Abstract: A speed-up circuit 10 is connected to a detection line 6 for feeding back the high voltage detection value of a high voltage detection circuit 5 to a high voltage stabilizing circuit 1. When a power supply switch is turned on, since a PNP transistor 12 of the speed-up circuit 10 is turned on, a resistor 11 is connected to the detection line 6, so that the high voltage detection value is reduced forcedly. Accordingly, the high voltage stabilizing circuit 1 increases the peak value of a flyback pulse generated by a resonance-type power supply circuit 2 to output higher high voltage thereby to shorten the rising time of the high voltage output supplied to the anode of a CRT. After the lapse of the predetermined time from the turning-on of the power supply switch, since the terminal voltage of a capacitor 13 having been charged through a resistor 14 exceeds almost the voltage at a point A, the PNP transistor 12 is turned off, so that the resistor 11 is separeted from the detection line.

Abstract: A battery charger includes a transformer having a primary coil and a secondary coil, a switch for duty control of a current flowing through the primary coil of the transformer, a detector for detecting a value of a current flowing through the secondary coil of the transformer, and a secondary controller for receiving the detected value from the detector and for outputting a charge control signal. The pulse of the charge control signal is modulated in accordance with the detected value by the detector.

Abstract: A DC voltage converter comprising: a switching transistor for establishing a load current circuit which connects a DC power source to a load to supply a load current to the load; a differentiating circuit connected in series to the load current circuit for producing a voltage drop corresponding to a differentiated value of the load current; an integrating capacitor connected in parallel with the load via an output terminal for outputting as an output voltage to be supplied to the load a voltage corresponding to an integrated value of a current flowing through the capacitor; a control width setting circuit for setting a width defined by upper and lower limits for controlling the output voltage in accordance with the voltage drop derived from the differentiating circuit; a ripple detection circuit receiving the output voltage from the capacitor and for detecting a ripple caused by an "ON-OFF" operation of the switching transistor; an output-reference-level setting circuit for setting a reference voltage of the