A DC-DC Converter with 91% @55mA Light Load Conversion Efficiency for Portable Medical Electronics
In order to enhance the performance of power supply and extend the battery run-time for portable medical electronic devices, a step-down CMOS DC-DC converter with a zero-crossing comparator (ZCC) and a high PSRR bandgap reference is presented in this paper. The ZCC for discontinuous mode was employed to improve the efficiency in light or medium load conditions. The high PSRR bandgap reference was realized by a pre-regulation circuit, which improved the line-regulation performance. The initial version of the converter was realized in a SMIC mixed-signal 0.18μm HV CMOS 1P6M technology. Experimental results showed that the bandgap reference had a high PSRR of 115dB, the line-regulation of the converter was approximate 1.00%/V, and the complete converter achieved a peak efficiency of 91% at load current of 55mA.
KeywordsZero-Crossing Comparator (ZCC) PFM DC-DC Bandgap reference
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