Hybrid Modulated DCDC Boost Converter for Wearable Devices

Abstract

Wearable devices require power management systems to achieve high conversion efficiency over a wide range of load currents. Multi-mode mixed modulation can be used in DCDC converters to achieve high efficiency over a wide load current range. The DCDC boost converter proposed in this paper uses a hybrid modulation of DGM (Deep Green Control Mode), PCMC (Peak current mode control)-PFM (Pulse Frequency Modulation) and PCMC-PWM (Pulse Width Modulation). The converter switches smoothly from PCMC-PFM to PCMC-PWM mode under load-current-based conditions and without any mode selection module. The proposed DCDC boost converter is fabricated in a 0.18 μm CMOS process with a Die area of 1.24 × 0.78 μm2. The input voltage range is 0.8–5 V, the output voltage is 5 V, and the load current range is 5–300 mA. Experimental results show that the boost converter can achieve 94.7% peak efficiency. Efficiency of more than 90% can be achieved in the load current range of 30–300 mA.