| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication terminal that reduces the size of a module and achieves cost reduction.SOLUTION: A range indicated by 43 can be used as an oscillation circuit for a transmission carrier wave. In other words, the range operates as an input impedance matching circuit and an RF-DC conversion circuit regarding a DC/DC booster circuit 38 at a subsequent stage as a load when switches 37, 41, 42 are off and a switch 36 is on. On the other hand, when the switch 37 is on and the switches 41, 42, 36 are off, if capacity 40 is sufficiently charged, it operates as an oscillation circuit for a transmission carrier wave because a node 44 can be regarded as a power source. In addition, a control circuit 45 can change the value of variable capacity. When a radio wave from a master unit is received, the value of variable capacity is sequentially changed, and DC voltage output is detected. Setting by which the DC voltage output is the highest is stored in the control circuit 45. The setting value is renewed every time when reception and power reception are executed. |
