Protection circuit and method

A method of protecting driven circuitry against voltage peaks in a radio frequency signal, “VRF”, past a predetermined voltage level “Vdetect”, the method comprising:

• receiving the radio frequency signal at an input;
• producing, by a linear chain of N differential amplification stages coupled to the input, an amplified signal based on Vdetect−VRF, wherein N is greater than 2;
• outputting, by an Nth differential amplification stage of the linear chain of N differential amplification stages, the amplified signal at an output;
• determining, from the amplified signal, whether a peak voltage Vpeak of the radio frequency signal exceeds Vdetect;
• and
• latching:
• a first detection value if Vpeak exceeds Vdetect;
• and
• a second detection value if Vpeak does not exceed Vdetect.

A protection circuit for protecting driven circuitry against voltage peaks in a radio frequency signal, “VRF”, past a predetermined voltage level “Vdetect”, the protection circuit comprising:

• an input for receiving the radio frequency signal;
• a linear chain of N differential amplification stages comprising:
• a first differential amplification stage coupled to the input;
• an Nth differential amplification stage having an output operable to output an amplified signal based on Vdetect−VRF;
• and
• at least one intermediate differential amplification stage coupled between the first amplification stage and the Nth differential amplification stage in the linear chain;
• and
• a hold circuit coupled to the output of the Nth differential amplification stage to determine, from the amplified signal, whether a peak voltage Vpeak of the radio frequency signal exceeds Vdetect and to produce a latched value from said determination for:
• enabling/disabling an output stage of the protection circuit or attenuating the radio frequency signal according to the latched value.