High efficiency, high density, PolyPhase converters for high current applications

As logic systems get larger and more complex, their supply current requirements continue to rise. Systems requiring 100 A are fairly common. A high current power supply to meet such requirements usually requires paralleling several power regulators to alleviate the thermal stress on the individual power components. PolyPhase converters reduce the input and output ripple currents by interleaving the clock signals of paralleled power stages. With a proper choice of phase number, the output ripple voltage and the input capacitor size can be minimized without increasing the switching frequency. Lower output ripple voltage and smaller output inductors help improve the circuit's dynamic performance during load transients. The low switching losses and driving losses of metal–oxide–semiconductor field-effect transistors (MOSFETs) at relatively low switching frequency, and the reduced power losses due to equivalent series resistances of the capacitors, help achieve high efficiency. The LTC1629 dual, PolyPhase current mode controller is able to achieve the benefits of the PolyPhase technique without complicating the control circuit. The LTC1629 helps minimize the external component count and simplify the complete power supply design by integrating two PWM current mode controllers, true remote sensing, selectable phasing control, current-sharing capability, high current MOSFET drivers, and protection features into one integrated circuit. The resulting manufacturing simplicity helps improve power supply reliability. The high current MOSFET drivers allow the use of low RDS(ON) MOSFETs to minimize the conduction losses for high current applications. Lower current ratings on the individual inductors and MOSFETs also make it possible to use low profile, surface mount components.