US 4,378,585 A · Free-running blocking oscillator-type converter

Abstract

A free-running blocking oscillator-type converter for producing a controlled output signal. The converter is provided with a primary winding of a transformer, a switching transistor, and a resistor which are connected in series with one another between first and second input terminals of the converter. The transformer is further provided with a feedback winding which is coupled to the base terminal of the switching transistor. In some embodiments, optoelectronic coupling devices are used in a sensor arrangement for providing a control signal responsive to variations in the magnitude of the output signal of the converter. In other embodiments, such variations in the output signal of the converter are sensed by a transformer winding. Circuitry is disclosed for applying the sensor control signal selectably to the base and emitter terminals of the switching transistor.

Claims7

Dependent claims

A free-running blocking oscillator-type converter of the type having a switching transistor in series with a primary winding of a transformer, the transformer having a secondary winding connected in series with a rectifier, and with a smoothing filter between first and second output terminals of the converter, the transformer further having a feedback winding which is coupled to a base terminal of the switching transistor, the converter further comprising:

first resistor means, diode means, and capacitor means, connected in series with one another between the first and second input terminals of the converter, said first resistor means and said diode means being coupled to one another at a first node, said first node being further connected to the base terminal of the switching transistor, said diode means and said capacitor means being coupled to one another at a second node;
sensor means for detecting variations in a voltage across the first and second output terminals, said sensor means being coupled to said second node;
and
second resistor means for coupling the switching transistor to said second input terminal of the converter.

1 more element

capacitor means, resistor means, and control transistor means connected in an electrically parallel combination, the parallel combination being electrically disposed between the switching transistor and the second input terminal of the converter;
and
sensor means for detecting variations in an output voltage of the converter, said sensor means being connected to a base terminal of said control transistor means for controlling a charge stored in said capacitor means.

Dependencies are inferred from the claim text.

Free-running blocking oscillator-type converter

Life of this patent

Free-running blocking oscillator-type converter

Life of this patent

Abstract

Claims7