| 摘要 |
A detection circuit, an RF circuit including the detection circuit, and a portable device including the detection circuit and the RF circuit are provided to reduce DC power consumption by a carrier detector for monitoring the signal level of a carrier signal received through an antenna in a communication RF circuit incorporated in a mobile device terminal utilizing communication for settlement with a non-contact reader/writer apparatus for non-contact electronic payment. An RF circuit(108) according to a preferred embodiment in connection with another aspect of the invention can be electrically connected to a processor(100,103) having a data processing function, and a microcomputer(106) having an encrypted electronic payment function. The RF circuit includes a detector for detecting a signal received from a non-contact reader/writer apparatus through an antenna(107). The detector monitors a signal level of the receive signal from the non-contact reader/writer apparatus, which has been received through the antenna. Also, the detector generates a detected signal in response to the signal level equal to or over a predetermined threshold, and supplies the detected signal to the processor. The processor generates a start signal in response to the detected signal, and supplies the start signal to the RF circuit. The RF circuit starts supplying an operation clock to the microcomputer in response to the start signal, whereby an encrypted electronic payment operation by the microcomputer is started. Payment transmit data resulting from the encrypted electronic payment operation is supplied to the RF circuit through electrical connection with the microcomputer. The RF circuit includes an RF transmit unit for sending the payment transmit data to the non-contact reader/writer apparatus through the antenna. |
