V+hu 2 +l Power Converter Control with Capacitor Current Ramp Compensation

摘要

Operation of a switching power converter having an output capacitor having a small equivalent series resistance (ESR) is stabilized and jitter reduced by sensing capacitor current with gain and combining the resulting signal with the output voltage signal to provide a feedback signal to control switching of the power converter. capacitor current can be sensed without interfering with operation of the filter capacitor by providing a branch circuit having a time constant matched to the output or filter capacitor but an arbitrarily high impedance so as to be effectively lossless. The gain provided in the capacitor current signal can be tuned to provide optimally short settling time after load transients; generally within one switching cycle. Matching of time constants and/or tuning of gain can be performed automatically.

主权项

1. A power converter comprising
an output or filter capacitor having an equivalent series resistance similar to that of a ceramic capacitor, a control circuit including a direct output voltage feedback path, a current sensor for measuring current in said output or filter capacitor to produce a voltage signal proportional to current in said output or filter capacitor, and an arrangement for combining said signal proportional to current in said output or filter capacitor with a signal in said direct output voltage feedback path.