Patent ID: 7710076

Claim:
A back-gate voltage generator circuit generating a back-gate voltage of a four-terminal back gate switching MOSFET for charge and discharge control, the back-gate voltage generator circuit comprising: first and second n-type MOSFETs connected in series through a common source electrode, wherein a voltage at the common source electrode of the first and second n-type MOSFETS connected in series serves as the back-gate voltage of the four-terminal back gate switching MOSFET, and the back-gate voltage is used as a reference voltage for generating signals for controlling the first and second n-type MOSFETS, and a first inverter to which a control signal generated from one of detection signals of overcharge, overdischarge, discharge overcurrent, and charge overcurrent of a secondary battery is input, and a second inverter to which an output of the first inverter is input, wherein the output of the first inverter is input to a gate of the first n-type MOSFET, an output of the second inverter is input to a gate of the second n-type MOSFET, and the back-gate voltage is used as a ground-side reference potential of each of the first inverter and the second inverter.