Patent ID: 9490662
Filing Date: 2016-11-08
CPC Classification: A61M,H02J,H03K

Claim Text:
1. A power source switching circuit for selectively connecting a first power source and a second power source where at least one of the first and second power sources is a battery power source to a load by switching the first power source and the second power source, the power source switching circuit comprising: a first power source connection part configured to enable the connection of the first power source thereto; a second power source connection part configured to enable the connection of the second power source thereto; a load connection part configured to enable the connection of the load thereto; a first switch part provided between the first power source connection part and the load connection part; a second switch part provided between the second power source connection part and the load connection part; and a switching control part configured to perform a switch control of the first switch part and the second switch part, wherein each one of the first switch part and the second switch part includes a plurality of field effect transistors which are serially connected in the same direction such that a cathode side of a body diode of each field effect transistor is arranged on a load connection part side, and are subjected to the switch control performed by the switching control part, and the number of plurality of field effect transistors is the number determined such that a sum of forward drop voltages of the plurality of serially connected body diodes exceeds the difference between a full charge voltage and a discharge voltage of the battery power source.