Design of Efficient Low Voltage High Current DC-DC Power Supplies

DC to DC power converters find major applications in all central processing unit (CPU) power supplies. The modern trend is to go towards lower power supply voltages; the reason for this is to limit power at high clock frequencies (in GHz) employed. The current demanded by the processors are high. On account of this development there is a great demand for DC to DC converters with low output voltages and high currents. Typically the operating voltage is 1.5V or less and current levels are higher than 50A as specified for the forthcoming INTEL P4 chips. The low voltage, high current power supplies have the option of powering from a 12V bus [1] or 48V bus [2]. The required efficiency of the power supply has to be greater than 80%. The challenge in such converters is achieving high efficiency. This thesis addresses the challenges involved in the design of efficient low voltage, high current DC to DC power supply. Synchronous rectifiers are used as a standard method for achieving high efficiency in low voltage output converters. This thesis, besides employing synchronous rectifiers, proposes two additional innovations towards the goal of high efficiency.