| 摘要 |
PURPOSE:To accurately detect the input voltage from a commercial power source in the transient period when the power source is turned on and properly control the heating output in response to it by providing an input voltage detecting means constituted of a resistor voltage dividing circuit and a smoothing capacitor. CONSTITUTION:An input voltage detecting means 10 is constituted of a rectifying circuit rectifying the commercial power, a resistance voltage dividing circuit voltage-dividing its output, a smoothing capacitor connected in parallel with the divided voltage output section of the resistor voltage dividing circuit via a forward-polarity diode, and a discharge resistor connected in parallel with the smoothing capacitor. When the power source is turned on, the smoothing capacitor is charged via the resistor of the resistor voltage dividing circuit and the diode in the means 10, and the effect of the smoothing capacitor is not given to the resistor voltage dividing circuit side by the diode. Even when the resistor of the resistor voltage dividing circuit having a small resistance value and the smoothing capacitor having a small capacity are used, no trouble occurs on the input voltage detection. The input voltage can be accurately detected, and the ripple of the output from the means 10 can be reduced. |
