Linear-in-dB log-amp with calibration for power detection

An apparatus comprising:

• a log amplifier circuit configured to generate an output signal in response to an offset between a first voltage and a second voltage;
• and
• a calibration circuit configured to (i) disconnect an input power and (ii) perform a cancellation of said offset when said input power is not present,
• wherein
• (a) said first voltage is generated by said apparatus in response to a power detection,
• (b) said second voltage is received from a reference circuit,
• (c) said cancellation of said offset extends a working range of said apparatus,
• (d) said output signal provides a linear-in-dB power detection,
• (e) said calibration circuit comprises a comparison circuit configured to determine a difference between said first voltage and said second voltage when said input power is not present,
• (f) said difference is used to control one or more programmable current sources, and
• (g) said cancellation is performed by adjusting said programmable current sources in response to said difference.