Input-Adaptive and Regulated Multi-Output Power Management Unit for Wireless Power Reception and Distribution in Multi-Unit Implantable Devices

Abstract

An input-adaptive and regulated power management unit with multiple outputs is presented for multi-unit implantable medical devices (IMDs), which are powered wirelessly. In such systems, the main controller unit receives the wireless power and provides supply voltages for its own circuits and the circuits in the connected sub-units. Automatic conversion ratio reconfiguration, according to the input voltage level, achieves high conversion efficiency over a wide input voltage range. In addition, the load selection switches provide more reconfigurability by selecting the most suitable converter for each output voltage, reducing the number of flying capacitors required for the reconfigurable conversion ratios to cover a wide input range. These selection switches are reused for regulating output voltages at desired levels, minimizing the overhead for regulation. The implemented IC achieves a conversion efficiency of 51% to 79% over a wide input range of 1.1 V to 4 V with 3-mV output ripple for a load current of 60 mA while providing multiple outputs (2 regulated, 2 unregulated) for multi-unit operation and the peak efficiency is 95.7% for unregulated outputs.