Noise Immunity and its Temperature Characteristics Study of the Capacitive-Loaded Level Shift Circuit for High Voltage Gate Drive IC

A new level shift circuit featuring with capacitive load instead of resistive load is proposed and investigated in this paper. The proposed design can help the high voltage gate drive integrated circuit (HVIC) to achieve the high dVs/dt noise immunity up to 85 V/ns and the allowable negative VS swing to - 12 V at 15 V supply voltage. The temperature characteristic of the above reliability items of the HVIC with the proposed capacitive-loaded level shift (CLLS) circuit are investigated for the first time and are an improvement when compared to those of the conventional resistive-loaded level shift circuit, which is verified by numerous theoretic analyses and experiments. Moreover, although four high voltage lateral double-diffused metal-oxide-semiconductor transistors are used in the proposed CLLS circuit, no extra chip size is needed due to the fact that the transistors can be embedded in the high voltage isolation structure base on 0.5 mu m Bipolar-CMOS-DMOS technology.