A Design of PMU for the OLED-on-Silicon Micro-Display Chip

A power management unit (PMU) is proposed that can be integrated in the OLED-on-Silicon micro-display devices. The PMU uses a new structure that combine a Cuk type DC-DC converter and low drop-out voltage regulator(LDO). The DC-DC converter is used to generate negative voltage output with PWM modulation, meanwhile the LDO generates positive voltage output. The PMU is designed under SMIC 0.18 μm 1.8V/5V CMOS mix-signal process. With the 3.3 V input power voltage, the output voltage has an adjustable positive voltage range of 2~5.5 V along and a negative voltage range of -2~-5.5 V. The simulation results show that the output ripple of voltage is less than 5 mV. The positive and negative voltage output linear regulation is 5 mV/V and 20mV/V. Also, a load regulation of 0.04 mV/mA and 0.15 mV/mA is designed to meet the PMU specification.