In order to meet the application requirements of the e-GaN half-bridge gate driver with multi-MHz frequencies, a low FOM level shifter with high speed, high reliability and low power consumption is proposed. The series controllable positive feedback level shifter ensured low transmission delay and high common mode transient immunity (CMTI) by only weakening the positive feedback during the conversion process, and a minimum short pulse circuit was adopted to reduce power consumption at the same time. The level shifter was designed and simulated in a 0.5 μm 80 V high voltage (HV) CMOS process. The results show that the circuit has a propagation delay of 960 ps, a CMTI of 50 V/ns, and an FOM value of 0.024 ns/(μm·V).