A Low-Power Forward and Reverse Body Bias Generator in CMOS 40 nm

Abstract

This brief presents a low-power forward and reverse body bias (FRBB) generator with body bias (BB) switches to dynamically set BB voltage. The reverse BB (RBB) P-well generator uses pulse frequency modulation (PFM)-based switching capacitor power converter to achieve low power consumption in a wide load current range of 1–30 $\mu ~\text{A}$ . The FBB adopts class-AB output stage and an over-current indicator to detect large body diode forward conduction leakage current. BB switch is introduced to dynamically configure the FRBB generated voltage. The proposed FRBB with BB switch is fabricated in a CMOS 40-nm triple well process, occupying an area of around 0.1 mm2. The 300k digital gates are used as the load for test. The measured active current for FBB and RBB are 13 and $5~\mu \text{A}$ , respectively.