Bioimpedance measurement circuit, method and electronic device

A bioimpedance measurement circuit, comprising:

• a set of terminals comprising:
• a first terminal for connecting a first electrode to be attached to a body;
• a second terminal for connecting a second electrode to be attached to the body;
• a third terminal for connecting a third electrode to be attached to the body;
• and
• a fourth terminal for connecting a fourth electrode to be attached to the body;
• a control circuit to control application of a stimulus current with a measurement frequency through a first subset of two selected terminals of the set of terminals and measurement of an input voltage in response to the stimulus current at a second subset of two selected terminals of the set of terminals;
• an evaluation circuit for determining a measured impedance in response to the stimulus current and the measured input voltage;
• and
• a signal processing circuit for determining a body impedance;
• wherein the control circuit is configured to control measurement of:
• the body impedance, where the stimulus current is applied through the first and the second terminal, and the input voltage is measured between the third and the fourth terminal;
• a first bodypart impedance, where the stimulus current is applied through the first and the third terminal, and the input voltage is measured between the first and the third terminal;
• and
• a second bodypart impedance, where the stimulus current is applied through the second and the fourth terminal, and the input voltage is measured between the second and the fourth terminal;
• and
• wherein the signal processing circuit is configured to:
• determine an error impedance based on the measured first bodypart impedance, the measured second bodypart impedance, a stored first parasitic bodypart impedance, a stored second parasitic bodypart impedance, and a stored input impedance;
• and
• determine a corrected body impedance based on the measured body impedance and the error impedance.