Patent ID: 8072200
Filing Date: 2011-12-06
Classification: G01R,H02M,Y10S

Abstract:
1. A current sensing circuit with AC and DC temperature compensation for sensing current through an output inductor of a voltage regulator, the output inductor comprising an inherent DC resistor having a resistance as a function of temperature, the current sensing circuit comprising: a first RC circuit comprising a first resistor and a first capacitor coupled in series across the output inductor, said first RC circuit having a first time constant; a first amplifier circuit having an input coupled across said first capacitor and an output providing a sense signal; a second RC circuit receiving said sense signal, wherein said second RC circuit comprises a second resistor and a second capacitor coupled in parallel between a first correction node and a reference node, wherein said second resistor has a resistance as a function of temperature so that said second RC circuit has a second time constant which is approximately equal to a time constant of the output inductor as a function of temperature; a third RC circuit having a third resistor and a third capacitor coupled in parallel between a second correction node and said reference node, wherein a resistance of said third resistor times a capacitance of said third capacitor is approximately equal to a resistance of said first resistor times a capacitance of said first capacitor; and a second amplifier circuit having first and second inputs coupled to said first and second correction nodes, respectively, and an output providing a corrected sense signal.