Noncontact transmission device

Abstract

A noncontact transmission deviceis provided with a driverfor driving a coil; a system clock oscillatorfor outputting a system clock; a monitoring clock oscillatorfor outputting a monitoring clock LFhaving a frequency lower than that of the system clock CK; and a control circuit. The control circuitoutputs a system clock oscillating control signal Sbased on the monitoring clock LFwhile being in a standby state and makes the system clock oscillatorintermittently output a system clock CKin synchronization with the control signal S. In a period when the system clock CKis being outputted, the coilis driven by a driver control signal SD and whether the deviceto which data is to be transmitted is arranged or not is detected.