A switching circuit to prevent cross-current of input current into the vehicle body.

Abstract

This utility model relates to the field of automotive lighting switch circuit technology, specifically a switch circuit for preventing cross-current from entering the vehicle body. A filter protection module A and a filter protection module B are connected in parallel and then connected to an anti-cross-current module. The output of the anti-cross-current module is connected to a drive control module. The anti-cross-current module includes NMOS transistors Q2 and Q3 controlled by high-side conduction and PMOS transistor Q1 controlled by low-side conduction. Pin 1 of NMOS transistor Q3 is connected to the rear end of filter protection module A, pin 3 of NMOS transistor Q3 is connected to the output of filter protection module B and pin 1 of NMOS transistor Q2, pin 3 of NMOS transistor Q2 is connected to pin 1 of PMOS transistor Q1, pin 2 of PMOS transistor Q1 is connected to the output of filter protection module B, and pin 3 of PMOS transistor Q1 is connected to the drive control module. The anti-cross-current module has lower cost and requires less space than increasing the number of control modules, effectively preventing vehicle body input current detection alarms.

Description

Technical Field

[0001] This utility model relates to the field of automotive lighting switch circuit technology, specifically a switch circuit for preventing cross-current of input current into the vehicle body. Background Technology

[0002] In existing technologies, to drive different functions of automotive lights, one approach is to input different power signals from the vehicle body. After passing through a filtering and protection module, different drive control modules are used to control different light functions. For example... Figure 1 As shown in Scheme 1, Function A and Function B are controlled by different drive control modules. With the continuous development of the industry, the requirements for scheme optimization and cost control are constantly increasing. When different functions within the same luminaire are designed in the same luminous area and will not light up simultaneously, engineers sometimes consider using the same drive control module to control two functions that will not light up at the same time, such as... Figure 1 As shown in Scheme 2, Function A and Function B are connected to the same drive control module after passing through their respective filter protection modules. The drive control module sends a power supply signal to the load circuit module to light up the light corresponding to Function A or Function B. Function A and Function B will not light up at the same time.

[0003] With the rapid development of automotive technology and the increasing demand for diversified automotive functions, the safety requirements for automotive lighting are gradually rising. Some vehicle bodies detect the input current of various lighting functions (A and B). If the detected input current is outside the normal operating range, a vehicle alarm is triggered, displaying a message on the dashboard to inform the driver of a lighting malfunction. Even if two different functions within the same lighting fixture do not illuminate simultaneously, the vehicle body may still provide signals to both functions concurrently. Generally, function priorities are set; for example, if both function A and function B have power signals, function A has a higher priority, so function A illuminates while function B remains off. However, considering optimization and cost control, if the same drive control module is used to control functions A and B, and both functions have power signals, with function A illuminated and function B off, there is a possibility that all current flows to function B's input power line, while the current to function A's input power line is 0A, i.e., current crosstalk. If the vehicle body has an input current detection function, it will trigger an alarm indicating a function A malfunction, even though function A is actually working normally, leading to a poor user experience.

[0004] Therefore, when using the same drive control module to control function A and function B in automotive lighting, how to avoid false alarms caused by current crosstalk is a technical problem that needs to be solved. Utility Model Content

[0005] The problem to be solved is to provide a technical solution to avoid false alarms caused by current crosstalk, specifically for automotive lighting systems that use the same drive control module to control functions A and B.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a switching circuit for preventing cross-current of vehicle body input current, comprising a filter protection module A, a filter protection module B, a drive control module, a load circuit module A, and a load circuit module B; the filter protection module A and the filter protection module B are connected in parallel and then connected to an anti-cross-current module, the output terminal of the anti-cross-current module is connected to the drive control module, and the output terminal of the drive control module is connected to the load circuit module A and the load circuit module B; wherein the anti-cross-current module includes NMOS transistors Q2 and Q3 controlled to conduct on the high side and PMOS transistor Q1 controlled to conduct on the low side; wherein pin 1 of NMOS transistor Q3 is connected to the rear end of filter protection module A, pin 2 of NMOS transistor Q3 is grounded, pin 3 of NMOS transistor Q3 is connected to the output terminal of filter protection module B and pin 1 of NMOS transistor Q2; pin 2 of NMOS transistor Q2 is grounded, pin 3 of NMOS transistor Q2 is connected to pin 1 of PMOS transistor Q1, pin 2 of PMOS transistor Q1 is connected to the output terminal of filter protection module B, and pin 3 of PMOS transistor Q1 is connected to the drive control module.

[0007] Preferably, the filter protection module A includes a transformer T1, a resistor R1, a capacitor C1 and a capacitor C2 connected in parallel, and a reverse protection diode D1 and a resistor R6 are connected in series between the filter protection module A and pin 1 of the NMOS transistor Q3.

[0008] Preferably, the filter protection module B includes a transformer T2, a resistor R2, a capacitor C4, and a capacitor C5 connected in parallel. A reverse protection diode D4 and a resistor R5 are connected in series between the filter protection module B and pin 1 of the NMOS transistor Q2.

[0009] Preferably, a resistor R8 and a capacitor C7 are connected in parallel between pins 1 and 2 of NMOS transistor Q3, a resistor R7 and a capacitor C6 are connected in parallel between pins 1 and 2 of NMOS transistor Q2, and a resistor R3, a capacitor C3 and a reverse protection diode D5 are connected in parallel between pins 1 and 2 of PMOS transistor Q1.

[0010] Preferably, a resistor R4 is provided between pin 3 of NMOS transistor Q2 and pin 1 of PMOS transistor Q1.

[0011] Preferably, a reverse protection diode D2 is provided between the filter protection module A and the drive control module, and the reverse protection diode D1 is connected in parallel with the reverse protection diode D2; a reverse protection diode D3 is provided between the filter protection module B and pin 2 of the PMOS transistor Q1, and the reverse protection diode D3 is connected in parallel with the reverse protection diode D4.

[0012] Compared with existing technologies, this utility model provides a switching circuit to prevent cross-current in the vehicle body, offering the following advantages: This utility model incorporates an anti-cross-current module in the input circuit at the front end of the drive circuit, enabling the same drive control module to drive two lights that will not illuminate simultaneously. Even with simultaneous power signals, the vehicle body alarm will not be triggered, reducing the need for multiple drive control modules to control the vehicle body separately to avoid alarms. The anti-cross-current module includes NMOS transistors Q2 and Q3 controlled by high-side conduction and PMOS transistor Q1 controlled by low-side conduction. The anti-cross-current module is designed using automotive-grade MOS transistors, resistors, capacitors, and other components, resulting in inexpensive and reliable components. The circuit cost and space occupied by the anti-cross-current module are lower than increasing the number of control modules to prevent vehicle body input current detection alarms.

[0013] Therefore, this utility model design can achieve the functions of vehicle body safety detection and normal operation, and use one drive control module to control two lights that do not light up at the same time, while maintaining low cost and high space utilization. Attached Figure Description

[0014] Figure 1 This is a block diagram of an existing technology circuit;

[0015] Figure 2 This is a circuit block diagram of the present invention;

[0016] Figure 3 This is the circuit diagram of the control system of this utility model. Detailed Implementation

[0017] The technical solutions of the present utility model will now be described with reference to the accompanying drawings in the embodiments of the present utility model:

[0018] When designing circuit drive schemes for vehicles with safety detection functions and multiple lighting functions, using the same drive control module to drive two lighting functions that will not be lit simultaneously may trigger vehicle alarms, resulting in a poor user experience. This invention designs a front-end input anti-crosstalk module, adding a current-preventing circuit to the front-end input of two lighting functions. This ensures that even if both functions have power signals simultaneously, driving two lighting functions that will not be lit at the same time will not trigger vehicle alarms.

[0019] Figure 1 The diagram shown is a circuit block diagram of a prior art headlight driving solution. Figure 2The diagram shown is a circuit block diagram of the present invention. The difference between the present invention and the prior art is that an anti-crossing current module is used, so that even when the vehicle body has an input current detection function, a single drive control module can still drive two modules that do not light up at the same time. The two modules that do not light up at the same time are load circuit module A and load circuit module B. Figure 3 The one shown is Figure 2 The system consists of a filter protection module A, a filter protection module B, and an anti-crosstalk module. The power supply signal output after passing through these modules is then used by the drive control module to power the two lamps. Filter protection modules A and B are connected in parallel and then connected to the anti-crosstalk module. The anti-crosstalk module sends the power supply signal to the drive control module, which then sends the power supply signal to either load circuit module A or load circuit module B. Figure 2 The circuit block diagram of this utility model is shown, including filter protection module A, filter protection module B, anti-crosstalk module, drive control module, load circuit module A and load circuit module B; filter protection module A and filter protection module B are connected in parallel and then connected to the anti-crosstalk module, the output terminal of the anti-crosstalk module is connected to the drive control module, and the output terminal of the drive control module is connected to the load circuit module A and the load circuit module B. Figure 3 The anti-crosstalk module circuit diagram includes NMOS transistors Q2 and Q3 controlled by high-side conduction and PMOS transistor Q1 controlled by low-side conduction. Pin 1 of NMOS transistor Q3 is connected to the rear end of filter protection module A, pin 2 of NMOS transistor Q3 is grounded, and pin 3 of NMOS transistor Q3 is connected to the output terminal of filter protection module B and pin 1 of NMOS transistor Q2. A resistor R8 and a capacitor C7 are connected in parallel between pins 1 and 2 of NMOS transistor Q3. Pin 2 of NMOS transistor Q2 is grounded, and pin 3 of NMOS transistor Q2 is connected to pin 1 of PMOS transistor Q1. A resistor R4 is provided between pin 3 of NMOS transistor Q2 and pin 1 of PMOS transistor Q1. A resistor R7 and a capacitor C6 are connected in parallel between pins 1 and 2 of NMOS transistor Q2. Pin 2 of PMOS transistor Q1 is connected to the output of filter protection module B. Pin 3 of PMOS transistor Q1 is connected to the drive control module. A resistor R3, a capacitor C3, and a reverse protection diode D5 are connected in parallel between pins 1 and 2 of PMOS transistor Q1.

[0020] Filter protection module A includes a transformer T1, resistor R1, capacitor C1, and capacitor C2 connected in parallel. A reverse protection diode D1 and resistor R6 are connected in series between filter protection module A and pin 1 of NMOS transistor Q3. Filter protection module B includes a transformer T2, resistor R2, capacitor C4, and capacitor C5 connected in parallel. A reverse protection diode D4 and resistor R5 are connected in series between filter protection module B and pin 1 of NMOS transistor Q2. A reverse protection diode D2 is also provided between filter protection module A and the drive control module; reverse protection diodes D1 and D2 are connected in parallel. A reverse protection diode D3 is also provided between filter protection module B and pin 2 of PMOS transistor Q1; reverse protection diodes D3 and D4 are connected in parallel.

[0021] In use, filter protection module A serves as the input filter protection module for function A, and includes transformer T1, resistor R1, capacitor C1, and capacitor C2. Filter protection module B serves as the input filter protection module for function B, and includes transformer T2, resistor R2, capacitor C4, and capacitor C5. D1 and D2 are reverse protection diodes for function A, connected to the rear end of filter protection module A and outputting the power-on detection signal for function A. D3 and D4 are reverse protection diodes for function B, connected to the rear end of filter protection module B and outputting the power-on detection signal for function B. Q2 and Q3 are NMOS transistors controlled to conduct on the high side, and Q1 is a PMOS transistor controlled to conduct on the low side. When the vehicle body sends a power supply signal for function A alone, the power supply passes through the input filter protection module A, the power-on detection signal for function A is high, NMOS transistor Q3 is on, and NMOS transistors Q2 and PMOS transistor Q1 are off. Function A can directly supply power to the drive control module and operates normally. When the vehicle body sends a power supply signal for function B alone, the power supply passes through the input filter protection module B of function B. The power-on detection signal of function B is high, while the power-on detection signal of function A is low. NMOS transistor Q3 is off, NMOS transistor Q2 is on, and therefore PMOS transistor Q1 is on. Function B supplies power to the drive control module through PMOS transistor Q1, and the system operates normally.

[0022] When the vehicle body sends power supply signals for both Function A and Function B simultaneously, Function A has a higher priority than Function B. At this time, the power supply passes through the input filtering protection modules A and B for Function A and Function B, respectively. Both the power-on detection signals for Function A and Function B are high, causing NMOS transistor Q3 to conduct. Therefore, NMOS transistor Q2 and PMOS transistor Q1 are also off. Thus, the power supply for Function A can conduct, powering the drive control module. The power supply for Function B cannot conduct because PMOS transistor Q1 is off. Therefore, all current exists only in the circuit of Function A, and there is no current in Function B, thus preventing the vehicle body alarm from being triggered. The circuit cost of the anti-crosscurrent module is lower than increasing the number of control modules, and the space occupied by the anti-crosscurrent module is also lower than increasing the number of control modules. This invention is superior to solutions that increase the number of control modules to avoid vehicle body input current detection alarms, and it ensures lower cost and higher space utilization.

[0023] This invention utilizes an anti-crossing current module containing three MOSFETs to prevent triggering of the vehicle body input current detection alarm. It allows a single control circuit to drive two lights that do not illuminate simultaneously, reducing the number of driver chip control modules, improving the user experience, and saving overall cost of the light driver and space in the lights.

[0024] The above embodiments are merely some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

Claims

1. A switching circuit for preventing cross-current of vehicle body input current, comprising a filter protection module A, a filter protection module B, a drive control module, a load circuit module A, and a load circuit module B; characterized in that: Filter protection module A and filter protection module B are connected in parallel and then connected to the anti-crosstalk module. The output of the anti-crosstalk module is connected to the drive control module, and the output of the drive control module is connected to load circuit module A and load circuit module B. The anti-crosstalk module includes NMOS transistors Q2 and Q3, which are controlled to be turned on by high-side control, and PMOS transistor Q1, which is controlled to be turned on by low-side control. Pin 1 of NMOS transistor Q3 is connected to the back end of filter protection module A, pin 2 of NMOS transistor Q3 is grounded, and pin 3 of NMOS transistor Q3 is connected to the output of filter protection module B and pin 1 of NMOS transistor Q2. Pin 2 of NMOS transistor Q2 is grounded, pin 3 of NMOS transistor Q2 is connected to pin 1 of PMOS transistor Q1, pin 2 of PMOS transistor Q1 is connected to the output of filter protection module B, and pin 3 of PMOS transistor Q1 is connected to the drive control module.

2. The switching circuit for preventing cross-current of vehicle body input current according to claim 1, characterized in that: The filter protection module A includes a transformer T1, a resistor R1, a capacitor C1 and a capacitor C2 connected in parallel. A reverse protection diode D1 and a resistor R6 are connected in series between the filter protection module A and pin 1 of the NMOS transistor Q3.

3. The switching circuit for preventing cross-current of vehicle body input current according to claim 2, characterized in that: The filter protection module B includes a transformer T2, a resistor R2, a capacitor C4, and a capacitor C5 connected in parallel. A reverse protection diode D4 and a resistor R5 are connected in series between the filter protection module B and pin 1 of the NMOS transistor Q2.

4. The switching circuit for preventing cross-current of vehicle body input current according to claim 1, characterized in that: A resistor R8 and a capacitor C7 are connected in parallel between pins 1 and 2 of NMOS transistor Q3. A resistor R7 and a capacitor C6 are connected in parallel between pins 1 and 2 of NMOS transistor Q2. A resistor R3, a capacitor C3, and a reverse protection diode D5 are connected in parallel between pins 1 and 2 of PMOS transistor Q1.

5. The switching circuit for preventing cross-current of vehicle body input current according to claim 1, characterized in that: A resistor R4 is provided between pin 3 of NMOS transistor Q2 and pin 1 of PMOS transistor Q1.

6. The switching circuit for preventing cross-current of vehicle body input current according to claim 3, characterized in that: A reverse protection diode D2 is provided between the filter protection module A and the drive control module. The reverse protection diode D1 is connected in parallel with the reverse protection diode D2. A reverse protection diode D3 is provided between the filter protection module B and pin 2 of the PMOS transistor Q1. The reverse protection diode D3 is connected in parallel with the reverse protection diode D4.

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