Circuits and methods for determining peak current

摘要

Embodiments include circuits and methods to determine peak current for current regulation. A control signal circuit monitors a current on the primary side of a transformer based a turn on time of a switch coupled to the primary side. The control signal circuit determines whether the monitored current exceeds an over-current protection threshold, and determines a duration that the monitored current exceeds the over-current protection threshold. The control signal circuit determines a peak primary current in the primary side based on the over-current protection threshold, the duration that the monitored current exceeds the over-current protection threshold, and the turn on time of the switch. The control signal circuit controls the turn on time for the switch based on the determined peak primary current.

主权项

1. A method comprising: monitoring a current on a primary side of a transformer based on an on time of a switch coupled to the primary side; determining a first threshold, a duration that the monitored current exceeds the first threshold, and the on time of the switch; and determining a peak primary current in the primary side by multiplying a second threshold, the second threshold being an over-current protection threshold corresponding to the first threshold, and a first ratio, the first ratio being the on time of the switch divided by the on time of the switch minus said duration.