METHOD AND APPARATUS FOR SENSING CURRENT IN POWER SUPPLIES

摘要

A circuit for detecting peak current pulses on a secondary transformer (T2) of a power supply and converting these peak current pulses into a direct current (DC) voltages, which can be used for various purposes such as current limiting or current sharing. A peak detection circuit (225) is coupled to the secondary transformer (T2) and is employed to detect a peak current pulse through the secondary transformer (T2). A sample and hold circuit (221) that is coupled to the peak detection circuit (225) samples the current through a current sense transformer (T1). The sample and hold circuit (221) provides the current pulse through the secondary transformer (T2) in a direct current voltage representation. The sample and hold circuit (221) includes a storage circuit (C3) for storing this direct current voltage representation of the current through the secondary transformer (T2). The sample and hold circuit (221) selectively samples the current through the current transformer (T1) in response to a control signal generated by the peak detection circuit (225).