Power supply circuit with a self-oscillating blocking oscillator

Claim 2

A self-sustaining blocking oscillator power supply circuit, comprising: a primary circuit formed of a DC supply voltage connected to a switching transistor through a primary of a transformer; rectifying means connected to a secondary of the transformer for producing a DC output voltage; regulating circuit means connecting to a control input of the switching transistor for controlling the switching transistor as a function of a comparison voltage derived from the primary circuit; an integration means connected parallel to the DC supply voltage for producing a periodic, approximately sawtooth-shaped signal which substantially corresponds to a current flowing in the primary circuit at the primary of the transformer, the sawtooth-shaped signal driving the regulating circuit means for triggering of the switching transistor; and the integration means comprising an RC member connected to be discharged via a switch means for synchronous operation with the switching transistor.

Claim 3

A self-sustaining blocking oscillator power supply circuit, comprising: a primary circuit formed of a DC voltage connected to a switching transistor through a primary of a transformer; rectifying means connected to a secondary of the transformer for producing a DC output voltage; regulating circuit means connecting to a control input of the switching transistor for controlling the switching transistor as a function of a comparison voltage derived from the primary circuit; an integration means connected parallel to the DC supply voltage for producing a periodic, approximately sawtooth-shaped signal which substantially corresponds to a current flowing in the primary circuit at the primary of the transformer, the sawtooth-shaped signal driving the regulating circuit means for triggering of the switching transistor; and a control means coupled to the switching transistor for converting said periodic sawtooth-shaped signal into a proportional current, an output current of said control amplifier means driving the switching transistor during its on time.

Claim 4

A self-sustaining blocking oscillator power supply circuit, comprising: a primary circuit formed of a DC voltage connected to a switching transistor through a primary of a transformer; rectifying means connected to a secondary of the transformer for producing a DC output voltage; regulating circuit means connecting to a control input of the switching transistor for controlling the switching transistor as a function of a comparison voltage derived from the primary circuit; an integration means connected parallel to the DC supply voltage for producing a periodic, approximately sawtooth-shaped signal which substantially corresponds to a current flowing in the primary circuit at the primary of the transformer, the sawtooth-shaped signal driving the regulating circuit means for triggering of the switching transistor; and a control means coupled to the switching transistor for converting said periodic sawtooth-shaped signal into a proportional current, an output current of said control amplifier means driving the switching transistor during its on time.

Claim 5

A power supply circuit according to claim 2 wherein said control amplifier means drives the switching transistor during its on time is coupled via a coupling capacitor to the switching transistor, said coupling capacitor forming a portion of a discharge circuit means for keeping constant during a blocking phase of the switching transistor an average DC voltage at the coupling capacitor.

Claim 6

A self-sustaining blocking oscillator power supply circuit, comprising: a primary circuit formed of a DC supply voltage connected to a switching transistor through a primary of a transformer; rectifying means connected to a secondary of the transformer for producing a DC output voltage; regulating circuit means connecting to a control input of the switching transistor for controlling the switching transistor as a function of a comparison voltage derived from the primary circuit; an integration means connected parallel to the DC supply voltage for producing a periodic, approximately sawtooth-shaped signal which substantially corresponds to a current flowing in the primary circuit at the primary of the transformer, the sawtooth-shaped signal driving the regulating circuit means for triggering of the switching transistor; the transformer having a feedback winding for production of a feedback means signal proportional to a signal in the primary winding; and a limiter amplifier means driven by the feedback signal for the production of a signal with two predetermined levels which correspond in each case to zero passages of the feedback signal which go positive or negative.

Claim 7

A self-sustaining blocking oscillator power supply circuit, comprising: a primary circuit formed of a DC supply voltage connected to a switching transistor through a primary of a transformer; rectifying means connected to a secondary of the transformer for producing a DC output voltage; regulating circuit means connecting to a control input of the switching transistor for controlling the switching transistor as a function of a comparison voltage derived from the primary circuit; an integration means connected parallel to the DC supply voltage for producing a periodic, approximately sawtooth-shaped signal which substantially corresponds to a current flowing in the primary circuit at the primary of the transformer, the sawtooth-shaped signal driving the regulating circuit means for triggering of the switching transistor; the transformer having a feedback winding for production of a feedback means signal proportional to a signal in the primary winding; and a limiter amplifier means driven by the feedback signal for the production of a signal with two predetermined levels which correspond in each case to zero passages of the feedback signal which go positive or negative.