FLOATING OUTPUT VOLTAGE BOOST-BUCK REGULATOR USING A BUCK CONTROLLER WITH LOW INPUT AND LOW OUTPUT RIPPLE

摘要

The converter produces an output voltage difference for a floating load such as an LED string. The converter receives the input voltage (Vin) from the power supply, and the floating output voltage difference may be greater or less than Vin. The converter uses a first switch and a first inductor in a boost mode configuration and uses a second switch and a second inductor in a buck mode configuration. The inductor has a common node. The first inductor has another end connected to ground, and the other end of the second inductor is connected to the load. Both inductors are charged and discharged together according to the conductivity of the switch. One end of the load will be approximately zero volts and the other end will be the negative voltage VEE. Two inductors reduce EMI by smoothing input current / voltage ripple and output current / voltage ripple.