| Summary: | 碩士 === 國立交通大學 === 電子研究所 === 108 === This paper presents a high-efficiency single inductor triple-outputs battery management unit for implantable medical device. To manage the medical Li-ion battery, we set the input voltage range of the battery management unit as 3.2V to 4.8V. The battery management unit regulates three DC voltage value, 6 V, −6 V for the adaptive stimulator and 2V for the control circuit of stimulator and other digital control circuit in the implantable medical device. To lower the cost, system on chip (SoC) is necessary, so the whole chip must be fabricated in same process. TSMC standard 180nm cmos process is chosen for higher performance and lower power waste. Nevertheless, the output voltage of the battery is range from 3.2V to 4.8V, so this paper presents a cascade structure of a single-inductor dual-output (SIDO) buck converter and charge pump circuits, stacked transistor in power stage and additional control circuit to avoid the overstress problem. For various output loading and output voltage, the buck converter operates in discrete continuous mode (DCM) and use pulse skip modulation (PSM). Both the positive and negative charge pump operate in free-running mode. The measurement waveforms show that the proposed BMU obtain a maximum power conversion efficiency of 82.9% with the Li-ion battery input of 3.2 V ~ 4.8 V, and the range of output power is from 0.6 mW to 40 mW.
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