Limphome safety system for vehicle body domain MCU charging control
By controlling the shutdown of the Limphome function through PWM charging, the static power consumption problem of the Limphome mode during parking and sleep is solved, the static power consumption of the entire vehicle is reduced and battery power feeding is prevented, ensuring the basic driving capability and driving safety of the vehicle.
Patent Information
- Application Number
- CN202422720810.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-08
- Publication Date
- 2025-10-10
- Estimated Expiration
- 2034-11-08
AI Technical Summary
In the prior art, the Limphome mode remains on when the vehicle is parked and dormant, which increases the static power consumption of the entire vehicle and causes battery power supply problems.
The PWM charging method is used to control the shutdown of the Limphome function. The PWM wave is output through the PWM port of the MCU and the DC signal is filtered through the capacitor. The transistor is turned on to cut off the input of the high-side MOS tube and disconnect the power supply of the IGN power circuit.
It effectively reduces the static power consumption of the entire vehicle, prevents battery power outages, and ensures the basic driving capability and driving safety of the vehicle under abnormal conditions.
Smart Images
Figure CN223428185U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of safety control, in particular to a Limphome safety system for vehicle body domain MCU charging control. Background Art
[0002] During a vehicle's journey, both gasoline and new energy vehicles rely on a functioning ignition switch (IGN) to drive the coordinated operation of multiple core control modules. A failure or instability in the safety power supply circuit can paralyze the entire vehicle's control system, leading to unforeseen driving risks and a serious threat to driving safety. For example, windshield wipers must not stop operating in heavy rain, lights must not be suddenly turned off during nighttime driving, and the engine must not be abruptly shut down.
[0003] Limphome mode (emergency driving mode) provides a solid backup for the vehicle, ensuring stable IGNON_VCC power supply in critical situations such as MCU (microcontroller unit) software errors, drive signal interruptions, and single or multiple failures in the SBC (system power control unit). This mechanism effectively prevents failure of multiple critical control modules, ensuring the vehicle maintains basic driving capabilities even in abnormal conditions, ensuring driver safety and continued travel. However, leaving limphome mode enabled during parking and hibernation increases the vehicle's static power consumption. Utility Model Content
[0004] Purpose of the present invention: In order to overcome the defects of the prior art, the present invention provides a Limphome safety system with vehicle body domain MCU charging control, which adopts PWM charging method to control the shutdown of the Limphome function. Cutting off the power supply can reduce the static power consumption of the whole vehicle and prevent battery feeding.
[0005] The technical solution of the present utility model is a Limphome safety system with vehicle body domain MCU charging control, comprising: a single-chip microcomputer MCU, a PWM charging circuit, a high-side MOS transistor, a relay, and an IGN power supply circuit. The MCU has a PWM port for outputting PWM waves and an HSD port for outputting high levels. The PWM port is connected to the input of the PWM charging circuit, the output of the PWM charging circuit is directly or indirectly connected to the input of the high-side MOS transistor, the HSD port is connected to the input of the high-side MOS transistor, and the output of the high-side MOS transistor is connected to the relay. The IGN power supply circuit is used to receive feedback signals from the relay and can provide power off. The PWM charging circuit has a capacitor C1 that can filter DC signals and a transistor Q1. When the vehicle is parked and dormant, the PWM port of the MCU outputs a PWM wave to the capacitor C1 to turn on Q1, causing the PWM charging circuit to output a low level and thus turn off the input to the high-side MOS transistor.
[0006] By adopting the above technical solutions:
[0007] When the vehicle is running, the PWM port of the MCU does not output PWM waves, and the HSD port outputs a high level. At this time, the high-side MOS tube is turned on, and the high-side MOS tube will always maintain continuous output to the relay. The IGN power circuit is powered normally and the limphome function is maintained.
[0008] When the vehicle is parked and in sleep mode, the MCU uses a PWM port to output a PWM wave. Capacitor C1 receives the PWM wave and filters out the DC signal. It then turns on transistor Q1, pulling the output voltage low and shutting off the input to the high-side MOSFET. This disconnects the input to the relay, de-energizing the IGN power circuit and disabling the system's limphome function. The MCU uses PWM charging to control the limphome function's shutdown. Cutting off power reduces the vehicle's static power consumption and prevents battery overload.
[0009] Preferably, the capacitor C1 is connected to the PWM port of the MCU, the transistor Q1 is directly or indirectly connected to the input of the high-side MOS tube, and a capacitor C2 and a resistor R4 are connected in parallel between the capacitor C1 and the transistor Q1.
[0010] Taking the above configuration a step further, the MCU uses PWM output, filters the DC signal through capacitor C1, and then charges capacitor C2, raising the voltage at resistor R4, thereby turning on transistor Q1. The circuit is only effective when outputting PWM; Q1 cannot be turned on.
[0011] Preferably, a self-holding circuit is connected between the output of the PWM charging circuit and the input of the high-side MOS tube, the output of the high-side MOS tube also supplies power to the input of the self-holding circuit, and the input to the high-side MOS tube is maintained by the self-holding circuit.
[0012] With the above further setting: the MCU normally outputs and controls the input and output of the high-side MOS. At the same time, the high-side MOS tube maintains the operation of the self-holding circuit. Moreover, the self-holding circuit can maintain a high-level input to the high-side MOS tube after the MCU loses power, thereby more effectively maintaining the limphome function.
[0013] Preferably, the relay includes an ON relay and a COMFORT relay, the high-side MOS tube has input ports IN2 and IN3 and output ports OUT2 and OUT3, the output of the PWM charging circuit is connected to two self-holding circuits in parallel, and the outputs of the two self-holding circuits are respectively connected to the input ports IN2 and IN3, the MCU has two HSD ports, which are HSD_D05 and HSD_D06 respectively, the two HSD ports are respectively connected to the input ports IN2 and IN3, the output ports OUT2 and OUT3 are respectively connected to the ON relay and the COMFORT relay, and the output ports OUT2 and OUT3 are also respectively powered to connect the inputs of the two self-holding circuits.
[0014] Using the above configuration, the MUC controls the output ports OUT2 and OUT3 of the high-side MOS transistor based on the vehicle's operating requirements. When the user activates the ON relay, HSD_D05 outputs a high level, turning on one channel of the high-side MOS transistor. When the user activates the COMFORT relay, HSD_D06 outputs a high level, turning on the other channel of the high-side MOS transistor. When the PWM charging circuit is activated, the output level is pulled low, disabling both self-holding circuits and thus shutting off the IN2 / IN3 inputs of the high-side MOS transistor, disconnecting OUT2 and OUT3.
[0015] Preferably, the single chip microcomputer MCU is CYT4BF.
[0016] Preferably, the high-side MOS tube is BTS7200-4EPA. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a control system diagram of a specific embodiment of the utility model;
[0018] Figure 2 Schematic diagram of multiple output ports of the MCU in a specific embodiment of the present utility model;
[0019] Figure 3 This is a PWM charging circuit diagram in a specific embodiment of the utility model;
[0020] Figure 4 This is a connection circuit diagram of the self-holding circuit, high-side MOS transistor, and relay in a specific embodiment of the utility model;
[0021] Figure 5 Two self-holding circuit diagrams in a specific embodiment of the utility model;
[0022] Figure 6 This is a circuit diagram of a high-side MOS tube in a specific embodiment of the utility model;
[0023] Figure 7 IGN power supply circuit diagram in the embodiment of the utility model. DETAILED DESCRIPTION
[0024] As Figure 1-7 shown, the utility model relates to a kind of Limphome safety systems of car body area MCU charging control, including: single-chip microcomputer MCU, PWM charging circuit, high-side MOS tube, relay and IGN power supply circuit, single-chip microcomputer MCU is CYT4BF, high-side MOS tube is BTS7200-4EPA, the MCU has the PWM port for outputting PWM wave and the HSD port for outputting high level, the input of PWM charging circuit is connected by PWM port, the output of PWM charging circuit is directly or indirectly connected the input of high-side MOS tube, the input of high-side MOS tube is connected by HSD port, the output of high-side MOS tube is connected relay, the IGN power supply circuit is used to accept the feedback signal given by relay, and can be powered off, the PWM charging circuit has the capacitor C1 that can filter out direct current signal and triode Q1, the capacitor C1 is connected the PWM port of MCU, the triode Q1 is directly or indirectly connected the input of high-side MOS tube, capacitor C2 and resistance R4 are also connected in parallel between capacitor C1 and triode Q1, self-holding circuit is also connected between the triode Q1 output of PWM charging circuit and the input of high-side MOS tube, the output of high-side MOS tube also supplies the input of self-holding circuit, and the input of high-side MOS tube is maintained by self-holding circuit, the power supply port of high-side MOS tube is also connected with vehicle battery VBAT1 / VBAT2.
[0025] Specifically, the relay includes ON relay and COMFORT, COMFORT represents automobile comfort mode, high-side MOS tube has input port IN2 and IN3 and output port OUT2 and OUT3, two self-holding circuits connected in parallel are connected to the output of triode Q1 of PWM charging circuit, the outputs of two self-holding circuits are respectively connected to input port IN2 and IN3, MCU has two HSD ports, and is respectively HSD_D05 and HSD_D06, two HSD ports are respectively connected to input port IN2 and IN3, output port OUT2 and OUT3 are respectively connected ON relay and COMFORT relay, and output port OUT2 and OUT3 also respectively supply the input of two self-holding circuits.
[0026] The specific working principle of the utility model is as follows:
[0027] When the vehicle is running, the MCU's PWM port stops outputting PWM waveforms and uses the HSD port to output a high level. This turns on the high-side MOSFET, maintaining continuous output to the relay. The high-side MOSFET outputs ICD_HSD_004 and ICD_HSD_006 also maintain the operation of two self-holding circuits. These self-holding circuits maintain a 40µs high input to the high-side MOSFET even after the MCU loses power. Because the MCU undervoltage detection delays the imphompe trigger by 50µs, the self-holding circuits effectively maintain the limhompe function. The MUC controls the high-side MOSFET outputs OUT2 and OUT3 based on vehicle operating requirements. To activate the ON relay, HSD_D05 outputs a high level, turning on one channel of the high-side MOSFET. To activate the COMFORT relay, HSD_D06 outputs a high level, turning on the other channel of the high-side MOSFET.
[0028] When the vehicle is parked and in hibernation, the MCU uses the PWM port to output a PWM wave. This wave is received by capacitor C1 and filtered out of the DC signal. This then charges capacitor C2, raising the voltage at resistor R4, turning on transistor Q1. This pulls the output IGN OFF level low, shutting down the input to the high-side MOS tube. The high-side MOS tube disconnects the input to the relay, de-energizing the IGN power circuit and stopping the system's limphome function. When the PWM charging circuit is activated, the output level is pulled low, shutting down both self-holding circuits and shutting down the IN2 / IN3 inputs of the high-side MOS tube. OUT2 and OUT3 are disconnected, and cutting off power can reduce the vehicle's static power consumption and prevent battery overload.
Claims
1. A Limphome safety system with MCU charging control in the vehicle body domain, characterized in that: include: A single-chip microcomputer (MCU), a PWM charging circuit, a high-side MOS transistor, a relay, and an IGN power supply circuit. The MCU has a PWM port for outputting PWM waves and an HSD port for outputting a high level. The PWM port is connected to the input of the PWM charging circuit, and the output of the PWM charging circuit is directly or indirectly connected to the input of the high-side MOS transistor. The HSD port is connected to the input of the high-side MOS transistor, and the output of the high-side MOS transistor is connected to the relay. The IGN power supply circuit is used to receive feedback signals from the relay and can provide power off. The PWM charging circuit has a capacitor C1 that can filter DC signals and a transistor Q1. When the vehicle is parked and dormant, the MCU's PWM port outputs a PWM wave to capacitor C1 to turn on Q1, causing the PWM charging circuit to output a low level, thereby turning off the input to the high-side MOS transistor.
2. The Limphome safety system for vehicle-domain MCU charging control according to claim 1 is characterized in that: The capacitor C1 is connected to the PWM port of the MCU, the transistor Q1 is directly or indirectly connected to the input of the high-side MOS tube, and a capacitor C2 and a resistor R4 are connected in parallel between the capacitor C1 and the transistor Q1.
3. The Limphome safety system for vehicle-domain MCU charging control according to claim 1 is characterized in that: A self-holding circuit is also connected between the output of the PWM charging circuit and the input of the high-side MOS tube. The output of the high-side MOS tube also supplies power to the input of the self-holding circuit, and the self-holding circuit maintains the input to the high-side MOS tube.
4. The Limphome safety system for vehicle-domain MCU charging control according to claim 3 is characterized by: The relays include an ON relay and a COMFORT relay. The high-side MOS tube has input ports IN2 and IN3 and output ports OUT2 and OUT3. The output of the PWM charging circuit is connected to two self-holding circuits in parallel. The outputs of the two self-holding circuits are respectively connected to the input ports IN2 and IN3. The MCU has two HSD ports, namely HSD_D05 and HSD_D06. The two HSD ports are respectively connected to the input ports IN2 and IN3. The output ports OUT2 and OUT3 are respectively connected to the ON relay and the COMFORT relay, and the output ports OUT2 and OUT3 are also respectively powered to connect the inputs of the two self-holding circuits.
5. The Limphome safety system for vehicle-domain MCU charging control according to claim 1, 2, 3, or 4, characterized in that: The microcontroller MCU is CYT4BF.
6. The Limphome safety system for vehicle-domain MCU charging control according to claim 1, 2, 3, or 4, characterized in that: The high-side MOS tube is BTS7200-4EPA.