A New Over-Temperature Protection Circuit Applied to Automotive Led Driver

This paper presents a new over-temperature protection circuit applied to automotive LED driver. The circuit generates a reference voltage when the LED driver works within the operating temperature range, and adjusts the system voltage adaptively when the temperature exceeds the operating range. Once the temperature reaches the over-temperature threshold, the circuit immediately cuts off the power to shut down the subsequent circuitry. The adaptive adjustment temperature range is set from 75℃ to 125℃, with 125℃ as the over-temperature shutdown threshold. The circuit is designed with a 0.18μm CMOS process on the Cadence Virtuoso platform. The simulation results show that the constant current output variation is less than 0.14% in the operating temperature ranging from -40℃ to 75℃. When the system temperature exceeds the normal range but has not yet reached the over-temperature value, the negative temperature regulation voltage coefficient is 12.49mV/℃. When the temperature exceeds 125℃, the circuit immediately cuts off the power to stop the subsequent circuits. The system restarts when the temperature drops to 75℃.