Automobile seat heating drive circuit and automobile seat heating system

Abstract

The invention discloses an automobile seat heating drive circuit and an automobile seat heating system, and relates to the technical field of automobile seat heating, the automobile seat heating drive circuit comprises an automobile seat heating element, a first power switch device, a second power switch device, a grid driver and a controller; the first power switch device, the automobile seat heating element and the second power switch device are sequentially connected and then are connected with a positive electrode of a power supply and the ground; the gate driver is connected with the control end of the first power switch device and the control end of the second power switch device. The controller is connected with the gate driver, and the controller is used for controlling the first power switch device and the second power switch device to be switched on or switched off through the gate driver. According to the invention, a high-performance high-side power switch can be replaced, and the cost and the supply chain can be ensured; according to the invention, potential safety hazards caused by a single-point fault can be effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile seat heating, and in particular to an automobile seat heating drive circuit and an automobile seat heating system. Background Art

[0002] At present, the car seat heating system generally adopts high-side drive solution to realize the driving, current monitoring and closed-loop control of the heating wire. Major semiconductor manufacturers have also launched single-chip power drive solutions for this application, such as BTS7008-2EPA, which is a dual-channel intelligent high-side power switch chip with protection and diagnosis functions, and recommends a rated drive operating current of 7.5A under TA = 85℃. This chip can meet the needs of most application scenarios.

[0003] However, more and more automakers are seeking to achieve applications where seats and seat backs are driven in parallel, which requires high-side power switch chips that can withstand 12A or even higher operating currents. However, the market for such products is mainly monopolized by foreign capital and the prices are high.

[0004] In addition, although the existing intelligent high-side power switch integrates functions such as overcurrent protection and short-circuit protection, once the internal MOSFET of the high-side power switch is damaged (such as a short circuit between the drain and source structures), the control capability will be lost, resulting in the inability to turn off the seat heating. In this case, as heat accumulates, there may be a significant risk of vehicle fire, posing a severe safety challenge to end users. Summary of the invention

[0005] The embodiments of the present invention provide a car seat heating drive circuit and a car seat heating system to solve the technical problems in the related art that the existing car seat heating system uses a high-side power switch chip to drive the heating wire, which is expensive and has safety hazards in the circuit after the high-side power switch chip fails.

[0006] In a first aspect, a car seat heating drive circuit is provided, comprising: a car seat heating element, a first power switch device, a second power switch device, a gate driver and a controller;

[0007] The first power switch device, the car seat heating element, and the second power switch device are connected in sequence and then connected to the positive pole of the power supply and the ground;

[0008] The gate driver is connected to the control terminals of the first power switch device and the second power switch device;

[0009] The controller is connected to the gate driver, and is used for controlling the first power switch device and the second power switch device to be turned on or off through the gate driver.

[0010] In some embodiments, the first power switch device and the second power switch device are both NMOS tubes.

[0011] In some embodiments, the automobile seat heating driving circuit further includes:

[0012] A current sampling unit is connected to the second power switch device and the controller.

[0013] In some embodiments, the current sampling unit includes a first resistor, a second resistor, a third resistor, a fourth resistor and an operational amplifier;

[0014] The first end of the first resistor is connected to the second end of the second power switch device, and the second end of the first resistor is grounded;

[0015] The first end of the second resistor is connected to the first end of the first resistor, and the second end of the second resistor is connected to the non-inverting input end of the operational amplifier;

[0016] The first end of the third resistor is connected to the inverting input terminal of the operational amplifier, and the second end of the third resistor is grounded;

[0017] The first end of the fourth resistor is connected to the inverting input end of the operational amplifier, and the second end of the fourth resistor is connected to the output end of the operational amplifier and then connected to the controller.

[0018] In some embodiments, the automobile seat heating driving circuit further includes:

[0019] A filter unit is provided between the positive pole of the power supply and the first power switch device.

[0020] In some embodiments, the filtering unit includes a first capacitor, a second capacitor and a first inductor, the first end of the first inductor is connected to the positive electrode of the power supply, the second end of the first inductor is connected to the first end of the first power switching device, the first end of the first capacitor is connected to the first end of the first inductor, the second end of the first capacitor is grounded, the first end of the second capacitor is connected to the second end of the first inductor, and the second end of the second capacitor is grounded.

[0021] In some embodiments, the automobile seat heating driving circuit further includes:

[0022] An anti-reverse connection unit is provided between the filter unit and the first power switch device and is connected to the gate driver.

[0023] In some embodiments, the anti-reverse connection unit includes a first diode, a second diode, a fifth resistor, a sixth resistor, a first transistor, and a third power switch element;

[0024] The first end of the third power switch element is connected to the second end of the first inductor, and the second end of the third power switch element is connected to the first end of the first power switch device;

[0025] The anode of the first diode is connected to the first end of the third power switch element, and the cathode of the first diode is connected to the third end of the third power switch element and then connected to the gate driver;

[0026] The first end of the fifth resistor is connected to the first end of the third power switch element, and the second end of the fifth resistor is connected to the third end of the third power switch element;

[0027] The cathode of the second diode is connected to the first end of the third power switch element, the anode of the second diode is connected to the emitter of the first transistor, and the collector of the first transistor is connected to the third end of the third power switch element;

[0028] A first end of the sixth resistor is connected to the base of the first transistor, and a second end of the sixth resistor is grounded.

[0029] In some embodiments, the automobile seat heating driving circuit further includes:

[0030] a third diode, wherein the anode of the third diode is connected to the anode of the power supply;

[0031] A voltage regulator, wherein an input end of the voltage regulator is connected to the cathode of the third diode, and an output end of the voltage regulator is connected to the gate driver and the controller.

[0032] In a second aspect, a car seat heating system is provided, comprising the aforementioned car seat heating drive circuit.

[0033] The beneficial effects brought about by the technical solution provided by the present invention include:

[0034] The embodiment of the present invention provides a car seat heating drive circuit and a car seat heating system, wherein the car seat heating drive circuit is provided with a car seat heating element, a first power switch device, a second power switch device, a gate driver and a controller, wherein the first power switch device, the car seat heating element and the second power switch device are connected in sequence and then connected to the positive pole of the power supply and the ground, and the controller controls the first power switch device and the second power switch device to turn on or off through the gate driver. On the one hand, the present invention adopts a gate driver + external power level switch device to meet the requirements of high current load driving of different specifications, and can replace high-performance high-side power switches. The gate driver and power level switch devices are low-cost and easy to purchase and supply, and the cost and supply chain can be guaranteed; on the other hand, the present invention sets power switch devices on both the high side and the low side of the car seat heating element, and even if one of the power switch devices fails and cannot be turned off, it can still be turned off through another power switch device, effectively avoiding the safety hazards caused by single point failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A principle block diagram of a car seat heating drive circuit provided by an embodiment of the present invention;

[0037] Figure 2 A circuit diagram of a car seat heating drive circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The embodiment of the present invention provides a car seat heating drive circuit, which can solve the technical problems that the existing car seat heating system uses a high-side power switch chip to drive the heating wire, which is expensive and has safety hazards in the circuit after the high-side power switch chip fails.

[0040] See also Figure 1 As shown, an embodiment of the present invention provides a car seat heating drive circuit, including: a car seat heating element RL, a first power switch device M1, a second power switch device M2, a gate driver U1 and a controller U2.

[0041] The first power switch device M1, the car seat heating element RL, and the second power switch device M2 are connected in sequence and then connected to the positive pole of the power supply and the ground.

[0042] The gate driver U1 is connected to the control terminals of the first power switch device M1 and the second power switch device M2.

[0043] The controller U2 is connected to the gate driver U1 , and the controller U2 is used to control the first power switch device M1 and the second power switch device M2 to turn on or off through the gate driver U1 .

[0044] Specifically, the first power switch device M1 and the second power switch device M2 are NMOS tubes. Figure 2 As shown, the first end (drain) of the first power switch device M1 is connected to the positive power supply V-BATT, the car seat heating element RL is arranged between the second end (source) of the first power switch device M1 and the first end (drain) of the second power switch device M2, and the second end (source) of the second power switch device M2 is grounded.

[0045] The gate driver U1 can be a multi-half-bridge gate driver chip, and one half-bridge (upper bridge GH and lower bridge GL) in the multi-half-bridge gate driver chip is used to control the gates of the first power switch device M1 and the second power switch device M2 respectively. The gate driver U1 controls the first power switch device M1 and the second power switch device M2 to turn on or off according to the control instruction of the controller U2. When the first power switch device M1 and the second power switch device M2 are both turned on, the car seat heating element RL is electrically heated to heat the car seat. When any one of the first power switch device M1 and the second power switch device M2 is turned off, the heating of the car seat is stopped, that is, when any one of the first power switch device M1 and the second power switch device M2 fails, the circuit can be turned off by another switch. Among them, the car seat heating element RL is generally a heating resistor.

[0046] In addition, the embodiment of the present invention can also utilize the drain-source voltage monitoring function integrated in the gate driver. The controller sets a suitable drain-source voltage threshold VDS through the SPI bus. When the drain-source voltage of the first power switch device exceeds the set threshold, the hardware chip automatically cuts off the first power switch device to achieve hardware chip-level protection.

[0047] The car seat heating drive circuit in the embodiment of the present invention is provided with a car seat heating element, a first power switch device, a second power switch device, a gate driver and a controller. The first power switch device, the car seat heating element and the second power switch device are connected in sequence and then connected to the positive pole of the power supply and the ground. The controller controls the first power switch device and the second power switch device to turn on or off through the gate driver. On the one hand, the present invention adopts the gate driver + external power level switch device to meet the needs of high current load driving of different specifications, and can replace high-performance high-side power switches. The gate driver and power level switch devices are low-cost and easy to purchase and supply, and the cost and supply chain can be guaranteed; on the other hand, the present invention sets power switch devices on both the high side and the low side of the car seat heating element. Even if one of the power switch devices fails and cannot be turned off, it can still be turned off through another power switch device, effectively avoiding the safety hazards caused by single point failure.

[0048] As an optional implementation, in an embodiment of the invention, see Figure 2 As shown, the automobile seat heating driving circuit further includes a current sampling unit, which is connected to the second power switch device M2 and the controller U2. The current sampling unit can realize real-time monitoring of the load current, so that the controller U2 can control the first power switch device M1 and the second power switch device M2 to turn on or off.

[0049] Further, see Figure 2 As shown, the current sampling unit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and an operational amplifier U3.

[0050] The first end of the first resistor R1 is connected to the second end of the second power switch device, and the second end of the first resistor R1 is grounded. The first end of the second resistor R2 is connected to the first end of the first resistor R1, and the second end of the second resistor R2 is connected to the non-inverting input end of the operational amplifier U3. The first end of the third resistor R3 is connected to the inverting input end of the operational amplifier U3, and the second end of the third resistor R3 is grounded. The first end of the fourth resistor R4 is connected to the inverting input end of the operational amplifier U3, and the second end of the fourth resistor R4 is connected to the output end of the operational amplifier U3 and then connected to the controller.

[0051] The current sampling unit collects the voltage at the first end of the first resistor R1, amplifies it through the operational amplifier U3 and outputs it to the controller U2. The controller U2 calculates the current flowing through the car seat heating element RL according to the collected voltage and the resistance value of the first resistor R1, thereby realizing real-time monitoring of the load current.

[0052] As an optional implementation, in an embodiment of the invention, see Figure 2 As shown, the automobile seat heating driving circuit further includes a filtering unit, and the filtering unit is arranged between the positive electrode of the power supply and the first power switch device M1, and the filtering unit can ensure the stability of the input power supply.

[0053] Further, see Figure 2 As shown, the filtering unit includes a first capacitor C1, a second capacitor C2 and a first inductor L1, the first end of the first inductor L1 is connected to the positive electrode of the power supply, the second end of the first inductor L1 is connected to the first end (drain) of the first power switch device M1, the first end of the first capacitor C1 is connected to the first end of the first inductor L1, the second end of the first capacitor C1 is grounded, the first end of the second capacitor C2 is connected to the second end of the first inductor L1, and the second end of the second capacitor C2 is grounded. The filtering unit is a π filter, which can suppress high-frequency signals and noise, improve signal quality, and improve the stability and performance of the circuit.

[0054] As an optional implementation, in an embodiment of the invention, see Figure 2 As shown, the car seat heating drive circuit also includes: an anti-reverse connection unit, which is arranged between the filter unit and the first power switch device M1 and connected to the gate driver U1. The anti-reverse connection unit can ensure the circuit safety in the case of reverse power supply.

[0055] Further, see Figure 2As shown, the anti-reverse connection unit includes a first diode D1, a second diode D2, a fifth resistor R5, a sixth resistor R6, a first transistor Q1 and a third power switch element M3. The third power switch element M3 may be an NMOS transistor.

[0056] The first end (source) of the third power switch element M3 is connected to the second end of the first inductor L1 , and the second end (drain) of the third power switch element M3 is connected to the first end (drain) of the first power switch device M1 .

[0057] The anode of the first diode D1 is connected to the first end of the third power switch element M3 , and the cathode of the first diode D1 is connected to the third end (gate) of the third power switch element M3 and then connected to the gate driver.

[0058] A first end of the fifth resistor R5 is connected to a first end of the third power switch element M3 , and a second end of the fifth resistor R5 is connected to a third end of the third power switch element M3 .

[0059] The cathode of the second diode D2 is connected to the first end of the third power switch element M3 , the anode of the second diode D2 is connected to the emitter of the first transistor Q1 , and the collector of the first transistor Q1 is connected to the third end of the third power switch element M3 .

[0060] A first end of the sixth resistor R6 is connected to the base of the first transistor Q1 , and a second end of the sixth resistor R6 is grounded.

[0061] When the power supply is normally connected, the gate driver U provides a voltage to turn on the source and drain of the third power switch element M3. When the power supply is reversely connected, the collector and emitter of the first transistor Q1 are turned on, the gate driver U cannot provide a voltage to the gate of the third power switch element M3, and the source and drain of the third power switch element M3 are disconnected, thereby achieving the purpose of anti-reverse protection.

[0062] As an optional implementation, in an embodiment of the invention, see Figure 2 As shown, the car seat heating drive circuit also includes: a third diode D3 and a voltage stabilizer, the anode of the third diode D3 is connected to the positive electrode of the power supply, the input end of the voltage stabilizer is connected to the cathode of the third diode D3, the output end of the voltage stabilizer is connected to the gate driver and the controller, and the third diode D3 is used in conjunction with the voltage stabilizer to provide a stable power supply for the gate driver and the controller.

[0063] An embodiment of the present invention further provides a car seat heating system, comprising the above-mentioned car seat heating driving circuit.

[0064] In the description of the present invention, it should be noted that the terms "upper", "lower", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0065] It should be noted that, in the present invention, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0066] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A car seat heating drive circuit, characterized in that: include: An automotive seat heating element, a first power switch device, a second power switch device, a gate driver, and a controller; The first power switch device, the car seat heating element, and the second power switch device are connected in sequence and then connected to the positive pole of the power supply and the ground; The gate driver is connected to the control terminals of the first power switch device and the second power switch device; The controller is connected to the gate driver, and is used for controlling the first power switch device and the second power switch device to be turned on or off through the gate driver.

2. The automobile seat heating driving circuit according to claim 1, characterized in that: The first power switch device and the second power switch device are both NMOS tubes.

3. The automobile seat heating drive circuit according to claim 2, characterized in that: Also includes: A current sampling unit is connected to the second power switch device and the controller.

4. The automobile seat heating driving circuit according to claim 3, characterized in that: The current sampling unit includes a first resistor, a second resistor, a third resistor, a fourth resistor and an operational amplifier; The first end of the first resistor is connected to the second end of the second power switch device, and the second end of the first resistor is grounded; The first end of the second resistor is connected to the first end of the first resistor, and the second end of the second resistor is connected to the non-inverting input end of the operational amplifier; The first end of the third resistor is connected to the inverting input terminal of the operational amplifier, and the second end of the third resistor is grounded; The first end of the fourth resistor is connected to the inverting input end of the operational amplifier, and the second end of the fourth resistor is connected to the output end of the operational amplifier and then connected to the controller.

5. The automobile seat heating driving circuit according to claim 1, characterized in that: Also includes: A filter unit is provided between the positive pole of the power supply and the first power switch device.

6. The automobile seat heating driving circuit according to claim 5, characterized in that: The filtering unit includes a first capacitor, a second capacitor and a first inductor, wherein the first end of the first inductor is connected to the positive electrode of the power supply, the second end of the first inductor is connected to the first end of the first power switching device, the first end of the first capacitor is connected to the first end of the first inductor, the second end of the first capacitor is grounded, the first end of the second capacitor is connected to the second end of the first inductor, and the second end of the second capacitor is grounded.

7. The automobile seat heating driving circuit according to claim 6, characterized in that: Also includes: An anti-reverse connection unit is provided between the filter unit and the first power switch device and is connected to the gate driver.

8. The automobile seat heating driving circuit according to claim 7, characterized in that: The anti-reverse connection unit includes a first diode, a second diode, a fifth resistor, a sixth resistor, a first triode and a third power switch element; The first end of the third power switch element is connected to the second end of the first inductor, and the second end of the third power switch element is connected to the first end of the first power switch device; The anode of the first diode is connected to the first end of the third power switch element, and the cathode of the first diode is connected to the third end of the third power switch element and then connected to the gate driver; The first end of the fifth resistor is connected to the first end of the third power switch element, and the second end of the fifth resistor is connected to the third end of the third power switch element; The cathode of the second diode is connected to the first end of the third power switch element, the anode of the second diode is connected to the emitter of the first transistor, and the collector of the first transistor is connected to the third end of the third power switch element; A first end of the sixth resistor is connected to the base of the first transistor, and a second end of the sixth resistor is grounded.

9. The automobile seat heating driving circuit according to claim 1, characterized in that: Also includes: a third diode, wherein the anode of the third diode is connected to the anode of the power supply; A voltage regulator, wherein an input end of the voltage regulator is connected to the cathode of the third diode, and an output end of the voltage regulator is connected to the gate driver and the controller.

10. A car seat heating system, characterized in that: include: The automobile seat heating drive circuit according to any one of claims 1 to 9.

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