A PTC control circuit and a PTC control device

Abstract

The utility model discloses a kind of PTC control circuit and PTC control device, the PTC control circuit includes high voltage input circuit, main control circuit, water heat load control branch and air heat load control branch, high voltage input circuit includes high voltage bus, water heat load control branch, air heat load control branch one end is connected with high voltage bus positive pole electricity, water heat load control branch, air heat load control branch other end is connected with high voltage bus negative pole electricity, water heat load control branch includes series water heat control switch and water heat load unit, water heat control switch is connected with water heat switch drive circuit electricity, water heat switch drive circuit is connected with main control circuit electricity, air heat load control branch includes series air heat control switch and air heat load unit, air heat control switch is connected with air heat switch drive circuit electricity, air heat switch drive circuit is connected with main control circuit electricity.The PTC control device of the utility model integrates air, water heat control, reduce cost and volume, and reliability is high.

Description

Technical Field

[0001] This utility model belongs to the field of automotive air conditioning heating technology, specifically relating to a PTC control circuit and a PTC control device. Background Technology

[0002] Traditional PTC systems are typically separate water-based or air-based control systems, resulting in a large footprint in the vehicle layout and hindering weight reduction. Furthermore, this approach requires two separate control systems, which is detrimental to the efficient use of system resources. Therefore, there is an urgent need for an integrated control solution combining air and water-based PTC systems. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a PTC control circuit and a PTC control device.

[0004] In a first aspect, this utility model provides a PTC control circuit, including a high-voltage input circuit, a main control circuit, a water-heat load control branch, and a wind-heat load control branch. The high-voltage input circuit includes a high-voltage bus. One end of each of the water-heat load control branch and the wind-heat load control branch is electrically connected to the positive terminal of the high-voltage bus, and the other end of each branch is electrically connected to the negative terminal of the high-voltage bus. The water-heat load control branch includes a water-heat control switch and a water-heat load unit connected in series. The water-heat control switch is electrically connected to a water-heat switch drive circuit, which is also electrically connected to the main control circuit. The wind-heat load control branch includes a wind-heat control switch and a wind-heat load unit connected in series. The wind-heat control switch is electrically connected to a wind-heat switch drive circuit, which is also electrically connected to the main control circuit.

[0005] In some embodiments, the high-voltage input circuit further includes a protection circuit, the protection circuit comprising:

[0006] The first protection branch has one end electrically connected to the positive terminal of the high-voltage bus and the other end electrically connected to the negative terminal of the high-voltage bus. The first protection branch is equipped with a capacitor for suppressing input differential mode interference.

[0007] And / or,

[0008] The second protection branch has one end connected to the positive terminal of the high-voltage busbar and the other end connected to the negative terminal of the high-voltage busbar. A TVS diode is installed on the second protection branch.

[0009] And / or,

[0010] The third protection branch has one end electrically connected to the positive terminal of the high-voltage bus and the other end electrically connected to the negative terminal of the high-voltage bus. The third protection branch is equipped with a capacitor for suppressing input common-mode interference.

[0011] And / or,

[0012] A reverse connection protection diode is connected in series with the high voltage bus.

[0013] In some embodiments, the PTC control circuit of this utility model further includes a common high-side control switch. One end of the common high-side control switch is connected to the positive terminal of the high-voltage bus, and the other end of the common high-side control switch is connected to one end of the water-heat load control branch and the air-heat load control branch. The common high-side control switch is connected to a common high-side switch drive circuit, and the common high-side switch drive circuit is connected to the main control circuit.

[0014] In some embodiments, the PTC control circuit of this invention further includes:

[0015] The high-voltage sampling circuit is used to collect the voltage of the high-voltage bus. The output terminal of the high-voltage sampling circuit is electrically connected to the first input terminal of the main control circuit.

[0016] and / or

[0017] The first current sampling circuit is used to collect the current flowing through the water-thermal load control branch. The output terminal of the first current sampling circuit is connected to the second input terminal of the main control circuit.

[0018] and / or

[0019] It also includes a second current sampling circuit for collecting the current flowing through the wind-heat load control branch, and the output of the second current sampling circuit is connected to the third input of the main control circuit.

[0020] and / or

[0021] It also includes an inlet and outlet temperature acquisition circuit for acquiring the inlet and outlet temperatures, the output of which is connected to the fourth input of the main control circuit.

[0022] and / or

[0023] It also includes a core temperature acquisition circuit, the output of which is connected to the fifth input of the main control circuit via an analog isolation circuit.

[0024] In some embodiments, the PTC control circuit of this utility model further includes a low-voltage power supply circuit, which includes a low-voltage input circuit, a power management circuit, and a first LDO circuit. The input terminal of the low-voltage input circuit is connected to the low-voltage power supply, the output terminal of the low-voltage input circuit is connected to the input terminal of the power management circuit, the input terminal of the first LDO circuit is connected to the output terminal of the power management circuit, and the output terminal of the first LDO circuit is connected to the main control circuit for supplying power to the main control circuit.

[0025] In some embodiments, the PTC control circuit of this utility model further includes a communication circuit, one end of which is connected to the main control circuit via a communication isolation circuit, and the other end of which is connected to a low-voltage connector.

[0026] In some embodiments, the PTC control circuit of this invention further includes an interlock detection circuit, which is connected to the main control circuit via an interlock isolation circuit.

[0027] In some embodiments, a first isolation circuit is provided between the main control circuit and the water-heating switch drive circuit;

[0028] and / or

[0029] A second isolation circuit is provided between the main control circuit and the air-heat switch drive circuit;

[0030] And / or,

[0031] Both the water-heat control switch and the air-heat control switch are transistors.

[0032] And / or,

[0033] Both the water-heating switch drive circuit and the air-heating switch drive circuit use transistor drive circuits.

[0034] In some embodiments, the transistor driving circuit includes an input and preamplifier circuit and a push-pull driving circuit. The input terminal of the input and preamplifier circuit is electrically connected to the output terminal of the main control circuit, the output terminal of the input and preamplifier circuit is electrically connected to the input terminal of the push-pull driving circuit, and the output terminal of the push-pull driving circuit is electrically connected to the gate of the transistor.

[0035] Secondly, this disclosure also provides a PTC control device, including the PTC control circuit as described in the first aspect.

[0036] In some embodiments, the PTC control device further includes a control board, the PTC control circuit is disposed on the control board, and a conductive layer is disposed on the surface of the high-voltage bus copper foil traces on the control board.

[0037] This utility model has at least the following beneficial effects:

[0038] This utility model's PTC control device integrates air and water heating control systems, meeting diverse customer needs for air and water heating PTC applications. This integrated solution significantly improves product compatibility and substantially reduces mass production costs. Furthermore, the integrated air and water heating control of this utility model reduces cost and size while maintaining high reliability.

[0039] This integrated solution is designed with isolation between the air, water, and heat control components, as well as high and low pressure isolation. The modular design allows for independent control of the air, water, and heat, ensuring that even if a failure occurs, the remaining components will not be affected, thus guaranteeing high product reliability.

[0040] Compared with traditional PTC circuit design, the integrated solution of this utility model has higher EMC requirements. In addition to using conventional anti-interference measures for the air-water-heating system in the PCB design, it also implements reverse connection protection and surge protection design for high voltage input.

[0041] This invention integrates a ventilation and heating control system, allowing for independent operation of the ventilation and heating control components without interference. Furthermore, it employs an independent high-voltage current acquisition unit for real-time monitoring of each heating module.

[0042] Furthermore, the system employs high- and low-side IGBT control, avoiding the vehicle-wide failure caused by IGBT failure in traditional PTC systems, resulting in high overall system reliability. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 A schematic block diagram of a PTC control circuit provided in one embodiment of this utility model;

[0045] Figure 2 A schematic diagram of a PTC control circuit provided for another embodiment of the present invention;

[0046] Figure 3 A circuit diagram of the high-voltage input circuit provided for an embodiment of this utility model;

[0047] Figure 4 Circuit diagram of the communication circuit provided in the embodiment of this utility model;

[0048] Figure 5 A circuit diagram of a communication isolation circuit provided for an embodiment of this utility model;

[0049] Figure 6 A circuit diagram of the IGBT driving circuit provided for an embodiment of this utility model;

[0050] Figure 7 A circuit diagram of the analog isolation circuit provided for an embodiment of this utility model;

[0051] Figure 8 The circuit diagram of the multi-channel isolation chip provided in the embodiment of this utility model. Detailed Implementation

[0052] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0053] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this utility model, unless otherwise stated, "a plurality of" or "several" means two or more.

[0054] See Figure 1 and Figure 2 This utility model provides a PTC control circuit, including a high-voltage input circuit, a main control circuit, a water-heat load control branch, and a wind-heat load control branch. The high-voltage input circuit includes a high-voltage bus. One end of each of the water-heat load control branch and the wind-heat load control branch is electrically connected to the positive terminal of the high-voltage bus, and the other end is electrically connected to the negative terminal of the high-voltage bus. The water-heat load control branch includes a water-heat control switch and a water-heat load unit connected in series. The water-heat control switch is electrically connected to a water-heat switch drive circuit, and the water-heat switch drive circuit is electrically connected to the main control circuit. The wind-heat load control branch includes a wind-heat control switch and a wind-heat load unit connected in series. The wind-heat control switch is electrically connected to a wind-heat switch drive circuit, and the wind-heat switch drive circuit is electrically connected to the main control circuit.

[0055] In some embodiments, the PTC control circuit further includes a high-voltage connector, through which high-voltage power is input to the high-voltage bus. In some embodiments, the PTC control circuit further includes a low-voltage connector, through which low-voltage power is input.

[0056] The main control circuit is used to control the heating of the air-cooled and water-cooled PTC loads, as well as product communication. The water-cooled load unit is used for heating in the water-cooled zone. The air-cooled load unit is used for heating in the air-cooled zone. The high-voltage connector is used for high-voltage power supply; the low-voltage connector is used for low-voltage power supply and communication.

[0057] This utility model's PTC control device comprises a water-heating control system and a wind-heating control system. The water-heating control system, due to its high heating comfort, is widely used in battery and air conditioning heating systems; the wind-heating control system, due to its rapid temperature exchange, is commonly used in vehicle auxiliary heating systems (including glass defrosting and defogging, and seat heating). This utility model's PTC control device integrates wind and water-heating control systems, meeting different customer needs for wind and water-heating PTC applications. This integrated solution greatly improves product compatibility and significantly reduces mass production costs. Furthermore, the integration of wind and water-heating control in this utility model reduces cost and size while maintaining high reliability.

[0058] In some embodiments, the main control circuit uses an MCU.

[0059] In some embodiments, the PTC control circuit further includes a high-voltage sampling circuit for acquiring the input high voltage, wherein the input terminal of the high-voltage sampling circuit is electrically connected to the high-voltage input circuit, and the output terminal of the high-voltage sampling circuit is electrically connected to the first input terminal of the main control circuit.

[0060] The high-voltage sampling circuit includes a voltage divider network, and one of the voltage divider nodes of the voltage divider network is a voltage sampling point.

[0061] The voltage divider network includes several resistors (the number of resistors is set as needed), which are connected in series between the positive and negative terminals of the high-voltage bus. An RC low-pass filter circuit is provided between the voltage divider node and the analog input interface (AI HV_INPUT) for noise suppression. The RC low-pass filter circuit includes resistor R14 and capacitor C14. One end of resistor R14 is connected to the voltage divider node, and the other end of resistor R14 is connected to one end of capacitor C14 and the analog input interface AI HV_INPUT of the main control circuit (such as the ADC of an MCU or the analog input interface of a data acquisition card channel). The other end of capacitor C14 is connected to high-voltage ground. Resistors R1, R2, R3, and R4 are connected in series between HV+ and HVGND, and their main function is voltage division: distributing the high voltage HV+ proportionally across different resistors, which can be used by subsequent circuits (such as high-voltage sampling circuits) to obtain appropriate voltage signals; at the same time, the resistors also serve as current limiters.

[0062] The high-voltage sampling circuit proportionally steps down and filters the high voltage, converting it into a low-voltage signal suitable for analog input (AI) acquisition, which facilitates the system's monitoring of the high-voltage power supply's voltage value.

[0063] In some embodiments, resistors R1, R2, R3, and R4 are connected in series between the positive and negative terminals of the high-voltage busbar, the negative terminal of the high-voltage busbar is connected to the high-voltage ground, and the voltage divider node is located between resistors R3 and R4.

[0064] In some embodiments, the high-voltage input circuit further includes a protection circuit, the protection circuit comprising:

[0065] The first protection branch has one end electrically connected to the positive terminal of the high-voltage bus and the other end electrically connected to the negative terminal of the high-voltage bus. The first protection branch is provided with a capacitor C1 for suppressing input differential mode interference.

[0066] The second protection branch has one end connected to the positive terminal of the high-voltage busbar and the other end connected to the negative terminal of the high-voltage busbar. TVS tubes (TVS1 and TVS2) are installed on the second protection branch.

[0067] The third protection branch has one end electrically connected to the positive terminal of the high-voltage bus and the other end electrically connected to the negative terminal of the high-voltage bus. The third protection branch is equipped with capacitors C2 and C3 for suppressing input common-mode interference, and the node between capacitors C2 and C3 is connected to PE.

[0068] A reverse connection protection diode is connected in series with the high voltage bus.

[0069] In some embodiments, the reverse polarity protection diode D1 is connected in series with the positive terminal of the high voltage bus.

[0070] like Figure 3 As shown, C1 is an X capacitor used to suppress input differential-mode interference; the PTC control device adopts a TVS diode design for the first time at the high-voltage input to prevent abnormal surges. When there is an abnormally large voltage at the input (such as lightning interference), the TVS diode can quickly respond and conduct. TVS1 and TVS2 shown are fast-response TVS diodes used to protect the subsequent circuits; C2 and C3 are Y capacitors used to suppress input common-mode interference; D1 is a high-voltage reverse connection protection diode used to prevent high-voltage power supply from being connected in reverse.

[0071] In some embodiments, the PTC control circuit further includes a common high-side control switch, one end of which is connected to the positive terminal of the high-voltage bus, and the other end of which is connected to one end of the water-heat load control branch and the air-heat load control branch. The common high-side control switch is connected to a common high-side switch drive circuit, and the common high-side switch drive circuit is connected to the main control circuit.

[0072] In some embodiments, the PTC control circuit further includes a first current sampling circuit for acquiring the current flowing through the water-heat load control branch, wherein the input terminal of the first current sampling circuit is connected to the water-heat load control branch, and the output terminal of the first current sampling circuit is connected to the second input terminal of the main control circuit.

[0073] In some embodiments, the PTC control circuit further includes a second current sampling circuit for acquiring the current flowing through the air-heat load control branch. The input terminal of the second current sampling circuit is connected to the air-heat load control branch, and the output terminal of the second current sampling circuit is connected to the third input terminal of the main control circuit.

[0074] In some embodiments, the PTC control circuit further includes an inlet / outlet temperature acquisition circuit for acquiring inlet and outlet temperatures, wherein the output terminal of the inlet / outlet temperature acquisition circuit is connected to the fourth input terminal of the main control circuit.

[0075] In some embodiments, the PTC control circuit further includes a core temperature acquisition circuit, the output of which is connected to the fifth input terminal of the main control circuit via an analog isolation circuit. Figure 7 As shown, the analog isolation circuit can be optocoupled.

[0076] In some embodiments, the PTC control circuit further includes a low-voltage power supply circuit, which includes a low-voltage input circuit, a power management circuit, and a first LDO circuit. The input terminal of the low-voltage input circuit is connected to the low-voltage power supply, and the output terminal of the low-voltage input circuit is connected to the input terminal of the power management circuit. The input terminal of the first LDO circuit is connected to the output terminal of the power management circuit, and the output terminal of the first LDO circuit is used to output a first voltage to power the main control circuit.

[0077] In some embodiments, the low-voltage power supply circuit further includes a second LDO circuit, the input terminal of which is connected to the output terminal of the power management circuit, and the output terminal of the second LDO circuit is used to output a second voltage to supply power to various isolation circuits (including communication isolation circuits, analog isolation circuits, etc.).

[0078] In some embodiments, the low-voltage input circuit includes a low-voltage filter circuit, the input terminal of which is connected to a low-voltage power supply, and the output terminal of which is connected to the input terminal of a power management circuit.

[0079] In some embodiments, the low-voltage power supply circuit further includes an isolation transformer. The input terminal of the isolation transformer is connected to the output terminal of the power management circuit, and the output terminal of the isolation transformer is connected to the input terminals of the first LDO circuit and the second LDO circuit. The output terminal of the isolation transformer outputs a third voltage to power each switch drive circuit (including the air-cooled switch drive circuit, the water-cooled switch drive circuit, and the common high-side switch drive circuit).

[0080] In some embodiments, the PTC control circuit further includes a low-voltage sampling circuit, the input of which is connected to the power management circuit, and the output of which is connected to the main control circuit via a digital isolation circuit.

[0081] The digital isolation circuit electrically isolates the LDUDC (low-voltage sampling signal) output by the low-voltage sampling circuit before transmitting it to the main control circuit.

[0082] In some embodiments, the PTC control circuit further includes a communication circuit, one end of which is connected to the main control circuit via a communication isolation circuit, and the other end of which is connected to a low-voltage connector.

[0083] In some embodiments, see Figure 4 and Figure 5 The communication circuit includes a LIN chip, which is connected to a low-voltage connector and connected to the main control circuit via a communication isolation circuit. The communication isolation circuit electrically isolates the TXD (transmit data) and RXD (receive data) signals between the LIN chip and the main control circuit, preventing interference or abnormal voltage from the LIN bus from affecting the main control circuit and improving communication reliability.

[0084] In some embodiments, the LIN chip is a TLE8457ALE model chip.

[0085] In some embodiments, the main control circuit is also connected to the LIN chip via a digital isolation circuit. The digital isolation circuit electrically isolates the SLP (sleep signal) output by the main control circuit before transmitting it to the LIN chip, which then transmits it via the LIN chip and a low-voltage connector.

[0086] In some embodiments, the PTC control circuit further includes an interlock detection circuit, which is connected to the main control circuit via an interlock isolation circuit. The core function of the interlock detection circuit is to monitor the physical connection status of the high-voltage plug (e.g., whether the high-voltage plug is securely inserted).

[0087] In some embodiments, the interlocking isolation circuit may employ an optocoupler.

[0088] The main control circuit receives the isolated interlock status signal. If "interlock disconnection" is detected, it immediately triggers protection actions (such as cutting off the common high-side control switch).

[0089] In some embodiments, a first isolation circuit is provided between the main control circuit and the water-heating switch drive circuit.

[0090] In some embodiments, a second isolation circuit is provided between the main control circuit and the air-heating switch drive circuit.

[0091] In some embodiments, a third isolation circuit is provided between the main control circuit and the first current sampling circuit.

[0092] In some embodiments, a fourth isolation circuit is provided between the main control circuit and the second current sampling circuit.

[0093] In some embodiments, the first isolation circuit, the second isolation circuit, the third isolation circuit, and the fourth isolation circuit all utilize a multi-channel isolation chip. See also Figure 8 This is a circuit diagram of a multi-channel isolation chip provided in one embodiment of the present invention. In some embodiments, the multi-channel isolation chip is model NSIP8940.

[0094] In some embodiments, the water-heat control switch, the air-heat control switch, and the common high-side control switch are all transistors.

[0095] In some embodiments, the transistor is an IGBT. The water-cooled switch drive circuit, the air-cooled switch drive circuit, and the common high-side switch drive circuit are all IGBT drive circuits. The IGBT drive circuit of this invention can use existing IGBT drive circuits. See also... Figure 6 This is a circuit diagram of an IGBT driving circuit provided in one embodiment of the present invention. The IGBT driving circuit is used to amplify the PWM (Pulse Width Modulation) control signal and drive the IGBT (Insulated Gate Bipolar Transistor) to achieve fast turn-on and turn-off.

[0096] The IGBT driving circuit includes an input and preamplifier circuit and a push-pull driving circuit. The input terminal of the input and preamplifier circuit is electrically connected to the output terminal of the main control circuit, the output terminal of the input and preamplifier circuit is electrically connected to the input terminal of the push-pull driving circuit, and the output terminal of the push-pull driving circuit is electrically connected to the gate of the IGBT.

[0097] In some embodiments, the input and preamplifier circuit includes transistors Q1 and Q2. The base of transistor Q1 is connected to the output terminal of the main control circuit, the emitter of transistor Q1 is grounded, the collector of transistor Q1 is connected to the base of transistor Q12 via resistor R15, the collector of transistor Q1 is connected to a first positive voltage (such as, but not limited to, +15V) via resistor R17, the base of transistor Q2 is grounded via capacitor C10, the emitter of transistor Q2 is grounded, the collector of transistor Q2 is electrically connected to the input terminal of the push-pull drive circuit via resistor R16, and the collector of transistor Q2 is connected to the first positive voltage (such as, but not limited to, +15V) via resistor R18.

[0098] In some embodiments, a PWM input and filtering circuit is provided between the base of transistor Q1 and the output terminal of the main control circuit. The PWM input and filtering circuit includes a resistor R14 and a capacitor C9. One end of resistor R14 is connected to the output terminal of the main control circuit, and the other end of resistor R14 is connected to one end of capacitor C9 and the base of transistor Q1. The other end of capacitor C9 is grounded. The PWM1 signal is input through resistor R14, and capacitor C9 is a filter / decoupling capacitor that stabilizes the input voltage and suppresses high-frequency interference.

[0099] The push-pull drive circuit includes transistors Q3 and Q4. The base of transistor Q3 is connected to the base of transistor Q4, serving as the input terminal of the push-pull drive circuit. It is also connected to the collector of transistor Q2 via resistor R16. The collector of transistor Q3 is connected to a first positive voltage. The emitter of transistor Q3 is connected to the emitter of transistor Q4, serving as the output terminal of the push-pull drive circuit. It is also connected to the gate of a transistor (such as an IGBT) via resistor R20. One end of resistor R20 is connected to one end of resistor R19 and the output terminal of the push-pull drive circuit. The other end of resistor R19 is connected to the cathode of diode D2. The anode of diode D2 is connected to the other end of resistor R20 and the gate of the transistor (such as an IGBT). The gate of the transistor (such as an IGBT) is connected to a first negative voltage via capacitor C11. The gate of the transistor (such as an IGBT) is also connected to a first negative voltage via resistor R21. Q3 (NPN type) and Q4 (PNP type) form a push-pull circuit, whose core function is to provide high current drive capability and accelerate the turn-on / turn-off speed of IGBT.

[0100] In some embodiments, capacitors C12 and C13 are connected in series between the collector and emitter of a transistor (such as an IGBT).

[0101] Diode D2 is a freewheeling diode, used to provide a path for the reverse discharge current of the gate when the IGBT is turned off, thereby accelerating the turn-off process.

[0102] Capacitor C11 is an accelerating capacitor that assists in the rapid charging and discharging of the gate, further improving the switching speed of the IGBT.

[0103] Based on the same inventive concept, this disclosure also provides a PTC control device, including the PTC control circuit provided in any of the preceding embodiments. The description of this PTC control circuit can be found in the preceding embodiments and will not be repeated here. The PTC control device further includes a housing and a control board located within the housing, with the PTC control circuit located on the control board. A low-voltage connector and a high-voltage connector are mounted and fixed on the housing.

[0104] Because integrated solutions have higher power outputs compared to traditional PTCs, the bus current increases. Furthermore, the high integration of the fan-water-heating system places higher demands on the controller's current-carrying capacity. Integrated solutions face space constraints but must still meet current-carrying requirements.

[0105] In some embodiments, the PTC control device further includes a control board, on which the PTC control circuit is mounted. A conductive layer (such as a solder layer, silver plating layer, or copper plating layer) is disposed on the surface of the high-voltage bus copper foil traces on the control board. For the control board containing the PTC control circuit, the high-voltage bus needs to transmit a large current. The current-carrying capacity of the copper foil itself may be limited by its thickness and width (due to PCB manufacturing limitations). The core purpose of covering it with an additional conductive layer is to increase the effective conductive cross-sectional area of ​​the conductor to improve the current-carrying capacity.

[0106] In some embodiments, when designing the high-voltage busbar, the high-voltage busbar trace on the control board (i.e., PCB) adopts an increased current-carrying design, specifically including: using no green solder mask treatment, and simultaneously adding a soldering process to increase the busbar's current-carrying capacity.

[0107] In some embodiments, the low-voltage connector uses a low-voltage connector and the high-voltage connector uses a high-voltage connector.

[0108] Connect the high and low voltage connectors of the product and supply power. When the WPTC working command is issued, the corresponding PTC1 is turned on and the water heat load unit starts heating. When the APTC working command is issued, the corresponding PTC2 is turned on and the air heat load unit starts heating. When both WPTC and APTC issue commands, both PTC1 and PTC2 are turned on and both air and water heat load units start heating.

[0109] This invention adopts separate control for air-heating and water-heating systems, which can simultaneously meet the different usage scenarios of users; at the same time, the current sampling and software protection strategies of the air-heating and water-heating components of this product adopt a separate design scheme, which greatly improves the reliability of the system.

[0110] This utility model's PTC control device includes a PTC integrated air, water, and heat control system, reducing the design and development of one control box and control board. Compared to traditional PTC control solutions, development costs are reduced by 40%, and the volume occupied is reduced by 30%. This design offers significant cost and lightweight advantages, making it particularly suitable for current new energy vehicles.

[0111] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A PTC control circuit, characterized in that: The system includes a high-voltage input circuit, a main control circuit, a water-heat load control branch, and a wind-heat load control branch. The high-voltage input circuit includes a high-voltage bus. One end of each water-heat load control branch and wind-heat load control branch is electrically connected to the positive terminal of the high-voltage bus, and the other end is electrically connected to the negative terminal of the high-voltage bus. Each water-heat load control branch includes a water-heat control switch and a water-heat load unit connected in series. The water-heat control switch is electrically connected to a water-heat switch drive circuit, which is also electrically connected to the main control circuit. Each wind-heat load control branch includes a wind-heat control switch and a wind-heat load unit connected in series. The wind-heat control switch is electrically connected to a wind-heat switch drive circuit, which is also electrically connected to the main control circuit.

2. The PTC control circuit as described in claim 1, characterized in that: The high-voltage input circuit also includes a protection circuit, which includes: The first protection branch has one end electrically connected to the positive terminal of the high-voltage bus and the other end electrically connected to the negative terminal of the high-voltage bus. The first protection branch is equipped with a capacitor for suppressing input differential mode interference. And / or, The second protection branch has one end connected to the positive terminal of the high-voltage busbar and the other end connected to the negative terminal of the high-voltage busbar. A TVS diode is installed on the second protection branch. And / or, The third protection branch has one end electrically connected to the positive terminal of the high-voltage bus and the other end electrically connected to the negative terminal of the high-voltage bus. The third protection branch is equipped with a capacitor for suppressing input common-mode interference. And / or, A reverse connection protection diode is connected in series with the high voltage bus.

3. The PTC control circuit as described in claim 1, characterized in that: It also includes a common high-side control switch, one end of which is connected to the positive terminal of the high-voltage bus, and the other end of which is connected to one end of the water-heat load control branch and the air-heat load control branch. The common high-side control switch is connected to a common high-side switch drive circuit, and the common high-side switch drive circuit is connected to the main control circuit.

4. The PTC control circuit as described in claim 1, characterized in that: It also includes a high-voltage sampling circuit for acquiring the voltage of the high-voltage bus, and the output terminal of the high-voltage sampling circuit is electrically connected to the first input terminal of the main control circuit; And / or, It also includes a first current sampling circuit for collecting the current flowing through the water-thermal load control branch, and the output of the first current sampling circuit is connected to the second input of the main control circuit. And / or, It also includes a second current sampling circuit for collecting the current flowing through the wind-heat load control branch, and the output of the second current sampling circuit is connected to the third input of the main control circuit. And / or, It also includes an inlet and outlet temperature acquisition circuit for acquiring the inlet and outlet temperatures, the output of which is connected to the fourth input of the main control circuit. And / or, It also includes a core temperature acquisition circuit, the output of which is connected to the fifth input of the main control circuit via an analog isolation circuit.

5. The PTC control circuit as described in claim 1, characterized in that: It also includes a low-voltage power supply circuit, which includes a low-voltage input circuit, a power management circuit, and a first LDO circuit. The input terminal of the low-voltage input circuit is connected to the low-voltage power supply, and the output terminal of the low-voltage input circuit is connected to the input terminal of the power management circuit. The input terminal of the first LDO circuit is connected to the output terminal of the power management circuit, and the output terminal of the first LDO circuit is connected to the main control circuit to supply power to the main control circuit.

6. The PTC control circuit as described in claim 5, characterized in that: The low-voltage input circuit includes a low-voltage filter circuit, the input terminal of which is connected to a low-voltage power supply, and the output terminal of which is connected to the input terminal of a power management circuit. And / or, It also includes a low-voltage sampling circuit, the input of which is connected to the power management circuit, and the output of which is connected to the main control circuit via a digital isolation circuit. And / or, It also includes an isolation transformer, the input of which is connected to the output of the power management circuit, and the output of which is connected to the input of the first LDO circuit.

7. The PTC control circuit as described in claim 1, characterized in that: It also includes a communication circuit, one end of which is connected to the main control circuit via a communication isolation circuit, and the other end of which is connected to a low-voltage connector. And / or, It also includes an interlock detection circuit, which is connected to the main control circuit via an interlock isolation circuit; And / or, A first isolation circuit is provided between the main control circuit and the water-heating switch drive circuit; And / or, A second isolation circuit is provided between the main control circuit and the air-heat switch drive circuit; And / or, Both the water-heat control switch and the air-heat control switch are transistors. And / or, Both the water-heating switch drive circuit and the air-heating switch drive circuit use transistor drive circuits.

8. The PTC control circuit as described in claim 7, characterized in that: The transistor driving circuit includes an input and preamplifier circuit and a push-pull driving circuit. The input terminal of the input and preamplifier circuit is electrically connected to the output terminal of the main control circuit. The output terminal of the input and preamplifier circuit is electrically connected to the input terminal of the push-pull driving circuit. The output terminal of the push-pull driving circuit is electrically connected to the gate of the transistor.

9. A PTC control device, characterized in that: Includes the PTC control circuit as described in any one of claims 1 to 8.

10. The PTC control device as described in claim 9, characterized in that: It also includes a control board, on which the PTC control circuit is mounted, and a conductive layer is provided on the surface of the high-voltage bus copper foil traces on the control board.

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