Control integrated circuit for a power transistor of a switching current regulator

摘要

An integrated circuit controls a switch of a switching current regulator. The current regulator includes primary and secondary windings where a first and a second current flow, respectively. The switch is adapted to initiate or interrupt the circulation of the first current in the primary winding. The control integrated circuit includes a comparator configured to compare a first signal representative of the first current to a second signal and a divider circuit configured to generate the second signal as a ratio of a third signal, proportional to a voltage on the primary winding, with a voltage on a capacitor. The capacitor is charged by a further current controlled by the third signal when the second current is different from zero. The capacitor is discharged through a parallel-connected resistor when the value of said second current is substantially zero.

主权项

1. A control circuit for controlling a first switch of a switching current regulator, said control circuit comprising:
a comparator configured to compare a first signal, representative of a first current through a primary winding of the switching current regulator, with a second signal; a charge/discharge circuit configured to selectively charge and discharge a capacitor; and a divider circuit configured to generate said second signal as a ratio of a third signal, proportional to a the input voltage of the switching current regulator, to a voltage on the capacitor.