US 12,445,054 B2
PMU technique for ultra-low leakage
Radhika Venkatasubramanian, Austin, TX (US); and Stephen Dow, Austin, TX (US)
Assigned to Cypress Semiconductor Corporation, San Jose, CA (US)
Filed by Cypress Semiconductor Corporation, San Jose, CA (US)
Filed on Jul. 14, 2023, as Appl. No. 18/352,786.
Prior Publication US 2025/0023469 A1, Jan. 16, 2025
Int. Cl. H02M 3/158 (2006.01); H02M 1/00 (2006.01); H02M 3/157 (2006.01)
CPC H02M 3/158 (2013.01) [H02M 1/0035 (2021.05); H02M 3/157 (2013.01)] 22 Claims
OG exemplary drawing
 
15. A power management unit (PMU) comprising:
a DC-DC converter operable to provide a reference voltage (Vref) on a regulated rail coupled to an output of the DC-DC converter, the DC-DC converter including:
a low reference voltage (Vref_low) generator operable to generate a low reference voltage (Vref_low);
a capacitively-charged switched reference (SR) coupled through a first switch (S1) to the Vref_low generator and operable to receive and store the Vref_low; and
a low-side-comparator having a first input coupled to the SR and a second input coupled to receive a feedback voltage (Vfb) from the Vref on the regulated rail,
wherein the DC-DC converter is operable to receive a window-mode enable (en_window) signal, and in a coasting-period to: open the first switch; suspend operation of all circuits and devices in the DC-DC converter, except the low-side-comparator; and compare the Vref_low stored on the SR to the Vfb to sense a change in the Vref on the regulated rail as the regulated rail is discharged through a load coupled thereto.