Capacitance determination in a switched mode power supply

摘要

A method of determining a measure of a total capacitance of one or more capacitive elements connected to an output of a switched mode power supply is described. The method includes generating a voltage control signal to cause an output voltage controller to sweep a voltage at the output of the switched mode power supply from an initial voltage value to a final voltage value. Sample values of a current at the output measured by a current sampler during the sweep of the output voltage are received, and an integrated current value representing a measure of the total capacitance using the received sample values is calculated.

主权项

1. A method of determining a measure of a total capacitance of one or more capacitive elements connected to an output of a switched mode power supply, comprising:
generating a voltage control signal to cause an output voltage controller to sweep a voltage (Vout) at the output of the switched mode power supply from an initial voltage value to a final voltage value; generating a sampler control signal to control a current sampler to sample a current at the output only before or only after the output voltage has passed a threshold value (Vstart, Vstop) different from the initial and final values; receiving sample values of the current at the output measured by the current sampler during the sweep of the output voltage; and calculating an integrated current value representing a measure of the total capacitance using the received sample values, the threshold value being such as to reduce an error in the calculated integrated current value.