Integrated circuit, wireless communication unit and method for providing a power supply

A wireless communication unit comprising a radio frequency (RF) power amplifier (PA) and a power supply for providing a power supply to the RF PA, the wireless communication unit comprising:

• a low-frequency power supply path comprising a switching regulator;
• and
• a high-frequency power supply path arranged to regulate an output voltage of a combined power supply at an output port of the integrated circuit for coupling to a load wherein the combined power supply is provided by the low-frequency power supply path and high-frequency power supply path;
• wherein the high-frequency power supply path comprises:
• an amplifier comprising a voltage feedback and arranged to drive a power supply signal on the high-frequency power supply path;
• and
• a capacitor operably coupled to the output of the amplifier and arranged to perform dc voltage level shifting of the power supply signal.

A method for providing a power supply to a radio frequency (RF) power amplifier (PA), the method comprising:

• providing a low-frequency power supply to a RF PA using a switching regulator;
• providing a high-frequency power supply to the RF PA via a high-frequency power supply path;
• driving a power supply for the RF PA from an amplifier that uses voltage-feedback on the high-frequency power supply path;
• and
• performing dc voltage level shifting of the power supply signal on the high-frequency power supply path.

An integrated circuit for providing a power supply to a radio frequency power amplifier, the integrated circuit comprising:

• a low-frequency power supply path;
• and
• a high-frequency power supply path arranged to regulate an output voltage of a combined power supply at an output node wherein the combined power supply is provided by the low-frequency power supply path and high-frequency power supply path;
• wherein the high-frequency power supply path comprises:
• an amplifier comprising a first input for receiving a voltage feedback and a second input for receiving a modulated envelope input signal and arranged to drive a power supply signal on the high-frequency power supply path;
• and
• a capacitor operably coupled to the output of the amplifier and arranged to perform dc voltage level shifting of the power supply signal,
• wherein when the amplifier operates in an envelope tracking mode, the low-frequency power supply path is controlled based on the output of the amplifier and a reference signal.