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 an amount of current in a primary side of a transformer based on a voltage that corresponds to the amount of current; monitoring an on-time of a switch coupled to the primary side of the transformer and configured to cause the amount of current in the primary side to increase during the on-time of the switch; determining a duration of time that the monitored amount of current exceeds a predefined threshold; and determining a peak amount of current in the primary side of the transformer by multiplying the predefined threshold and a ratio comprising the on-time of the switch divided by a difference of the on-time of the switch minus the duration of time that the monitored current exceeds the predefined threshold.