Adjustable Power Limiter with Integrated Power Detector

A self-activating power limiter having an adjustable limiting threshold and an integrated power detector, the self-activating power limiter including:

• (a) a self-activating limiter stack comprising one or more series-connected field-effect transistors (FETs) configured to be coupled between circuit ground and a signal line between a source and a receiver, each FET having a corresponding gate resistor configured to be coupled to a first control voltage to adjustably control the limiting threshold of the FETs, each FET having an ON resistance RON;
• and
• (b) a power detector circuit, coupled to the gate resistors of the FETs in the limiter stack and configured to be coupled to the signal line between the source and the receiver, for generating a second control voltage as a function of the signal power at a node on the signal line;
• wherein the first control voltage and the second control voltage are combined and applied to the gate resistors to set a power limiting level for the limiter stack and modulate the ON resistance RON of the FETs to reduce leakage power reaching the receiver.