A 60 V Tolerance Transceiver With ESD Protection for FlexRay-Based Communication Systems

In this paper, a 60 V tolerance transceiver with ESD (electrostatic discharge) protection is proposed for FlexRay-based communication systems. The FlexRay transceiver comprises three protective devices, including an over-voltage detector, high-voltage ESD devices, and high-voltage diodes. The over-voltage detector is in charge of detecting bus (BP and BM) status to distinguish whether any hazard has happened. If the over-voltage detector is activated, the FlexRay transceiver must be turned off for safety. The high-voltage ESD device uses a base-floating PNP serving as a bi-directional device. Besides, it can protect the FlexRay transceiver whenever it is short-circuited in positive or negative high voltages. Notably, the high-voltage diode will eliminate the negative leakage current when negative high voltage hazards appear in FlexRay channels. An experimental prototype is implemented using a 0.18 μm CMOS mixed-signal based generation II HV BCD process. The measurement results justify the functional correctness and 60 V tolerance of the proposed FlexRay transceiver design.