Abstract: A transformer includes a bobbin. The bobbin includes a first cylindrical member, and a second cylindrical member having a larger diameter than the first cylindrical member. The first cylindrical member and the second cylindrical member are integrally formed in a concentric arrangement with a gap therebetween. A first winding, implemented by an air-core coil, is inserted into the gap between the first and second cylindrical members of the bobbin, and serves as an input winding which allows a large current in association with a low voltage to flow therethrough. A second winding is wound on the second cylindrical member of the bobbin, and serves as an output winding which allows a small current in association with a high voltage to flow therethrough.

Abstract: A self-oscillation type switching power supply comprises a transformer having a primary winding, a secondary winding, a feedback winding, and a control winding as necessary, a switching transistor interrupting a current in said primary winding, a control transistor controlling a positive feedback signal from said feedback winding to the switching transistor, and a time constant circuit charged by a starting voltage of said feedback winding or said control winding with a predetermined time constant and further applying a control voltage to said control transistor. The self-oscillation type switching power supply further comprises an impedance circuit which blocks a reverse bias from said feedback winding or said control winding to said control transistor, disposed between a control voltage input block to said control transistor and said time constant circuit.

Abstract: A self-oscillation switching power supply including a transformer having a primary winding, a secondary winding, and a feedback winding, and further including a control winding if necessary; a switching transistor for turning on and off the current of the primary winding; a control transistor for controlling a positive feedback signal from the feedback winding or control winding to the switching transistor; and a time constant circuit which is charged by a voltage generated across the feedback winding or control winding and which supplies a control voltage to the control transistor. The self-oscillation switching power supply further comprises an electronic switch which is opened and closed in response to the positive feedback signal from the control winding or feedback winding wherein an external voltage source is connected to the time constant circuit via said electronic switch so that the charging time of the time constant circuit is varied according to an output voltage detection signal.

Abstract: A self-oscillation type switching power supply includes a transformer having a primary winding, a secondary winding, a feedback winding, and a control winding as required, a switching transistor to turn on and off a current flowing in the primary winding, a controlling transistor to control a positive feedback signal from the feedback winding or the control winding to said switching transistor, and a time constant circuit to charge a generated voltage across the feedback winding or the control winding with a fixed time constant and to give a controlling voltage to said controlling transistor. A delay transistor to delay the turn-on of said switching transistor is contained in a controlling signal input portion to said switching transistor, and a delay circuit is provided to delay a positive feedback signal from the control winding or the feedback winding with a fixed time constant and to give the delayed signal as a controlling signal to said delay transistor.