In automotive automatic air-conditioning systems, the detection of load status and the diagnosis of fault handling are very important to the stability of the system. The main diagnostic requirements include: short-circuit to ground, short-circuit to power, open circuit detection, short-circuit detection, etc.
When these faults occur, the relevant output must be turned off first, and the system must read the feedback information in time and make corresponding alarm prompts. For some signals, it is necessary to constantly retry (regularly restart the output) to detect whether the fault is restored.
Implementation of Fault Diagnosis and Protection of Damper Motor Drive Based on NCV7718
NCV7718 is a multi-channel half-bridge drive with a built-in power drive module, and it is also a drive specially developed for low-power DC servo motors. Its single-channel output capacity of up to 550mA can fully meet the driving needs of the low-power servo motor in the air-conditioning damper actuator.
The built-in perfect protection function of the chip makes its peripheral circuit and its introduction, and the 3.3V/5V compatible logic communication interface can also meet the needs of platform design. The main internal protection functions of NCV7718 include:
*Low/overvoltage output lockout: used to prevent the load from malfunctioning under abnormal power supply voltage
*Over-current protection: prevent large spike current in the loop from damaging the load
*Over-temperature alarm: When the working temperature of the chip reaches an abnormal value, an alarm information will be fed back to the system
* Thermal shutdown: when the junction temperature of the chip exceeds the maximum operating temperature, all outputs are turned off to protect the system and the driver
*Light load detection: judge whether the load is open or the connector pins are in poor contact
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