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 3 V power supply, the rectifier can process input amplitude range from plusmn250 mV to plusmn2.5 V. The rectifier is implemented in a standard 0.5 mum Hynix analog CMOS process with high-value poly-silicon resistors. It occupies 200 mum times 300 mum silicon area and it consumes less than 450 muA.