A New High-Frequency CMOS Full-Wave Rectifier For Backlight Controllers

This paper presents a new high-frequency CMOS full-wave rectifier appropriate to handle sense currents and voltages from Cold Cathode Fluorescent Lamp (CCFL) backlight converters. To achieve its high speed, the rectifier incorporates two methods: First, it uses a pair of single stage common-source amplifiers instead of an operational amplifier (op-amp). Second, it uses class-AB buffer output stage to drive its feedback resistor. The rectifier maximum input frequency is 500 kHz. Using single 3V power supply, the rectifier can process input amplitude range from +/- 250mV to +/- 2.5V. The rectifier is implemented in a standard 0.5 mu m Hynix analog CMOS process with high-value poly-silicon resistors. It occupies 200 mu m x 300 mu m silicon area and it consumes less than 450 mu A.