| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an electronic circuit with three terminals capable of external communication without applying a voltage pulse significantly larger than a normal use range to a power source terminal.SOLUTION: When an adjusting apparatus 5 is connected, an operation mode is switched between a user mode and an adjustment mode under the condition that a mode changeover signal MCSG oscillating in a voltage range lower than VDD_U, VDD voltage used in the user mode, is supplied to a power source terminal TVDD of an electronic circuit with three terminals 1, and a signal indicating a prescribed mode changeover signal pattern is input into a signal terminal TSG. In the adjustment mode, an adjustment signal is input and output between a control circuit 25 and the adjusting apparatus 5 via a signal terminal DSG on the basis of an adjustment signal AJS superposed on the VDD voltage.</p> |
