Design Of A High-Efficiency Boost DC/DC Converter

Power supply is necessary for modern electronic devices and equipment. To satisfy requirements of compact electronic instruments with high performances and small weight, a high-efficiency boost DC/DC converter is designed based on CMOS technology and using HSPICE simulation tool. The research work includes circuit operating principle, circuit system design, simulation, and layout design, physical validation.First, synchronous rectification technology and automatic Burst Mode operation at light loads are designed in the chip. The synchronous rectification technology replaces the schottky diode with a low on-resistance power MOSFET, so the rectifier's power losses has decreased to schottky diode's power loss's 1/3 and the efficiency of the converter has been increased. Burst Mode operation is initiated if the output load current falls below an internally programmed threshold. Once initiated, the burst mode operation circuitry shuts down most of the device. When the output voltage has dropped approximately 1% from nominal, the chip wakes up and commences normal PWM operation. This operation has improved efficiency of the converter at light loads.Second, a zero current comparator and anti-ringing module are proposed for the Discontinuous-Conduction Mode (DCM) of the converter. The zero current comparator can prevent the inductor current from reversing in polarity improving efficiency at DCM. The anti-ringing module prevents high frequency ringing of the SW pin as the inductor current goes to zero by connecting the Vin pin and the SW pin with a transmission gate. This converter has successfully been used for a 3.3 V step-up switching regulator system, and high efficiency at both light and heavy loads is confirmed through HSPICE simulation, with the highest efficiency of 92.78% when the input voltage is 1.5 V and the load current is 60 mA.