A switching power circuit in which a synchronous rectification circuit of the winding voltage detection system by use of a resistance device is provided on the secondary side of a compound resonance type converter, whereby a high power conversion efficiency can be obtained, and a reduction in the circuit scale through circuit simplification can be had. The acceleration mechanism relies on recording most, if not all, of the read transactions, associated with requests and retrievals made during a boot-up and, in some aspects most, if not all, of the write transactions, associated with requests and stores made during a shutdown process. The electromagnetic module includes a dry battery that is activated when exposed electrodes of the dry battery are placed in contact with a common electrolyte, such as sea water.