Group delay determination in a communication circuit

A communication circuit comprising:

• a power amplifier circuit configured to amplify a radio frequency (RF) signal associated with a time-variant input power based on a modulated voltage and induce a modulated current that tracks the time-variant input power of the RF signal;
• and
• a power amplifier integrated circuit (PMIC) comprising:
• a voltage modulation circuit configured to generate the modulated voltage based on a modulated target voltage;
• and
• a group delay determination circuit comprising:
• a group delay detection circuit configured to:
• receive a rectangular current signal related to the modulated current, wherein the rectangular current signal comprises a plurality of current rising edges and a plurality of current falling edges;
• receive a rectangular voltage signal related to the modulated voltage, wherein the rectangular voltage signal comprises a plurality of voltage rising edges and a plurality of voltage falling edges;
• determine a rising edge group delay between a respective one of the plurality of current rising edges and a respective one of the plurality of voltage rising edges;
• and
• determine a falling edge group delay between a respective one of the plurality of current falling edges and a respective one of the plurality of voltage falling edges;
• and
• a group delay output circuit configured to determine a relative group delay between the modulated current and the modulated voltage based on the determined rising edge group delay and the determined falling edge group delay.

A method for determining a group delay in a communication circuit, the method comprising:

• receiving a rectangular current signal related to a modulated current, wherein the rectangular current signal comprises a plurality of current rising edges and a plurality of current falling edges;
• receiving a rectangular voltage signal related to a modulated voltage, wherein the rectangular voltage signal comprises a plurality of voltage rising edges and a plurality of voltage falling edges;
• determining a rising edge group delay between a respective one of the plurality of current rising edges and a respective one of the plurality of voltage rising edges;
• determining a falling edge group delay between a respective one of the plurality of current falling edges and a respective one of the plurality of voltage falling edges;
• and
• determining a relative group delay between the modulated current and the modulated voltage based on the determined rising edge group delay and the determined falling edge group delay.