FS23-based dipped headlight controller

Abstract

The utility model relates to the technical field of dipped headlight controllers, in particular to a dipped headlight controller based on FS23. Comprising a headlamp control module which is connected with a power supply and a vehicle body end signal. The headlamp control module comprises a master control microcontroller, an SBC chip and a boost-buck chip, and the SBC chip is used for receiving a vehicle body end signal and inputting power through a power supply; 5V power supply is provided for the master control microcontroller by the SBC chip, and the master control microcontroller is connected with the dipped headlight LED through the boost-buck chip, and the boost-buck chip is further connected with the power supply; the LHI pin of the boost-buck chip outputs current through a resistor R21 and a resistor R25. According to the utility model, the design of the current setting circuit in the step-up and step-down chip standalone mode is added, thereby reducing or avoiding the failure of electronics and electricity or software, and reducing the possibility of dangerous accidents.

Description

Technical Field

[0001] This utility model relates to the field of low beam headlight controller technology, specifically a low beam headlight controller based on FS23. Background Technology

[0002] In existing technologies, the 5V output of the SBC (Self-Powered Circuit Board) is used to power the MCU and the internal digital-to-analog circuitry of the back-end buck-boost chip. However, with the advancement of intelligent and connected vehicles, the complexity of automotive functions is increasing, and QM (Quality Management) SBCs can no longer meet the reliability power requirements of lighting controllers. The MCU's operating voltage is provided by the SBC; a failure in the SBC's output voltage will cause MCU malfunction and controller failure. QM-level SBCs cannot provide a sufficiently reliable and stable output voltage or an independent safety mechanism for monitoring the output voltage. ASIL-level SBCs, developed according to the ISO 26262 process, can prevent systemic failures and incorporate independent safety mechanisms in their design, resulting in a sufficiently low rate of random hardware failures. In the functional safety reviews conducted by more and more OEMs, there is increasing skepticism regarding whether QM SBCs can meet ASIL B power supply requirements. Therefore, the use of ASIL B SBCs in safety-critical systems is becoming increasingly necessary. The existing architecture design does not consider functional safety requirements. When the FS23 enters fail-safe mode, it will shut down all external outputs of the SBC, causing the MCU and the back-end buck-boost chip to lose power. This will prevent the low beam headlights from being turned on safely, which could lead to dangerous events. For example, if the low beam headlights cannot be turned on when needed, it may cause the vehicle to lose its forward lighting and cause an accident.

[0003] Therefore, it is essential to find a solution to the problem of the MCU and back-end buck-boost chips losing 5V power supply and failing to light up the low beam headlights. Utility Model Content

[0004] Problem to be solved: This utility model adds a current setting circuit for the buck-boost chip in standalone mode to prevent the MCU and the back-end buck-boost chip from losing 5V power supply and failing to light up the low beam headlights.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a low beam headlight controller based on FS23, including a headlight control module connected to a power supply and vehicle body signals; the headlight control module includes a main control microcontroller, an SBC chip, and a buck-boost chip; the SBC chip receives vehicle body signals and is powered by the power supply; the main control microcontroller is powered by the SBC chip at 5V and connected to the low beam LED via the buck-boost chip, which is also connected to the power supply; the LHI pin of the buck-boost chip is configured with output current through resistors R21 and R25.

[0006] Preferably, the SBC chip integrates an external watchdog timer.

[0007] Preferably, the resistance values ​​of resistors R21 and R25 are determined according to the rated current requirements of the low beam headlights.

[0008] Preferably, the main control microcontroller is model S32K312, the SBC chip is model FS23, and the buck-boost chip is model TPS92520.

[0009] Preferably, it also includes an SPI communication interface for data transmission between the main control microcontroller and the buck-boost chip, which triggers the buck-boost chip to enter limp mode when communication times out.

[0010] Compared with the prior art, this utility model provides a low beam headlight controller based on FS23, which has the following beneficial effects: by adding a current setting circuit for the standalone mode of the buck-boost chip, the failure of electronic, electrical or software is reduced or avoided, thereby reducing the possibility of dangerous accidents and ensuring the personal safety of drivers, passengers and pedestrians. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of this utility model;

[0012] Figure 2 This is the circuit schematic diagram of this utility model;

[0013] Explanation of reference numerals in the attached diagram: 1. Headlight control module; 11. Main control microcontroller; 12. SBC chip; 13. Buck converter chip; 2. Power supply; 3. Vehicle side signal; 4. Low beam LED. Detailed Implementation

[0014] The technical solutions of the present utility model will now be described with reference to the accompanying drawings in the embodiments of the present utility model:

[0015] To address the problems mentioned in the background art, this utility model provides a low beam headlight controller based on FS23, such as... Figure 1The diagram shows a headlight control module 1, which is connected to a power supply 2 and a vehicle-side signal 3. The headlight control module 1 receives vehicle commands via the vehicle-side signal 3 to control the switching and brightness of the low beam LED 4. The headlight control module 1 includes a main control microcontroller 11, an SBC chip 12, and a buck-boost chip 13. The main control microcontroller 11 is an S32K312, responsible for overall logic control, signal processing, and communication management. The SBC chip 12 is an FS23, and the buck-boost chip 13 is a TPS92520. The SBC chip 12 receives the vehicle-side signal 3 and is powered by the power supply 2. The SBC chip 12 integrates an external watchdog timer. The main control microcontroller 11 is powered by a 5V SBC chip 12 and connected to the low beam LED 4 via a buck-boost chip 13. The buck-boost chip 13 is also connected to the power supply 2. The LHI pin of the buck-boost chip 13 outputs current through resistors R21 and R25, the values ​​of which are determined according to the rated current requirements of the low beam. Data transmission between the main control microcontroller 11 and the buck-boost chip 13 is achieved through an SPI communication interface. When communication times out, the buck-boost chip 13 is triggered to enter limp mode.

[0016] like Figure 1 The example shown is a low beam headlight controller based on the FS23. It incorporates a current setting circuit in standalone mode using a buck-boost chip 13 to prevent violations of a safety objective. The safety objective is "unintended shutdown of low beam LED4," and it is ASIL B functional safety certified. In the event of a fault, the system enters a safe state, and low beam LED4 is turned on.

[0017] KL30 is power supply 2, serving as the input power supply for SBC chip 12 and buck-boost chip 13. BODY CAN is the vehicle body signal 3, and HCM is the headlight control module 1, which operates the low beam LED4 by switching it on and off based on the received vehicle body signal. One power supply path is the standard 5V output from SBC chip 12, which is supplied to the main control microcontroller 11 and buck-boost chip 13. The main control microcontroller 11 controls the output current of the buck-boost chip 13 channel to light up the low beam LED4.

[0018] When the main microcontroller 11's software program malfunctions and fails to feed the external watchdog integrated into the SBC chip 12, resulting in a failure to reach the set fault error counter threshold, communication between the main microcontroller 11 and the buck-boost chip 13 times out. The buck-boost chip 13 then enters its own limp-safe mode and outputs according to the limp-safe register configured during power-on initialization. Conversely, when the main microcontroller 11's software program malfunctions and fails to feed the external watchdog integrated into the SBC chip 12, resulting in a failure to reach the set fault error counter threshold, the SBC chip 12 is triggered to enter fail-safe mode. The SBC chip 12 interrupts all outputs for 100ms, and the main microcontroller 11 and the backend buck-boost chip 13 lose power. Because the buck-boost chip 13 loses its 5V power supply to the analog-to-digital circuit, the limp-safe register configured during power-on initialization is lost, preventing output based on the limp-safe register settings. After 100ms, the FS23 exits fail-safe mode and powers on again. At this time, due to the power-down of the main microcontroller 11 causing a timeout in the SPI communication between the main microcontroller 11 and the buck-boost chip 13, the power supply to the digital-to-analog circuit of the buck-boost chip 13 exceeds the set threshold, thus entering standalone mode. Figure 2 The current setting output on the LHI pin of the buck-boost chip 13, via resistors R21 and R25, illuminates the low beam LED4, ensuring it meets safety requirements. Without standalone mode configured, after the FS23 exits fail-safe mode and powers back on, the MCU needs to reinitialize the BootLoader and APP software, and simultaneously configure the buck-boost chip's limp-mode. This process takes longer than the FTTI time specified in the customer's functional safety requirements, violating safety objectives. With standalone mode configured, there is only a 100ms delay before the low beam lights up, less than the standard 500ms FTTI time for low beams, thus meeting safety requirements.

[0019] During the system architecture design phase, functional safety requirements can be achieved at a lower cost through top-level system safety design, thereby avoiding or reducing dangerous accidents caused by electronic, electrical, or software failures of the front combination lamp controller.

[0020] like Figure 1The safety control mechanism is as follows: When the communication between the main microcontroller 11 and the SBC chip 12 is abnormal, the SBC chip 12 is triggered to enter fail-safe mode and shut off the external power supply. The buck-boost chip 13 enters standalone mode and illuminates the low beam LED4 according to the current setting circuit to meet the safety target. When the buck-boost chip 13 detects a 5V power supply loss, it automatically switches to standalone mode and outputs a constant current based on the resistor configuration of the LHI pin. The preset threshold is the fault error counter threshold, which is implemented through software configuration. The current setting circuit includes a voltage divider resistor network, and the resistance values ​​of resistors R21 and R25 are determined according to the rated current requirements of the low beam. The output current range of the buck-boost chip 13 in standalone mode is 0.5A to 2A to meet the power requirements of different low beams. The fail-safe mode of the SBC chip 12 includes shutting off all external power supply outputs while retaining power supply to the internal logic circuit.

[0021] The main control microcontroller 11 sends dimming commands to the buck-boost chip 13 via SPI to drive the low beam LED 4. The main control microcontroller 11 also receives vehicle commands (such as light switch commands) via the vehicle body signal 3 and forwards them to the main control microcontroller 11 for execution. This system uses the S32K312 as its core, coordinating with modules such as the HCM and TPS92520 via BODY CAN and SPI buses to achieve intelligent control of the low beam. KL30 and 5V@1 provide power support, while a watchdog and reset mechanism ensure reliability. The hardwired and communication lines have clearly defined roles, balancing real-time performance and flexibility.

[0022] like Figure 2 The schematic diagram of step-up / step-down chip 13 is shown. VIN1 and VIN2 are connected to the input power supply and stepped down through the internal Buck circuit. BST1 and BST2 are used as step-up pins, and external capacitors (such as C17 and C53) are connected to enhance the driving capability. SW1 and SW2 are connected to inductors (L3 and L7) and diodes (D2) to form a Buck topology to drive LED channels (CH1 and CH2). SP10-SCLK (24), SP10-MISO (23), and SP10-MOSI (22) communicate with the SPI bus. Figure 1The main microcontroller 11 in the communication receives dimming commands. CS-BUCK1 (25) is the chip select signal used to enable the Buck converter. Inductors L3 and L7, along with capacitors C19, C17, C52, and C53, form a filter network to stabilize the Buck circuit output and reduce ripple. Resistors R8, R14, R20, and R14 are used for current sampling or voltage division, feeding back to the CSN pin of the buck-boost chip 13. Resistors R20, R21, and R25 are used to set the current limit or dimming ratio of the low beam LED4. Diode D2 is a freewheeling diode used to protect the SW node from reverse voltage surges. The input power supply (e.g., +5V-I) enters the TRS92520 through VIN1 and VIN2, is stepped down by the internal Buck circuit, and is output to the LED channel through SW1 and SW2. GND and PGND (power ground) are laid out separately to reduce noise interference. The S32K312 sends dimming commands to the TRS92520 via the SPI bus (SP10-SCLK / MOSI / MISO). The TRS92520 adjusts the PWM duty cycle or output current according to the commands to drive the brightness of the LEDs in CH1 and CH2. The CS-BUCK1 signal, controlled by the S32K312, is used to select and activate the corresponding Buck channel (such as CH1 or CH2). The LED driving path includes the CH1 path and the CH2 path: CH1 path: SW1→L3→LED CH1→current sensing resistor (such as R14)→GND; CH2 path: SW2→L7→LED CH2→current sensing resistor (such as R25)→GND.

[0023] Figure 2 This section details the implementation of the LED driver. The TRS92520-QI works in conjunction with the S32K312 via SPI, utilizing Buck topology and external filtering components to precisely control two LED channels. Combined with the system framework shown in the first diagram, the overall system achieves intelligent dimming, communication, and power management for the headlights. Key modules have clearly defined roles, and the signal flow is clear, ensuring the reliability and flexibility of the lighting system.

[0024] Detailed implementation: Specific design parameters for the current setting circuit are provided: R21 = 1.5kΩ, R25 = 1kΩ; the relationship between R21, R25 and the output current is as follows:

[0025] Rcs=0.9*Vdac(FS) / 14*Iled(max);

[0026] Vdac(FS) = 2.48V, Rcs = 0.1;

[0027] Iled=Vlhi / (14*Rcs), Iled=1.43A;

[0028] Vlhi = 1.43 * 14 * Rcs = 2;

[0029] Confirm the ratio between R21 and R25, and set R21 = 1.5kΩ and R25 = 1kΩ; where Vdac(FS) is the full-scale voltage value of the chip (10-bit ADC), Iled is the output current in independent mode, and Vlhi is... Figure 2 The voltage value on the LHI pin. Rcs is... Figure 2 R8 and RCS set the sampling accuracy of the output current.

[0030] The communication protocol between the main microcontroller 11 and the buck-boost chip 13 is as follows: the SPI frequency setting range is 100kHz to 2.2MHz; the data frame format is as follows: the command frame consists of one CMD bit, 6 bits of ADDRESS, one parity bit (parity check), and 8 bits of DATA. The command bit (CMD) is defined as follows: CMD = 1 indicates a write command; CMD = 0 indicates a read command; the 6-bit ADDRESS (A5:A0) parity bit (PAR) is set by the following formula: PARITY = XNOR(CMD, A5..A0, D7..D0).

[0031] This utility model includes a communication timeout detection mechanism. The buck-boost chip 13 has a built-in communication watchdog timer. The register corresponding to the communication timeout will be incremented. When the increment reaches 3, the buck-boost chip 13 enters its own imp home mode.

[0032] This invention effectively solves the safety hazard of unexpected shutdown of the low beam LED4 due to power failure of the main control microcontroller 11 and the buck-boost chip 13 by introducing a standalone mode current setting circuit for the buck-boost chip 13. Specifically, through the resistance configuration of resistors R21 and R25, the buck-boost chip 13 can automatically switch to standalone mode when the system fails (such as the SBC chip 12 entering fail-safe mode), outputting a constant current according to the preset resistor network, ensuring that the low beam can still maintain basic lighting function under fault conditions, meeting the ASIL B functional safety level requirements. Through the combination of system-level safety mechanisms and hardware redundancy design, this invention achieves high reliability with a simplified architecture while ensuring functional safety, significantly reducing the risk of dangerous accidents caused by electronic, electrical, or software failures, and possessing outstanding practicality and economic advantages.

[0033] The above embodiments are merely some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

Claims

1. A low beam controller based on FS23, characterized in that, The front lamp control module (1) is connected with a power supply (2) and a vehicle body end signal (3); the front lamp control module (1) comprises a main control microcontroller (11), an SBC chip (12) and a step-up and step-down chip (13); the SBC chip (12) is used for receiving the vehicle body end signal (3) and inputting power supply through the power supply (2); the main control microcontroller (11) is powered by 5V provided by the SBC chip (12) and connected with a low beam LED (4) through the step-up and step-down chip (13), and the step-up and step-down chip (13) is also connected with the power supply (2); the LHI pin of the step-up and step-down chip (13) is configured to output current through a resistor R21 and a resistor R25.

2. The FS23-based low-beam controller of claim 1, wherein, The SBC chip (12) is integrated with an external watchdog.

3. The FS23-based low-beam controller of claim 2, wherein, The resistance values of the resistor R21 and the resistor R25 are determined according to the rated current demand of the low beam.

4. The FS23-based low-beam controller of claim 1, wherein, The model of the main control microcontroller (11) is S32K312, the model of the SBC chip (12) is FS23, and the model of the step-up and step-down chip (13) is TPS92520.

5. The FS23-based low-beam controller of claim 4, wherein, An SPI communication interface is further included, which is used for data transmission between the main control microcontroller (11) and the step-up and step-down chip (13), and when communication times out, the step-up and step-down chip (13) is triggered to enter a limp mode.

Images