Magnetic DC-to-DC converter

Abstract

Magnetic direct current to direct current converter with the input isolated from the output. A pulse generator from the feedback is incorporated in the feedback circuitry to regulate the output relative to the input.

I claim: 
     
       1. A direct current to direct current converter comprising, in combination: a power transformer with a primary winding and a secondary winding, said primary winding having a first connection means for receiving a direct current supply source and a second connection means for connection to a first ground reference, and said secondary winding being connected to a second ground reference;   a primary control circuit including a switching means connected to said primary winding for controlling the duty cycle of power delivered to said primary winding from said source, and a comparator means for receiving and comparing a reference signal and a feedback signal and generating an error signal relative to a comparison and in turn generating responsive control signals to said switching means; and   a feedback network including a first inductive means connected to sense . .a.!. .Iadd.an .Iaddend.electrical load connected to said secondary winding, a feedback inductor .Iadd.for generating a feedback signal and .Iaddend.magnetically coupled to said first inductive means, said first inductive means connected in series with a first unidirectional conductive valve and a second unidirectional conductive valve, said first and second unidirectional conductive valves being connected to opposing ends of said secondary winding, said feedback inductor connected in series with a third unidirectional conductive valve, a sampling switch connected to said third unidirectional conductive . .gate.!. .Iadd.valve .Iaddend.and to said comparator means to control current flow intermediate said third unidirectional conductive . .gate.!. .Iadd.valve .Iaddend.and said comparator means, said sampling switch including a control gate for controlling conduction through said sampling switch, and gate control means connected to said gate and to the primary control circuit to control said sampling switch responsive to the status of said error signal .Iadd.for sampling said feedback signal during a steady state portion of said feedback signal.Iaddend..   
     
     
       2. The converter of claim 1 wherein, said first inductive means and said feedback inductor are windings on a common core in transformer relationship, the turns ratio of said first inductive means and feedback inductor being one. 
     
     
       3. The converter of claim . .1.!. .Iadd.4 .Iaddend.wherein, said first and second unidirectional conductive valves are diodes of which the . .matching.!. electrical characteristics are .Iadd.substantially .Iaddend.equal. 
     
     
       4. A direct current to direct current converter comprising, in combination: a power transformer with a primary winding and a secondary winding, said primary winding having a first connection means for receiving a direct current supply source and a second connection means for connection to a first ground reference, and said secondary winding being connected to a second ground reference;   a primary control circuit including a switching means connected to said primary winding for controlling the duty cycle of power delivered to said primary winding from said source, and a comparator means for receiving a reference signal and a feedback signal and generating an error signal relative to the comparison and in turn generating responsive control signals to said switching means; and   a feedback network to sense an electrical load connected to said secondary winding, the feedback network including a first inductive means and a feedback inductor magnetically coupled to said first inductive means, said first inductive means .Iadd.being .Iaddend.connected in series with a first unidirectional conductive valve . .and a second unidirectional conductive valve, said first and second unidirectional valves being connected to opposing ends of said secondary winding.!., said feedback inductor connected in series with a . .third.!. .Iadd.second .Iaddend.unidirectional conductive valve, a sampling switch connected to said . .third.!. .Iadd.second .Iaddend.unidirectional conductive . .gate.!. .Iadd.valve .Iaddend.and to said comparator means to control current flow intermediate said . .third.!. .Iadd.second .Iaddend.unidirectional conductive . .gate.!. .Iadd.valve .Iaddend.and said comparator means, said sampling switch including a control gate for controlling conduction through said sampling switch, . .gate.!. .Iadd.inductive .Iaddend.control means . .connected to said gate and to the primary control circuit to control said sampling switch responsive to the status of said error signal.!., and a second inductive means magnetically coupled to said first inductive means and to said feedback inductor, said second inductive means and feedback inductor being connected to said first ground reference, and said second inductive means being connected to said . .gate.!. .Iadd.inductive .Iaddend.control means.   
     
     
       5. The converter of claim 4 wherein, said first inductive means, second inductive means and feedback inductor are all wound on a common core; said first .Iadd.inductive means .Iaddend.and said feedback .Iadd.inductor having .Iaddend.winding.Iadd.s which .Iaddend.are wound with the same polarity and opposite to that of said . .feedback inductor.!. .Iadd.second inductive means.Iaddend..   
     
     
       6. The converter of claim 5 wherein, said . .gate.!. .Iadd.inductive .Iaddend.control means is a trigger pulse generator.   
     
     
       7. The converter of claim 5 wherein, said first inductive means, second inductive means and feedback inductor are wound on a gapped core . .with said second inductive means being placed within said gap.!..   
     
     
       8. The converter of claim 7 wherein, the turns ratio of said first inductive means, second inductive means and feedback inductor is one. . . 
     
     
       9.  The converter of claim 8 wherein, the polarity of said first inductive means and feedback inductor are the same and opposite respectively to the polarity of said second inductive means..!.   
     
     
       10. A direct current to direct current converter comprising, in combination: a power transformer with a primary winding and a secondary winding, said primary winding having a first connection means for receiving a direct current supply source and a second connection means for connection to a first ground reference, and said secondary winding being connected to a second ground reference;   a switching means connected to said primary winding for controlling the duty cycle of power delivered to said primary winding from said source;   a first unidirectional control valve connected to a first end of said secondary winding and in series with a first inductive means for connection to an electrical load;   a second unidirectional control valve connected to a second end of said secondary winding and in series with said first inductive means;   a feedback signal generating means for generating a feedback signal representative of output voltage of the converter and including a second inductive means .Iadd.for generating a feedback signal .Iaddend.magnetically coupled to said first inductive means, said second inductive means being connected between said first ground reference and a third unidirectional control valve, and a voltage storage means connected between said . .third.!. .Iadd.second .Iaddend.inductive means and said first ground reference whereby a feedback potential may be generated across said voltage storage means;   a differential amplifier means connected to said voltage storage means and to receive a select reference voltage for comparing a select reference voltage to a . .signal.!. .Iadd.feedback .Iaddend.potential representative of said feedback . .potential.!. .Iadd.signal.Iaddend.;   a sampling driver means connected to receive a signal representative of the output of the differential amplifier means and for generating a delayed pulse signal representative of the output of the differential amplifier means with said pulse signal delayed a select time period dependent on a waveform of said feedback potential .Iadd.to sample said feedback signal during a steady state period of said feedback signal.Iaddend.; and   a sampling switch means connected to the sampling driver means, the differential . .driver.!. .Iadd.amplifier .Iaddend.means and to said third unidirectional control valve, whereby said feedback . .signal.!. .Iadd.potential .Iaddend.representative of said feedback . .potential.!. .Iadd.signal .Iaddend.is controlled responsive to said delayed pulse signal.   
     
     
       11. The converter of claim 10 wherein, said first inductive means and said second inductive means are windings on a common core in transformer relationship, the turns ratio of said first and second inductive means being one. . .12. The converter of claim 11 wherein,   the first unidirectional control valve and said second unidirectional control valve are diodes of which the matching electrical characteristics   
     
     
        are equal..!.13. The converter of claim . .12.!. .Iadd.11 .Iaddend.wherein, the . .polarity.!. .Iadd.polarities .Iaddend.of said first and second   
     
     
        inductive means are . .the.!. opposite relative to each other. 14. The converter of claim 13 wherein, the sampling switch means is in the form of a three terminal electronic switch having a gate connected to the sampling driver means for receiving   
     
     
        said delayed pulse signal. 15. In an electronic transformer circuit wherein a primary winding of the circuit is connected to a first ground reference and a secondary winding is connected to a second ground reference and including a primary control circuit for controlling conduction of the primary winding, the improvement comprising: a feedback network to sense an electrical load connected to said secondary winding, the feedback network including a first inductor connected in series with a first unidirectional conductive valve and a second unidirectional conductive valve, said first and second unidirectional conductive valves being connected to opposing ends of said secondary winding, a feedback inductor connected to said first ground reference and magnetically coupled to said first inductor and connected in series with a third unidirectional conductive valve, a sampling switch having one terminal connected with said third unidirectional conductive valve, said sampling switch including a gate for controlling conduction through said sampling switch of signals through said . .second.!. .Iadd.third .Iaddend.unidirectional conductive valve and means connecting said sampling switch with said primary winding; and gate control means connected to said gate and to said primary control circuit to control conduction of said sampling switch as a function of the conduction of said primary winding.Iadd., for sampling said feedback signal during a steady   
     
     
        state period of said feedback signal.Iaddend.. 16. An electronic transformer circuit of claim 15 wherein, said first inductor and said feedback inductor are windings on a common core in transformer relationship, the turns ratio of said first inductor   
     
     
        and said feedback inductor being one. 17. An electronic transformer circuit of claim . .16.!. .Iadd.18 .Iaddend.wherein, said first and second unidirectional conductive valves are diodes of which the . .matching.!. electrical . .characters.!. .Iadd.characteristics   
     
     
        .Iaddend.are .Iadd.substantially .Iaddend.equal. 18. In an electronic transformer circuit wherein a primary winding of the circuit is connected to a first ground reference and a secondary winding is connected to a second ground reference and including a primary control circuit for controlling conduction of the primary winding, the improvement comprising: a feedback network to sense an electrical load connected to said secondary winding, the feedback network including a first inductor connected in series with a first unidirectional conductive valve . .and a second unidirectional conductive valve, said first and second unidirectional conductive valves being diodes connected to opposing ends of said secondary winding and of which the matching electrical characteristics are equal.!., a feedback inductor .Iadd.for generating a feedback signal .Iaddend.connected to said first ground reference and magnetically coupled to said first inductor and connected in series with a . .third.!. .Iadd.second .Iaddend.unidirectional conductive valve, said first inductor and said feedback inductor are windings on a common core in transformer relationship . .with the turns ratio of said first inductor and said feedback inductor being one.!., a sampling switch having one terminal connected with said . .third.!. .Iadd.second .Iaddend.unidirectional conductive valve, said sampling switch including a gate for controlling conduction through said sampling switch of signals through said . .third.!. .Iadd.second .Iaddend.unidirectional conductive valve and means connecting said sampling switch with said primary winding, . .gate.!. .Iadd.inductive .Iaddend.control means . .connected to said gate and to said primary control circuit to control conduction of said sampling switch.!. .Iadd.to control the generation of said feedback signal .Iaddend.as a function of the conduction of said . .primary winding.!. .Iadd.first inductor.Iaddend., a second inductor magnetically coupled to said first inductor and to said feedback inductor, said second and feedback inductors being connected to said first ground reference and said second inductor being connected to said . .gate.!. .Iadd.inductive   
     
     
        .Iaddend.control means. .Iadd.19. A power supply having an input including a return terminal such as a ground, a direct current output having a return terminal such as a ground, the return terminals being isolated from each other, and a feedback regulating circuit coupled between the output and input for regulating the transfer of power between the input and output while preserving said isolation, the feedback regulating circuit comprising: (1) a control circuit for controlling the transfer of power; and   (2) a regulating circuit including: (a) a monitoring circuit responsive to said power supply output and having a clamping characteristic;   (b) a feedback circuit inductively coupled to said monitoring circuit for supplying a signal indicative of the output condition to said control circuit; and   (c) a trigger circuit for initiating a magnetic transient in the coupling between said monitoring circuit and said feedback circuit;     whereby a correcting signal is applied to the control circuit.   
     
     
        .Iaddend..Iadd.20.  The power supply of claim 19 including a power transformer connected between said input and output and wherein said control circuit comprises a pulse width modulator for controlling conduction in the primary of said transformer. .Iaddend..Iadd.21. The power supply of claim 19 or claim 20 wherein said monitoring circuit receives a signal which is a function of said power supply output. .Iaddend..Iadd.22. The power supply of claim 19 or claim 20 including a source of reference signal and wherein said correcting signal is combined with said reference signal to form an error signal for controlling said control circuit. .Iaddend..Iadd.23. The power supply of claim 19 or claim 20 wherein said trigger circuit supplies a pulse to an inductor for initiating said magnetic transient. .Iaddend..Iadd.24. A power supply as defined in claim 19 or claim 20 wherein said feedback circuit includes an inductance magnetically coupled to said monitoring circuit. .Iaddend..Iadd.25. A power supply as defined in claim 19 or claim 20 wherein said monitoring circuit includes an inductance clamped by a signal which is a function of said power supply output. .Iaddend..Iadd.26. The power supply of claim 19 or claim 20 wherein said monitoring circuit and said feedback circuit each include at least one diode, the diode characteristics being substantially equal. .Iaddend..Iadd.27. The power supply of claim 19 or claim 20 wherein said monitoring circuit and said feedback circuit each include inductive and diode characteristics, the 
     
     
        diode characteristics being substantially equal. .Iaddend..Iadd.28.  A method of converting a DC signal to a DC signal in a power supply, comprising the steps of: (A) supplying direct current to a power supply having (1) an input including a return terminal such as a ground, (2) a direct current output including a return terminal such as a ground, said return terminals being isolated from each other, (3) a control circuit having an input coupled to said power supply output, and (4) a power controller connected between the output of said control circuit and said power supply input;   (B) regulating the transfer of power between said input power supply and output while preserving said isolation, by applying a clamped correcting signal derived from said output to said control circuit; and   (C) initiating a magnetic transient in the control circuit to produce a regulating action in said power controller which is responsive to said clamped correcting signal. .Iaddend..Iadd.29. The method of claim 28 including a power transformer connected between said input and output and wherein said power controller comprises a pulse width modulator for controlling conduction in the primary of said transformer. .Iaddend..Iadd.30. The method of claim 28 or claim 29 wherein said clamped correcting signal which is a function of said power supply output. .Iaddend..Iadd.31. The method of claim 28 or claim 29 including a source of reference signal and wherein said clamped correcting signal is combined with said reference signal to form an error signal for controlling said   
     
     
        power controller. .Iaddend..Iadd.32.  The method of claim 28 or claim 29 wherein said magnetic transient is initiated by a trigger circuit in said control circuit supplying a pulse to an inductor. .Iaddend..Iadd.33. The method of claim 28 or claim 29 wherein said control circuit includes an inductance magnetically coupled to a monitoring circuit. .Iaddend..Iadd.34. The method of claim 33 wherein said monitoring circuit includes an inductance clamped by a signal which is a function of said 
     
     
        power supply output. .Iaddend..Iadd.35.  The method of claim 34 wherein said monitoring circuit and said control circuit each include at least one diode, the diode characteristics being substantially equal. .Iaddend..Iadd.36. The method of claim 34 wherein said monitoring circuit and said control circuit each include inductive and diode characteristics, the diode characteristics being substantially equal. .Iaddend.