Headlight drive circuit and headlight assembly

Abstract

This utility model provides a vehicle lamp driving circuit and vehicle lamp assembly, including: a controllable switch, a first resistor and a current shunt circuit; the first end of the controllable switch is connected to a regulated power supply, the second end of the controllable switch is connected to the vehicle lamp, the third end of the controllable switch is grounded through the first resistor, and the current shunt circuit is connected in parallel between the second end and the third end of the controllable switch, which can reduce power consumption and improve optimization efficiency, and is suitable for a high-reliability, low-cost constant current driving architecture for automotive-grade LED lighting.

Description

Technical Field

[0001] This utility model relates to the field of vehicle technology, specifically to a vehicle lamp driving circuit and a vehicle lamp assembly. Background Technology

[0002] Linear constant current drive still holds a certain market share in some low- to mid-range automotive lighting designs due to its low cost and simple drive circuit. However, its main problems are high power consumption and severe heat generation, especially when the power is high, the drive components (such as transistors) need to withstand a large current, leading to increased heat loss and affecting the system lifespan.

[0003] In existing linear driving schemes for light-emitting diode (LED) automotive lights, transistor constant current driving circuits are commonly used to drive the lights. The current is regulated by the base-emitter voltage. Since the transistor bears the entire LED current, its power consumption is equal to the product of the collector-emitter voltage and the collector current. Especially when the input voltage is high, the heat loss of the transistor is extremely large, requiring additional heat dissipation measures, which leads to increased size, high operating temperature, and affects the reliability of the device.

[0004] Therefore, how to reduce the power consumption of the linear drive circuit of LED automotive lights is an urgent problem to be solved. Utility Model Content

[0005] In view of this, the present invention aims to provide a vehicle lamp driving circuit and a vehicle. By introducing a current shunt circuit into the vehicle lamp driving circuit, current shunt can be performed to reduce power consumption and improve optimization efficiency. It is suitable for high reliability and low cost constant current drive of automotive-grade vehicle lamp lighting.

[0006] To achieve the above technical objectives, the embodiments of this specification provide the following technical solutions:

[0007] In a first aspect, embodiments of this application provide a vehicle light driving circuit, including: a controllable switch, a first resistor, and a current shunt circuit; the first terminal of the controllable switch is connected to a regulated power supply, the second terminal of the controllable switch is connected to the vehicle light, the third terminal of the controllable switch is grounded through the first resistor, and the current shunt circuit is connected in parallel between the second and third terminals of the controllable switch.

[0008] Optionally, the current shunt circuit includes at least one second resistor connected between the second and third terminals of the controllable switch.

[0009] Optionally, the current shunt circuit is a resistor network consisting of multiple resistors, which is connected in parallel between the second and third terminals of the controllable switch.

[0010] Optionally, the vehicle light driving circuit further includes a voltage regulator circuit, which is connected to the first terminal of the controllable switch to provide the regulated power supply.

[0011] Optionally, the voltage regulator circuit includes a first diode and a second diode, the anode of the first diode is connected to the first terminal of the controllable switch, the cathode of the first diode is connected to the anode of the second diode, and the cathode of the second diode is grounded.

[0012] Optionally, the vehicle light driving circuit further includes a current limiting circuit, which is connected between the voltage regulator circuit and the first terminal of the controllable switch.

[0013] Optionally, the headlight drive circuit further includes a first capacitor and a second capacitor, with one end of the current limiting circuit away from the first end of the controllable switch grounded through the first capacitor, and the other end of the current limiting circuit close to the first end of the controllable switch grounded through the second capacitor.

[0014] Optionally, the vehicle light is an LED light, and the vehicle light driving circuit further includes a voltage divider circuit, wherein the second terminal of the controllable switch is connected to the cathode of the LED light through the voltage divider circuit, and the anode of the LED light is connected to a reference voltage.

[0015] Optionally, the controllable switch is a transistor.

[0016] Secondly, another objective of this application is to provide a vehicle lamp assembly, wherein the vehicle lamp assembly includes the vehicle lamp driving circuit described above.

[0017] As can be seen from the above technical solution, the vehicle lamp driving circuit provided in this specification includes: a controllable switch, a first resistor, and a current shunt circuit; the first terminal of the controllable switch is connected to a regulated power supply, the second terminal of the controllable switch is connected to the vehicle lamp, the third terminal of the controllable switch is grounded through the first resistor, and the current shunt circuit is connected in parallel between the second and third terminals of the controllable switch; by shunting the operating current of the vehicle lamp through the current shunt circuit, power consumption is reduced, making it suitable for higher power vehicle lamps, improving optimization efficiency, and providing a high-reliability, low-cost constant current driving architecture suitable for automotive-grade LED lighting.

[0018] The above description is merely an overview of the technical solution disclosed herein. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure are described below. Attached Figure Description

[0019] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this disclosure. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0020] Figure 1 The diagram shown is a structural schematic of a vehicle headlight driving circuit according to an embodiment of this application;

[0021] Figure 2 The diagram shown is a specific circuit diagram of a vehicle headlight driving circuit provided in one embodiment of this application;

[0022] Figure 3 The diagram shown is a specific circuit diagram of a vehicle headlight driving circuit provided in another embodiment of this application;

[0023] Figure 4 The diagram shown is a specific circuit diagram of a vehicle headlight driving circuit provided in another embodiment of this application;

[0024] Figure 5 The diagram shown is a structural schematic of a vehicle lighting assembly provided in one embodiment of this application. Detailed Implementation

[0025] Unless otherwise defined, the technical or scientific terms used in the embodiments of this specification shall have the ordinary meaning understood by one of ordinary skill in the art to which this specification pertains. The terms "first," "second," and similar terms used in the embodiments of this specification do not indicate any order, quantity, or importance, but are merely used to avoid confusion of constituent elements.

[0026] Unless the context otherwise requires, throughout this specification, "a plurality of" means "at least two," and "including" is interpreted as open-ended or encompassing, that is, "including, but not limited to." In the description of this specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this specification. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example.

[0027] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0028] In existing automotive lighting constant current drive circuits, transistors are used as controllable switches. These transistors bear the entire operating current, resulting in high power consumption, significant temperature rise, and impacting system reliability. Even in applications with relatively low power requirements, high-power transistors are still necessary. Furthermore, because transistors operate at high temperatures for extended periods, parameter drift can affect the stability of the operating current and even shorten the transistor's lifespan.

[0029] Based on this, this application provides a vehicle headlight driving circuit. By setting a current shunt circuit for the controllable switch, the current flowing through the controllable switch is shunt, reducing power consumption and improving optimization efficiency. This allows for the use of a lower power controllable switch, thereby reducing costs.

[0030] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] This application provides a vehicle headlight driving circuit, such as... Figure 1 As shown, the vehicle headlight drive circuit includes: a controllable switch 11, a first resistor R1, and a current shunt circuit 12. The first terminal of the controllable switch 11 is connected to a regulated power supply, the second terminal of the controllable switch 11 is connected to the vehicle headlight, the third terminal of the controllable switch 11 is grounded through the first resistor R1, and the current shunt circuit 12 is connected between the second and third terminals of the controllable switch 11.

[0032] By setting up a current shunt circuit 12 to shunt the current flowing through the controllable switch 11, the current flowing through the controllable switch 11 can be reduced, thus reducing the power consumption of the controllable switch 11. This is suitable for a high-reliability, low-cost constant current drive architecture for automotive-grade LED lighting.

[0033] In some embodiments of this application, see Figure 2 The specific circuit of the vehicle headlight drive circuit includes a current shunt circuit 12 comprising at least one second resistor R2 connected between the second and third terminals of the controllable switch 11. A portion of the headlight current bypasses the controllable switch 11 and flows through the second resistor R2, thereby reducing the current that the controllable switch 11 needs to handle. It should be noted that the second resistor R2 can be selected with different resistance values ​​as needed, or an adjustable resistor can be used directly.

[0034] The first resistor R1 is used to detect the operating current of the headlight and also provides negative feedback to maintain current stability. The first resistor R1 is typically a low-resistance resistor, such as one with a resistance in the range of 0.1Ω-0.5Ω. This minimizes the power consumption of the first resistor R1 and has little impact on the overall efficiency of the headlight drive circuit.

[0035] In some embodiments of this application, see Figures 2-4 In the specific circuit of the vehicle headlight drive circuit, the controllable switch 11 is preferably a transistor Q1, such as an NPN bipolar transistor. In the embodiments of this application, transistor Q1 is used as the controllable switch 11, which results in a simple circuit structure and low cost. The following description uses a transistor as an example: the first terminal of the controllable switch Q1 is the base of transistor Q1, the second terminal is the collector of transistor Q1, and the third terminal is the emitter of transistor Q1.

[0036] Transistor Q1 operates in the amplification or saturation region. The current flowing through the headlight is sampled by the first resistor R1, and this sample is used to adjust the base current of transistor Q1, keeping the headlight current constant. The current distribution relationship of the headlight driver circuit is I... LED =I Q1 +I R2 , among which, I LED I is the operating current of the vehicle headlight, and I is the current that transistor Q1 can withstand. R2 The current shunted by the second resistor R2. If the voltage drop across transistor Q1 in a traditional constant current drive circuit is Vce = 9V, the operating current I of the headlight... LED If the current is 1A, then the power consumption is P = 9W. If the second resistor R2 shuns 50% of the current, that is, the current I that transistor Q1 carries... Q1 If the current is reduced to 0.5A, the power consumption of transistor Q1 drops to 4.5W, which means the heat loss is reduced by half. It is evident that by using a second resistor R2 to shunt the current flowing through transistor Q1, the power consumption of transistor Q1 can be significantly reduced.

[0037] In some embodiments of this application, the current shunt circuit 12 is a resistor network composed of multiple resistors. The resistor network is connected in parallel between the second and third terminals of the controllable switch 11. That is, the current shunt circuit 12 can be composed of multiple resistors connected in series, in parallel, or in a series-parallel configuration. The voltage across the current shunt circuit 12 is the collector-emitter voltage of the transistor Q1. The desired current shunt by the current shunt circuit 12 is determined, and the total resistance value of the current shunt circuit 12 is obtained by dividing the collector-emitter voltage by the current shunt voltage. The resistor network of the current shunt circuit 12 is constructed based on this total resistance value. The embodiments of this application do not limit the number of resistors in the resistor network or the specific connection relationships between the resistors.

[0038] For example Figure 3The current shunt circuit 12 includes a fifth resistor R5 and a sixth resistor R6, which are connected in parallel. The total resistance of the current shunt circuit 12 is the combined resistance of the fifth resistor R5 and the sixth resistor R6. In this embodiment, the number of resistors connected in parallel is not limited; multiple resistors can be connected in parallel to form the current shunt circuit 12. Of course, in other embodiments of this application, multiple resistors can also be connected in series to form the current shunt circuit 12.

[0039] For example Figure 4 The current shunt circuit 12 includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10. The seventh resistor R7 is connected in parallel between the second and third terminals of transistor Q1. The ninth resistor R9 and the tenth resistor R10 are connected in parallel. One end of the ninth resistor R9 and the tenth resistor R10 is connected to the second terminal of transistor Q1, and the other end of the ninth resistor R9 and the tenth resistor R10 is connected to the third terminal of transistor Q1 through the eighth resistor R8. The total resistance of the current shunt circuit 12 is R21 / / (R24+R22 / / R23). It should be noted that this embodiment does not specifically limit the specific resistor network structure of the current shunt circuit 12; it only requires that the total resistance value of the constructed resistor network equals the desired resistance value.

[0040] Thus, by constructing a suitable resistor network structure for the current shunt circuit 12, the shunt ratio of the working current of transistor Q1 can be controlled, that is, a preset current can be shunted from the working current of transistor Q1 to reduce the power consumption of transistor Q1 and improve circuit reliability.

[0041] Additionally, it should be noted that the resistors in the current shunt circuit 12 need to be selected with appropriate power ratings to ensure they can withstand the power consumption of the shunt current. For example... Figure 2 In the above, assume the current I in the second resistor R2 is... R2 =0.5A, the voltage is 9V, then the power of the second resistor R2 is 4.5W. The second resistor R2 selected in this way can withstand at least 4.5W of power and 0.5A of current.

[0042] In some embodiments of this application, the vehicle headlight driving circuit further includes a voltage regulator circuit 13, which is connected to the first terminal of the controllable switch 11 and is used to provide a regulated power supply. The embodiments of this application do not limit the actual circuit structure used in the voltage regulator circuit 13; it can be a Zener diode or an existing voltage regulator chip, as long as it meets the voltage regulation requirements of this application. The voltage regulator circuit 13 provides a regulated power supply, enabling stable and reliable control of the vehicle headlights, suitable for high-reliability applications of automotive-grade LED lighting.

[0043] In some embodiments of this application, the voltage regulator circuit 13 includes a first diode D1 and a second diode D2. The anode of the first diode D1 is connected to the first terminal of the controllable switch 11, the cathode of the first diode D1 is connected to the anode of the second diode D2, and the cathode of the second diode D2 is grounded to GND. When the first diode D1 and the second diode D2 are turned on, the forward voltage across them is fixed, thereby achieving voltage regulation. For example, if the first diode D1 and the second diode D2 are diodes made of silicon, then when they are turned on, the forward voltage across both the first diode D1 and the second diode D2 is approximately 0.7V. Considering that the first diode D1 and the second diode D2 are connected in series, the voltage across the voltage regulator circuit 13 is stabilized at approximately 1.4V. Of course, if the first diode D1 and the second diode D2 are diodes made of germanium, then when they are turned on, the forward voltage across both the first diode D1 and the second diode D2 is approximately 0.3V. The embodiments of this application provide a stable voltage through the series connection of the first diode D1 and the second diode D2, ensuring the stable and reliable performance of the vehicle lamp drive circuit.

[0044] If the voltage regulator circuit 13 uses a Zener diode or a voltage regulator chip, it generally regulates the voltage within a suitable range, meaning the output voltage fluctuates within that appropriate range. However, the voltage regulator circuit 13, composed of the first diode D1 and the second diode D2, can stabilize the voltage at around 1.4V (silicon material), providing greater voltage stability and ensuring the stable and reliable performance of the vehicle lighting drive circuit. Furthermore, compared to Zener diodes and voltage regulator chips, diodes are significantly cheaper.

[0045] In some embodiments of this application, the vehicle light is an LED light, and the vehicle light driving circuit further includes a voltage divider circuit 14. The second terminal of the controllable switch 11 is connected to the cathode of the LED light through the voltage divider circuit 14, and the anode of the LED light is connected to a reference voltage VCC. The reference voltage VCC is the power supply voltage of the LED light. The voltage divider circuit 14 is used to divide the voltage to adjust the voltage between the second and third terminals of the controllable switch 11. The voltage divider circuit 14 preferably uses a third resistor R3, that is, the third resistor R3 is directly connected between the collector of the transistor Q1 and the cathode of the LED light. In embodiments of this application, the resistance value of the third resistor R3 can be selected as needed.

[0046] For example Figures 2-4 In the headlight drive circuit, the collector-emitter voltage Vce of transistor Q1 is equal to U. VCC -V F -I LED *(R3+R1), where V F This is the operating voltage of the LED. The collector-emitter voltage Vce of transistor Q1 can be adjusted by the voltage division of the third resistor R3, thereby controlling whether transistor Q1 operates in the amplification region or the saturation region.

[0047] In some embodiments of this application, the vehicle lamp driving circuit further includes a current limiting circuit 15, which is connected between the voltage regulator circuit 13 and the first terminal of the controllable switch 11. Specifically, one end of the current limiting circuit 15 is connected to the first terminal of the controllable switch 11, and the other end is connected to the anode of the first diode D1. The current limiting circuit 15 is used to limit the current, specifically limiting the operating current of the first diode D1, the second diode D2, and the transistor Q1, to prevent excessive current from damaging the electronic components. The current limiting circuit 15 is preferably a fourth resistor R4, and the resistance value of the fourth resistor R4 can be determined according to the current that needs to be limited for each electronic component in the vehicle lamp driving circuit, and is not specifically limited.

[0048] The vehicle headlight drive circuit also includes a first capacitor C1 and a second capacitor C2. One end of the current limiting circuit 15, furthest from the first terminal of the controllable switch 11, is grounded to GND through the first capacitor C1, and the other end of the current limiting circuit 15, closest to the first terminal of the controllable switch 11, is grounded to GND through the second capacitor C2. The first capacitor C1 and the second capacitor C2 are used for filtering to remove ripple and noise from the vehicle headlight drive circuit.

[0049] In some embodiments of this application, for example, with Figure 2 Taking the headlight drive circuit as an example, the operating current I of the headlight is set. LED =1A, and it is desired that 50% of the current is shunted by the current shunt circuit 12, then the current I of the second resistor is... R2 =0.5A. Assume the power supply voltage is VCC, and the operating voltage of the headlight is V... F Then the voltage V across the second resistor R2 R2 =U VCC -V F -I LED *(R3+R1), the resistance value of the second resistor R2 is R2=(U VCC -V F -I LED *(R4+R1)) / I R2 By selecting a second resistor R2 with the corresponding resistance value, the desired current shunting can be achieved.

[0050] In some embodiments of this application, the transistor Q1 can be selected according to the actual power requirements of the vehicle headlight driver circuit. For example, if the transistor Q1 in a traditional vehicle headlight driver circuit uses a BCP56-16T transistor, then in the vehicle headlight driver circuit of this application embodiment, a low-power transistor can be selected, such as a MMBP3904-AU transistor. The MMBP3904-AU transistor has lower power and is much cheaper, resulting in lower cost. The BCP56-16T transistor, when used in the vehicle headlight driver circuit of this application embodiment, can be used for higher-power LED headlights. Therefore, compared with a traditional vehicle headlight driver circuit, for the same power LED headlight, the current handling capability of the transistor Q1 in the vehicle headlight driver circuit of this application embodiment is reduced, for example, from 1A to 0.5A, resulting in lower power. This allows the use of a lower-power transistor, and lower power means less heat dissipation, further reducing cost and heat dissipation requirements. For the same type of transistor, that is, when the transistor power is the same, the LED vehicle lamp in the vehicle lamp driving circuit of this application embodiment can output higher power, that is, the vehicle lamp driving circuit of this application embodiment can be used for higher power LED vehicle lamps.

[0051] For high-power LED vehicle lights, the transistors in the vehicle light driving circuit of this application embodiment can be selected as high-power transistors. For example, the transistor of model BD139 can handle a current of 1.5A, and the transistor of model TIP41C can handle a current of 6A, which can be used for higher power LED vehicle lights. This can improve the applicability of the vehicle light driving circuit and improve the optimization efficiency of the vehicle light driving circuit.

[0052] Compared to traditional DC-DC solutions, the vehicle headlight drive circuit in this application embodiment only needs to add a current shunt circuit composed of resistors to the original constant current circuit to achieve the purpose of reducing power consumption and optimizing temperature distribution. Power consumption can be optimized using a simple circuit, which maintains the advantages of simple circuit design and low cost while ensuring technological advancement.

[0053] In summary, the vehicle lamp driving circuit of this application connects a current shunt circuit in parallel between the second and third terminals of the controllable switch, introducing part of the operating current of the vehicle lamp into the shunt resistor, which can reduce power consumption and improve optimization efficiency, and is suitable for a high-reliability, low-cost constant current driving architecture for automotive-grade LED lighting.

[0054] In one exemplary embodiment of this specification, a vehicle lighting assembly is also provided. For example, as shown... Figure 5 As shown, the vehicle lighting assembly 500 includes a vehicle lighting drive circuit 5001.

[0055] The vehicle lighting assembly according to the present invention uses the aforementioned vehicle lighting drive circuit, which can reduce power consumption, improve optimization efficiency, save development time, and reduce development costs.

[0056] In one exemplary embodiment of this specification, a vehicle is also provided. Exemplarily, the vehicle includes the headlight assembly of the previous embodiment.

[0057] In the description of this disclosure, it should be understood that if the terms "upper", "lower", "front", "rear", "left" and "right" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the position or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0058] It should be noted that, in the embodiments of this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0059] The above are merely embodiments of this disclosure and are not intended to limit the scope of this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of the claims of this disclosure.

Claims

1. A vehicle lamp driving circuit, characterized by comprising: The vehicle headlight drive circuit includes: a controllable switch, a first resistor, and a current shunt circuit; The first terminal of the controllable switch is connected to a regulated power supply, the second terminal of the controllable switch is connected to the vehicle light, the third terminal of the controllable switch is grounded through the first resistor, and the current shunt circuit is connected in parallel between the second and third terminals of the controllable switch.

2. The vehicle headlight driving circuit according to claim 1, characterized in that, The current shunt circuit includes at least one second resistor connected between the second and third terminals of the controllable switch.

3. The vehicle lamp driving circuit according to claim 2, characterized by The current shunt circuit is a resistor network consisting of multiple resistors, which are connected in parallel between the second and third terminals of the controllable switch.

4. The vehicle lamp driving circuit according to claim 1, characterized by The vehicle headlight drive circuit also includes a voltage regulator circuit, which is connected to the first terminal of the controllable switch to provide a regulated power supply.

5. The vehicle lamp driving circuit according to claim 4, characterized by The voltage regulator circuit includes a first diode and a second diode. The anode of the first diode is connected to the first terminal of the controllable switch, the cathode of the first diode is connected to the anode of the second diode, and the cathode of the second diode is grounded.

6. The vehicle lamp driving circuit according to claim 4, characterized by The vehicle headlight drive circuit further includes a current limiting circuit, which is connected between the voltage regulator circuit and the first terminal of the controllable switch.

7. The vehicle lamp driving circuit according to claim 6, characterized by The vehicle headlight drive circuit also includes a first capacitor and a second capacitor. One end of the current limiting circuit away from the first end of the controllable switch is grounded through the first capacitor, and the other end of the current limiting circuit close to the first end of the controllable switch is grounded through the second capacitor.

8. The vehicle lamp driving circuit according to claim 1, characterized by The vehicle light is an LED light, and the vehicle light driving circuit further includes a voltage divider circuit. The second terminal of the controllable switch is connected to the cathode of the LED light through the voltage divider circuit, and the anode of the LED light is connected to a reference voltage.

9. The vehicle lamp driving circuit according to claim 1, characterized by The controllable switch is a transistor.

10. A vehicle lamp assembly characterized by, The vehicle lighting assembly includes a vehicle lighting drive circuit as described in any one of claims 1-9.

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