Improved Turn-On Speed of Low-Power Loads in Pulsed Power Supply Scheme and High-Energy Efficiency

Abstract

There are cases in energy supply applications with low-power batteries, where the power required by the load is larger than the supply maximum deliverable power. Using a capacitor to create a high instantaneous power for the load was investigated as a useful solution. To increase the charging efficiency, a stepwise method for charging the capacitor was employed. This paper presents a new pulsed power supply approach in which the charging process is resumed after high instantaneous power delivery. Through this, the loss of residual energy in the capacitor was decreased and load turn-on speed and energy efficiency were significantly improved. The proposed structure consists of a buck converter that charges the capacitor using inductor current. A pulse frequency modulation (PFM) technique was used to generate the necessary signals for the buck converter switches, which resulted in controlling the inductor current. The proposed circuit was designed and simulated in a 0.18 [Formula: see text]m CMOS technology. It was shown that the designed CMOS circuit could reach a peak energy efficiency of 93.2% with a sleep period of 1.05 ms when the load consumes 7.06 [Formula: see text]J of energy.