Circuit, detection system and equipment

Abstract

The invention relates to a circuit, a detection system and equipment. The circuit is used for being coupled with a heating induction unit so as to control the heating induction unit to execute an induction function at a first time and execute a heating function at a second time. The circuit comprises a high-side driving unit, a signal processing unit and a switch unit, the first end of the switch unit is grounded, the second end of the switch unit is connected with the output end of the high-side driving unit, and the third end of the switch unit is connected with the signal processing unit. And the signal processing unit controls the switch unit to be switched on so as to enable the output end of the high-side driving unit to be grounded. According to the circuit, by bypassing the capacitor at the side of the high-side driving unit, the influence on the capacitance change in the induction detection channel under the experiment scenes such as battery voltage change and power line conduction immunity is reduced, and the detection accuracy and the stability, reliability and safety of related products are improved.

Description

Technical Field

[0001] The present disclosure relates to the field of detection technologies, and in particular, to a circuit, a detection system, and a device. Background Art

[0002] To improve the driving safety of vehicles, the hands-on / off detection (HOD) technology has been widely applied to many vehicles. In an existing steering wheel design, the HOD module and the heating wire of the steering wheel are separately arranged independently, and a shielding layer is provided therebetween to shield the influence of the heating wire on the HOD module. This design has high requirements for the internal space of the steering wheel, requiring at least three structural layers (MAT), and the cost is relatively high. Another existing design is to integrate the heating function into the HOD module, enabling the metal wire to switch between the sensing state and the heating state, thereby saving the internal space of the steering wheel and significantly reducing the material cost and the manufacturing cost of the process of the steering wheel. However, integrating the heating and sensing functions means that a circuit is required to perform fast time-sharing control on the metal wire to execute the heating function or the sensing function. There are the following technical difficulties: When the heating function is switched or when a transient conduction interference (CIPulse, a type of automotive electronics anti-interference test) caused by simulating the interference of the vehicle's power supply line is applied, resulting in a voltage fluctuation of the heating power supply, it will cause the value of the raw data (Rawdata) representing the capacitance change to fluctuate, and the fluctuation amplitude is approximately the same as that caused by a human hand touch, posing a challenge to accurately identifying the capacitance change caused by a gesture, which may lead to mis-triggering of related functions, thereby reducing the driving safety of the vehicle.

[0003] In addition, in addition to the hands-off detection module of the steering wheel, other products that integrate the heating function and the sensing function and require a circuit to perform time-sharing control on the switching between the heating function and the sensing function also have similar problems. Summary of the Invention

[0004] In view of the above defects in the prior art, the present invention provides a circuit, a detection system, and a device. When the heating and sensing unit executes the sensing function, the output terminal of the high-side driving unit is short-circuited to the ground, bypassing the capacitor on the high-side driving unit side, thereby reducing the influence on the capacitance change in the sensing detection channel when the heating function and the sensing function are switched, and improving the accuracy of detection and the stability, reliability, and safety of related products.

[0005] According to a first aspect of the present invention, a circuit is provided for coupling with a heating induction unit to control the heating induction unit to perform an induction function at a first time and a heating function at a second time. The circuit includes: a high-side drive unit, a signal processing unit, and a switching unit. The first end of the switching unit is grounded, the second end is connected to the output end of the high-side drive unit, and the third end is connected to the signal processing unit. Wherein, when the heating induction unit performs the induction function, the signal processing unit controls the switching unit to conduct so that the output end of the high-side drive unit is grounded.

[0006] According to the foregoing first aspect, any of the following preferred features may be included individually or in combination.

[0007] Preferably, the circuit includes an overcurrent protection unit. Its first end is grounded, the second end is connected to the control end of the high-side drive unit, and the third end is connected to the third end of the switching unit, for turning off the output of the high-side drive unit to implement overcurrent protection when the heating induction unit performs the heating function and the switching unit conducts abnormally.

[0008] Preferably, the circuit includes an anti-reverse connection protection unit, which is connected in series between the switching unit and the ground, and its control end is connected to a turn-off power supply, for disconnecting when the power supply is reversely connected to implement anti-reverse connection protection.

[0009] Preferably, the switching unit, the overcurrent protection unit, and / or the anti-reverse connection protection unit are metal-oxide semiconductor field-effect transistors.

[0010] Preferably, the circuit includes a multi-zone induction detection channel. Each zone of the multi-zone induction detection channel includes a high-side electrically isolated transistor and a low-side electrically isolated transistor. The sum of the output capacitances and other parasitic capacitances of all transistors in the multi-zone induction detection channel under the DC bias voltage is less than the upper limit of the load capacity of the signal processing unit.

[0011] Preferably, the sum of the output capacitances and other parasitic capacitances of all transistors in the multi-zone induction detection channel under the DC bias voltage is less than sixty percent of the upper limit of the load capacity of the signal processing unit.

[0012] Preferably, the high-side electrically isolated transistor is a P-type field-effect transistor. The P-type field-effect transistors are all reversely connected to block the potential path through the body diode to the source. The control ends of the P-type field-effect transistors are all grounded through resistors.

[0013] Preferably, the low-side electrically isolated transistor is an N-type field-effect transistor, and the control end of the N-type field-effect transistor is connected to the signal processing unit.

[0014] Preferably, the switching unit is an N-type field-effect transistor.

[0015] According to a second aspect of the present invention, a detection system is provided. The detection system includes the circuit described above and a heating induction unit coupled to the circuit. The circuit controls the heating induction unit to perform an induction function at a first time and a heating function at a second time.

[0016] Preferably, the heating induction unit is a metal layer. When performing the induction function, the metal layer forms a capacitance with a part of the human body located within the sensing area of the metal layer. The detection system obtains capacitance information or capacitance characterization information through the capacitance.

[0017] According to a third aspect of the present invention, a device is provided. The device is a steering wheel system or a seat system including the circuit described above or the detection system described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features and advantages of the present invention will be better understood through the following preferred embodiments described in detail in conjunction with the drawings, in which the same reference numerals represent the same or similar components.

[0019] Figure 1 FIG. shows an exemplary block diagram of a circuit for coupling to a heating induction unit to control the heating induction unit to perform an induction function at a first time and a heating function at a second time according to an embodiment of the present invention.

[0020] Figure 2 FIG. shows a circuit diagram of a detection system according to an embodiment of the present invention.

[0021] Figure 3 FIG. shows Figure 2 a schematic diagram of the working principle when the detection system performs the heating function.

[0022] Figure 4 FIG. shows Figure 2 a schematic diagram of the working principle when the detection system performs the induction function. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In the prior art, for products that integrate heating functions and sensing functions and require a circuit to control the switching between the heating function and the sensing function in a time-sharing manner, such as a steering wheel hand-off detection module with an integrated heating function or a seat occupancy detection module with an integrated heating function, when the heating function is switched on or the heating power supply voltage fluctuates due to other factors, the Rawdata value representing the change in capacitance will fluctuate, which poses a challenge to the accuracy and reliability of the product detection function, and may even lead to mis-triggering of related functions, affecting the driving safety of the vehicle.

[0024] As described below, some exemplary embodiments of the present disclosure provide a circuit, a detection system, and a device to solve the above problems.

[0025] Referring to Figure 1 , a block diagram of a circuit 100 according to an embodiment of the present invention is shown. The circuit 100 is used to be coupled with a heating induction unit to control the heating induction unit to perform an induction function at a first time and a heating function at a second time. As Figure 1 shown, the circuit 100 includes a signal processing unit 110, a switch unit 120, and a high-side drive unit 130. A first end of the switch unit 120 is grounded, a second end is connected to an output end of the high-side drive unit 130, and a third end is connected to the signal processing unit 110. When the heating induction unit performs the induction function, the signal processing unit 110 controls the switch unit 120 to conduct, so that the output end of the high-side drive unit 130 is grounded.

[0026] In some examples, the circuit 100 further includes an overcurrent protection unit 140. A first end of the overcurrent protection unit 140 is grounded, a second end is connected to a control end of the high-side drive unit 130, and a third end is connected to the third end of the switch unit 120, and is used to turn off the output of the high-side drive unit 130 to implement overcurrent protection when the heating induction unit performs the heating function and the switch unit conducts abnormally.

[0027] In some examples, the circuit 100 further includes an anti-reverse connection protection unit 150. The anti-reverse connection protection unit 150 is connected in series between the switch unit 120 and the ground, and its control end is connected to a turn-off power supply, and is used to disconnect when the power supply is reversely connected to implement anti-reverse connection protection.

[0028] Referring to Figures 2-4 , where Figure 2 a circuit diagram of a detection system according to an embodiment of the present invention is shown, Figure 3 shows Figure 2 a schematic diagram of the working principle when the detection system of Figure 4 shows Figure 2 performs the heating function, and

[0029] shows

[0030] a schematic diagram of the working principle when the detection system of

[0029] performs the induction function. The dotted line represents the working circuit for performing the corresponding function. The detection system includes the circuit 100 and the heating induction unit described above, which are used to be coupled with the heating induction unit to control the heating induction unit to perform the induction function at a first time and the heating function at a second time.

[0029] In some examples, the heating induction unit is a metal layer. When performing the induction function, the metal layer forms a capacitor with a part of the human body located in the sensing area of the metal layer, and the detection system obtains capacitance information or capacitance characterization information through the capacitor.

[0030] In some examples, the heating induction unit is a metal wire or a metal mesh (which can also be referred to as a conductive layer or a metal layer), and it can be arranged in a large area at a desired position (such as on the steering wheel or seat of a vehicle). This metal wire layer or metal mesh layer has two interfaces for connecting to the corresponding interfaces in the circuit 100 respectively. Exemplarily, Figure 2 the heating induction unit in it is three metal wires w1, w2, and w3, which are respectively used as capacitance detection sensors and heating wires for three zones.

[0031] Such as Figure 2 shown, the detection system includes: a signal processing unit U2, a high-side drive unit U1, a switch unit Q8, and a heating induction unit (w1, w2, and w3). Among them, the first end (input end) of the high-side drive unit U1 is connected to the heating power supply, the second end (control end) is connected to the signal processing unit U2, and the third end (output end) is connected to the heating induction unit. The first end of the switch unit Q8 is grounded, the second end is connected to the output end of the high-side drive unit U1, and the third end (control end) is connected to the signal processing unit U2. The first end of the heating induction unit is connected to the high-side drive unit U1, and the second end is grounded. When the heating induction unit performs the induction function, the signal processing unit U2 controls the switch unit Q8 to conduct so that the output end of the high-side drive unit U1 is grounded. It should be noted that Figure 2 although the heating induction units w1, w2, and w3 are taken as examples for illustration, the present application itself does not limit the number of heating induction units, the number of induction channels or regions.

[0032] Optionally, the signal processing unit U2 can either be a microcontroller (MCU) integrating a capacitance detection processing unit or a discrete architecture of a general-purpose MCU cooperating with a capacitance detection processing unit. The capacitance detection processing unit is used to identify and process the capacitance signals obtained when the heating induction unit performs the induction function.

[0033] Optionally, the high-side drive unit U1 is an intelligent high-side power switch, which is a high-side power switch integrating overcurrent, overvoltage and other protections and having open-circuit and short-circuit diagnosis functions, and is used to control the on-off of the heating power supply.

[0034] Optionally, the switching unit Q8 can be a metal-oxide-semiconductor field-effect transistor (MOSFET), junction field-effect transistor, power transistor, triode, or IGBT. Among them, preferably, the switching unit Q8 is a MOSFET, especially an N-type MOSFET, which is beneficial to reducing the number of components required for the product, thereby reducing the manufacturing cost. Specifically, during the process of heating and capacitance detection multiplexing, the signal processing unit needs to frequently set the Gate of Q8 high / low to control whether the output terminal of the high-side driving unit is grounded or not. During the heating period, the Gate is set low and Q8 is turned off; during the sensing period, the Gate is set high and Q8 is turned on, and the output terminal of the high-side driving unit is shorted to ground, bypassing the capacitor C1, thus avoiding the influence of the capacitance value change of C1 caused by the voltage change on the capacitance detection.

[0035] Optionally, the detection system further includes an overcurrent protection unit Q7. Its first terminal is grounded, the second terminal is connected to the control terminal of the high-side driving unit U1, and the third terminal (control terminal) is connected to the third terminal (control terminal) of the switching unit Q8, and is used to turn off the output of the high-side driving unit U1 to implement overcurrent protection when the heating and sensing unit executes the heating function and the switching unit Q8 conducts abnormally, preventing the Q8 from being damaged by overcurrent due to the MCU software logic failure. In some examples, the overcurrent protection unit Q7 is a metal-oxide-semiconductor field-effect transistor. Specifically, since the signal processing unit needs to frequently set the Gate of Q8 high / low to control whether the output terminal of the high-side driving unit is grounded or not during the process of heating and capacitance detection multiplexing, in order to prevent the Gate of Q8 from being abnormally set high during the heating period due to software timing disorder, resulting in overcurrent damage to Q8 and Q9, a hardware protection measure Q7 can be added to improve the stability of the system. Specifically, Q8 and Q7 are controlled by the same control pin of the signal processing unit, so that when the Gate of Q8 is abnormally set high during the heating period, Q7 will act to pull down the control pin of the high-side driving unit, thereby turning off the output of the high-side driving unit, and further protecting Q8 and Q9 from being damaged by overcurrent.

[0036] Optionally, the detection system further includes an anti-reverse connection protection unit Q9, which is connected in series between the switching unit Q8 and the ground, and its control terminal is connected to a turn-off power supply (for example, connected to the power supply through the power switch S1 (Power Switch) in the figure), and is used to disconnect when the power supply is reversely connected to implement anti-reverse connection protection. In some examples, the anti-reverse connection protection unit Q9 is a metal oxide semiconductor field effect transistor. Specifically, since there is a risk of anti-reverse connection failure in the circuit after introducing Q8, Q9 is introduced for anti-reverse connection. In some examples, the Gate pole of Q9 is controlled by a turn-off power switch (power switch, S1) controlled by a triode. When the power supply is connected correctly, the power supply controlled by the triode is turned on, the Gate pole is approximately equal to the power supply voltage, Q9 is turned on, and the output of the high-side drive unit passes through Q8 and then through Q9 to the ground; when the power supply is reversely connected, the power supply controlled by the triode is turned off, the Gate is at a low level, and Q9 is turned off, so as to achieve the purpose of anti-reverse connection.

[0037] Optionally, the detection system further includes high-side electrical isolation transistors (for example, Q1, Q3, Q5) and low-side electrical isolation transistors (for example, Q2, Q4, Q6). As Figure 2 shown, the first ends of the heating induction units (w1, w2, w3) are connected to the output terminals of the high-side drive unit U1 through the high-side electrical isolation transistors (Q1, Q3, Q5), and the second ends are grounded through the low-side electrical isolation transistors (Q2, Q4, Q6).

[0038] In some examples, the high-side electrical isolation transistor and / or the low-side electrical isolation transistor is a field effect transistor. The high-side electrical isolation transistor is used for high-side electrical isolation of each area capacitance acquisition channel. The low-side electrical isolation transistor is used for low-side electrical isolation of each area capacitance acquisition channel.

[0039] In some examples, the high-side electrical isolation transistor is a P-type field effect transistor. The P-type field effect transistors are all reversely connected to block the potential path through the body diode to the source. The control terminals of the P-type field effect transistors are all grounded through resistors. In this example, the control logic is simplified by pulling down the gate (G gate) of the P-type field effect transistor, and the parasitic circuits in the heating on and off states are unified to avoid the influence of heating on capacitance acquisition. In the prior art, the switching of the on / off state of the heating function will generate noise in the signal of the induction detection channel (capacitance detection channel). When the heating function is turned on, the signal processing unit sets the G gates of the P-type field effect transistors (Q1, Q3, and Q5) high to turn on the field effect transistors in the three regions. There will be a parasitic circuit in the capacitance detection channel from the body diode of the P-type field effect transistor to the source (S pole), then through the GS bridging resistor, the G pole current-limiting resistor to the ground. When the heating function is turned off and the capacitance detection channel is turned on, there will be a parasitic circuit in the capacitance detection channel from the body diode of the P-type field effect transistor to the S pole, then through the GS bridging resistor, the G pole capacitor to the ground. In both states, the parasitic capacitance of the circuit is different. Moreover, during the stage of turning off the heating function and performing the induction function (i.e., the capacitance detection channel works), the discharge of the capacitor at the G pole will also cause a change in the parasitic capacitance value of the circuit. In summary, the switching of the heating function will cause a change in the parasitic capacitance of the capacitance detection channel, thereby interfering with the detection of the capacitance change caused by the target object. In addition, there is also mutual interference in the detection results between multiple regions in the prior art (i.e., touching one region will interfere with the other regions). In this example, by reversely connecting each region's P-type field effect transistor to block the potential path through the body diode to the S pole and grounding the control terminals through resistors, the above problems are effectively solved, making the P-type field effect transistor not require the control of the information processing unit, simplifying the software control logic and not affecting the heating function; making the parasitic circuits the same when the heating function is turned on and off, avoiding the influence of the switching between the heating function and the induction function on capacitance detection; and moreover, the existence of the body diode realizes more thorough electrical isolation for each region, avoiding mutual interference in the detection results between multiple regions.

[0040] In some examples, the low-side electrical isolation transistor is an N-type field effect transistor. The control terminal of the N-type field effect transistor is connected to the signal processing unit U2. When an abnormality occurs in the high-side circuit, the signal processing unit U2 can turn off the heating path by controlling the low-side electrical isolation transistor to cut off, so as to meet the functional safety goal.

[0041] The detection system includes multi-zone inductive detection channels (SEN1, SEN2, SEN3). Preferably, the sum of the output capacitances (Coss) and other parasitic capacitances of all transistors (e.g., Q1 - Q6 in the figure) in the multi-zone inductive detection channels is less than the upper limit of the load capacity of the signal processing unit U2. The reasons are as follows: Due to the existence of the output capacitance Coss of the high-side and low-side electrically isolated transistors, during the period when the heating function is turned off and the inductive function is turned on, the Coss of the high-side and low-side electrically isolated transistors is incorporated, resulting in an excessive or even exceeding parasitic capacitance in the inductive detection channel. The larger the Coss of the transistor, the larger the parasitic capacitance of the detection channel, and the smaller the detectable signal amount. An excessive Coss of the transistor will cause the total parasitic capacitance of the detection channel to exceed the upper limit of the load capacity of the capacitance acquisition and drive chip (for example, the upper limit of the recognizable capacitance change of the AS8579 chip of AMS is 2000pf), resulting in no obvious change in the sensed data after a finger or palm touches the steering wheel. Based on this, the present invention proposes to select a MOSFET with a smaller Coss at the DC bias voltage of the drive signal of the signal processing unit (capacitance detection chip) (for example, the DC bias voltage of the AS8579 chip of AMS is Min: 1.18V, Typ: 1.23V, Max: 1.28V), so as to weaken the influence of the parasitic capacitance of the transistor on the incremental detectable signal.

[0042] Furthermore, the sum of the output capacitances and other parasitic capacitances of all transistors in the multi-zone inductive detection channels is less than 60% of the upper limit of the load capacity of the signal processing unit U2. The reasons are as follows: Based on the characteristic that capacitance increases at high temperatures and practical experience, controlling the parasitic capacitance below 60% of the upper limit can effectively reduce the influence of the ambient temperature on the detection result and improve the detection accuracy. Under the same other external factors, the smaller the output capacitance Coss of the transistors in the detection channel, the smaller the total parasitic capacitance on the capacitance detection channel, which is more conducive to improving the signal amount in the detection channel and the detection accuracy.

[0043] Optionally, the detection system may further include a system base chip (SBC, System Base Chip). The SBC integrates basic chips such as a low dropout linear regulator (LDO, Low Drop Output), a transceiver, and a watchdog, and has functions such as supplying power to the signal processing unit U2, CAN or LIN transceiver, and external watchdog monitoring, and has advantages such as high system integration, low cost, and small PCB space occupation. In some other examples, the SBC can also be implemented using a discrete IC architecture that can achieve the above functions.

[0044] Reference Figure 3, the working principle of the detection system for performing the heating function is described as follows: During this period, the three capacitance detection channels of SEN1, SEN2, and SEN3 are closed. Q7 and Q8 are closed because their G poles are controlled to be low by U2. Although Q9 is open, it becomes meaningless due to the closure of Q8. U1 is opened under the control of the U2 pin. The S poles of the P-channel MOSFETs Q1, Q3, and Q5 obtain a high voltage through their body diodes, making VGS less than the conduction threshold and thus opening. The N-channel MOSFETs Q2, Q4, and Q6 are opened because the control pin LS_EN of U2 is set high. Therefore, a heating circuit for the first zone is formed from the heating power supply through U1, Q1, W1, Q2 to the ground; a heating circuit for the second zone is formed from the heating power supply through U1, Q3, W2, Q4 to the ground; a heating circuit for the third zone is formed from the heating power supply through U1, Q5, W3, Q6 to the ground. Note: Heating itself does not require zoning. Due to the requirements of the HOD in the three zones, the three metal wires cannot have electrical connections, so the heating is divided into three zones. In fact, the heating in the three zones is switched on and off simultaneously.

[0045] Reference Figure 4 , the working principle of the detection system for performing the induction function is described as follows: During this period, the three capacitance detection channels of SEN1, SEN2, and SEN3 are open. Q7 and Q8 are opened because their G poles are controlled to be high by U2. U1 is closed when the U2 pin is set low or pulled low by the opening of Q7. The output terminal of U1 is shorted to the ground. The P-channel MOSFETs Q1, Q3, and Q5 cannot meet the conduction conditions and are closed. The N-channel MOSFETs Q2, Q4, and Q6 are closed because the control pin LS_EN of U2 is set low. Therefore, the parasitic capacitance of the SEN1 capacitance detection channel is equivalent to: Coss1 + Coss2 + Cp1 (capacitance of devices such as TVS) + Cp2 (parasitic capacitance of the trace), and Coss1 + Coss2 >> Cp1 + Cp2; the parasitic capacitance of the SEN2 capacitance detection channel is equivalent to Coss3 + Coss4 + Cp3 (capacitance of devices such as TVS) + Cp4 (parasitic capacitance of the trace), and Coss3 + Coss4 >> Cp3 + Cp4; the parasitic capacitance of the SEN3 capacitance detection channel is equivalent to Coss5 + Coss6 + Cp5 + Cp6, and Coss5 + Coss6 >> Cp5 + Cp6. Therefore, by selecting MOSFETs with smaller Coss under the DC bias voltage, the parasitic capacitance can be reduced and the signal volume can be increased.

[0046] Another embodiment of the present invention proposes a device, which can be a steering wheel system including the circuit 100 or the detection system described above, or a seat system including the circuit 100 or the detection system described above.

[0047] It should be noted that the present invention (such as the inventive concept, etc.) has been described in the specification of this patent document and / or illustrated in the figures according to exemplary embodiments; the embodiments of the present invention are presented by way of example only and are not intended to limit the scope of the present invention. The structure and / or arrangement of the elements of the inventive concept embodied in the present invention as described in the specification and / or illustrated in the figures are merely illustrative. Although the exemplary embodiments of the present invention have been described in detail in this patent document, it is readily understood by those of ordinary skill in the art that equivalents, modifications, variations, etc. of the subject matter of the exemplary embodiments and alternative embodiments are possible and are considered to be within the scope of the present invention; all such subject matter (such as modifications, variations, embodiments, combinations, equivalents, etc.) is intended to be included within the scope of the present invention. It should also be noted that various / other modifications, variations, substitutions, equivalents, alterations, omissions, etc. can be made in the configuration and / or arrangement of the exemplary embodiments (such as in terms of concept, design, structure, device, form, assembly, construction, means, function, system, process / method, steps, order of process / method steps, operation, operating conditions, performance, materials, composition, combination, etc.) without departing from the scope of the present invention; all such subject matter (such as modifications, variations, embodiments, combinations, equivalents, etc.) is intended to be included within the scope of the present invention. The scope of the present invention is not intended to be limited to the subject matter described in the specification and / or figures of this patent document (such as details, structure, function, materials, behavior, steps, order, system, results, etc.). Considering that the claims of this patent document will be appropriately construed to cover the full scope of the subject matter of the present invention (such as including any and all such modifications, variations, embodiments, combinations, equivalents, etc.); it should be understood that the terms used in this patent document are for the purpose of describing the subject matter of the exemplary embodiments and not as a limitation on the scope of the present invention.

[0048] It should also be noted that, according to exemplary embodiments, the present invention may include conventional technologies (such as technologies implemented and / or integrated in exemplary embodiments, modifications, variations, combinations, equivalents), or may include any other applicable technologies (present and / or future) having the ability to perform the functions and processes / operations described in the specification and / or illustrated in the figures. All such technologies (such as technologies implemented in the form of embodiments, modifications, variations, combinations, equivalents, etc.) are considered to be within the scope of the present invention in this patent document.

Claims

1. A circuit for coupling with a heating induction unit to control the heating induction unit to perform an induction function at a first time and a heating function at a second time, the circuit comprising: A high-side drive unit, a signal processing unit, and a switching unit, A first end of the switching unit is grounded, a second end is connected to an output end of the high-side drive unit, and a third end is connected to the signal processing unit. Wherein, when the heating induction unit performs the induction function, the signal processing unit controls the switching unit to conduct so that the output end of the high-side drive unit is grounded.

2. The circuit according to claim 1, comprising: An overcurrent protection unit, a first end of which is grounded, a second end is connected to a control end of the high-side drive unit, and a third end is connected to the third end of the switching unit, for turning off the output of the high-side drive unit to implement overcurrent protection when the heating induction unit performs the heating function and the switching unit conducts abnormally.

3. The circuit according to claim 1, comprising: An anti-reverse connection protection unit, which is connected in series between the switching unit and the ground, and its control end is connected to a turn-off power supply, for disconnecting when the power supply is reversely connected to implement anti-reverse connection protection.

4. The circuit according to any one of claims 1 to 3, wherein The switching unit, the overcurrent protection unit, and / or the anti-reverse connection protection unit is a metal oxide semiconductor field effect transistor.

5. The circuit according to claim 1, comprising a multi-zone induction detection channel, each zone of the multi-zone induction detection channel comprising a high-side electrical isolation transistor and a low-side electrical isolation transistor, and the sum of the output capacitances and other parasitic capacitances of all transistors in the multi-zone induction detection channel under the DC bias voltage is less than the upper limit of the load capacity of the signal processing unit.

6. The circuit according to claim 5, wherein, The sum of the output capacitances and other parasitic capacitances of all transistors in the multi-zone induction detection channel under the DC bias voltage is less than sixty percent of the upper limit of the load capacity of the signal processing unit.

7. The circuit according to claim 5, wherein, The high-side electrical isolation transistor is a P-type field effect transistor, and the P-type field effect transistors are all reversely connected to block the potential path through the body diode to the source, and the control ends of the P-type field effect transistors are all grounded through resistors.

8. The circuit according to claim 5, wherein The low-side electrical isolation transistor is an N-type field effect transistor, and the control end of the N-type field effect transistor is connected to the signal processing unit.

9. The circuit according to claim 1, wherein, The switching unit is an N-type field effect transistor.

10. A detection system, which comprises the circuit according to any one of claims 1 to 9 and a heating induction unit coupled to the circuit, and the circuit controls the heating induction unit to perform an induction function at a first time and a heating function at a second time.

11. The detection system according to claim 10, wherein, The heating induction unit is a metal layer, which forms a capacitor with a part of the human body located within the sensing area of the metal layer when performing the induction function, and the detection system obtains capacitance information or capacitance characterization information through the capacitor.

12. An apparatus, which is a steering wheel system or a seat system comprising the circuit according to any one of claims 1 to 9 or the detection system according to any one of claims 10 to 11.

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