A 50-V 50-MHz High-Noise-Immunity Capacitive-Coupled Level Shifter With Digital Noise Blanker for GaN Drivers

In this paper, a high-noise-immunity capacitive coupled level shifter with digital noise blanker (DNB) is presented for GaN drivers. During and after d V/dt transitions, the DNB blanks the common mode noise induced by d V/dt and converts the differential mode noise due to mismatch effect to common mode noise. This enables high dV/dt immunity of 200V/ns and high mismatch tolerance not less than 15%. Moreover, a dynamic discharge control (DDC) circuit prevents coupling capacitor from charging the floating power rail within a wide negative dV/dt transition range and achieves fast reset for high frequency operation. High speed, low power consumption and down to -5V negative floating power rail tolerance are also achieved. The proposed level shifter is fabricated in a 0.5-mu m BCD process and occupies an active chip area of 0.051mm(2). Experimental results confirm that the proposed level shifter works at 50V 50MHz, achieving power consumption of 27.3pJ/transition and 1.26ns average delay with a small figure of merit (5.5(pJmiddotns)/(mu m(3)middotV)). The effect of the DDC is confirmed within negative dV/dt transition range of-5V/ns similar to-50V/ns.