A power amplifying circuit includes: a first amplifier that includes a field effect transistor as an amplifying element, amplifies a first radio frequency signal, and outputs a second radio frequency signal; a second amplifier that includes a bipolar transistor as an amplifying element, amplifies the second radio frequency signal, and outputs a third radio frequency signal; a control part that outputs a control signal, the control signal controlling a first power supply voltage to be supplied to the first amplifier; and a regulator that outputs the first power supply voltage to the first amplifier, the first power supply voltage being a voltage that depends on the control signal. A second power supply voltage to be supplied to the second amplifier is an envelope tracking voltage.

System and apparatus for measuring biopotential and implementation thereof. A device for mitigating electromagnetic interference (EMI) thereby increasing signal-to-noise ratio is disclosed. Specifically, the present disclosure relates to an elegant, novel circuit for measuring a plurality of biopotentials in useful in a variety of medical applications. This allows for robust, portable, low-power, higher S/N devices which have historically required a much bigger footprint.

System and apparatus for measuring biopotential and implementation thereof. A device for mitigating electromagnetic interference (EMI) thereby increasing signal-to-noise ratio is disclosed. Specifically, the present disclosure relates to an elegant, novel circuit for measuring a plurality of biopotentials in useful in a variety of medical applications. This allows for robust, portable, low-power, higher S/N devices which have historically required a much bigger footprint.

A current leakage mitigation circuit is provided. The circuit includes a charge storage circuit for receiving a control signal output, and a correction circuit connected to a bottom plate of the charge storage device. The control signal is output by an amplifier circuit connected to the current leakage mitigation circuit. The correction circuit samples the control signal, applies a filter to the control signal for to extracting a predefined frequency component, amplifies the filtered control signal, and applies the amplified control signal to the bottom plate of the current storage device.