公开(公告)号：US20210215765A1

公开(公告)日：2021-07-15

申请号：US17215723

申请日：2021-03-29

Applicant: Silicon Laboratories Inc.

Inventor： Jeffrey L. Sonntag ,  Timothy J. Dupuis ,  Jiwen Xiao

IPC: G01R31/387 ,  G01R31/3832

Abstract: A calibration current load is selectively coupled to an output of a pulse frequency modulated (PFM) DC-DC converter during a calibration operation to increase charge supplied from a battery supplying an input voltage to the converter. A voltage across a sense resistor in series with the battery is integrated during a measurement interval while the calibration current load is coupled to the output. A charge drawn per pulse from the battery is determined based on the sense resistor, the integrated voltage and the number of pulses during the measurement interval. Alternatively, a first PFM frequency is determined with a first calibration current load coupled to the converter output. A second PFM frequency is determined with a second calibration current load. The charge drawn per pulse from the battery is determined based on the first and second PFM frequencies and the first and second calibration current loads.