A kind of automobile wiper enabler and speed regulation circuit with detecting relay abnormal function

Abstract

The utility model provides a kind of with the enablement and speed regulation circuit of the abnormal function of detecting relay of automobile wiper, comprising: main control circuit, including first protection circuit, and external wiper power supply is connected;Wiper enable relay is connected with first protection circuit, external wiper power supply and automobile wiper first internal control signal respectively;Wiper speed regulation relay is connected with wiper enable relay, wiper motor speed regulation gear and second internal control signal respectively;Second protection circuit is connected with wiper speed regulation relay;First detection circuit is used for monitoring the working state of enabling wiper enable relay;Second detection circuit is used for monitoring the working state of speed regulation wiper speed regulation relay;First indicating part is used for indicating wiper enable relay working state;Second indicating part is connected with the second detection circuit, for indicating wiper speed regulation relay working state.The present application realizes the abnormal detection function of relay, and realizes simple structure, low cost.

Description

Technical Field

[0001] This utility model relates to the technical field of control and detection alarm circuits, and in particular to an automotive windshield wiper enable and speed control circuit. Background Technology

[0002] Windshield wipers are an important accessory for cars, playing a crucial role in ensuring driving safety in rainy weather. Therefore, it is essential that the windshield wipers activate promptly and adjust to the correct setting when needed. If the wipers fail to activate in time or are not adjusted to the correct setting, it can significantly threaten driving safety and potentially lead to serious consequences.

[0003] In the current field of vehicle body control, the body control module (BCM) is mostly responsible for the overall vehicle control function. The control circuit for automotive windshield wipers is also often designed within the BCM or other control units, integrated and packaged with other functional control modules. This involves various electronic components such as relays, diodes, transistors, MOSFETs, capacitors, and resistors, all soldered or plugged into PCBs. While this integrated packaging design is advantageous, it also hides potential risks. In particular, relays, as normally open / closed devices, can experience contact problems due to wear and tear over long-term use, introducing potential safety hazards. Therefore, designing an automotive windshield wiper control circuit with a function to detect relay malfunctions is essential.

[0004] For example, utility model patent CN220085007U describes an automotive relay testing device for traditional four-wire or five-pin relays. This detector includes a power supply, indicator lights, a switch, and terminals, among other components. The terminals, containing multiple terminals, form two detection loops with other components in the testing circuit. When the terminals are connected to the relay circuit under test, the indicator lights can quickly detect whether the relay is functioning correctly, simplifying the operation compared to traditional multimeter testing methods. However, this testing device is suitable for externally packaged testing of relays in a circuit, but not for scenarios where it is built into automotive electronics and can continuously detect relay malfunctions while the vehicle is running. Utility Model Content

[0005] To address the technical problem that existing automotive windshield wiper circuits cannot achieve real-time fault detection of relays, this invention proposes an automotive windshield wiper enable and speed control circuit with relay fault detection function. While achieving fault detection, it also achieves a simple structure and low cost.

[0006] To achieve the above objectives, the technical solution of this utility model is implemented as follows: A car windshield wiper enable and speed control circuit with relay malfunction detection function includes: The main control circuit includes a first protection circuit connected to the external wiper power supply; a wiper enable relay connected to the first protection circuit, the external wiper power supply, and the first internal control signal of the car wiper; a wiper speed control relay connected to the wiper enable relay, the wiper motor speed control position, and the second internal control signal of the car wiper; and a second protection circuit connected to the wiper speed control relay. The first detection circuit is connected to the wiper enable relay and is used to monitor the working status of the wiper enable relay. The second detection circuit is connected to the wiper speed control relay and is used to monitor the working status of the speed control wiper speed control relay. The first indicator section is connected to the first detection circuit and is used to indicate the working status of the wiper enable relay. The second indicator section is connected to the second detection circuit and is used to indicate the working status of the wiper speed control relay.

[0007] Specifically, the wiper enable relay is a five-pin relay. The common pin of the wiper enable relay is connected to the common pin of the wiper speed control relay. The normally closed pin of the wiper enable relay is grounded. The normally open pin of the wiper enable relay is connected to the external wiper power supply and the first detection circuit, respectively. The ground pin of the wiper enable relay is grounded. The internal control signal pin of the wiper enable relay is connected to the first internal control signal of the car wiper and the first detection circuit, respectively.

[0008] Specifically, the wiper speed control relay is a five-pin relay. The normally closed pin of the wiper speed control relay is connected to the first speed control position of the wiper motor and the Q3 detection circuit, respectively. The normally open pin of the wiper speed control relay is connected to the second speed control position of the wiper motor and the Q4 detection circuit, respectively. The grounding pin of the wiper speed control relay is grounded, and the internal control signal pin of the wiper speed control relay is connected to the second internal control signal of the car's wipers.

[0009] Specifically, the first protection circuit includes: The first protection diode has its anode connected to the external windshield wiper power supply and its cathode connected to the positive power supply. The second protection diode has its cathode connected to the external wiper power supply and its anode grounded. The second protection circuit includes: The third protection diode has its anode grounded and its cathode connected to the normally closed pin of the wiper speed control relay. The fourth protection diode has its anode grounded and its cathode connected to the normally open pin of the wiper speed control relay.

[0010] Specifically, the first detection circuit includes a transistor detection circuit I and a transistor detection circuit II. The transistor detection circuit I is connected to the normally open pin of the wiper enable relay, and the transistor detection circuit II is connected to the internal control signal pin of the wiper enable relay. The second detection circuit includes a MOSFET detection circuit I and a MOSFET detection circuit II. The MOSFET detection circuit I is connected to the normally closed pin of the wiper speed control relay, and the MOSFET detection circuit II is connected to the normally open pin of the wiper speed control relay.

[0011] Specifically, the transistor detection circuit I includes a first transistor, the base of which is connected to the normally open pin of the wiper enable relay through a first protection resistor, the emitter of which is connected to the first indicator section, a sixth protection resistor is connected in parallel between the base and emitter of the first transistor, and the collector of which is connected to the transistor detection circuit II.

[0012] Specifically, the transistor detection circuit II includes a second transistor. The base of the second transistor is connected to the internal control signal pin of the wiper enable relay through a second protection resistor. The emitter of the second transistor is connected to the collector of the first transistor. The collector of the second transistor is connected to the common pin of the wiper enable relay through a third protection resistor.

[0013] Specifically, the MOS transistor detection circuit I includes a first MOS transistor. The gate of the first MOS transistor is connected to the normally closed pin of the wiper speed control relay through a fourth protection resistor. The drain of the first MOS transistor is connected to the common pin of the wiper speed control relay through an eighth protection resistor. The source of the first MOS transistor is connected to the second indicator section.

[0014] Specifically, the MOS transistor detection circuit II includes a second MOS transistor. The gate of the second MOS transistor is connected to the normally open pin of the wiper speed control relay through a fifth protection resistor. The drain of the second MOS transistor is connected to the drain of the first MOS transistor, and the source of the second MOS transistor is connected to the second indicator section.

[0015] Specifically, the first instruction portion includes: The anode of the first indicator diode is connected to the emitter of the first transistor; The ninth protection resistor has one end connected to the cathode of the first indicator diode and the other end grounded. The second instruction portion includes: The anode of the second indicator diode is connected to the source of the first MOS transistor and the source of the second MOS transistor, respectively. The tenth protection resistor has one end connected to the cathode of the second indicator diode and the other end grounded.

[0016] The beneficial effects of this utility model are as follows: The main control circuit of this invention uses four protection diodes to effectively control the voltage value of the external wiper power supply input and the voltage value of the two different motor speed settings, thus playing the role of protection circuit.

[0017] The first detection circuit of this invention uses two NPN transistors connected in series to detect whether the wiper enable relay is working properly. The first detection circuit is activated only when both diodes are conducting simultaneously, causing the indicator diode to light up. Using two diodes for redundant judgment can effectively improve the accuracy of the judgment and prevent the circuit from mis-activating and giving the user incorrect information.

[0018] The second detection circuit of this invention uses two NMOS transistors connected in parallel to determine whether the wiper speed control relay is working properly. When working properly, the two outputs of the wiper speed control relay will be one high level and one low level, thus ensuring that one NMOS transistor is conducting and the indicator diode lights up. When the wiper speed control relay is faulty, this phenomenon will not occur, thus effectively determining whether the wiper speed control relay is working properly.

[0019] The control and detection circuit proposed in this invention has a simple overall structure, making it easy to implement and install in automotive electronic products such as Body Control Module (BCM) or other body control units.

[0020] This invention uses two indicator diodes as indicator signals to indicate whether the two relays are working properly, enabling vehicle owners and maintenance personnel to quickly understand the cause of the fault. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0023] 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 protection scope of the present utility model.

[0024] For the specific scenario of controlling car windshield wipers, this utility model proposes a car windshield wiper enable and speed control circuit, which achieves the function while maintaining a simple structure and low cost. At the same time, to address the problem of relays in the control circuit possibly malfunctioning, this utility model designs two detection circuits to detect whether the two relays in the control circuit are working properly.

[0025] Example 1 A car windshield wiper enable and speed control circuit with relay fault detection function, such as Figure 1 As shown, it includes: The main control circuit drives the wiper motor through external power input and internal control signals, realizing the wiper enable (start / stop) and speed control (gear switching) functions. Its core components are a relay group and a diode protection circuit. The main control circuit includes a first protection circuit connected to the external wiper power supply; a wiper enable relay K1 connected to the first protection circuit, the external wiper power supply, and the vehicle's first internal control signal for the wipers; a wiper speed control relay K2 connected to the wiper enable relay K1, the wiper motor speed control gear, and the second internal control signal; and a second protection circuit connected to the wiper speed control relay K2.

[0026] In this embodiment, the wiper enable relay K1 provides a 12V high level according to the first internal control signal control pin, i.e., the internal control signal pin 86a. A voltage difference is formed between the internal control signal pin 86a and the ground pin 85a, which energizes the coil of the wiper enable relay K1, causing the wiper enable relay K1 to engage and thus enable the wipers. The wiper enable relay K1 is a five-pin relay, wherein the normally open pin 87b serves as the input, the common pin 30a serves as the output, the common pin 30a of the wiper enable relay K1 is connected to the common pin 30b of the wiper speed control relay K2, the normally closed pin 87a of the wiper enable relay K1 is grounded, the normally open pin 87b of the wiper enable relay K1 is connected to the external wiper power supply and the first detection circuit, the ground pin 85a of the wiper enable relay K1 is grounded, and the internal control signal pin 86a of the wiper enable relay K1 is connected to the first internal control signal of the car wipers and the first detection circuit.

[0027] In this embodiment, the wiper speed control relay K2 provides a 12V high level according to the second internal control signal control pin, i.e., the internal control signal pin 86b. A voltage difference is formed between 86b and 85b, which energizes the relay coil, causing the relay to engage and thus realizing the speed control function of the wiper. The wiper speed control relay K2 is a five-pin relay, wherein the common pin 30b is used as the input, and the normally closed pin 87c and normally open pin 87d are used as the output. The common pin 30b of the wiper speed control relay K2 is connected to the common pin 30a of the wiper enable relay K1. The normally closed pin 87c of the wiper speed control relay K2 is connected to the first speed control position and the second detection circuit of the wiper motor, respectively. The normally open pin 87d of the wiper speed control relay K2 is connected to the second speed control position and the second detection circuit of the wiper motor, respectively. The ground pin 85b of the wiper speed control relay K2 is grounded, and the internal control signal pin 86b of the wiper speed control relay K2 is connected to the second internal control signal of the car wiper.

[0028] In this embodiment, the first protection circuit is used to clamp the voltage of the external wiper power supply input to prevent overvoltage damage to subsequent circuits. The first protection circuit includes: The first protection diode D1 has its anode connected to the external wiper power supply and its cathode connected to the positive power supply. The second protection diode D2 has its cathode connected to the external windshield wiper power supply and its anode grounded. In this embodiment, the second protection circuit is used to protect the output path of the wiper speed control relay K2, ensuring voltage stability when the wiper motor speed control gear is switched. The second protection circuit includes: The third protection diode D3 has its anode grounded and its cathode connected to the normally closed pin 87c of the wiper speed control relay K2. The fourth protection diode D4 has its anode grounded and its cathode connected to the normally open pin 87d of the wiper speed control relay K2.

[0029] The other structures and principles are the same as in Example 1.

[0030] The main control circuit works as follows: When the wipers are not needed, the external wiper power supply is clamped by the first protection diode D1 and the second protection diode D2. The normally open pin 87b of the wiper enable relay K1 is at a high level. However, since the wipers are not needed, the first internal control signal is at a low level, that is, the internal control signal pin 86a of the wiper enable relay K1 is at a low level. Therefore, the wiper enable relay K1 does not engage. Since the common pin 30a of the wiper enable relay K1 is connected to the normally closed pin 87a (grounded) of the wiper enable relay K1, the common pin 30a of the wiper enable relay K1 outputs a low level, and the external wipers do not work.

[0031] When the wipers need to be turned on, the external wiper power supply is clamped by the first protection diode D1 and the second protection diode D2. The normally open pin 87b of the wiper enable relay K1 is at a high level. Since the wipers need to be turned on, the first internal control signal is at a high level, that is, the internal control signal pin 86a of the wiper enable relay K1 is at a high level, and the wiper enable relay K1 is energized. Therefore, the common pin 30a of the wiper enable relay K1 outputs a high level. When the wipers are in the first speed setting, the second internal control signal is at a low level, and the wiper speed relay K2 is not energized. After being clamped by the third protection diode D3, the normally closed pin 87c of the wiper speed relay K2 outputs a voltage to drive the wiper motor to run at the first speed setting. When the wipers are in the second speed setting, the second internal control signal is at a high level, and the wiper speed relay K2 is energized. After being clamped by the fourth protection diode D4, the normally open pin 87d of the wiper speed relay K2 outputs a voltage to drive the wiper motor to run at the second speed setting.

[0032] Example 2 A car windshield wiper enable and speed control circuit with relay fault detection function, such as Figure 1 As shown, it includes: The first detection circuit is connected to the wiper enable relay K1 and is used to monitor the working status of the wiper enable relay K1.

[0033] In this embodiment, the first detection circuit includes a transistor detection circuit I and a transistor detection circuit II connected in series. Transistor detection circuit I is connected to the normally open pin 87b of the wiper enable relay K1, and transistor detection circuit II is connected to the internal control signal pin 86a of the wiper enable relay K1; a transistor redundancy judgment mechanism is adopted.

[0034] In this embodiment, the transistor detection circuit I includes a first transistor Q1, which is an NPN transistor. The base of the first transistor Q1 is connected to the normally open pin 87b of the wiper enable relay K1 through a first protection resistor R1. The emitter of the first transistor Q1 is connected to the first indicator section. A sixth protection resistor R6 is connected in parallel between the base and emitter of the first transistor Q1. The collector of the first transistor Q1 is connected to the transistor detection circuit II.

[0035] The first protection resistor R1 is used to limit the current input from the external wiper power supply to the base of the first transistor Q1, protecting the first transistor Q1 and ensuring its saturation conduction. The sixth protection resistor R6 is used to ensure that the base and emitter potentials of the first transistor Q1 are consistent when no definite conduction signal is given in the entire circuit, preventing the first transistor Q1 from being mis-conducted.

[0036] In this embodiment, the transistor detection circuit II includes a second transistor Q2, which is an NPN transistor. The base of the second transistor Q2 is connected to the second control terminal of the wiper enable relay K1 through a second protection resistor R2. The emitter of the second transistor Q2 is connected to the collector of the first transistor Q1. The collector of the second transistor Q2 is connected to the common pin 30a of the wiper enable relay K1 through a third protection resistor R3.

[0037] The second protection resistor R2 is used to limit the current flowing from the first internal control signal into the base of the second transistor Q2, protecting the second transistor Q2 and ensuring its saturation conduction. The seventh protection resistor R7 is used to ensure that the base and emitter potentials of the second transistor Q2 are consistent when no definite conduction signal is given in the entire circuit, preventing the first transistor Q1 from being mis-conducted. The third protection resistor R3 is used to limit the current flowing from the common pin 30a of the wiper enable relay K1 to the collector of the second transistor Q2, protecting the entire conducting circuit.

[0038] In this embodiment of the application, the first indication part is connected to the first detection circuit and is used to indicate the working state of the wiper enable relay K1.

[0039] The first instruction portion includes: The first indicator diode D5 is a light-emitting diode used to indicate the working state of the wiper enable relay K1. The anode of the first indicator diode D5 is connected to the emitter of the first transistor Q1. The ninth protection resistor R9 is used to limit the current value of the circuit of the first indicator diode D5 to prevent the current value from being too large. One end of the ninth protection resistor R9 is connected to the cathode of the first indicator diode D5, and the other end is grounded.

[0040] The operation of the first detection circuit and the first indication section is as follows: When the wipers are not needed, the base of the first transistor Q1 is connected to the external wiper power supply through the first protection resistor R1, which is at a high level. The first internal control signal is at a low level. Therefore, the base of the second transistor Q2 is at a low level, and the wiper enable relay K1 is not energized. That is, the common pin 30a of the wiper enable relay K1 outputs a low level, and the collector of the second transistor Q2 is at a low level. Therefore, the second transistor Q2 is not conducting, and the emitter of the second transistor Q2 outputs a low level. The collector of the first transistor Q1 is connected to the emitter of the second transistor Q2, so the collector of the first transistor Q1 is also at a low level. The voltage is lower than that of the base of the first transistor Q1, so the first transistor Q1 is not conducting. Therefore, no voltage difference is generated across the first indicator diode D5, and no current flows through it. The first indicator diode D5 does not light up.

[0041] When the windshield wipers need to be activated, the first internal control signal is high, therefore the base of the second transistor Q2 is high. At this time, the emitter voltage of transistor Q2 is lower than that of the base, and the emitter junction is forward biased. To ensure that the transistor is in deep saturation, the second protection resistor R2 is adjusted to a relatively high value (e.g., 4.7kΩ) to ensure that the base current of the second transistor Q2 is at a low value, making the collector current of the second transistor Q2 much greater than that of the base, thus ensuring that the second transistor Q2 is in the conduction saturation region. For the collector of the second transistor Q2, power is drawn from pin 30A through resistor R3. To ensure the collector potential of Q2, the resistance of R3 can be adjusted (e.g., 100Ω) to act as a voltage divider for the entire circuit. For the first transistor Q1, to ensure it is in a deep saturation conduction state, the first protection resistor R1 is adjusted to a relatively high resistance value (e.g., 4.7kΩ), so that the base current of the first transistor Q1 is much smaller than that of the collector of the first transistor Q1, ensuring that the first transistor Q1 can be in a deep saturation conduction state when it needs to be turned on. For the light-emitting diode D5, for easy indication, a red LED with a voltage drop of about 2V and a current of about 20mA and a matching current-limiting resistor R9 (e.g., 1kΩ) can be selected to ensure that the current through the light-emitting diode is about 10-20mA, so that D5 can light up normally, indicating that the circuit is working normally. The reference selection for the first transistor Q1 and the second transistor Q2 is BC846B.

[0042] The other structures and principles are the same as in Example 1.

[0043] Example 3 A car windshield wiper enable and speed control circuit with relay fault detection function, such as Figure 1 As shown, it includes: The second detection circuit is connected to the wiper speed control relay K2 and is used to monitor the working status of the wiper speed control relay K2.

[0044] In this embodiment, the second detection circuit includes a parallel MOSFET detection circuit I and a MOSFET detection circuit II. The MOSFET detection circuit I is connected to the normally closed pin 87c of the wiper speed control relay K2, and the MOSFET detection circuit II is connected to the normally open pin 87d of the wiper speed control relay K2, using a parallel MOSFET judgment mechanism.

[0045] In this embodiment, the MOS transistor detection circuit I includes a first MOS transistor Q3, which is an enhancement-mode NMOS transistor. The gate of the first MOS transistor Q3 is connected to the normally closed pin 87c of the wiper speed control relay K2 through a fourth protection resistor R4. The drain of the first MOS transistor Q3 is connected to the common pin 30b of the wiper speed control relay K2 through an eighth protection resistor R8. The source of the first MOS transistor Q3 is connected to the second indicator portion.

[0046] In this embodiment, the MOS transistor detection circuit II includes a second MOS transistor Q4, which is an enhancement-mode NMOS transistor. The gate of the second MOS transistor Q4 is connected to the normally open pin 87d of the wiper speed control relay K2 through a fifth protection resistor R5. The drain of the second MOS transistor Q4 is connected to the drain of the first MOS transistor Q3, and the source of the second MOS transistor Q4 is connected to the second indicator portion.

[0047] The fourth protection resistor R4 and the fifth protection resistor R5 are used to limit the current flowing from the two outputs of the wiper speed control relay K2 to the first MOSFET Q3 and the second MOSFET Q4, thus protecting the first MOSFET Q3 and the second MOSFET Q4. The eighth protection resistor R8 is used for voltage divider protection to ensure that the voltage value entering the drain of the MOSFET does not exceed the withstand voltage value of the second indicator diode D6 and the withstand voltage value of the MOSFET. At the same time, it ensures that after the MOSFET is turned on, the voltage reaching the source through the drain is still less than the gate voltage, thus turning on the MOSFET.

[0048] In this embodiment, the second indication part is connected to the second detection circuit and is used to indicate the working status of the wiper speed control relay K2.

[0049] The second instruction portion includes: The second indicator diode D6 is a light-emitting diode used to indicate the working status of the wiper speed control relay K2. The anode of the second indicator diode D6 is connected to the source of the first MOSFET Q3 and the source of the second MOSFET Q4, respectively. The tenth protection resistor R10 is used to limit the circuit current of the second indicator diode D6. One end of the tenth protection resistor R10 is connected to the cathode of the second indicator diode D6, and the other end is grounded.

[0050] The operation of the second detection circuit and the second indication section is as follows: When the wipers are not activated, K1 and K2 are normal: When the wipers are not needed, the first indicator diode D5 does not light up, the second internal control signal is low, and the wiper speed control relay K2 is not engaged. Since the common pin 30a of the wiper enable relay K1 outputs a low level, the normally closed pin 87c and normally open pin 87d of the wiper speed control relay K2 both output a low level. The gates of the first MOSFET Q3 and the second MOSFET Q4 are connected to the normally closed pin 87c and normally open pin 87d of the wiper speed control relay K2, respectively. Therefore, the gates of the first MOSFET Q3 and the second MOSFET Q4 are both low. The drains of the first MOSFET Q3 and the second MOSFET Q4 are both connected to the common pin 30b of the wiper speed control relay K2 through the eighth protection resistor R8, and are also low. Therefore, neither the first MOSFET Q3 nor the second MOSFET Q4 is conducting, and the second indicator diode D6 does not light up.

[0051] Startup, K1 and K2 normal: When the wipers need to be turned on, and the wiper enable relay K1 is working properly, the first indicator diode D5 illuminates. When the second internal control signal is low, the wiper speed control relay K2 is not energized, controlling the normally closed pin 87c of the wiper speed control relay K2 to output a high level. When the second internal control signal is high, the wiper speed control relay K2 is energized, controlling the normally open pin 87d of the wiper speed control relay K2 to output a high level. In both cases, the gate of the first MOSFET Q3 and the second MOSFET Q4 is high. The drain of the first MOSFET Q3 and the drain of the NMOS are both connected to the common pin 30a of relay K1, which is also the common pin of the wiper speed control relay K2, and are both high. Only one of the first MOSFET Q3 and the second MOSFET Q4 will conduct, and the second indicator diode D6 illuminates. To ensure that the MOSFETs can conduct normally, the drains of the two MOSFETs are powered from the common pin 30b, by the eighth protection resistor R8 and the internal voltage drop V of the MOSFET. DS The voltage drop across LED D6 and the tenth protection resistor R10 form a current-carrying circuit. By adjusting the resistance value of R8 (e.g., 100Ω), the voltage difference between the source and gate of the MOSFET is made greater than the turn-on threshold, allowing the MOSFET to remain on and LED D6 to remain lit. For NMOS, ZMSA032N04HNC can be selected, ensuring that the voltage difference between the gate and source is greater than the turn-on voltage V of this MOSFET model. DS(TH) It will then conduct. For better indication, a red LED with a voltage drop of approximately 2V and a current of approximately 20mA can be selected as the indicator.

[0052] Start-up, K1 malfunctions, K2 is normal: When the wipers need to be turned on, and the wiper enable relay K1 is malfunctioning, the first indicator diode D5 does not light up, the common pin 30a of the wiper enable relay K1 outputs a low level, and the common pin 30a of the wiper enable relay K1 cannot properly transmit the external wiper power input signal. At this time, the first MOSFET Q3 and the second MOSFET Q4 are not conducting, similar to the situation when the wipers do not need to be turned on. The second indicator diode D6 does not light up.

[0053] Start-up, K1 normal, K2 abnormal: When the wipers need to be turned on and the wiper enable relay K1 is working normally, the first indicator diode D5 lights up, and the common pin 30a of the wiper enable relay K1 outputs a high level. If the wiper speed control relay K2 is working abnormally, both the normally closed pin 87c and the normally open pin 87d of the wiper speed control relay K2 output a low level. Therefore, the first MOSFET Q3 and the second MOSFET Q4 are not turned on, and the second indicator diode D6 does not light up.

[0054] The other structures and principles are the same as in Example 2.

[0055] 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. An automobile wiper enabler and speed regulation circuit with a relay abnormal function detection, characterized in that, include: The main control circuit includes a first protection circuit connected to the external wiper power supply; a wiper enable relay connected to the first protection circuit, the external wiper power supply, and the first internal control signal of the car wiper; a wiper speed control relay connected to the wiper enable relay, the wiper motor speed control position, and the second internal control signal of the car wiper; and a second protection circuit connected to the wiper speed control relay. The first detection circuit is connected to the wiper enable relay and is used to monitor the working status of the wiper enable relay. The second detection circuit is connected to the wiper speed control relay and is used to monitor the working status of the speed control wiper speed control relay. The first indicator section is connected to the first detection circuit and is used to indicate the working status of the wiper enable relay. The second indicator section is connected to the second detection circuit and is used to indicate the working status of the wiper speed control relay.

2. The automobile wiper enabler and speed regulation circuit with relay abnormal function detection of claim 1, wherein, The wiper enable relay is a five-pin relay. The common pin of the wiper enable relay is connected to the common pin of the wiper speed control relay. The normally closed pin of the wiper enable relay is grounded. The normally open pin of the wiper enable relay is connected to the external wiper power supply and the first detection circuit, respectively. The ground pin of the wiper enable relay is grounded. The internal control signal pin of the wiper enable relay is connected to the first internal control signal of the car wiper and the first detection circuit, respectively.

3. The wiper enable and speed control circuit with relay abnormal function detection of claim 2, wherein, The aforementioned wiper speed control relay is a five-pin relay. The normally closed pin of the wiper speed control relay is connected to the first speed control position of the wiper motor and the Q3 detection circuit, respectively. The normally open pin of the wiper speed control relay is connected to the second speed control position of the wiper motor and the Q4 detection circuit, respectively. The grounding pin of the wiper speed control relay is grounded, and the internal control signal pin of the wiper speed control relay is connected to the second internal control signal of the car's wipers.

4. The wiper enable and speed control circuit with relay abnormal function detection of claim 3, wherein, The first protection circuit includes: The first protection diode has its anode connected to the external windshield wiper power supply and its cathode connected to the positive power supply. The second protection diode has its cathode connected to the external wiper power supply and its anode grounded. The second protection circuit includes: The third protection diode has its anode grounded and its cathode connected to the normally closed pin of the wiper speed control relay. The fourth protection diode has its anode grounded and its cathode connected to the normally open pin of the wiper speed control relay.

5. The wiper enable and speed control circuit with relay abnormal function detection of claim 4, wherein, The first detection circuit includes a transistor detection circuit I and a transistor detection circuit II. The transistor detection circuit I is connected to the normally open pin of the wiper enable relay, and the transistor detection circuit II is connected to the internal control signal pin of the wiper enable relay. The second detection circuit includes a MOSFET detection circuit I and a MOSFET detection circuit II. The MOSFET detection circuit I is connected to the normally closed pin of the wiper speed control relay, and the MOSFET detection circuit II is connected to the normally open pin of the wiper speed control relay.

6. The wiper enable and speed control circuit with relay abnormal function detection of claim 5, wherein, The transistor detection circuit I includes a first transistor. The base of the first transistor is connected to the normally open pin of the wiper enable relay through a first protection resistor. The emitter of the first transistor is connected to the first indicator section. A sixth protection resistor is connected in parallel between the base and emitter of the first transistor. The collector of the first transistor is connected to the transistor detection circuit II.

7. The wiper enable and speed control circuit with relay abnormal function detection of claim 6, wherein, The transistor detection circuit II includes a second transistor. The base of the second transistor is connected to the internal control signal pin of the wiper enable relay through a second protection resistor. The emitter of the second transistor is connected to the collector of the first transistor. The collector of the second transistor is connected to the common pin of the wiper enable relay through a third protection resistor.

8. The wiper enable and speed control circuit for a motor vehicle wiper with a relay abnormal function detector according to any one of claims 5 to 7, characterized in that, The MOS transistor detection circuit I includes a first MOS transistor. The gate of the first MOS transistor is connected to the normally closed pin of the wiper speed control relay through a fourth protection resistor. The drain of the first MOS transistor is connected to the common pin of the wiper speed control relay through an eighth protection resistor. The source of the first MOS transistor is connected to the second indicator section.

9. The wiper enable and speed control circuit with relay abnormal function detection of claim 8, wherein, The MOS transistor detection circuit II includes a second MOS transistor. The gate of the second MOS transistor is connected to the normally open pin of the wiper speed control relay through a fifth protection resistor. The drain of the second MOS transistor is connected to the drain of the first MOS transistor, and the source of the second MOS transistor is connected to the second indicator section.

10. The wiper enable and speed control circuit with relay abnormal function detection of claim 9, wherein, The first instruction portion includes: The anode of the first indicator diode is connected to the emitter of the first transistor; The ninth protection resistor has one end connected to the cathode of the first indicator diode and the other end grounded. The second instruction portion includes: The anode of the second indicator diode is connected to the source of the first MOS transistor and the source of the second MOS transistor, respectively. The tenth protection resistor has one end connected to the cathode of the second indicator diode and the other end grounded.

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