of voltage spikes or step voltages, optimizing the trigger response of the Zener diode.

[0017] According to one embodiment of this utility model, a fourth capacitor can be connected to ground at the control terminal of the first switching transistor; and / or a fifth capacitor can be connected to ground at the control terminal of the second switching transistor; and / or a third capacitor can be connected to ground at the control terminal of the third switching transistor. Here, the third, fourth, and fifth capacitors can perform high-frequency filtering to prevent malfunctions in these switching transistors.

[0018] According to one embodiment of this utility model, two reverse-biased diodes connected in series can be connected to the control terminal of the first switching transistor. Here, by using these two diodes, the control terminal of the first switching transistor (such as a PMOS transistor) can be clamped at approximately -1.4V when the power supply voltage is positive, ensuring that the first switching transistor is turned on at this time.

[0019] According to one embodiment of this utility model, the first and second switching transistors can be configured as MOSFETs, junction field-effect transistors, or bipolar transistors; and / or the third switching transistor can be configured as a bipolar transistor, MOSFET, or junction field-effect transistor. Here, it is preferable to use MOSFETs with bidirectional conduction capabilities as the first and second switching transistors to eliminate the need for a freewheeling diode connected in parallel, as is done when using other switching transistors, and to minimize the voltage drop and power consumption in the entire overvoltage protection circuit.

[0020] According to a particularly preferred embodiment of this invention, the first and second switching transistors can be configured as common-source PMOS transistors; and the third switching transistor can be configured as a PNP transistor. Here, to simplify the bias circuits at the control terminals of each switching transistor, a common-source structure of two PMOS transistors is preferred. That is, the drain of the first switching transistor (configured as a PMOS transistor) is connected to the input terminal of the overvoltage protection circuit, and the drain of the second switching transistor (configured as a PMOS transistor) is connected to the output terminal of the overvoltage protection circuit. The gate of the second switching transistor is connected to the collector of the third switching transistor (configured as a PNP transistor).

[0021] The second aspect of this utility model relates to a sensor assembly, the sensor assembly including a sensor and at least one overvoltage protection circuit as described above, the overvoltage protection circuit being connected to the power input terminal and / or signal output terminal of the sensor.

[0022] A third aspect of this utility model is a controller assembly, the controller assembly including a controller and at least one overvoltage protection circuit as described above, the overvoltage protection circuit being connected to the power input terminal and / or signal output terminal of the controller.

[0023] It should be noted that the aforementioned sensors and controllers can relate to any sensors and controllers used in vehicles or industrial settings. A fourth aspect of this invention relates to a vehicle comprising at least one of the following: an overvoltage protection circuit as described above; a sensor assembly as described above; and a controller assembly as described above.

[0024] Herein, the vehicle according to this utility model can be understood as any type of vehicle, by means of which one or more persons and / or goods can be transported. The vehicle can be a passenger car or commercial vehicle, particularly a sedan, truck, motorcycle, bus, etc. The vehicle can relate to internal combustion engine vehicles (ICE), electric vehicles (EV), such as fuel cell vehicles (FCV) and battery electric vehicles (BEV), as well as hybrid electric vehicles (HEV), such as plug-in hybrid electric vehicles (PHEV) and range-extended hybrid electric vehicles (EREV), etc.

[0025] It should be noted that the features, functions, effects, and advantages of one aspect of this utility model can also be referred to the above description of other aspects of this utility model. Furthermore, the various aspects described in this utility model can be combined with each other in various ways.

[0026] Other features of this invention are derived from the accompanying drawings and the detailed description. All features and combinations thereof mentioned above in the specification, as well as features and combinations thereof mentioned below in the detailed description and / or shown separately in the drawings, can be used not only in the corresponding combinations given, but also in other combinations, or in their individual states. Attached Figure Description

[0027] Figure 1 This is a circuit diagram of an overvoltage protection circuit according to an embodiment of the present invention. Detailed Implementation

[0028] Figure 1 A circuit diagram of an overvoltage protection circuit according to an embodiment of the present invention is shown. Figure 1 The illustrated overvoltage protection circuit can be configured to protect a load, such as a sensor and / or controller, to provide transient overvoltage protection, DC overvoltage protection, and reverse polarity protection. For this purpose, the overvoltage protection circuit can be connected not only to the power input of the sensor and / or controller to prevent transient overvoltages, DC overvoltages, and reverse polarity voltages from being input into the sensor and / or controller, but also to the signal output of the sensor and / or controller to prevent transient overvoltages, DC overvoltages, and reverse polarity voltages from being input into the sensor and / or controller via the signal output port.

[0029] exist Figure 1 The power supply is indicated by the reference numeral V1 on the left side of the diagram. This power supply V1 can be, for example, the supply voltage output by the vehicle control unit (ECU) to various sensors, controllers, etc., such as a 5V supply voltage, but it can also involve the supply voltage of the low-voltage vehicle electrical grid, etc. The power supply voltage of V1 is input to the overvoltage protection circuit via the input terminal IN of the overvoltage protection circuit. Figure 1 On the right side, the load to be protected, particularly the sensor and / or controller, is indicated by the load resistor R5. The overvoltage protection circuit outputs a standard power supply voltage to the load, particularly the sensor and / or controller, through its output terminal OUT, while blocking transient overvoltages, DC overvoltages, and reverse polarity voltages from being output to the load.

[0030] according to Figure 1The voltage protection circuit shown includes a first switch M1 and a second switch M2 connected back-to-back between the input terminal IN and the output terminal OUT. The potential at the control terminal of the second switch M2 is controlled by a third switch Q1. The switching path of the third switch Q1 is connected in series with the first resistor R1 between the power supply side and the ground side. A series circuit consisting of the second resistor R2, the reverse-biased Zener diode D1, and the third resistor R3 is connected between the power supply side and the ground side. The control terminal of the third switch Q1 is connected to the cathode of the Zener diode D1.

[0031] exist Figure 1 In the illustrated embodiment, PMOS transistors are preferably used as the first switch M1 and the second switch M2. The first switch M1 and the second switch M2 are configured as a common source structure. In this case, the switching paths of the first switch M1 and the second switch M2 extend on the power supply side between the input terminal IN and the output terminal OUT, and the sources of the first switch M1 and the second switch M2 are connected to each other, the drain of the first switch M1 is connected to the input terminal IN, and the drain of the second switch M2 is connected to the output terminal OUT.

[0032] Here, the first switching transistor M1 can provide reverse polarity protection when the power supply voltage is reversed. The critical value of the reverse power supply voltage depends on the withstand voltage of the first switching transistor M1. Preferably, the gate of the first switching transistor M1 is grounded through the fourth resistor R4, the fourth capacitor C4, and two reverse-biased diodes D2 and D3 connected in series. The fourth capacitor C4, such as a 0.001μF capacitor, can achieve high-frequency filtering to prevent the first switching transistor M1 from being mistakenly turned on or off due to high-frequency interference. By using the two diodes D2 and D3, the gate of the first switching transistor M1 can be clamped at about -1.4V when the power supply voltage is positive, ensuring that the first switching transistor M1 is turned on at this time. Therefore, when the polarity of the power supply voltage at the input terminal IN is correct, the gate voltage Vgs of the first switch M1 is less than the gate voltage threshold Vgsth, and thus the first switch M1 is in the conducting state, allowing current to flow normally. However, when the polarity of the power supply voltage at the input terminal IN is reversed, the gate voltage Vgs of the first switch is no longer less than its threshold, and the first switch M1 is in the cutoff state, preventing current from flowing, thus achieving reverse polarity protection. Here, the critical value of the reverse-connected power supply voltage depends on the withstand voltage of the first switch M1, that is, the drain-source rated voltage or drain-source breakdown voltage that can be applied before avalanche breakdown occurs. Here, corresponding to the reverse polarity voltage that may occur, especially in vehicles, this withstand voltage can be selected as 40V, 60V, 80V, or higher.

[0033] The second switching transistor M2 provides overvoltage protection in the event of an overvoltage in the power supply voltage. The overvoltage threshold can be set by the voltage regulation of the Zener diode D1. The voltage regulation of the Zener diode D1 can be, for example, 12V, 24V, 36V, or 48V. Considering the potential for overvoltage situations, particularly in vehicles, the voltage regulation of the Zener diode D1 is preferably 24V. Accordingly, in the series circuit, the second resistor R2 and the third resistor R3 can be 100kΩ and 39kΩ, respectively.

[0034] exist Figure 1 In the overvoltage protection circuit shown, the potential at the control terminal of the second switch M2 is controlled by the third switch Q1. Preferably, the third switch Q1 is a PNP transistor, with its emitter connected to the power supply side, or in other words, connected to the source of the second switch M2. The collector of the third switch Q1 is connected to the gate of the second switch M2. To limit the current in the third switch Q1 when it is turned on, its switching path is connected in series with the first resistor R1. A fifth capacitor C5, such as a 0.001μF capacitor, is connected in parallel with the first resistor R1 to achieve high-frequency filtering and prevent the second switch M2 from being mistakenly turned on or off due to high-frequency interference.

[0035] The third switch Q1 is triggered by the Zener diode D1 in the series circuit. Specifically, the reverse-biased Zener diode D1 in the series circuit conducts when the power supply voltage exceeds its regulated voltage. At this time, the base of the third switch Q1 is regulated at this voltage. As the power supply voltage increases further, a current is formed from the emitter to the base of the third switch Q1, causing the third switch Q1 to conduct. When the third switch Q1 is on, the gate voltage Vgs of the second switch M2 is no longer less than the gate voltage threshold Vgsth, thus turning off the second switch M2. In this overvoltage protection circuit according to the present invention, this switching process depends only on the regulated voltage of the Zener diode. Therefore, both transient overvoltages and DC overvoltages higher than this regulated voltage can be accurately and reliably blocked without being input to the connected load, such as a sensor or controller, especially protecting the chip therein from transient overvoltages caused by electromagnetic interference and DC overvoltages caused by aging, damage, or immersion in water.

[0036] In addition, a third capacitor C3, such as a 0.001μF capacitor, can be connected to ground at the base of the third switch Q1 to achieve high-frequency filtering and prevent malfunctions of the third switch Q1.

[0037] In addition, a first capacitor C1 is preferably connected upstream of the series circuit between the power supply side and the ground side. This first capacitor C1, such as a 0.1μF capacitor, can mitigate the voltage spikes or step voltages and optimize the trigger response of the Zener diode.

[0038] Alternatively or additionally, a second capacitor C2, such as a 0.1μF capacitor, can preferably be connected upstream of the first switching transistor between the power supply side and the ground side. This enables high-frequency decoupling, reduces high-frequency noise interference to the signal, and optimizes the EMC performance of the overvoltage protection circuit.

[0039] It should be noted that this utility model is not limited to Figure 1 The illustrated embodiment shows the switching transistors and circuit layout. It is also conceivable that the first switch M1 and the second switch M2 could be configured as other types of MOSFETs such as NMOS transistors; or junction field-effect transistors or bipolar transistors could be chosen. For this, it might be necessary to equip the first switch M1 and the second switch M2 with corresponding freewheeling diodes, or design additional control circuitry. Furthermore, instead of the PNP transistor shown, an NPN transistor could also be considered, with corresponding changes to the position of the resistor connected in series with it and the connection point to the gate of the second switch M2.

[0040] In addition, the overvoltage protection circuit according to this invention is preferably integrated with a sensor to form a sensor assembly and / or preferably integrated with a controller to form a controller assembly, thereby enabling the sensor and / or controller to have higher robustness against transient overvoltages, DC overvoltages, and reverse polarity voltages. The sensor and controller mentioned herein can be any sensor and controller used in vehicles or industrial applications. Specifically, an overvoltage protection circuit can be configured separately for the power input and signal output terminals of the same sensor; and / or a separate overvoltage protection circuit can be configured for the power input and signal output terminals of the same controller.

[0041] This invention also relates to vehicles including the aforementioned overvoltage protection circuit, sensor assembly, and / or controller assembly. The vehicle may be a passenger car or a commercial vehicle. The vehicle may include internal combustion engine vehicles (ICE), electric vehicles (EVs), such as fuel cell vehicles (FCVs) and battery electric vehicles (BEVs), as well as hybrid electric vehicles (HEVs), such as plug-in hybrid electric vehicles (PHEVs) and range-extended hybrid electric vehicles (EREVs).

[0042] This invention is not limited to the embodiments shown, but includes or extends to all technical equivalents that fall within the scope of the appended claims. The positional descriptions chosen in the specification, such as, for example, top, bottom, left, right, etc., refer to the direct description and the accompanying drawings, and can be adapted to new positions according to their meaning when the positions change.

[0043] The features disclosed in this application are important for the implementation of embodiments in different design aspects, not only individually but also in any combination.

[0044] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. An overvoltage protection circuit, characterized in that, The overvoltage protection circuit (1) includes a first switch (M1) and a second switch (M2) connected back-to-back between the input terminal (IN) and the output terminal (OUT). The potential at the control terminal of the second switch (M2) is controlled by a third switch (Q1). The switching path of the third switch (Q1) is connected in series with the first resistor (R1) between the power supply side and the ground side. A series circuit consisting of the second resistor (R2), the reverse-biased Zener diode (D1), and the third resistor (R3) is connected between the power supply side and the ground side. The control terminal of the third switch (Q1) is connected to the cathode of the Zener diode (D1).

2. The overvoltage protection circuit according to claim 1, characterized in that, The first switch (M1) provides reverse polarity protection when the power supply voltage is reversed, and the critical value of the reversed power supply voltage depends on the withstand voltage of the first switch (M1).

3. The overvoltage protection circuit according to claim 1, characterized in that, The second switch (M2) provides overvoltage protection when an overvoltage occurs in the power supply voltage, and the threshold of the overvoltage is set by the Zener diode (D1).

4. The overvoltage protection circuit according to claim 3, characterized in that, The Zener diode (D1) has a Zener voltage of 12V, 24V, 36V or 48V.

5. The overvoltage protection circuit according to any one of claims 1 to 4, characterized in that, A first capacitor (C1) is connected upstream of the series circuit between the power supply side and the ground side; and / or a second capacitor (C2) is connected upstream of the first switch between the power supply side and the ground side.

6. The overvoltage protection circuit according to any one of claims 1 to 4, characterized in that, A fourth capacitor (C4) is connected to ground at the control terminal of the first switch (M1); and / or a fifth capacitor (C5) is connected to ground at the control terminal of the second switch (M2); and / or a third capacitor (C3) is connected to ground at the control terminal of the third switch (Q1).

7. The overvoltage protection circuit according to any one of claims 1 to 4, characterized in that, Two reverse-biased diodes connected in series are connected to the control terminal of the first switching transistor (M1).

8. The overvoltage protection circuit according to any one of claims 1 to 4, characterized in that, The first switch (M1) and the second switch (M2) are configured as MOSFETs, junction field-effect transistors, or bipolar transistors; and / or the third switch (Q1) is configured as a bipolar transistor, MOSFET, or junction field-effect transistor.

9. The overvoltage protection circuit according to claim 8, characterized in that, The first switch (M1) and the second switch (M2) are configured as common-source PMOS transistors; and the third switch (Q1) is configured as a PNP transistor.

10. A sensor assembly, characterized in that, The sensor assembly includes a sensor and at least one overvoltage protection circuit according to any one of claims 1 to 9, the overvoltage protection circuit being connected to the power input terminal and / or signal output terminal of the sensor.

11. A controller assembly, characterized in that, The controller assembly includes a controller and at least one overvoltage protection circuit according to any one of claims 1 to 9, the overvoltage protection circuit being connected to the power input terminal and / or signal output terminal of the controller.

12. A vehicle, characterized in that, The vehicle includes at least one of the following: The overvoltage protection circuit according to any one of claims 1 to 9; The sensor assembly according to claim 10; and The controller assembly according to claim 11.

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