A heating device

Abstract

The present invention provides a heating device, which is used for heating the hands on the steering wheel and detecting whether the driver's hands are close to the steering wheel, and is also used for heating the human body on the seat and detecting whether the driver and the passenger are sitting on the seat. It has: a heating element that can generate heat when powered on, at least one switch that controls whether the heating element is powered on, a heating control circuit that controls the switch state, and a detection circuit that detects the proximity of human hands or human bodies. It is characterized in that the heating element is multiplexed in time, and the cooperation of the heating control circuit and the switch uses the heating element to realize the first function of heating the human hand or human body; the detection circuit also uses the heating element as a sensor to realize the second function of detecting the proximity of human hands or human bodies. Due to the reuse of sensors and actuators, the system cost and product space occupied are greatly reduced.

Description

Technical Field

[0001] The present invention relates to a heating device capable of detecting the approach or contact of a human body, and is particularly used for detecting whether there are passengers on vehicle seats and heating the passengers, or for detecting whether the driver's hands are placed on the steering wheel and heating the hands at the same time. Background Art

[0002] The human body approach detection system and heating system on the market are completely separate and independent. The heating circuit controls the heating element to heat up, and the human body detection circuit collects the signal of the human body approach contact sensor and sends it to the whole vehicle. The heating element and the human body approach contact sensor are electrically independent of each other, but they are structurally separated by insulating materials to form a multi-layer bonding structure. Therefore, if a system that combines the two electrically can be invented, the system cost will be greatly reduced. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a heating device that can detect the approach or contact of a human body. The device uses a heating element to perform both the heating function and the human body approach contact sensor function, and eliminates all inductors, thereby reducing system costs. At the same time, a new human body detection circuit is provided to ensure the feasibility of the heating device of the present invention.

[0004] The heating device of the present invention has a human body detection circuit 103 and a heating state control circuit 104 and a series circuit including a first switch 101, a first terminal 98, a heating element 100, a second terminal 99, and a second switch 102 (if any). The series circuit is electrically connected between the positive and negative poles of the power supply. The human body detection circuit 103 is electrically connected to a certain point in the wiring path of the first terminal 98 or the heating element 100, and uses an electromagnetic field to detect whether there is a driver or a hand holding the seat. The heating state control circuit 104 controls the first switch 101 and the second switch 102 (if any) to be turned on or off, so that the heating element 100 emits the necessary heat to heat and keep the human body or hand warm, and feeds back the switch control state to the human body detection circuit 103. The human body detection circuit 103 timely adjusts the threshold for judging the state of the human hand or human body according to the different states of the switch, or invalidates the detection results in some states or some time periods.

[0005] Effects of the Invention

[0006] According to the heating device of the present invention, the heating element 100 is used as both a heating element and a human body detection sensor, which are combined into one, thereby reducing the system cost. According to the human body detection circuit 103 of the present invention, it can adapt to all common capacitive human body proximity contact sensors on the market including the heating device of the present invention, and avoids the complex structures such as traditional constant current sources and various AC sources, thereby further reducing the system cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of a first configuration example of the heating device of the present invention.

[0008] Figure 2 It is a schematic diagram of a second configuration example of the heating device of the present invention.

[0009] Figure 3 It is a schematic diagram of a third configuration example of the heating device of the present invention.

[0010] Figure 4 It is a schematic diagram of a fourth configuration example of the heating device of the present invention.

[0011] Figure 5 1 is a block diagram of the human body detection circuit 103 module of the present invention.

[0012] Figure 6 It is a specific example of the human body detection circuit 103 of the present invention.

[0013] Figure 7 1 is a voltage curve at the input terminal of the comparator in the specific example of the human body detection circuit 103 of the present invention. DETAILED DESCRIPTION

[0014] A heating device involved in the present invention comprises: a heating element 100 with a first terminal 98 and a second terminal 99 arranged on a steering wheel rim or a seat, a first switch 101 connected in series with the first terminal 98 of the heating element 100, and a possible second switch 102 connected in series with the second terminal 99 of the heating element 100. The series structure formed by the heating element 100 and the switch is connected in series between the positive and negative poles of the power supply. In addition, a necessary heating control circuit 104 controls the opening and closing of the switch to make the heating element 100 heat up. In combination with a temperature sensor, the steering wheel or seat is always in a temperature range suitable for human hands or human bodies, thereby achieving the first purpose of heating. In order to achieve the second purpose of human body approach contact detection, the heating element 100 is also used as a human body approach contact sensor. The human body detection circuit 103 is electrically connected to the first terminal 98 of the heating element 100.

[0015] The heating element 100 may include a heating wire connected between the first terminal 98 and the second terminal 99 and arranged in a plurality of circuitous ways in the area to be heated, or a plurality of heating wires in parallel. It may also be a planar heating body or a plurality of planar heating bodies in parallel.

[0016] The first switch 101 and the second switch 102 (if any) refer to any switch or circuit or combination of switches and circuits that can cut off or turn on the power supply of the heating element 100 in any mechanical or electronic sense, including but not limited to mechanical switches, temperature control switches, thermostats, relays, reed switches, diodes, triodes, field effect transistors, thyristors, thyristors, etc.

[0017] The steering wheel can be built with multiple sets of the heating device of the present invention, so that multi-zone heating and multi-zone independent human hand detection can be formed, and the heating and detection effects are more refined. According to different areas, single hand and double hand, as well as different grip postures such as whether the human hand is wrapped around the steering wheel rim can be detected.

[0018] The seat can be equipped with multiple sets of the heating device of the present invention. Through reasonable area layout, the size of the human body in contact with the seat can be identified, thereby achieving the purpose of identifying the occupant classification of adults and children; the actual contact area can also be known, and energy saving can be achieved by heating only the contact area. The heating device of the present invention is arranged on the back of the seat, which can identify whether the driver and the passenger are in contact with the back of the seat, as well as the distance from the back of the seat, and can accurately identify the posture of the driver and the passenger, so that the vehicle can make the most appropriate safety strategy. For example, the airbag detonation curve, the tightening strategy of the pre-tightened seat belt, etc.

[0019] According to this composition, Figure 1 In the schematic diagram of the first configuration example of the heating device shown in the figure, one end of the first switch 101 is electrically connected to the first terminal 98 of the heating element 100, and the other end of the first switch 101 is electrically connected to the positive electrode of the power supply. One end of the second switch 102 is electrically connected to the second terminal 99 of the heating element 100, and the other end of the second switch 102 is electrically connected to the negative electrode of the power supply. The detection point of the detection circuit 103 is the first terminal 98 close to the positive electrode of the power supply. The heating control circuit 104 controls the opening and closing of the first switch 101 and the second switch 102, and sends the control state to the detection circuit 103.

[0020] According to this composition, Figure 2 In the schematic diagram of the second configuration example of the heating device shown in the figure, one end of the first switch 101 is electrically connected to the first terminal 98 of the heating element 100, and the other end of the first switch 101 is electrically connected to the negative pole of the power supply. One end of the second switch 102 is electrically connected to the second terminal 99 of the heating element 100, and the other end of the second switch 102 is electrically connected to the positive pole of the power supply. The detection point of the detection circuit 103 is the first terminal 98 close to the negative pole of the power supply. The heating control circuit 104 controls the opening and closing of the first switch 101 and the second switch 102, and sends the control state to the detection circuit 103.

[0021] According to this composition, Figure 3In the third configuration example of the heating device shown in FIG. 1 , one end of the first switch 101 is electrically connected to the first terminal 98 of the heating element 100, and the other end of the first switch 101 is electrically connected to the positive electrode of the power supply. The second switch 102 is omitted, and the second terminal 99 of the heating element 100 is directly electrically connected to the negative electrode of the power supply. The detection point of the detection circuit 103 is the first terminal 98 close to the positive electrode of the power supply. The heating control circuit 104 controls the opening and closing of the first switch 101, and sends the control state to the detection circuit 103.

[0022] According to this composition, Figure 4 In the fourth configuration example of the heating device shown in FIG. 1 , one end of the first switch 101 is electrically connected to the first terminal 98 of the heating element 100, and the other end of the first switch 101 is electrically connected to the negative pole of the power supply. The second switch 102 is omitted, and the second terminal 99 of the heating element 100 is directly electrically connected to the positive pole of the power supply. The detection point of the detection circuit 103 is the first terminal 98 close to the negative pole of the power supply. The heating control circuit 104 controls the opening and closing of the first switch 101, and sends the control state to the detection circuit 103.

[0023] The present invention relates to a human body detection circuit 103. Figure 5, the charge and discharge controller 114 of the human body detection circuit 103 charges and discharges the heating element 100 through the charge and discharge current limiter 112. As the output of the voltage comparator 115 is continuously turned over, the charge and discharge process is also continuously alternated, and the voltage of the inverting input terminal of the voltage comparator 115 also alternately rises and falls. Through the reasonable adjustment of the threshold value adjuster 111 electrically connected to the in-phase input terminal, the voltage of the inverting input terminal will be higher than the set threshold value at the non-phase input terminal from time to time, and lower than the set threshold value at the non-phase input terminal from time to time. In this way, the output of the voltage comparator 115 will form a repeated reversal of high and low levels, and the whole system will form a continuous oscillation and a continuous repeated reversal of the level. However, since the threshold value of the in-phase input terminal is only a determined threshold point, the inverting input terminal will repeatedly oscillate at this threshold point at high frequency, which is not conducive to later measurement and calculation. Therefore, a threshold hysteresis module 113 is added to make a reasonable change in the reference threshold of the in-phase input terminal. When the voltage of the inverting input terminal is low, the threshold is set higher; when the voltage of the inverting input terminal is high, the threshold is set lower, so that the threshold forms an effective hysteresis effect. By reasonably setting the threshold hysteresis effect, the system oscillation frequency returns to the desired level. When all parameter settings are fixed, when a human hand or human body comes into contact with the heating element 100 as a proximity sensor, the equivalent capacitance of the proximity sensor will change, and then the oscillation frequency of the system will change accordingly. The microcontroller can identify the degree of proximity of the human hand or human body by monitoring the changes in the oscillation frequency. In general, the closer the human hand or human body is to the heating element 100, the larger the equivalent capacitance and the lower the oscillation frequency will be. It should be noted that Figure 5 The equivalent capacitor 110 connected to the ground is just an equivalent network model, not an obvious capacitor connected to the ground through a visible electrical wire. The equivalent to the actual electrical situation is: the equivalent capacitance formed by the heating element 100 through the air and various metal or non-metal materials around it to the various electrical dielectrics of the ground. The actual situation may be equivalent to a complex series-parallel network of resistors, capacitors and inductors, but in this application, the capacitor component plays a dominant role. Figure 5 In the block diagram, only capacitor 110 is drawn to replace the complex impedance network.

[0024] The human body detection circuit 103 only works or outputs valid during the time period when the first switch 101 and the second switch 102 (if any) are turned off and the heating element 100 stops heating. Considering the inductance of the heating element 100, it takes a certain amount of time for the current to be released during the transition period from the switch being turned on to the switch being turned off. Therefore, after the switch is turned off, a delay period is required to ensure that the current of the heating element 100 is completely released before the human body detection circuit 103 starts to work or the output of the human body detection circuit 103 is considered valid.

[0025] Figure 6It is a specific example according to the structure. In this specific example, C1 is the equivalent capacitance of the human body approaching the contact detection sensor, and the charge and discharge controller is a resistor R23 electrically connected between the output terminal and the inverting input terminal of the voltage comparator U1. When the voltage comparator outputs a high level, the charge and discharge circuit is charged, and when the voltage comparator outputs a low level, the charge and discharge circuit is discharged, so as to achieve the purpose of controlling the charge and discharge; the charge and discharge current limiter 112 is a resistor R24, one end of which is connected in series with the capacitance sensor to the ground, and the other end is connected to the inverting input terminal of the voltage comparator, which effectively limits the charge and discharge current; in some cases, R24 can be omitted and replaced by the charge and discharge controller R23. The threshold regulator is two resistors R20 and R21 connected in series between the power supply and the ground, forming a basic threshold reference voltage, which is electrically connected to the non-inverting input terminal of the voltage comparator U1; the threshold hysteresis is a resistor R22 electrically connected between the output terminal and the non-inverting input terminal of the voltage comparator U1, which is positively fed back to the threshold regulator, so that the threshold produces a step effect of two different values. When the voltage at the inverting input terminal is low, the voltage comparator U1 outputs a high level, and the threshold hysteresis device makes the reference voltage at the positive input terminal at a higher high threshold point. The voltage at the inverting input terminal needs to be continuously charged to a higher level at the high threshold point before the output of the voltage comparator U1 will flip to a low level. At the same time, since the voltage comparator U1 outputs a high level, the charge and discharge controller is in the charging mode, so that the voltage at the inverting input terminal continues to increase until it exceeds the high threshold point, and the output of the voltage comparator U1 will flip; when the voltage at the inverting input terminal is high, the voltage comparator U1 outputs a low level, and the threshold hysteresis device makes the reference voltage at the positive input terminal at a lower low threshold point. The charge and discharge controller is in the discharge mode, and the voltage at the inverting input terminal will continue to decrease until it is lower than the low threshold point, and the output of the voltage comparator U1 will flip again. With repeated oscillations, the system will convert different equivalent capacitances into corresponding frequency signals with different frequency values. When the single-chip microcomputer detects different frequency changes, it can sense changes in the proximity or contact state of a human hand or human body. According to the circuit of this specific example, Figure 7 The solid line in the curve shown is the threshold voltage change waveform of the positive input terminal of the voltage comparator U1. Figure 7 The dotted line in the curve is the voltage change waveform of the charge and discharge circuit at the inverting input of the voltage comparator U1. As can be seen from the figure, the voltage at the positive input jumps back and forth between the high threshold point and the low threshold point, and the voltage at the inverting input repeatedly charges and discharges following the threshold change. The output signal of the voltage comparator ( Figure 7 (not shown) is a frequency signal with the same frequency and duty cycle as the positive phase input terminal, but the high and low level amplitudes are different.

[0026] Explanation of symbols:

[0027] 98 First terminal

[0028] 99 Second terminal

[0029] 100 Heating Elements

[0030] 101 First Switch

[0031] 102 Second switch

[0032] 103 Human body approaching contact detection circuit

[0033] 104 Heating control circuit

[0034] 110 Human body close to the equivalent capacitance of the contact sensor

[0035] 111 Threshold Adjuster

[0036] 112 Charge and discharge current limiter

[0037] 113 Threshold Hysteresis

[0038] 114 Charge and Discharge Controller

[0039] 115 voltage comparator.

Claims

1. A heating device, characterized in that: include A heating element is arranged on a steering wheel or a seat, and the heat generated by energizing it can heat a human hand or a human body, and it has a first terminal and a second terminal electrically connected to other electrical elements; A first switch, one end of which is electrically connected to the first terminal of the heating element, and the other end of which is electrically connected to the positive or negative electrode of the power supply, and the heating element can be controlled to be powered on or off by turning the switch on and off; a second switch, one end of which is electrically connected to the second terminal of the heating element, and the other end of which is electrically connected to the negative electrode or the positive electrode of the power supply, and which controls the power-on state of the heating element together with the first switch; and A human body detection circuit is electrically connected to the first terminal of the heating element to detect whether a hand touches the steering wheel or whether a human body sits on the seat; The heating device further comprises: a heating state control unit for controlling the first switch and the second switch to be turned on or off; the heating state control unit controls the first switch and the second switch to be turned on or off and synchronizes the on or off state of the first switch and the second switch to the human body detection circuit, so that the human body detection circuit can effectively detect whether a human hand or human body is close to or in contact with the steering wheel or the seat by setting different thresholds in different states using the heating element; The human body detection circuit includes: The threshold regulator is electrically connected to the non-inverting input terminal of the voltage comparator; The capacitance sensor and the charge and discharge current limiter are connected in series to form a charge and discharge circuit, which is electrically connected to the inverting input terminal of the voltage comparator; The threshold hysteresis device is electrically connected between the output terminal and the non-inverting input terminal of the voltage comparator, and positively feeds back the output signal to the threshold regulator to cause a certain hysteresis in the threshold value; The charge and discharge controller is electrically connected between the output terminal and the inverting input terminal of the voltage comparator, and negatively feeds back the output signal to the charge and discharge circuit, so that the capacitance sensor is repeatedly charged and discharged, so as to achieve the purpose of converting the capacitance value into a frequency signal.

2. The heating device according to claim 1, characterized in that: If the second switch is not present, the second terminal of the heating element is directly electrically connected to the negative or positive pole of the power supply.

3. The heating device according to claim 1, characterized in that: The first switch and the second switch refer to switches or circuits or a combination of switches and circuits that can cut off or turn on the power supply to the heating element.

4. The heating device according to claim 1, characterized in that: The heating element comprises a heating wire connected between the first terminal and the second terminal and arranged in a plurality of circuitous ways in the area to be heated, or a plurality of sections of heating wire connected in parallel.

5. The heating device according to claim 1, characterized in that: The heating element includes a planar heating body connected between the first terminal and the second terminal and arranged in the area to be heated, or a plurality of planar heating bodies connected in parallel.

6. The heating device according to claim 1, characterized in that: By controlling the power-on state of the heating element through the first switch and the second switch and combining with the temperature sensor, the steering wheel or the seat can be kept at a temperature state that is comfortable for the human body.

7. The heating device according to claim 1, characterized in that: The human body detection circuit obtains the on or off status information of the first switch and the second switch from the heating status control unit, thereby specifically adjusting the threshold for judging the state of the hand or human body or invalidating the detection results in some states or some time periods.

8. The heating device according to claim 1, characterized in that: The threshold regulator is two resistors R20 and R21 connected in series between the power supply and the ground, forming a basic threshold reference voltage, which is electrically connected to the non-inverting input terminal of the voltage comparator U1; the threshold hysteresis device is a resistor R22 electrically connected between the output terminal and the non-inverting input terminal of the voltage comparator U1, and positively fed back to the threshold regulator, so that the threshold produces two different steps; the charge and discharge controller is a resistor R23 electrically connected between the output terminal and the inverting input terminal of the voltage comparator U1, and when the voltage comparator U1 outputs a high level, the charge and discharge circuit is charged, and when the voltage comparator U1 outputs a low level, the charge and discharge circuit is discharged, thereby achieving the purpose of controlling charge and discharge; the charge and discharge current limiter is a resistor R24, one end of which is connected in series with the capacitive sensor, and the other end is connected to the inverting input terminal of the voltage comparator U1, which effectively limits the charge and discharge current.

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