Driving circuit, driving system and vehicle

Abstract

The present disclosure relates to a driving circuit, a driving system and a vehicle, comprising a first switch tube, a second switch tube and a first resistor; wherein in the case that a driving signal is a high level, the first switch tube can be turned off or turned on based on the voltage between the first end and the second end of the first resistor, so as to control the second switch tube to be turned on or turned off. Through the above technical solution, compared with the related art, the structure of the setting circuit is simple without the setting of the integrated chip.

Description

Technical Field

[0001] This disclosure relates to the field of control technology, and more specifically, to drive circuits, drive systems, and vehicles. Background Technology

[0002] LED (Light-Emitting Diode) driver circuits primarily provide stable and efficient current or voltage to LEDs to ensure their stable operation. In related technologies, LEDs are driven using integrated chips; however, this method results in a complex structure. Utility Model Content

[0003] The purpose of this disclosure is to provide drive circuits, drive systems, and vehicles to solve the technical problems existing in the related art.

[0004] To achieve the above objectives, in a first aspect, this disclosure provides a driving circuit, including: a first switching transistor, a second switching transistor, and a first resistor;

[0005] The first terminal of the first switching transistor and the first end of the first resistor are used to connect to the power supply, the second terminal of the first switching transistor is connected to the second end of the first resistor, and the third terminal of the first switching transistor is connected to the second terminal of the second switching transistor.

[0006] The first terminal of the second switch is connected to the second terminal of the first resistor, the second terminal of the second switch is used to connect to the input terminal of the drive signal, and the third terminal of the second switch is used to connect to the light source.

[0007] When the drive signal is high, the first switch can be turned on or off based on the voltage between the first and second terminals of the first resistor, so as to control the second switch to be turned on or off.

[0008] Optionally, when the voltage between the first and second terminals of the first resistor is less than the turn-on voltage of the first switch, the first and third terminals of the first switch are disconnected, and the first and third terminals of the second switch are connected.

[0009] When the voltage between the first and second terminals of the first resistor is greater than or equal to the turn-on voltage of the first switching transistor, the first and third terminals of the first switching transistor are connected, and the first and third terminals of the second switching transistor are disconnected.

[0010] Optionally, the driving circuit further includes a switching transistor control unit, a first terminal of which is adapted to be connected to the input terminal of the driving signal, a second terminal of which is adapted to be connected to the power supply, and a third terminal of which is connected to the second electrode of the second switching transistor.

[0011] When the drive signal is high, the second and third terminals of the switching transistor control unit are turned on;

[0012] When the drive signal is low, the second and third terminals of the switching transistor control unit are disconnected.

[0013] Optionally, the switching transistor control unit includes: a first voltage divider unit and a second voltage divider unit;

[0014] The first end of the first voltage divider unit is used to connect to the power supply, and the second end of the first voltage divider unit is connected to the first end of the second voltage divider unit and the second electrode of the second switching transistor;

[0015] The second terminal of the second voltage divider unit is used to connect to the input terminal of the drive signal, and the third terminal of the second voltage divider unit is used to ground.

[0016] When the drive signal is high, the first and third terminals of the second voltage divider unit are turned on, so that the voltage at the second terminal of the first voltage divider unit can drive the first and third terminals of the second switching transistor to turn on.

[0017] Optionally, the second voltage divider unit includes a second resistor and a third switching transistor;

[0018] The first terminal of the third switch is adapted to be grounded, the second terminal of the third switch is adapted to be connected to the input terminal of the drive signal, and the third terminal of the third switch is connected to the second terminal of the second resistor.

[0019] The first end of the second resistor is connected to the second end of the first voltage divider unit;

[0020] When the drive signal is high, the first and third terminals of the third switch are connected, so that the first and third terminals of the second voltage divider unit are connected.

[0021] Optionally, the second voltage divider unit further includes a third resistor and a fourth switching transistor;

[0022] The first terminal of the fourth switch is connected to the third terminal of the third switch, the second terminal of the fourth switch is grounded, and the third terminal of the fourth switch is connected to the second terminal of the third resistor.

[0023] The first end of the third resistor is connected to the second end of the first voltage divider unit;

[0024] When the first and third terminals of the third switching transistor are connected, the second and third terminals of the fourth switching transistor are connected, so that the third resistor is connected in parallel with the second resistor.

[0025] Optionally, the second voltage divider unit further includes a fourth resistor, a fifth resistor, and a first capacitor. The second terminal of the third switch is adapted to be connected to the input terminal of the drive signal through the fourth resistor, and the second terminal of the third switch is adapted to be grounded through the fifth resistor. The input terminal of the drive signal is also used to be grounded through the first capacitor.

[0026] Optionally, the first voltage divider unit includes a sixth resistor;

[0027] The first end of the sixth resistor is used to connect to the power supply, and the second end of the sixth resistor is connected to the first end of the third resistor, the first end of the second resistor, and the second terminal of the second switching transistor.

[0028] The ratio between the resistance values ​​of the sixth resistor, the second resistor, and the third resistor is a preset ratio.

[0029] Optionally, the driving circuit further includes an anti-reverse unit;

[0030] The first end of the anti-reverse unit is connected to the first electrode of the first switching transistor and the first end of the first resistor, respectively.

[0031] When the second terminal of the anti-reverse unit is grounded and the third terminal of the anti-reverse unit is adapted to be connected to a power supply, the first terminal of the anti-reverse unit is disconnected from the second terminal.

[0032] When the second end of the anti-reverse unit is used to connect to a power source and the third end of the anti-reverse unit is adapted to be grounded, the first end of the anti-reverse unit is connected to the second end.

[0033] Optionally, the anti-reverse unit includes a fifth switch, a seventh resistor, and an eighth resistor;

[0034] The first terminal of the fifth switch is connected to the first terminal of the seventh resistor, the first terminal of the first switch, and the first terminal of the first resistor, respectively; the second terminal of the fifth switch is connected to the first terminal of the eighth resistor and the second terminal of the seventh resistor, respectively.

[0035] The second terminal of the eighth resistor is grounded;

[0036] When the third terminal of the fifth switch is grounded and the second terminal of the eighth resistor is adapted to be connected to a power supply, the first terminal of the fifth switch is disconnected from the third terminal.

[0037] When the third terminal of the fifth switching transistor is used to connect to the power supply, and the second terminal of the eighth resistor is adapted to be grounded, the first terminal and the third terminal of the fifth switching transistor are connected.

[0038] Optionally, the anti-reverse unit further includes a second capacitor and a diode, the anode of the diode being connected to the first terminal of the fifth switching transistor, the cathode of the diode being connected to one end of the eighth resistor; the third terminal of the fifth switching transistor being connected to one end of the second capacitor, and the other end of the second capacitor being grounded.

[0039] Optionally, the driving circuit further includes a third capacitor, with the third terminal of the second switching transistor connected to one end of the third capacitor and the other end of the third capacitor grounded.

[0040] Secondly, this disclosure also provides a driving system, the driving system comprising:

[0041] LED;

[0042] The driving circuit according to any one of the first aspects of this disclosure is connected to an LED.

[0043] Thirdly, this disclosure also provides a vehicle including the drive system provided in the second aspect of this disclosure, or the drive circuit provided in any one of the first aspects of this disclosure.

[0044] With the above technical solution, based on the circuit connecting the first switch, the second switch, and the first resistor, when the driving signal is high, the first switch can be turned on or off based on the voltage between the first and second ends of the first resistor, thereby controlling the second switch to turn on or off, and thus controlling the driving of the light source. Compared with related technologies that drive the light source by setting an integrated chip, this solution does not require the setting of an integrated chip, and its setting circuit structure is simple.

[0045] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0046] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0047] Figure 1 This is a circuit diagram for driving LEDs in related technologies.

[0048] Figure 2 This is a schematic diagram of a drive circuit module according to an exemplary embodiment of the present disclosure.

[0049] Figure 3 This is a schematic diagram of a driving circuit according to an exemplary embodiment of the present disclosure.

[0050] Figure 4This is a schematic diagram of a drive circuit module according to an exemplary embodiment of the present disclosure.

[0051] Figure 5 This is a block diagram illustrating a drive system according to an exemplary embodiment.

[0052] Figure 6 This is a block diagram illustrating a vehicle according to an exemplary embodiment.

[0053] Figure 7 This is a block diagram illustrating a vehicle according to an exemplary embodiment.

[0054] Explanation of reference numerals in the attached figures

[0055] 1. First switching transistor; 2. Second switching transistor; 3. First resistor; 4. First voltage divider unit; 5. Second voltage divider unit; 6. Reverse protection unit. Detailed Implementation

[0056] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0057] With the widespread adoption and application of automotive LED driver power supplies, LEDs have experienced rapid development and are now used in numerous applications, such as various interior lights in automobiles. Currently, most LED driver power supplies on the market use switching power supplies. Among them, the low-side driver buck converter structure has become the mainstream due to its simple system structure and low cost.

[0058] In related technologies, such as Figure 1 As shown, the main process of driving the LED is as follows: The chip is powered on, the power transistor setting module is activated, the power transistor is turned on, and the LED is driven to work. At the same time, the current in the detection resistor R0 increases linearly. Then, the output current integrator integrates the current in the detection resistor R0, and the output current multiplier multiplies the current in the detection resistor R0. When the output current multiplication result is greater than the output current integration result, the switching transistor M0 is turned off, and the driving of the LED stops. After a fixed off time or a fixed period, the power transistor is turned on again, and so on.

[0059] However, the inventors discovered that when driving LEDs using methods in related technologies, the circuit structure is mainly built using integrated chips such as PWM (Pulse Width Modulation) comparators, current integrators, and current multipliers, resulting in a complex circuit structure.

[0060] In view of this, the present disclosure provides a drive circuit, a drive system, and a vehicle to solve the technical problems existing in the related art.

[0061] like Figure 2 As shown, Figure 2 This is a schematic diagram illustrating a driving circuit according to an exemplary embodiment of the present disclosure, with reference to... Figure 2 It includes: first switching transistor 1, second switching transistor 2, and first resistor 3;

[0062] The first terminal of the first switch transistor 1 and the first terminal of the first resistor 3 are used to connect to the power supply, the second terminal of the first switch transistor 1 is connected to the second terminal of the first resistor 3, and the third terminal of the first switch transistor 1 is connected to the second terminal of the second switch transistor 2.

[0063] The first terminal of the second switch 2 is connected to the second terminal of the first resistor 3, the second terminal of the second switch 2 is used to connect to the input terminal of the drive signal, and the third terminal of the second switch 2 is used to connect to the light source.

[0064] When the drive signal is high, the first switch 1 can be turned on or off based on the voltage between the first and second terminals of the first resistor to control the second switch 2 to be turned on or off.

[0065] With the above technical solution, based on the circuit connecting the first switch 1, the second switch 2, and the first resistor 3, when the driving signal is high, the first switch 1 can be turned on or off based on the voltage between the first and second ends of the first resistor 3, thereby controlling the second switch 2 to be turned on or off, and thus controlling the driving of the light source. Compared with the related technology that drives the light source by setting an integrated chip, this solution does not require the setting of an integrated chip, and its setting circuit structure is simple.

[0066] To enable those skilled in the art to better understand the driving circuits provided in this disclosure, detailed examples of the above circuits are provided below.

[0067] For example, both the first switch 1 and the second switch 2 can be NMOS (N-channel Metal-Oxide-Semiconductor Field-Effect Transistor) or PMOS (P-channel Metal-Oxide-Semiconductor Field-Effect Transistor). This embodiment of the present disclosure does not specifically limit the choice. The light source can be an LED; this embodiment of the present disclosure does not specifically limit the choice either.

[0068] In this embodiment of the disclosure, after the circuit formed by the first switch 1, the second switch 2, and the first resistor 3, when the light source is an LED, such as Figure 2As shown, when the drive signal is high, the second switch can be turned on or off based on the on or off state of the first switch. The on or off state of the first switch can be controlled by the voltage between the first and second terminals of the first resistor.

[0069] In one possible manner, when the voltage between the first and second terminals of the first resistor 3 is less than the turn-on voltage of the first switch 1, the first and third terminals of the first switch 1 are disconnected and the first and third terminals of the second switch 2 are connected.

[0070] When the voltage between the first and second terminals of the first resistor 3 is greater than or equal to the turn-on voltage of the first switch 1, the first and third terminals of the first switch 1 are connected, and the first and third terminals of the second switch 2 are disconnected.

[0071] It should be understood that, in Figure 2 In this circuit, the circuit containing the first resistor 3 and the second switch 2 can drive the LED when it is conducting. When the first switch 1 is off and the second switch 2 is on, current flows through the first resistor 3 and the second switch 2 to the LED, thereby driving the LED. Under the influence of external environmental factors, such as as the LED's operating time increases, the LED's inherent resistance may decrease, which may cause the current in the circuit containing the first resistor 3 and the second switch 2 to increase. This increases the voltage between the first and second terminals of the first resistor 3. When this voltage exceeds the turn-on voltage of the first switch 1, it can directly trigger the first switch 1 to turn off, and then the current flows through the first switch 1 to the second switch 2, thus turning off the second switch 2 without driving the LED, thereby protecting the LED.

[0072] In specific implementation, taking an example where both the first switch 1 and the second switch 2 are PMOS transistors and the light source is an LED, the first stage of both the first switch 1 and the second switch 2 are the sources of the PMOS transistors; the second stage of both the first switch 1 and the second switch 2 are the gates of the PMOS transistors; and the third stage of both the first switch 1 and the second switch 2 are the drains of the PMOS transistors. The conduction condition of the PMOS transistor is that the voltage at the gate of the PMOS transistor is less than the voltage at the source of the PMOS transistor. For example... Figure 3As shown, the first switch 1 can be a PMOS transistor Q2, the second switch 2 can be a PMOS transistor Q3, the first resistor 3 can be a resistor R2, and the power supply voltage can be VCC. When the voltage of the drive signal is less than the voltage of the power supply and the drive signal is a high-level signal, the voltage at the gate of PMOS transistor Q3 is less than the voltage at the source of the second switch 2, so PMOS transistor Q3 is turned on. Meanwhile, the voltage difference between the gate and source of PMOS transistor Q2 is not greater than the turn-on voltage, so PMOS transistor Q2 is turned off. At this time, the circuit containing resistor R2 and PMOS transistor Q3 is connected, and the current flows through resistor R2 and PMOS transistor Q3 to drive the LED. After continuously driving the LED for a period of time, the current in the circuit containing resistor R2 and PMOS transistor Q3 increases, and the voltage generated at the first and second terminals of resistor R2 increases. When the voltage on resistor R2 is greater than the turn-on voltage of PMOS transistor Q2, PMOS transistor Q2 enters the on-state. When PMOS transistor Q2 is turned on, current flows directly from Q2 to the gate of PMOS transistor Q3. The gate voltage of PMOS transistor Q3 is the power supply voltage, which is higher than the source voltage. This allows PMOS transistor Q3 to be turned off, thus stopping the LED drive. The LED will only light up again when the drive signal reaches a high level for the next cycle. Therefore, when the drive signal is high and the drive current in the circuit containing the LED is less than a preset current value, the LED is lit. The current can be adjusted by using resistor R2 to regulate the voltage across resistor R2, while also protecting the LED from damage.

[0073] When the drive signal is low, there is no voltage difference between the gate and source of PMOS transistor Q3. PMOS transistor Q3 is in the off state, the LED will not be lit, no current flows through the LED, no voltage difference is formed across resistor R2, and PMOS transistor Q2 will not work.

[0074] The circuit consisting of the first switch 1, the second switch 2, and the first resistor 3 can drive the LED and automatically detect the current on the LED. If the current to the LED is too high, the circuit around the LED will automatically disconnect to protect it. Compared to related technologies that use integrated chips to drive the LED, this circuit eliminates the need for integrated chips, simplifying the circuit structure and reducing costs. Furthermore, disconnecting the LED drive when the voltage between the first and second terminals of the first resistor 3 exceeds the turn-on voltage of the first switch protects the LED from damage and extends its lifespan.

[0075] In one possible embodiment, the drive circuit further includes a switching transistor control unit, a first terminal of which is adapted to be connected to the input terminal of the drive signal, a second terminal of which is adapted to be connected to the power supply, and a third terminal of which is connected to the second electrode of the second switching transistor 2.

[0076] When the drive signal is high, the second and third terminals of the switching transistor control unit are turned on;

[0077] When the drive signal is low, the second and third terminals of the switching transistor control unit are disconnected.

[0078] It should be understood that in this drive circuit, the drive signal can be controlled by the switching transistor control unit. For example... Figure 4 As shown, the switching transistor control unit can output a high-level drive signal or a low-level drive signal. When the drive signal output by the switching transistor control unit is high, the second and third terminals of the switching transistor control unit are connected, thereby triggering the second switch 2 to conduct and drive the LED. When the drive signal output by the switching transistor control unit is low, the second and third terminals of the switching transistor control unit cannot be connected, the second switch 2 is disconnected, and the LED cannot be driven.

[0079] In a possible configuration, the switching control unit includes: a first voltage divider unit 4 and a second voltage divider unit 5;

[0080] The first end of the first voltage divider unit 4 is used to connect to the power supply, and the second end of the first voltage divider unit 4 is connected to the first end of the second voltage divider unit 5 and the second electrode of the second switching transistor 2.

[0081] The second terminal of the second voltage divider unit 5 is used to connect to the input terminal of the drive signal, and the third terminal of the second voltage divider unit 5 is used to ground.

[0082] When the drive signal is high, the first and third terminals of the second voltage divider unit 5 are turned on, so that the voltage at the second terminal of the first voltage divider unit 4 can drive the first and third terminals of the second switch 2 to turn on.

[0083] It should be understood that when the drive signal is high, the first and third terminals of the second voltage divider unit 5 can be turned on, so that the circuit where the first voltage divider unit 4 and the second voltage divider unit 5 are located is turned on, and the current flows from the first voltage divider unit 4 to the second voltage divider unit 5. At this time, the voltage on the first voltage divider unit 4 can be used as a drive signal and input to the gate of the second switching transistor 2 to turn on the first and third terminals of the second switching transistor 2.

[0084] In one possible configuration, the second voltage divider unit 5 includes a second resistor and a third switching transistor;

[0085] The first terminal of the third switch is adapted to be grounded, the second terminal of the third switch is adapted to be connected to the input terminal of the drive signal, and the third terminal of the third switch is connected to the second terminal of the second resistor.

[0086] The first end of the second resistor is connected to the second end of the first voltage divider unit 4;

[0087] When the drive signal is high, the first and third terminals of the third switch are connected, so that the first and third terminals of the second voltage divider unit 5 are connected.

[0088] It should be understood that the third switching transistor can be either an NMOS transistor or a PMOS transistor, and this embodiment does not specifically limit it. In this embodiment, taking an NMOS transistor as an example, the first terminal of the third switching transistor is the source of the NMOS transistor, the second terminal is the gate of the NMOS transistor, and the third terminal is the drain of the NMOS transistor. When the drive signal is high, the drain and source of the third switching transistor are connected, which enables the first and third terminals of the second voltage divider unit 5 to conduct, thereby enabling the circuit containing the first voltage divider unit 4 and the second resistor to conduct. Current can pass through the first voltage divider unit 4, the second resistor, and the third switching transistor to ground. Thus, a voltage signal exists on the first voltage divider unit 4. This voltage signal is used as a drive signal and sent to the second terminal of the second switching transistor 2 to enable the first and third terminals of the second switching transistor 2 to conduct.

[0089] In the specific implementation process, such as Figure 3As shown, the first voltage divider unit 4 can be a resistor R4, the second resistor can be a resistor R8, and the third switch can be an NMOS transistor Q5. The gate of the NMOS transistor Q5 is connected to the second end of the resistor R13. The second end of the resistor R13 is connected to the input terminal of the drive signal and the capacitor C13, respectively. The gate of the NMOS transistor Q5 is connected to the ground after the resistor R15 is connected. When the input drive signal is high, the high level is applied to the gate of the NMOS transistor Q5. The voltage at the gate of the NMOS transistor Q5 is greater than the voltage at the source of the NMOS transistor Q5, so the NMOS transistor is turned on. The first and second ends of the second voltage divider unit 5 are turned on, which in turn turns on the circuit containing the resistor R4, the resistor R8, and the NMOS transistor Q5. The current flows through the resistor R4, the resistor R7, and then to the NMOS transistor Q5 and then to the ground. The voltage across the resistor R4 is naturally divided, and the voltage across the resistor R4 is input to the gate of the second switch 2, which serves as the drive signal to turn on the source and drain of the second switch 2. When the input drive signal is low, when this low level is applied to the gate of NMOS transistor Q5, the voltage at the gate of NMOS transistor Q5 is less than the voltage at the source of NMOS transistor Q5, and therefore NMOS transistor Q5 will not be turned on.

[0090] In some possible configurations, the second voltage divider unit 5 may also include a third resistor and a fourth switching transistor;

[0091] The first terminal of the fourth switch is connected to the third terminal of the third switch, the second terminal of the fourth switch is grounded, and the third terminal of the fourth switch is connected to the second terminal of the third resistor.

[0092] The first end of the third resistor is connected to the second end of the first voltage divider unit 4;

[0093] When the first and third terminals of the third switch are connected, the second and third terminals of the fourth switch are connected, so that the third resistor is connected in parallel with the second resistor.

[0094] It should be understood that the fourth switching transistor can be a transistor, and this disclosure does not specifically limit its application. The first terminal of the fourth switching transistor can be the base of the transistor, the second terminal can be the collector of the transistor, and the third terminal can be the emitter of the transistor. In this disclosure embodiment, as... Figure 3As shown, the third resistor can be resistor R7, and the fourth switch can be transistor Q4. When the drive signal is high, the fourth switch is also conducting when the third switch is on. At this time, the circuit containing resistors R4, R8, and NMOS transistor Q5 is conducting, and the current flows sequentially through resistors R4, R8, and Q5 before reaching ground. The circuit containing resistors R4, R7, and Q4 is also conducting, with the current flowing sequentially through resistors R4, R8, and Q5 before reaching ground. The circuit containing resistors R8 and Q5 is connected in parallel with the circuit containing resistors R7 and Q4. The resistance of the parallel circuit can be calculated based on the resistance values ​​of resistors R7 and R8, and the voltage drop across resistor R4 can be calculated based on the resistance value of resistor R4.

[0095] In one possible configuration, the second voltage divider unit further includes a fourth resistor, a fifth resistor, and a first capacitor. The second terminal of the third switch is adapted to be connected to the input terminal of the drive signal via the fourth resistor. The second terminal of the third switch is adapted to be grounded via the fifth resistor. The input terminal of the drive signal is also used to be grounded via the first capacitor.

[0096] It should be understood that, such as Figure 2 As shown, the first capacitor can be capacitor C3, the fourth resistor can be resistor R13, and the fifth resistor can be resistor R15. Setting resistors R13 and R15 in the second voltage divider unit allows for voltage division. Setting capacitor C3 allows for filtering of the drive signal.

[0097] In one possible configuration, the first voltage divider unit 4 includes a sixth resistor;

[0098] The first end of the sixth resistor is used to connect to the power supply, and the second end of the sixth resistor is connected to the first end of the third resistor, the first end of the second resistor, and the second terminal of the second switching transistor 2.

[0099] The ratio between the resistance values ​​of the sixth resistor, the second resistor, and the third resistor is a preset ratio.

[0100] It should be understood that the sixth resistor can be as follows: Figure 2 As shown, in the first voltage divider unit 4 and the second voltage divider unit 5, the resistance values ​​of resistors R4, R7, and R8 are in a certain ratio. For example, when the resistance of resistor R4 is R, the resistance values ​​of resistors R7 and R8 can both be 2R. Therefore, it can be calculated that the voltage across resistor R4 is half of the power supply voltage.

[0101] Specifically, such as Figure 3As shown, taking resistor R4 with a resistance of R and resistors R7 and R8 both with a resistance of 2R as an example, after normal power supply, a drive signal of a certain frequency output from the MCU is input to the gate of NMOS transistor Q5. When the drive signal is high, NMOS transistor Q5 is turned on, and the power supply VCC, resistors R4 and R8, and NMOS transistor Q5 form a loop. At this time, a voltage divider is generated across resistors R4 and R8. When the resistance of resistor R8 is 2R and the resistance of resistor R4 is R, according to the voltage distribution principle of series resistors, the voltage drop across resistor R8 is 2 / 3VCC. This voltage drop is greater than the forward voltage of transistor Q4 between its base and emitter, so transistor Q4 is turned on and enters the saturation conduction state. The voltage difference between the base and emitter of transistor Q4 is 0.7V.

[0102] At this point, the power supply VCC, resistors R4 and R8, and NMOS transistor Q5 form the first loop, with current flowing sequentially from resistor R4 to resistor R8 and then to NMOS transistor Q5. The power supply VCC, resistors R4 and R7, and transistor Q4 form the second loop, with current flowing sequentially from resistor R4 to resistor R7 and then to transistor Q4. Therefore, a series circuit consisting of resistor R8 and NMOS transistor Q5, followed by a parallel circuit consisting of resistor R7 and transistor Q4, results in a parallel circuit where the resistance value can be the value of R8 / / R7. When the resistance of resistor R7 is 2R, the resistance of the parallel circuit can be calculated using the parallel resistor calculation formula, resulting in R. This parallel circuit is then connected in series with resistor R4 to divide the voltage, and the voltage drop across resistor R4 is 1 / 2 VCC.

[0103] Without the parallel resistor R7 and transistor Q4, the existing circuit can only form a first loop. Calculations show that the voltage drop across resistor R4 is R / 3R*VCC = 1 / 3VCC. If a second loop is added, the calculated voltage drop across R4 becomes 1 / 2VCC. Therefore, the second voltage divider unit can increase the voltage division ratio of resistor R4, thereby enabling the second switch 2 to conduct. Simultaneously, it can reduce the on-resistance of the second switch 2, and also reduce power consumption and heat generation.

[0104] When the drive signal is low, NMOS transistor Q5 will not be turned on. At this time, resistor R8 and NMOS transistor Q5 do not form a circuit, and there is no voltage difference between the base and emitter of transistor Q4, so transistor Q4 is off. Consequently, there is no voltage difference between the gate and source of PMOS transistor Q3, so PMOS transistor Q3 is off, the LED will not be driven, there is no voltage across resistor R2, so PMOS transistor Q2 is off.

[0105] Therefore, when the drive signal is high, the maximum current value of the circuit containing the LED can be calculated based on the turn-on voltage of PMOS transistor Q2. For example, when the resistance of resistor R2 is r and the turn-on voltage of PMOS transistor Q2 is VGS-th, the maximum current of the circuit containing the LED, resistor R2, and PMOS transistor Q3 can be calculated as VGS-th / r, and this current value can be used as the maximum current limit value for this circuit.

[0106] When the drive signal frequency is high, the human eye will not perceive the LED being turned off; it will appear to be constantly lit. Changing the drive signal frequency or the duty cycle of the high-level signal alters the LED's on and off times. Different time percentages result in different average currents and brightness levels for the LED; a higher average current leads to greater brightness, and vice versa. By changing the value of resistor R2, the maximum current flowing through it can be altered, thus protecting the LED.

[0107] In some possible configurations, the drive circuit further includes an anti-reverse unit 6;

[0108] The first end of the anti-reverse unit 6 is connected to the first pole of the first switch tube 1 and the first end of the first resistor 3, respectively.

[0109] When the second terminal of the anti-reverse unit 6 is grounded and the third terminal of the anti-reverse unit 6 is adapted to be connected to a power supply, the first terminal of the anti-reverse unit 6 is disconnected from the second terminal.

[0110] When the second end of the anti-reverse unit 6 is used to connect to the power supply and the third end of the anti-reverse unit 6 is adapted to be grounded, the first end of the anti-reverse unit 6 is connected to the second end.

[0111] It should be understood that the anti-reverse unit 6 prevents the circuit from conducting when the power supply is connected to the ground terminal of the drive circuit, thus protecting the LED from damage. For example... Figure 4 As shown, the second terminal of the reverse protection unit 6 can be connected to the input terminal of the power supply, and the first terminal of the reverse protection unit 6 is connected to the first terminal of the first switching transistor 1 and the first terminal of the first resistor 3. When the second terminal of the reverse protection unit 6 is connected to the power supply, the power supply can pass through the reverse protection unit 6 to the first resistor 3 and the first switching transistor 1. When the second terminal of the reverse protection unit 6 is grounded and connected to the power supply in the direction of LED grounding, it indicates that the circuit is reversed, the reverse protection unit 6 cannot conduct, and thus protects the LED from damage.

[0112] In a possible configuration, the anti-reverse unit 6 includes a fifth switch, a seventh resistor, and an eighth resistor;

[0113] The first terminal of the fifth switch is connected to the first terminal of the seventh resistor, the first terminal of the first switch 1, and the first terminal of the first resistor 3, respectively; the second terminal of the fifth switch is connected to the first terminal of the eighth resistor and the second terminal of the seventh resistor, respectively.

[0114] The second terminal of the eighth resistor is grounded;

[0115] When the third terminal of the fifth switch is grounded, and the second terminal of the eighth resistor and the third terminal of the second switch 2 are used to connect to the power supply, the first terminal of the fifth switch is disconnected from the third terminal.

[0116] When the third terminal of the fifth switching transistor is used to connect to the power supply, and the second terminal of the eighth resistor and the third terminal of the second switching transistor 2 are grounded, the first and third terminals of the fifth switching transistor are connected.

[0117] It should be understood that the fifth switch can be either an NMOS transistor or a PMOS transistor, and this embodiment does not specifically limit it. In this embodiment, a PMOS transistor is used as an example. The first terminal of the fifth switch can be the source of the PMOS transistor, the second terminal of the fifth switch can be the gate of the PMOS transistor, and the third terminal of the fifth switch can be the drain of the PMOS transistor.

[0118] In the embodiments disclosed herein, such as Figure 3 As shown, the seventh resistor can be resistor R5, the eighth resistor can be resistor R1, and the fifth switching transistor can be PMOS transistor Q1. When all GND pins in the drive circuit are connected to the GND pins of the digital power supply device, and the BAT_VCC pin of the reverse protection unit 6 is connected to the positive input of the digital power supply device, the power supply passes through the body diode of PMOS transistor Q1, and then through resistors R1 and R5 to form a loop, generating current. The voltage drop is distributed according to the resistance values ​​of resistors R1 and R5, ensuring that the voltage at the gate of PMOS transistor Q1 is less than the voltage at the source. When the voltage difference between the gate and source of PMOS transistor Q1 is greater than the turn-on voltage, the P-channel of PMOS transistor Q1 conducts, effectively short-circuiting the drain and source, thus allowing the circuit to operate normally.

[0119] When all GND terminals in the driver circuit are connected to the positive input of the digital power supply device, and BAT_VCC is connected to the ground of the digital power supply device, the voltage at the gate of PMOS transistor Q1 is equal to the voltage at its source, and the voltage difference between the gate and source of PMOS transistor Q1 is 0V. According to the switching principle of PMOS transistors, a negative voltage difference must be formed between the gate and source of the PMOS transistor, and this voltage difference must be greater than the turn-on voltage for the P-channel to open. At this time, the voltage difference between the gate and source of PMOS transistor Q1 is 0V, the P-channel is not opened, PMOS transistor Q1 does not work, and the drain and source of PMOS transistor Q1 are in an open circuit state, which plays a role in preventing reverse polarity.

[0120] In one possible configuration, the anti-reverse unit 6 further includes a second capacitor and a diode, the anode of which is connected to the first terminal of the fifth switching transistor, and the cathode of which is connected to one end of the eighth resistor; the third terminal of the fifth switching transistor is connected to one end of the second capacitor, and the other end of the second capacitor is grounded.

[0121] It should be understood that the second capacitor can be Figure 2 The capacitor C1 shown can be replaced by a Zener diode De1. In this driving circuit, the drain of the PMOS transistor Q1 is also grounded through capacitor C1. This capacitor C1 mainly filters the input power supply, removing high-frequency signals and preventing high-frequency signal interference from turning on the PMOS transistor Q1. The gate of the PMOS transistor Q1 is also connected to the anode of the Zener diode De1, and the source of the PMOS transistor Q1 is also connected to the cathode of the Zener diode De1. The Zener diode De1 prevents the voltage difference between the gate and source of the PMOS transistor Q1 from becoming too large, thus ensuring that the PMOS transistor Q1 will not be burned out.

[0122] In one possible configuration, the drive circuit further includes a third capacitor, with the third terminal of the second switching transistor connected to one end of the third capacitor and the other end of the third capacitor grounded.

[0123] It should be understood that in the drive circuit, the third terminal of the second switching transistor is connected to a third capacitor, which can be... Figure 2 The capacitor C2 shown is used to filter out interference signals from the current input to the LED power supply.

[0124] The above technical solution, using switching transistors and resistors to drive the LED circuit, simplifies the circuit and reduces setup costs. The current in the LED conduction loop can be monitored based on the voltage difference across resistor R2, allowing control of the MOSFET Q2's turn-off and ultimately controlling the maximum current output, simplifying the control principle. Adding a reverse protection unit 6 at the power supply protects the LED, improving input protection levels. The cooperation between the first switch 1 and the second switch 2 forms an LED constant current source driver circuit that automatically detects the maximum current in the loop containing resistor R2 and the second switch 2. By using transistor Q4, the voltage drop across resistor R4 is increased, maximizing the conduction of the second switch 2 while minimizing its internal resistance, thus reducing power consumption and heat generation.

[0125] Based on the same concept, this embodiment also discloses a driving system, which includes an LED and a driving circuit disclosed in this embodiment, and the driving circuit is connected to the LED.

[0126] Figure 5 This is a block diagram illustrating a drive system 501 according to an exemplary embodiment. Figure 5 As shown, the drive system 501 is equipped with the drive circuit 502 and LED 503 provided in this embodiment.

[0127] Based on the same concept, this embodiment also discloses a vehicle, including the drive system disclosed in this embodiment, or the drive circuit disclosed in this embodiment.

[0128] Figure 6 This is a block diagram illustrating a vehicle 601 according to an exemplary embodiment. Figure 6 As shown, the vehicle 601 is equipped with the drive system 501 provided in this embodiment.

[0129] Figure 7 This is a block diagram illustrating a vehicle 700 according to an exemplary embodiment. Figure 7 As shown, the vehicle 700 is equipped with the drive circuit 502 provided in this embodiment.

[0130] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0131] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0132] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A driving circuit, characterized in that, include: First switch (1), second switch (2), first resistor (3); The first terminal of the first switch (1) and the first end of the first resistor (3) are used to connect to the power supply, the second terminal of the first switch (1) is connected to the second end of the first resistor (3), and the third terminal of the first switch (1) is connected to the second terminal of the second switch (2). The first terminal of the second switch (2) is connected to the second terminal of the first resistor (3), the second terminal of the second switch (2) is used to connect to the input terminal of the drive signal, and the third terminal of the second switch (2) is used to connect to the light source; When the drive signal is high, the first switch (1) can be turned on or off based on the voltage between the first and second terminals of the first resistor (3) to control the second switch (2) to be turned on or off.

2. The driving circuit according to claim 1, characterized in that, When the voltage between the first and second terminals of the first resistor (3) is less than the turn-on voltage of the first switch (1), the first and third terminals of the first switch (1) are disconnected and the first and third terminals of the second switch (2) are connected. When the voltage between the first and second terminals of the first resistor (3) is greater than or equal to the turn-on voltage of the first switch (1), the first and third terminals of the first switch (1) are connected, and the first and third terminals of the second switch (2) are disconnected.

3. The driving circuit according to claim 1, characterized in that, The driving circuit also includes a switching transistor control unit, the first end of which is adapted to be connected to the input end of the driving signal, the second end of which is adapted to be connected to the power supply, and the third end of which is connected to the second pole of the second switching transistor (2). When the drive signal is high, the second and third terminals of the switching transistor control unit are turned on; When the drive signal is low, the second and third terminals of the switching transistor control unit are disconnected.

4. The driving circuit according to claim 3, characterized in that, The switching transistor control unit includes: a first voltage divider unit (4) and a second voltage divider unit (5); The first end of the first voltage divider unit (4) is used to connect to the power supply, and the second end of the first voltage divider unit (4) is connected to the first end of the second voltage divider unit (5) and the second pole of the second switching tube (2); The second end of the second voltage divider unit (5) is used to connect to the input end of the drive signal, and the third end of the second voltage divider unit (5) is used to ground; When the drive signal is high, the first and third terminals of the second voltage divider unit (5) are turned on so that the voltage at the second terminal of the first voltage divider unit (4) can drive the first and third terminals of the second switch (2) to turn on.

5. The driving circuit according to claim 4, characterized in that, The second voltage divider unit (5) includes a second resistor and a third switching transistor; The first terminal of the third switch is adapted to be grounded, the second terminal of the third switch is adapted to be connected to the input terminal of the drive signal, and the third terminal of the third switch is connected to the second terminal of the second resistor. The first end of the second resistor is connected to the second end of the first voltage divider unit (4); When the drive signal is high, the first and third terminals of the third switch are connected, so that the first and third terminals of the second voltage divider unit (5) are connected.

6. The driving circuit according to claim 5, characterized in that, The second voltage divider unit (5) also includes a third resistor and a fourth switching transistor; The first terminal of the fourth switch is connected to the third terminal of the third switch, the second terminal of the fourth switch is grounded, and the third terminal of the fourth switch is connected to the second terminal of the third resistor. The first end of the third resistor is connected to the second end of the first voltage divider unit (4); When the first and third terminals of the third switch are connected, the second and third terminals of the fourth switch are connected, so that the third resistor is connected in parallel with the second resistor.

7. The driving circuit according to claim 5, characterized in that, The second voltage divider unit (5) further includes a fourth resistor, a fifth resistor, and a first capacitor. The second terminal of the third switch is adapted to be connected to the input terminal of the drive signal through the fourth resistor. The second terminal of the third switch is adapted to be grounded through the fifth resistor. The input terminal of the drive signal is also used to be grounded through the first capacitor.

8. The driving circuit according to claim 6, characterized in that, The first voltage divider unit (4) includes a sixth resistor; The first end of the sixth resistor is used to connect to the power supply, and the second end of the sixth resistor is connected to the first end of the third resistor, the first end of the second resistor, and the second pole of the second switch (2). The ratio between the resistance values ​​of the sixth resistor, the second resistor, and the third resistor is a preset ratio.

9. The driving circuit according to claim 1, characterized in that, The driving circuit also includes an anti-reverse unit (6). The first end of the anti-reverse unit (6) is connected to the first pole of the first switch (1) and the first end of the first resistor (3); When the second end of the anti-reverse unit (6) is grounded and the third end of the anti-reverse unit (6) is adapted to be connected to a power supply, the first end of the anti-reverse unit (6) is disconnected from the second end; When the second end of the anti-reverse unit (6) is used to connect to the power supply and the third end of the anti-reverse unit (6) is adapted to be grounded, the first end of the anti-reverse unit (6) is connected to the second end.

10. The driving circuit according to claim 9, characterized in that, The anti-reverse unit (6) includes a fifth switch, a seventh resistor, and an eighth resistor; The first terminal of the fifth switch is connected to the first terminal of the seventh resistor, the first terminal of the first switch (1), and the first terminal of the first resistor (3), respectively; the second terminal of the fifth switch is connected to the first terminal of the eighth resistor and the second terminal of the seventh resistor, respectively. The second terminal of the eighth resistor is grounded; When the third terminal of the fifth switch is grounded and the second terminal of the eighth resistor is adapted to be connected to a power supply, the first terminal of the fifth switch is disconnected from the third terminal. When the third terminal of the fifth switching transistor is used to connect to the power supply, and the second terminal of the eighth resistor is adapted to be grounded, the first terminal and the third terminal of the fifth switching transistor are connected.

11. The driving circuit according to claim 10, characterized in that, The anti-reverse unit (6) also includes a second capacitor and a diode. The anode of the diode is connected to the first terminal of the fifth switch, and the cathode of the diode is connected to one end of the eighth resistor. The third terminal of the fifth switch is connected to one end of the second capacitor, and the other end of the second capacitor is grounded.

12. The driving circuit according to any one of claims 1-11, characterized in that, The driving circuit also includes a third capacitor, the third terminal of the second switching transistor (2) is connected to one end of the third capacitor, and the other end of the third capacitor is grounded.

13. A drive system, characterized in that, The drive system includes: LED; The driving circuit according to any one of claims 1-12, wherein the driving circuit is connected to an LED.

14. A vehicle, characterized in that, It includes the drive system as described in claim 13, or the drive circuit as described in any one of claims 1-12.

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