Abstract: A mobile terminal with electronic compass is provided with a first housing that houses a geomagnetic sensor, a second housing connected to the first housing, with relative position thereto being variable, a state detection unit that detects a relative position state between the first housing and the second housing, an offset correction initial value storage unit that stores an offset correction initial value for each of a plurality of relative position states detected by the state detection unit, and an offset correction value determination unit that determines whether the offset correction value calculated by a calibration unit is valid or invalid.

Abstract: A synchronous rectification type converter includes a main transformer having a primary winding to which an unrectified input voltage is applied and a main switch connected in series with the primary winding of the main transformer. A series-coupled capacitor and clamp switch are connected across the primary winding of the main transformer, where the clamp switch is biased substantially opposite to the main switch such that the reset voltage at the primary winding of the main transformer is clamped. First and second series-coupled synchronous rectifiers which are operated in synchronism with the operation of the main switch are connected across a secondary winding of the main transformer.