Patent ID: 7868599
Filing Date: 2011-01-11
Classification: G01R,H02M

Abstract:
1. A current sensing circuit comprising: a power switch coupled to receive a current from a switching input, the power switch being controlled by a gate signal, wherein a turn on of the power switch causes the current to have an initial transient spike; a buffer having a buffer input and a buffer output, the buffer input being coupled to receive the gate signal and provide a buffered gate signal at the buffer output; a sense switch coupled to receive a portion of the current from the switching input, the sense switch being turned on by the buffered gate signal after the initial transient spike, wherein the buffer is configured to not turn on the sense switch on when the gate signal is less than an input high threshold (Vih) voltage, the Vih being configured to be greater than a Miller plateau voltage of the power switch to avoid the initial transient spike; and a sense resistor coupled to receive the portion of the current from the sense switch.