| 摘要 |
PURPOSE: A voltage-to-frequency converting circuit is provided to widen a control range by providing an offset to an output of a digital-to-analog converter. CONSTITUTION: An R-2R ladder circuit(111) receives digital output signals(A0-A7) of a microcomputer and outputs a multi-step voltage based on the respective digital signals. An offset power input part(113) adds a power supply voltage to an output voltage of the R-2R ladder circuit(111). An operational amplifier circuit(112) amplifies and outputs an output voltage of the R-2R ladder circuit(111) to which an offset voltage is applied through the offset power input part(113). A timer(20) varies a multi-step frequency input through a control pin based on an output of the operational amplifier circuit.
|
