Step-down and step-up gallium nitride driving system for vehicle lamp control and vehicle lamp controller

Abstract

The invention provides a step-down and step-up gallium nitride driving system for vehicle lamp control and a vehicle lamp controller. Gallium nitride is adopted as a switching device to replace a synchronous step-down driving unit of a traditional silicon MOS, and the synchronous step-down driving unit and a control unit are packaged in the same chip. The size of a chip, the size of a peripheral inductor and the weight of a radiator are reduced by utilizing the characteristics of high efficiency, high switching frequency and large power density of gallium nitride, so that the size and the cost of a system are further reduced. Gallium nitride is adopted as a switching device to replace a synchronous boost driving scheme of a traditional silicon MOS. The weight of the radiator is reduced by utilizing the characteristics of high efficiency, high switching frequency and large power density of gallium nitride, and the sizes of the inductor and the capacitor are reduced, so that the size and the cost of the system are further reduced.

Description

Technical Field

[0001] This invention relates to the field of automotive lighting controller technology, specifically to a buck and boost gallium nitride drive system and automotive lighting controller for automotive lighting control. Background Technology

[0002] Current solutions utilize single-phase asynchronous boost circuits, primarily composed of silicon MOSFETs and diodes. Their switching frequency is limited to 200kHz to 500kHz; increasing the switching frequency leads to a sharp increase in losses. Furthermore, in asynchronous boost circuits, the switching transistor is a diode. Due to the inherent forward voltage drop of diodes, more losses are generated during the diode rectification stage, further reducing the overall circuit efficiency. Higher power output applications require two or even multiple phases in parallel. This architecture is complex, requires more space and heat sinks, increasing costs and failing to meet the current demand for miniaturized and cost-competitive controllers.

[0003] Patent application CN120769394A discloses a driving system, driving method, and vehicle for an automotive lighting fixture, relating to the field of automotive lighting technology. The driving system includes a single-ended primary inductor converter and a control module. The single-ended primary inductor converter includes a power supply module and a gallium nitride (GaN) switch module, which is connected to the power supply module and the automotive lighting fixture. The control module is connected to the GaN switch module and the automotive lighting fixture, and is used to detect the load current of the automotive lighting fixture and switch the on / off state of the GaN switch module and the operating mode of the driving system based on the load current. The operating modes include pulse width modulation (PWM) mode, pulse frequency modulation (PWM) mode, and burst mode. However, this patent cannot completely solve the existing technical problems, nor can it meet the needs of this invention. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a buck and boost gallium nitride drive system and a vehicle lighting controller for vehicle lighting control.

[0005] The buck and boost gallium nitride drive system for vehicle lighting control provided by the present invention includes: a buck drive unit, a boost drive unit, and a control unit; The buck drive unit uses gallium nitride switching devices to form a synchronous buck circuit; The boost drive unit uses gallium nitride switching devices to form a synchronous boost circuit; The control unit is connected to the buck drive unit and the boost drive unit respectively, and is used to output control signals to the buck drive unit and the boost drive unit, and receive feedback signals.

[0006] Preferably, the buck drive unit includes a first gallium nitride switch Q1, a second gallium nitride switch Q2, an output inductor L1, an input capacitor C1, an output capacitor C2, and a sampling resistor R1; The first gallium nitride switch Q1 and the second gallium nitride switch Q2 are connected in series to form a half-bridge circuit, which is connected between the positive terminal of the input power supply and ground. The first end of the output inductor L1 is connected to the series connection point of the first gallium nitride switch Q1 and the second gallium nitride switch Q2, and the second end of the output inductor L1 is connected to the positive output terminal of the buck drive unit. The input capacitor C1 is connected between the positive terminal of the input power supply and ground; The output capacitor C2 is connected between the positive output terminal of the buck drive unit and ground. The sampling resistor R1 is connected in the output circuit of the buck drive unit and is used to collect the output current signal and the output voltage feedback signal.

[0007] Preferably, the control unit includes a gallium nitride drive circuit, a current and voltage control circuit, and a diagnostic circuit; The gallium nitride driving circuit is connected to the first gallium nitride switch Q1 and the second gallium nitride switch Q2, and is used to generate driving signals according to control logic and insert configurable dead time between driving signals. The current and voltage control circuit is connected to the sampling resistor R1 and is used to receive the voltage across the sampling resistor R1 and compare it with a preset current or voltage value to control the buck drive unit to work in constant current mode or constant voltage mode. The diagnostic circuit is connected to the buck drive unit and the logic units inside the control unit. It is used to read the input / output status and internal status, and send the status signals to the gallium nitride drive circuit for protection and to the control signal bus.

[0008] Preferably, the current and voltage control circuit achieves constant current control by comparing the output current value set by the control signal with the voltage across the sampling resistor R1; and achieves constant voltage control by comparing the output voltage value set by the control signal with the voltage at the output terminal CSN of the sampling resistor R1.

[0009] Preferably, the boost drive unit includes a first gallium nitride switch Q1, a second gallium nitride switch Q2, an inductor L1, an input capacitor C1, and an output capacitor C2; In this circuit, the first gallium nitride switch Q1 and the inductor L1 constitute an inductor charging circuit, and the second gallium nitride switch Q2 is connected to the inductor L1 and the output capacitor C2 to form an inductor discharging boost circuit.

[0010] Preferably, the control unit provides a configurable dead time for the boost drive unit, and the dead time is set by a control signal; the dead time is configured to delay the second gallium nitride switch Q2 for a period of time after the first gallium nitride switch Q1 is turned off.

[0011] Preferably, the gallium nitride switching device in the buck drive unit and the control unit are integrated and packaged in the same chip using silicon-based gallium nitride technology to form a gallium nitride buck drive chip.

[0012] Preferably, the gallium nitride switching device in the boost drive unit and the control unit are integrated and packaged in the same chip using silicon-based gallium nitride technology to form a gallium nitride boost drive chip.

[0013] Preferably, the control unit configures the driving voltage, switching frequency, output current, and output voltage parameters of the buck drive unit and / or the boost drive unit through control signals.

[0014] The vehicle lighting controller provided by the present invention includes the aforementioned buck and boost gallium nitride drive system for vehicle lighting control.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses gallium nitride switching devices to replace traditional silicon-based MOSFETs to construct synchronous buck and synchronous boost drive circuits; by utilizing the inherent high efficiency, high switching frequency (up to 2MHz and above) and low loss characteristics of gallium nitride materials, the energy loss during the switching process is significantly reduced; this not only improves the conversion efficiency of the entire drive system, but also allows it to work at higher frequencies, thus laying the physical foundation for achieving higher power density.

[0016] (2) Based on the high switching frequency advantage of gallium nitride devices, the solution described in this invention can significantly reduce the numerical value and physical size of key passive components in the circuit (such as output inductor L1, filter capacitors C1 and C2); at the same time, due to the improvement of the overall system efficiency, the heat generated is reduced, and the demand for and dependence on heat sinks are significantly reduced, which helps to reduce the size and weight of heat sinks; the combined effect of these factors enables the vehicle lighting controller containing this driving solution to be optimized in terms of size and weight, which is in line with the development trend of miniaturization and lightweighting of electronic devices.

[0017] (3) In terms of boost applications, the synchronous boost circuit of this invention uses gallium nitride switch Q2 to replace the diode in the traditional asynchronous boost circuit, eliminating the losses caused by the forward voltage drop of the diode; the single-phase gallium nitride synchronous boost circuit can achieve or even exceed the power output capability of the multi-phase silicon MOS parallel boost circuit, thereby avoiding the problems of increased circuit complexity, increased number of components and increased layout area caused by multi-phase parallel connection; in terms of buck applications, by integrating gallium nitride switching devices with the control unit, the use of discrete devices is reduced; the simplification of the architecture and the reduction of the number of components directly reduce material costs and production costs, and enhance the market competitiveness of the product.

[0018] (4) The control unit described in this invention integrates a configurable drive voltage, an adjustable dead time, a precise current and voltage control loop, and a comprehensive diagnostic circuit. The configurable drive voltage is compatible with different types of gallium nitride devices, improving the versatility of the solution. The adjustable dead time mechanism effectively prevents the risk of shoot-through (common) between the upper and lower bridge arms in synchronous buck or synchronous boost circuits, while optimizing the dead time for the characteristics of gallium nitride devices, further reducing switching losses. The precise constant current / constant voltage control ensures the stability of the vehicle lamp load operation. The diagnostic circuit monitors the system status in real time, realizing fault detection and protection, and enhancing the functional safety and operational reliability of the system.

[0019] (5) This invention proposes to use technologies such as "GaN on Si" to integrate gallium nitride power switching devices and control units responsible for logic control, driving and protection into the same chip to form a highly integrated gallium nitride buck or boost driver chip. This integrated solution not only further compresses the physical size of the solution and reduces the complexity of the peripheral circuit, but also helps to optimize parasitic parameters, improve the consistency and reliability of system performance, and provides an advanced hardware foundation for the large-scale, standardized mass production of vehicle lighting controllers. Attached Figure Description

[0020] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the synchronous buck circuit unit structure; Figure 2 A schematic diagram of a gallium nitride step-down driver chip structure; Figure 3 This is a schematic diagram of the synchronous boost circuit unit structure; Figure 4 This is a schematic diagram of a gallium nitride boost driver chip. Detailed Implementation

[0021] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0022] Example This invention provides a buck and boost gallium nitride drive system for vehicle lighting control, comprising: a buck drive unit, a boost drive unit, and a control unit; The buck drive unit uses gallium nitride switching devices to form a synchronous buck circuit; The boost drive unit uses gallium nitride switching devices to form a synchronous boost circuit; The control unit is connected to the buck drive unit and the boost drive unit respectively, and is used to output control signals to the buck drive unit and the boost drive unit, and receive feedback signals.

[0023] The buck driver unit consists of components such as gallium nitride switches, inductors, capacitors, and control chips. Figure 1 A half-bridge circuit is formed by connecting a first gallium nitride (GaN) switch Q1 and a second GaN switch Q2 in series. L1 is an output inductor that limits the output current. A sampling resistor R1 collects the output current and feedback the output voltage. C1 and C2 are input and output capacitors, respectively, used for filtering. The controller sends a PWM signal to control the GaN switches. When the first GaN switch Q1 is turned on, the current is limited by inductor L1 and then charges capacitor C2. When the current reaches the set value, the first GaN switch Q1 is turned off and the second GaN switch Q2 is turned on. Inductor L1 continues to charge C2, and the cycle repeats, thereby achieving the purpose of voltage reduction and current limiting.

[0024] The control unit circuit consists of a gallium nitride drive circuit, a current and voltage control circuit, a diagnostic circuit, etc.

[0025] 1. Gallium nitride driver circuit The gallium nitride (GaN) driver circuit turns Q1 and Q2 on and off separately according to the control logic of the buck / boost driver unit, while adding a dead time between the two switches to prevent Q1 and Q2 from being turned on simultaneously. The dead time can be configured via a control signal.

[0026] Different models of gallium nitride (GaN) batteries have different drive voltages. To accommodate different GaN types, several fixed voltage settings are required. The drive voltage can be set via a control signal.

[0027] 2. Current and voltage control circuit The current and voltage control circuit supplies power to the analog circuit module by sampling the voltage across resistor R1. When the circuit operates in constant current mode, it first compares the output current value set by the control signal with the voltage across the resistor (CSP and CSN) to accurately detect the current flowing through the load. When operating in constant voltage mode, it compares the output voltage value set by the control signal with the voltage at the output terminal CSN of the resistor to achieve constant voltage control.

[0028] 3. Diagnostic circuit The diagnostic circuit is used to read the input and output status of the buck driver unit and the status of each logic unit inside the chip, and sends the signal to the gallium nitride buck / boost driver unit for protection, while sending the status signal to the control signal bus.

[0029] By utilizing gallium nitride on silicon (GaN on Si) technology, the gallium nitride switching transistors and control units of the above buck / boost driver units are packaged into a single chip, thus forming a gallium nitride buck driver chip. For example... Figure 2 The buck driver chip structure mainly consists of a gallium nitride buck driver unit and a control unit. The buck driver unit comprises... Figure 1 The system is structured to reduce the input voltage to adapt to different load voltages. The control unit compares the input control signal and the output signal to control the duty cycle of the buck driver unit, thereby adjusting the output. Control signals are used to configure parameters such as current, voltage, and switching frequency of the driver circuit to meet various application requirements of the lighting load. Simultaneously, the control signals can also read the operating status of each unit circuit to meet increasing functional safety requirements.

[0030] The boost drive unit consists of components such as gallium nitride switches, inductors, capacitors, and control chips. Figure 3 The circuit consists of a first gallium nitride (GaN) switch Q1 and an inductor L1. When Q1 is on, capacitor C1 charges inductor L1. When Q1 is off, the second GaN switch Q2 is on, and inductor L1 charges capacitor C2. This utilizes the principle of inductor discharge to achieve voltage boost. A controller provides a PWM signal to control the GaN switches. When the first GaN switch Q1 is on, after the magnetized energy stored in inductor L1 reaches a certain current, Q1 is turned off while the second GaN switch Q2 is turned on. The demagnetized freewheeling current from inductor L1 charges the subsequent capacitor through Q2. Q1 and Q2 cycle repeatedly in this sequence, thus achieving voltage boost.

[0031] The boost drive unit is a synchronous boost circuit, which requires a dead time to address the issue of simultaneous conduction of Q1 and Q2 causing circuit failure. However, the reverse conduction voltage drop of gallium nitride (GaN) is much higher than that of silicon MOSFETs, resulting in greater losses for GaN Q2 during the dead time. Therefore, to further reduce the losses of the GaN switch and improve the overall efficiency of the boost circuit, an adjustable dead time controller is used to reduce the losses of Q2, while also resolving the issue of Q1 and Q2 being simultaneously active.

[0032] Therefore, to further reduce the losses of the gallium nitride (GaN) switching transistors and improve the efficiency of the entire boost circuit, the control unit provides a configurable dead time set by a control signal. The principle of the dead time in a synchronous boost circuit is typically that when Q1 turns on and then off, there is a delay before Q2 turns on. During this dead time, the GaN Q2 operates in off mode, with a high reverse conduction voltage, resulting in losses. By setting the dead time through a control signal, the time during which the GaN Q2 operates with its reverse conduction voltage is reduced, thus lowering losses and also resolving the issue of Q1 and Q2 sharing the same operating voltage.

[0033] like Figure 4 The boost driver chip structure mainly consists of a gallium nitride boost driver unit and a control unit. The boost driver unit comprises... Figure 3 The system consists of a boost drive unit that increases the input voltage to adapt to different load voltages, and a control unit that controls the duty cycle of the boost drive unit by comparing the input control signal and the output signal, thereby adjusting the output.

[0034] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0035] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A buck and boost gallium nitride drive system for vehicle lighting control, characterized in that, include: Buck drive unit, boost drive unit, and control unit; The buck drive unit uses gallium nitride switching devices to form a synchronous buck circuit; The boost drive unit uses gallium nitride switching devices to form a synchronous boost circuit; The control unit is connected to the buck drive unit and the boost drive unit respectively, and is used to output control signals to the buck drive unit and the boost drive unit, and receive feedback signals.

2. The buck and boost gallium nitride drive system for vehicle lighting control according to claim 1, characterized in that, The buck drive unit includes a first gallium nitride switch Q1, a second gallium nitride switch Q2, an output inductor L1, an input capacitor C1, an output capacitor C2, and a sampling resistor R1. The first gallium nitride switch Q1 and the second gallium nitride switch Q2 are connected in series to form a half-bridge circuit, which is connected between the positive terminal of the input power supply and ground. The first end of the output inductor L1 is connected to the series connection point of the first gallium nitride switch Q1 and the second gallium nitride switch Q2, and the second end of the output inductor L1 is connected to the positive output terminal of the buck drive unit. The input capacitor C1 is connected between the positive terminal of the input power supply and ground; The output capacitor C2 is connected between the positive output terminal of the buck drive unit and ground. The sampling resistor R1 is connected in the output circuit of the buck drive unit and is used to collect the output current signal and the output voltage feedback signal.

3. The buck and boost gallium nitride drive system for vehicle lighting control according to claim 2, characterized in that, The control unit includes a gallium nitride drive circuit, a current and voltage control circuit, and a diagnostic circuit. The gallium nitride driving circuit is connected to the first gallium nitride switch Q1 and the second gallium nitride switch Q2, and is used to generate driving signals according to control logic and insert configurable dead time between driving signals. The current and voltage control circuit is connected to the sampling resistor R1 and is used to receive the voltage across the sampling resistor R1 and compare it with a preset current or voltage value to control the buck drive unit to work in constant current mode or constant voltage mode. The diagnostic circuit is connected to the buck drive unit and the logic units inside the control unit. It is used to read the input / output status and internal status, and send the status signals to the gallium nitride drive circuit for protection and to the control signal bus.

4. The buck and boost gallium nitride drive system for vehicle lighting control according to claim 3, characterized in that, The current and voltage control circuit achieves constant current control by comparing the output current value set by the control signal with the voltage across the sampling resistor R1; and achieves constant voltage control by comparing the output voltage value set by the control signal with the voltage at the output terminal CSN of the sampling resistor R1.

5. The buck and boost gallium nitride drive system for vehicle lighting control according to claim 1, characterized in that, The boost drive unit includes a first gallium nitride switch Q1, a second gallium nitride switch Q2, an inductor L1, an input capacitor C1, and an output capacitor C2; In this circuit, the first gallium nitride switch Q1 and the inductor L1 constitute an inductor charging circuit, and the second gallium nitride switch Q2 is connected to the inductor L1 and the output capacitor C2 to form an inductor discharging boost circuit.

6. The buck and boost gallium nitride drive system for vehicle lighting control according to claim 5, characterized in that, The control unit provides a configurable dead time for the boost drive unit, and the dead time is set by a control signal; the dead time is configured to delay the second gallium nitride switch Q2 for a period of time after the first gallium nitride switch Q1 is turned off.

7. The buck and boost gallium nitride drive system for vehicle lighting control according to claim 1, characterized in that, The gallium nitride switching device in the buck drive unit and the control unit are integrated and packaged in the same chip using silicon-based gallium nitride technology, forming a gallium nitride buck drive chip.

8. The buck and boost gallium nitride drive system for vehicle lighting control according to claim 1, characterized in that, The gallium nitride switching device in the boost drive unit and the control unit are integrated and packaged in the same chip using silicon-based gallium nitride technology, forming a gallium nitride boost drive chip.

9. The buck and boost gallium nitride drive system for vehicle lighting control according to claim 1, characterized in that, The control unit configures the driving voltage, switching frequency, output current, and output voltage parameters of the buck drive unit and / or the boost drive unit through control signals.

10. A vehicle lighting controller, characterized in that, It includes the buck and boost gallium nitride drive system for vehicle lighting control as described in any one of claims 1 to 9.

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