Patent ID: 9065331
Filing Date: 2015-06-23
Classification: H02M,H05B,Y02B

Abstract:
1. An inductor current detection circuit configured in a switching mode power supply under discontinuous conduction mode, the inductor current detection circuit comprising: a) a voltage detection circuit coupled to a secondary winding of a transformer of said switching mode power supply and configured to generate a sampling voltage based on a drain-source voltage of a power switch in said switching mode power supply; b) a voltage holding circuit configured to receive said sampling voltage, and to generate a holding voltage through a sampling and holding operation; and c) a comparison circuit coupled to an input and an output of said voltage holding circuit and configured to compare said sampling voltage against said holding voltage, and to generate a zero-crossing signal when said sampling voltage is less than said holding voltage, wherein said zero-crossing signal is configured to represent an inductor current ending time of said switching mode power supply.