| 摘要 |
PURPOSE:To obtain constant current and constant voltage characteristics in a small current and low voltage area by providing a changing means for an off time fixing value and changing the off time fixing value as an on time reference set value is made smaller. CONSTITUTION:The output terminal of a comparing amplifier 10 is connected to the base of a transistor 12, and the collector current thereof is controlled by the potential thereof. A series circuit of a diode 13 and a capacitor 14 is connected between the collector and earth of the TR12 to for a charging line P; at the same time, a discharging line Q which is a changing means for an off time fixing value is formed via a timer IC17. An IC of the characteristics that it is set when the potential of the input terminal A attains 1/3VC and is reset when it attains 2/3VC is used for the IC17. Further, an output setting volume 11 and an off time setting volume control 16 are interlocked, so that when the range of the reference on time is set small with the control 11 the resistance value of the control 16 rises to increase the off time range automatically. |
