A 7-nm All-Digital Leakage-Current-Supply Circuit for Analog LDO Dropout Voltage Reduction

A 7-nm leakage-current-supply (LCS) circuit monitors leakage across process and temperature variations and controls PFET block-head switches (BHSs) to supply the slow-changing leakage current while a high-bandwidth analog low-dropout (LDO) voltage regulator supplies the fast-changing dynamic current. By decreasing the LDO maximum current demand (
$I_{\mathrm{ MAX}}$
), LCS test-chip measurements demonstrate a 70 mV (44%) reduction in the minimum dropout voltage (
$V_{\mathrm{ DO,MIN}}$
), resulting in a wider voltage range of LDO usage for power savings of 14%–22%.