Multi-load power supply circuit, electronic equipment and automobile

Abstract

The utility model provides a multi-load power supply circuit, an electronic device and an automobile, loads in the multi-load power supply circuit share one step-down circuit module, and in order to ensure reliable work of the loads, a corresponding sub step-down circuit and a driving chip are configured for each load. The voltage drop values of the sub-step-down circuits corresponding to the loads with different rated voltage values are different, so that the output voltage of the step-down circuit module reaches the rated voltage values of the loads after being lost through the sub-step-down circuits and the driving chip, reliable work of the loads is ensured, meanwhile, the sub-step-down circuits only need to provide proper voltage drop, and the cost is reduced. Compared with the prior art, voltage conversion, PWM control and the like in the step-down circuit module are not involved, so that the cost is lower than that of the step-down circuit module, and compared with an existing scheme, the cost is lower, and a circuit basis is provided for a low-cost LED lamp.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, and particularly relates to a multi-load power supply circuit, an electronic device and an automobile. Background Art

[0002] With the development of vehicle lamp technology, various flowing water and dynamic effect lamp products have emerged. The number of light emitting diodes (LEDs) ranges from more than a dozen to hundreds or thousands, and they are all applied. For example Figure 1 is a typical application case of current LED power supply. Figure 1 On the left, power is taken from the vehicle's battery system (the typical value of the vehicle battery is 13.5V). After being processed by the buck circuit module, it is reduced to an output V0 with a constant voltage value and supplied to the subsequent power-consuming unit (LED linear drive chip). Figure 1 On the right, after the LED linear drive chip receives the V0 voltage at point A, it consumes its own voltage Vx (taking 1V as an example), and outputs a constant current at pins 1, 2, 3,..., n to control the lighting of each channel of LEDs. The lighting condition of the LEDs is that the voltage applied to the LEDs must be greater than the threshold voltage of the LEDs (Vf-LED). Therefore, for Figure 1 applications, the voltage of V0 needs to satisfy V0≥(Vf-LED)+1V. Most of the current LED linear drive chips support controlling the number of LEDs to be 12, 16, and 24. More-channel chips may appear in the future. Therefore, in circuit design, it is necessary to consider how to supply power to multiple LEDs, how to design the circuit according to the number of LEDs connected to each channel, and how to design the circuit for LED particles with different threshold voltages.

[0003] When Figure 2 the number of LEDs connected to each channel of the shown LED linear drive chip is the same, the output voltage of each channel needs to reach N*(Vf-LED), where N is the number of LEDs connected to each channel. The constant voltage output by the buck circuit module needs to satisfy V0’≥N*(Vf-LED)+Vx, where Vx is the voltage consumption of the LED linear drive chip. If Figure 2 the number of LEDs connected to each channel in Figure 1 is different from the number of LEDs connected to each channel in Figure 1 and Figure 2 the schemes cannot share a buck circuit module. When these two LED connection methods exist, at least two buck circuit modules are required, resulting in high costs.

[0004] When there are red, yellow, and white light-emitting diodes (LEDs) in a lamp (the threshold voltages of red LEDs, yellow LEDs, and white LEDs are different (the typical value of Vf - red for red LEDs is approximately 2V, the typical value of Vf - yellow for yellow LEDs is approximately 2.5V, and the typical value of Vf for white LEDs is approximately 3V));

[0005] Taking the example of connecting one LED to each channel, it can be deduced that:

[0006] When the LED is a red LED, V0’’ ≥ (Vf - red) + 1 = 3V;

[0007] When the LED is a yellow LED, V0’’ ≥ (Vf - yellow) + 1 = 3.5V;

[0008] When the LED is a white LED, V0’’ ≥ (Vf - white) + 1 = 4V;

[0009] Therefore, when Figure 3 the light-emitting type of the LED in the channel of the circuit shown is different from Figure 1 the light-emitting type of the LED shown, there is also no way to Figure 3 share a step-down circuit module with Figure 1 When these three colors of LEDs exist, at least three step-down circuit modules are required, resulting in high costs.

[0010] Therefore, when there are multiple different light LEDs in an LED lamp, or when the corresponding numbers of different LED branches are different, multiple step-down circuit modules need to be configured inside the LED lamp, thus increasing the cost of the LED lamp. Summary of the Invention

[0011] In view of this, embodiments of the present invention provide a multi-load power supply circuit, an electronic device, and an automobile to provide a low-cost multi-load power supply circuit.

[0012] To achieve the above object, embodiments of the present invention provide the following technical solutions:

[0013] A multi-load power supply circuit includes:

[0014] A step-down circuit module, the input end of which is used to obtain an input voltage;

[0015] N sub-step-down circuits and N driving chips, the sub-step-down circuits and the driving chips corresponding one by one;

[0016] The input ends of the N sub-step-down circuits are connected to the output end of the step-down circuit module;

[0017] The output terminal of each sub-step-down circuit is connected to the input terminal of the corresponding driver chip;

[0018] The output terminal of each driver chip is connected to the corresponding load;

[0019] Among them, the step-down values provided by different sub-step-down circuits are different, and the rated voltages corresponding to different loads are different.

[0020] Optionally, in the above multi-load power supply circuit, each sub-step-down circuit includes:

[0021] A switching tube, a zener diode, and a pull-up resistor;

[0022] The input terminal of the switching tube serves as the input terminal of the sub-step-down circuit, and the output terminal of the switching tube serves as the output terminal of the sub-step-down circuit;

[0023] The pull-up resistor is connected between the input terminal of the switching tube and the control terminal of the switching tube;

[0024] The cathode of the zener diode is connected to the control terminal of the switching tube, and the anode of the zener diode is grounded.

[0025] Optionally, in the above multi-load power supply circuit, the zener voltages of the zener diodes in different sub-step-down circuits are different.

[0026] Optionally, in the above multi-load power supply circuit, the resistance value of the pull-up resistor in the sub-step-down circuit is:

[0027] R = (V - Vd) / Id, where R is the resistance value of the pull-up resistor, V is the output voltage of the step-down circuit module, Vd is the zener voltage of the zener diode, and Id is the over-current value of the zener diode.

[0028] Optionally, in the above multi-load power supply circuit, the switching tube is a power triode or a MOS tube.

[0029] Optionally, in the above multi-load power supply circuit, when the switching tube is a power triode, the selection of the power triode is:

[0030] The rated power of the power triode is not less than the target power;

[0031] The target power is calculated based on the voltage drop and the passing current;

[0032] The voltage drop is the difference between the input voltage of the step-down circuit module and the input voltage of the corresponding driver chip;

[0033] The passing current is the ratio of the total power of the driver chip and the load to the input voltage of the driver chip.

[0034] Optionally, in the above multi-load power supply circuit, the load is an LED circuit;

[0035] Each LED circuit is composed of multiple LED lighting branches, and the structures of the LED lighting branches of the same LED circuit are the same;

[0036] The rated powers of the LED lighting branches are different.

[0037] Optionally, in the above multi-load power supply circuit, the driving chip is a linear driving chip.

[0038] An electronic device is applied with the multi-load power supply circuit described in any one of the above.

[0039] A vehicle is applied with the electronic device described in any one of the above.

[0040] Based on the above technical solution, the above solution provided by the embodiment of the present invention discloses a multi-load power supply circuit. Each load in the multi-load power supply circuit shares a buck circuit module. And to ensure the reliable operation of the load, a corresponding sub-buck circuit and driving chip are configured for each load respectively. The voltage drop values of the sub-buck circuits corresponding to loads with different rated voltage values are different. Thus, after the output voltage of the buck circuit module is lost through the sub-buck circuit and the driving chip, it reaches the rated voltage value of the load, ensuring the reliable operation of the load. At the same time, since the sub-buck circuit only needs to provide an appropriate voltage drop and is not involved in voltage conversion, PWM control, etc. in the buck circuit module, therefore, its cost is relatively low compared with the buck circuit module. Therefore, compared with the existing solution, the cost of this solution is low, providing a circuit basis for low-cost LED lamps. Description of the Drawings

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0042] Figure 1 It is a schematic circuit diagram of an LED lamp in a certain scenario disclosed in the prior art;

[0043] Figure 2 It is a schematic circuit diagram of an LED lamp in another scenario disclosed in the prior art;

[0044] Figure 3 It is a schematic circuit diagram of an LED lamp in yet another scenario disclosed in the prior art;

[0045] Figure 4 Schematic diagram of the multi-load power supply circuit disclosed in the embodiment of the present application;

[0046] Figure 5 Schematic diagram of the multi-load power supply circuit disclosed in another embodiment of the present application;

[0047] Figure 6 Schematic diagram of the multi-load power supply circuit disclosed in another embodiment of the present application;

[0048] Figure 7 Schematic diagram of the multi-load power supply circuit disclosed in another embodiment of the present application;

[0049] Figure 8 Schematic diagram of the multi-load power supply circuit disclosed in another embodiment of the present application. Detailed implementation manners

[0050] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] The present application discloses a multi-load power supply circuit. In the multi-load power supply circuit, the rated input voltages of the respective loads are different, and each load corresponds to a driving chip. By configuring a sub-step-down circuit with an appropriate voltage drop between the load and the driving chip, in this way, the driving chip can provide an appropriate input voltage for its corresponding load, ensuring the normal operation of the load. In this circuit, only one step-down circuit module is required, which reduces the circuit cost compared with the prior art in which multiple step-down circuit modules are provided.

[0052] See Figure 4 , the present application discloses a multi-load power supply circuit, and this circuit includes:

[0053] A step-down circuit module 100, a sub-step-down circuit 200, and N driving chips 300, and the sub-step-down circuit 200 and the driving chips 300 are in one-to-one correspondence.

[0054] The input end of the step-down circuit module 100 is used to obtain an input voltage, and the input voltage can be provided by a power supply system. The output end of the step-down circuit module 100 is connected to the input ends of the N sub-step-down circuits 200. The main function of the step-down circuit module 100 is to convert the input high voltage into a lower and stable output voltage. Such modules are widely used in various electronic devices, especially in systems that require different voltage supplies.

[0055] The working principle of the buck circuit module 100 is as follows: Based on the PWM technology, by adjusting the duty cycle of the PWM signal (i.e., the ratio of the conduction time of the switching transistor to the entire cycle time), the energy stored in the inductor can be controlled, and thus the magnitude of the output voltage can be controlled. When the switching transistor is conducting, the inductor is charged; when the switching transistor is turned off, the inductor discharges, driving the load and charging the capacitor. By continuously repeating this process, a stable output voltage can be obtained.

[0056] There are various types of buck circuit modules 100, including linear buck modules and switching buck modules (such as Buck converters), etc. Although the linear buck module is simple, its efficiency is relatively low, especially when the input-output voltage difference is large. The switching buck module, on the other hand, has a higher efficiency but is relatively complex in design. When selecting the buck circuit module 100, the factors that designers need to consider include the input voltage range, output voltage and current requirements, efficiency, ripple and noise levels, operating temperature range, package size, and cost, etc. In addition, the reliability and protection functions of the module, such as overcurrent protection, overheat protection, etc., also need to be considered, so as to select a suitable type of buck circuit module 100.

[0057] The input ends of the N sub-buck circuits 200 are connected to the output end of the buck circuit module 100, and the output end of each sub-buck circuit 200 is connected to the input end of the corresponding drive chip 300; the sub-buck circuit 200 also plays a bucking role. However, in this application, the input voltages of different sub-buck circuits 200 are the same, but the voltage values consumed on different sub-buck circuits 200 (the bucking values provided by the sub-buck circuits 200) are different, and the voltage value it consumes is related to the rated voltage value of the load. The larger the rated voltage value of the load, the smaller the voltage value consumed on the corresponding sub-buck circuit 200;

[0058] The output end of each drive chip 300 is connected to the corresponding load. There is a one-to-one correspondence between the sub-buck circuit 200, the drive chip 300, and the load, and the corresponding sub-buck circuit 200, drive chip 300, and load are connected in sequence; among them, the rated voltages of different loads are different. If the rated voltage values of the loads are the same, these loads can share a group of sub-buck circuits 200 and drive chips 300.

[0059] Regarding the driving chip 300, the driving chip 300 is the core device for controlling the working conditions of the load. The type of the driving chip 300 is determined according to the type of the load. For example, it may include an LCD driving chip 300, an LED driving chip 300, a motor control chip, a power management chip, a touch screen control chip, a sound output chip, a wireless communication chip, or a sensor chip, etc. When the load is an LED, the driving chip 300 may be an LED driving chip 300, specifically an LED linear driving chip 300. The LED linear driving chip 300 is a chip used to supply power to the LED, which can achieve a constant current output, and the number of control channels ranges from several to dozens.

[0060] As can be seen from the above solution, the present application discloses a multi-load power supply circuit. Each load in the multi-load power supply circuit shares a buck circuit module 100. And to ensure the reliable operation of the load, a corresponding sub-buck circuit 200 and a driving chip 300 are respectively configured for each load. The voltage drop values of the sub-buck circuits 200 corresponding to loads with different rated voltage values are different. Thus, after the output voltage of the buck circuit module 100 is lost through the sub-buck circuit 200 and the driving chip 300, it reaches the rated voltage value of the load, ensuring the reliable operation of the load. At the same time, since the sub-buck circuit 200 only needs to provide an appropriate voltage drop, it is not involved in voltage conversion, PWM control, etc. in the buck circuit module 100. Therefore, its cost is relatively low compared with the buck circuit module 100. Therefore, compared with the existing solutions, the cost of this solution is lower.

[0061] In the technical solution disclosed in this embodiment, the function of the sub-buck circuit 200 is to provide an appropriate voltage drop value. In the existing solutions, Figure 5 the shown resistor or Figure 6 the method of controlling the duty cycle of the control switch tube shown can be used to achieve this function. However, the applicant considered that if a resistor is used to provide this voltage drop value, the temperature of the resistor will rise during operation. After the temperature rises, the resistance value of the resistor will change, and further the voltage drop value provided by it will change. The resistor cannot provide a stable voltage drop value. If the method of controlling the duty cycle of the switch tube is used to provide this voltage drop value, a PWM signal generator needs to be configured, and the output signal of the PWM signal generator is used to control the duty cycle of the switch tube. Although one PWM signal generator can be used to control the duty cycles of multiple switch tubes at the same time, the cost of the PWM signal generator in this application is relatively high. The design of the PWM signal generator will undoubtedly increase the circuit cost. In this regard, the present application discloses a stable and low-cost design method for the sub-buck circuit 200. Refer to Figure 7 , the sub-buck circuit 200 includes:

[0062] a switch tube Q1, a zener diode D1, and a pull-up resistor R1;

[0063] The input end of the switching transistor Q1 serves as the input end of the sub-step-down circuit 200, and the output end of the switching transistor Q1 serves as the output end of the sub-step-down circuit 200;

[0064] The pull-up resistor R1 is connected between the input end and the control end of the switching transistor Q1;

[0065] The cathode of the pull-up voltage-regulating diode D1 is connected to the control end of the switching transistor Q1, and the anode of the pull-up voltage-regulating diode D1 is grounded. The pull-up voltage-regulating diode D1 is a semiconductor device that can stabilize the voltage applied across it within a fixed voltage range when the voltage conditions are met. Usually, this range is very small and can be approximated as a constant voltage.

[0066] In the above solution, when the voltage reduction circuit module has an output voltage V, the voltage at the control end of the switching transistor Q1 increases, and the control end of the switching transistor Q1 enters the saturation state. Then, the switching transistor Q1 conducts, and current flows through the switching transistor Q1 into the driving chip 300. The pull-up voltage-regulating diode D1 monitors the voltage value V of the current flowing through the switching transistor Q1. When it detects that the voltage value V exceeds its regulated voltage value V1, the pull-up voltage-regulating diode D1 is broken down to regulate the input voltage of the driving chip 300 and stabilize the input voltage of the driving chip 300 to V1. Due to different design parameters and types of the pull-up voltage-regulating diode D1, the regulated voltage values provided are different. In this application, the rated voltages of the loads connected to each driving chip 300 are different, and the voltage reduction values of the sub-step-down circuits 200 corresponding to the driving chips 300 are different. In this embodiment, by selecting a pull-up voltage-regulating diode D1 with an appropriate regulated voltage value, sub-step-down circuits 200 with different voltage reduction values can be provided. By selecting an appropriate pull-up voltage-regulating diode D1, the output voltage value of the driving chip 300 can be made equal to the rated voltage of the load connected to it, ensuring reliable operation of the load. The sub-step-down circuit 200 composed of the switching transistor Q1, the voltage-regulating diode D1, and the pull-up resistor R1 has low power consumption, a stable voltage reduction value, does not require a corresponding controller to be configured, and has a low cost.

[0067] To ensure the reliable operation of the sub-step-down circuit 200 composed of the switching transistor Q1, the voltage-regulating diode D1, and the pull-up resistor R1, this application also discloses a selection method for the pull-up resistor R1. In this embodiment, the resistance value of the pull-up resistor R1 is: R = (V - Vd) / Id, where R is the resistance value of the pull-up resistor R1, V is the output voltage of the voltage reduction circuit module 100, Vd is the regulated voltage value of the pull-up voltage-regulating diode D1, and Id is the over-current value of the pull-up voltage-regulating diode D1 configured in advance.

[0068] In this embodiment, the switching transistor Q1 can be a power triode or a MOS transistor. To ensure the reliable operation of the sub-step-down circuit 200, the power triode is selected as follows:

[0069] The rated power of the power triode is not less than the target power;

[0070] The target power is calculated based on the voltage drop and the passing current, that is, P = U×I. Here, P is the target power, U is the voltage drop, and I is the passing current;

[0071] The voltage drop is the difference between the input voltage of the step-down circuit module 100 and the corresponding driving chip 300;

[0072] The passing current is the ratio of the total power of the driving chip 300 and the load to the input voltage of the driving chip 300.

[0073] After determining the target power, a power triode with a power greater than the target power can be selected as the power triode in the sub-step-down circuit 200.

[0074] The type of the load can be selected according to requirements. For example, it can be an LED circuit. Each LED circuit is composed of multiple LED lighting branches, and the structures of the LED lighting branches in the same LED circuit are the same; the rated powers of different LED lighting branches are different.

[0075] The rated power of the LED lighting branch can be determined by the number of LEDs and the type of LEDs in the LED lighting branch. In the technical solution disclosed in this embodiment, the number of LEDs and / or the type of LEDs in the LED lighting branches in different LED circuits.

[0076] Figure 8 It is a schematic structural diagram of a multi-load power supply circuit in a specific scenario provided by this application.

[0077] Figure 8 The shown multi-load power supply circuit reflects a circuit structure in a complex scenario, that is, there are different numbers of LEDs connected to the driving chip in the circuit, and there are also LEDs with different threshold voltages.

[0078] When the number of LEDs connected to the driving chip is different or the threshold voltages of the LEDs are different, ultimately, different power supplies V1, V2, and V3 need to be input to the driving chip by the upper level. However, to simplify the circuit and ensure that the buck circuit module is shared, the present utility model designs a sub-buck circuit 200 to be added between the buck circuit module and each driving chip. Moreover, when designing this part of the circuit, it can be placed on the same PCB as each driving chip. By simply changing the parameters of the voltage-regulating diode D1 in each sub-buck circuit 200, different constant voltage values can be output for V1~V3 to meet the requirements of the LED load.

[0079] For example Figure 8 : Assume that the LEDs used in area ① are red LEDs. Calculated according to V ｆ－红 = 2V, V1 = 2 + 1 = 3V;

[0080] Assume that the LEDs used in area ② are yellow LEDs. Calculated according to V ｆ－黄 = 2.5, V2 = 5 + 1 = 6V;

[0081] Assume that the LEDs used in area ③ are white LEDs. Calculated according to V ｆ－白 = 3V, V3 = 3 + 1 = 4V.

[0082] At this time, the output voltage V of the buck circuit module needs to be set to be greater than the maximum value V2 calculated above, that is, V > V2. Here, the output voltage of the buck circuit module can be selected as 7V. Then, the parameter design of the voltage-regulating circuit area needs to follow:

[0083] ① For the voltage-regulating diode D1 in area ①, the voltage-regulating parameter Vz = V1 + 0.7V = 3.7V (0.7V is the voltage drop Vbe between the base and emitter of Q1 when successful voltage regulation occurs);

[0084] ② For the voltage-regulating diode D1 in area ②, the voltage-regulating parameter Vz = V2 + 0.7V = 6.7V (0.7V is the voltage drop Vbe between the base and emitter of Q1 when successful voltage regulation occurs);

[0085] ③ For the voltage-regulating diode D1 in area ③, the voltage-regulating parameter Vz = V3 + 0.7V = 4.7V (0.7V is the voltage drop Vbe between the base and emitter of Q1 when successful voltage regulation occurs).

[0086] Based on the above voltage-regulating parameters, the voltage-regulating diodes in each sub-buck circuit 200 are selected. At this time, it can be ensured that the input voltage of each LED is its rated voltage value, guaranteeing the reliable operation of each LED. Moreover, since there is no need to configure multiple buck circuit modules in the circuit, the circuit cost is relatively low.

[0087] Corresponding to the above multi-load power supply circuit, the present application also provides an electronic device, which applies the multi-load power supply circuit described in any one of the above embodiments.

[0088] Correspondingly, the application discloses a vehicle, which applies the electronic device described in any one of the above embodiments.

[0089] For the convenience of description, when describing the above system, it is divided into various modules according to functions for separate description. Of course, when implementing the present utility model, the functions of each module can be realized in the same or multiple software and / or hardware.

[0090] In the description of the present utility model, it should be understood that terms such as "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present utility model, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0091] In the present utility model, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0092] In the present utility model, terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0093] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0094] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For related parts, reference can be made to the description in the method part.

[0095] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-load power supply circuit, characterized in that: include: A step-down circuit module, wherein the input end of the step-down circuit module is used to obtain an input voltage; N sub-buck circuits and N driving chips, wherein the sub-buck circuits and the driving chips correspond one to one; The input ends of the N sub-step-down circuits are connected to the output end of the step-down circuit module; The output end of each sub-step-down circuit is connected to the input end of the corresponding driving chip; The output end of each driver chip is connected to the corresponding load; Different step-down sub-circuits provide different step-down values, and different loads correspond to different rated voltages.

2. The multi-load power supply circuit according to claim 1, characterized in that: Each sub-step-down circuit includes: Switching tube, voltage regulator diode and pull-up resistor; The input end of the switch tube serves as the input end of the sub-buck circuit, and the output end of the switch tube serves as the output end of the sub-buck circuit; The pull-up resistor is connected between the input end of the switch tube and the control end of the switch tube; The cathode of the voltage stabilizing diode is connected to the control end of the switch tube, and the anode of the voltage stabilizing diode is grounded.

3. The multi-load power supply circuit according to claim 2, characterized in that: The voltage stabilization values ​​of the voltage stabilizing diodes in different sub-step-down circuits are different.

4. The multi-load power supply circuit according to claim 2, characterized in that: The resistance of the pull-up resistor in the sub-step-down circuit is: R=(V-Vd) / Id, where R is the resistance of the pull-up resistor, V is the output voltage of the step-down circuit module, Vd is the voltage stabilization value of the Zener diode, and Id is the overcurrent value of the Zener diode.

5. The multi-load power supply circuit according to claim 2, characterized in that: The switch tube is a power triode or a MOS tube.

6. The multi-load power supply circuit according to claim 5, characterized in that: When the switch tube is a power transistor, the selection of the power transistor is: The rated power of the power transistor is not less than the target power; The target power is calculated based on the voltage drop and the current; The voltage drop is the difference between the input voltage of the step-down circuit module and the input voltage of the corresponding driving chip; The through current is the ratio of the total power of the driver chip and the load to the input voltage of the driver chip.

7. The multi-load power supply circuit according to claim 5, characterized in that: The load is an LED circuit; Each LED circuit is composed of multiple LED light-emitting branches, and the structures of the LED light-emitting branches in the same LED circuit are the same; The rated power of the LED light-emitting branches is different.

8. The multi-load power supply circuit according to claim 5, characterized in that: The driving chip is a linear driving chip.

9. An electronic device, characterized in that: The multi-load power supply circuit according to any one of claims 1 to 8 is applied.

10. An automobile, characterized in that: The multi-load power supply circuit according to any one of claims 1 to 8 is applied.

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