Circuit arrangement for a dc to dc converter

Claim 2

A circuit arrangement for a dc to dc converter comprising: a switching transistor including a base, a collector and an emitter, and operable into a state of saturation; a transformer including a primary winding and a secondary winding, said primary winding connected in series with said collector and an operating voltage; rectifier means connected to said secondary winding for providing at least one stabilized dc voltage; and a load dependent control element connected to said switching transistor for controlling actuation and blocking said switching transistor, said control element including voltage comparison means for constantly comparing the collector-emitter voltage of said switching transistor with a reference value and blocking base current from said switching transistor in response to an actual voltage greater than the reference voltage just as said switching transistor comes out of saturation.

Claim 3

A circuit arrangement according to claim 1, comprising: a capacitance connected to said primary winding to form an oscillator circuit, said voltage comparison means operable to actuate said switching transistor in response to an oscillating circuit voltage of or less than the reference voltage.

Claim 4

A circuit arrangement according to claim 1, comprising means for switching said switching transistor on and off during a zero transition of its collector-emitter voltage.

Claim 5

A circuit arrangement according to claim 1, comprising a voltage divider connected to said voltage comparison means to establish the reference potential.

Claim 6

A circuit arrangement according to claim 1, comprising: an auxiliary winding on said transformer close-coupled to said primary winding and connected to said voltage comparison means for tapping the collector-emitter voltage of said switching transistor.

Claim 7

A circuit arrangement according to claim 5, comprising: a voltage divider connecting said auxiliary winding to the operating voltage of said switching transistor.

Claim 8

A circuit arrangement according to claim 6, wherein said load-dependent control element comprises: a regulator device connected to said auxiliary winding; and a switching device connected between said voltage comparison means and said base of said switching transistor.

Claim 9

A circuit arrangement for a dc to dc converter comprising: a switching transistor including a base, a collector and an emitter; a transformer including a primary winding and a secondary winding, said primary winding connected in series with said collector and an operating voltage; rectifier means connected to said secondary winding for providing at least one stabilized dc voltage; a load dependent control element connected to said switching transistor for controlling actuation and blocking of said switching transistor, said control element including voltage comparison means for comparing the collector-emitter voltage of said switching transistor with a reference value and blocking base current from said switching transistor in response to an actual voltage greater than the reference voltage; an auxiliary winding on said transformer close-coupled to said primary winding and connected to said voltage comparison means for tapping the collector-emitter voltage of said switching transistor; a voltage divider connecting said auxiliary winding to the operating voltage of said switching transistor; and means for blocking said switching transistor by connecting the base to zero potential, including a switching device connected between said voltage comparison device and said base.

Claim 10

A circuit arrangement for a dc to dc converter comprising: a switching transistor including a base, a collector and an emitter; a transformer including a primary winding and a secondary winding, said primary winding connected in series with said collector and an operating voltage; rectifier means connected to said secondary winding for providing at least one stabilized dc voltage; a load dependent control element connected to said switching transistor for controlling actuation and blocking of said switching transistor, said control element including voltage comparison means for comparing the collector-emitter voltage of said switching transistor with a reference value and blocking base current from said switching transistor in response to an actual voltage greater than the reference voltage; an auxiliary winding on said transformer close-coupled to said primary winding and connected to said voltage comparison means for tapping the collector-emitter voltage of said switching transistor; a voltage divider connecting said auxiliary winding to the operating voltage of said switching transistor; and means for blocking said switching transistor by connecting the base to zero potential, including a switching device connected between said voltage comparison device and said base.

Claim 11

A circuit arrangement according to claim 8, comprising: a feedback circuit connected to said auxiliary winding; and timing means effective to couple said feedback circuit to said base for a predetermined interval in response to application of the operating voltage.

Claim 12

A circuit arrangement according to claim 9, wherein said feedback circuit includes a differentiator element.

Claim 13

A circuit arrangement according to claim 9, wherein said feedback circuit is coupled to said base by way of said voltage comparison means.