High-speed Resonant Dc/dc Converter Of A Single Lithium Battery Cell Voltage

摘要

The objectives of power supplies have been to reduce the size,volume and cost whilst increasing efficiency, speed and reliability. These are considered to be the main challenges of the future power supplies.The proposed discrete resonant self-oscillating DC/DC converter operable at high speed with high efficiency comprises cascoded power stage, automatic dead time circuitry and a transformer. Primary side of the transformer delivers power to the load and secondary side of the transformer provides inductive feedback to drive switching transistors. Driving stage composed of duty cycle detector and pulse shaping circuit. Since there is no external control, proposed topology offers fast response, adaptive dead-time and increased reliability in terms of EMI considerations. Switching losses caused by high frequency operation is reduced by ensuring ZVS operation which is performed by optimizing dead-time driving signals. Efficiency of the converter is further enhanced by adding automatic dead-time latch circuitry by 1.3%. SPICE simulations of the proposed converter is conducted by employing real SPICE models of the components and the likelihood of parasitic components that can emerge with high frequency in PCB is taken into account and they are modeled thoroughly based on practical requirements. Hence, PCB implementation is applicable. As the converter designed for discrete implementation, it makes proposed topology to be cost effective since most of the high speed converter are designed for silicon process. Proposed discrete resonant self oscillating DC/DC converter operates at 3.4 MHz with 72.3% efficiency and drives 10$Omega$ resistive load. Supply voltage is 4 V and generated average output voltage is 2.34 V$pm$ 30mW with 58.5% duty ratio.