AC and DC temperature compensation scheme for DCR current sense

摘要

A current sensing circuit with AC and DC temperature compensation for sensing current through an output inductor which has an inherent DC resistor with a temperature varying resistance. A first RC circuit is coupled across the output inductor and has a time constant. The first amplifier provides a sense signal indicative of voltage of the first RC circuit. The second RC circuit is coupled to a first correction node and receives the sense signal. The second resistor has a temperature varying resistance so that the second RC circuit has a time constant commensurate with a time constant of the output inductor. The third RC circuit is coupled to a second correction node and has a time constant equal commensurate with the first RC circuit. The second amplifier provides a corrected sense signal based on the correction nodes.