Voltage and current sense circuits for measuring a load connected to a power amplifier

A current sense circuit for measuring a load connected to a power amplifier wherein the load is configured to receive a first voltage at a first end and a second voltage at a second end, wherein the first and the second voltages are in opposite phase, wherein the current sense circuit comprises:

• a first input terminal coupled to the first voltage;
• a second input terminal coupled to the second voltage;
• a third input terminal coupled to the third voltage;
• a fourth input terminal coupled to the fourth voltage;
• a first output terminal;
• a second output terminal;
• and
• a common mode loop circuit comprising a first input, a second input, a third input and an output wherein the first and the second inputs are configured to receive a common mode voltage at the first and second output terminals, the third input is configured to receive a reference voltage, and to generate a control signal at the output to switch the current sense circuit such that the common mode voltage equals the reference voltage;
• wherein the current sense circuit further comprising a first, second, third and fourth conversion resistors comprising a first end and a second end, the first end of the first, second, third and fourth conversion resistors are respectively coupled to the first, second, third and fourth input terminals.

A method of operating a voltage sense circuit for measuring a load connected to a power amplifier wherein the load is configured to receive a first voltage at a first end and a second voltage at a second end, wherein the first and the second voltages are in opposite phase, the method comprising the steps of:

• receiving, at an input of a first voltage divider circuit of the voltage sense circuit, the first voltage;
• receiving, at an input of a second voltage divider circuit of the voltage sense circuit, the second voltage;
• receiving, at a first input of a driver circuit of the voltage sense circuit, a reference voltage, and
• receiving, at a second input of the driver circuit, a common mode signal from the first and the second voltage divider circuits;
• and
• driving, by the driver circuit, an output common mode voltage of the first and the second voltage divider circuits with the reference voltage;
• wherein the driver circuit comprises a first resistor and a second resistor, a first end of the first resistor is connected to the first output terminal, a second end of the first resistor is connected to a first end of the second resistor, a second end of the second resistor is connected to the second output terminal, and the second input of the driver circuit is connected to the first end of the first resistor and the second end of the second resistor.