US4837452A — Off-line dc power supply

Claim 1

Independent Claim 171 words

A method for controlling an off-line dc power supply circuit including a power transformer which separates said power supply circuit into a primary side and a secondary side, and a printed circuit board supporting components of said power supply circuit, said method comprising the steps of: (a) generating a source of unregulated dc input power; (b) selectively connecting said unregulated dc input power to a primary winding of the power transformer which also has at least one secondary winding; (c) comparing an output dc voltage generated at a secondary winding of said power transformer to a reference voltage to generate an error signal representative of the difference error therebetween; (d) coupling said error signal from the secondary side of said power supply circuit to the primary side of said power supply circuit through the printed circuit board via a capacitor formed from traces on opposite sides of said printed circuit board; and (e) controlling step (b) in the primary side of said power supply circuit in response to said error signal.

Claim 2

Independent Claim 171 words

A method for controlling an off-line dc power supply circuit including a power transformer which separates said power supply circuit into a primary side and a secondary side, and a printed circuit board supporting components of said power supply circuit, said method comprising the steps of: (a) generating a source of unregulated dc input power; (b) selectively connecting said unregulated dc input power to a primary winding of the power transformer which also has at least one secondary winding; (c) comparing an output dc voltage generated at a secondary winding of said power transformer to a reference voltage to generate an error signal representative of the difference error therebetween; (d) coupling said error signal from the secondary side of said power supply circuit to the primary side of said power supply circuit through the printed circuit board via a capacitor formed from traces on opposite sides of said printed circuit board; and (e) controlling step (b) in the primary side of said power supply circuit in response to said error signal.

Claim 3

Dependent Claim 59 words

A method for controlling an off-line dc power supply circuit as claimed in claim 1 wherein step (d) of coupling said error signal from the secondary side of said power supply circuit to the primary side of said power supply circuit comprises converting said error signal to a variable frequency signal, the frequency of which represents said difference error.

Claim 4

Dependent Claim 49 words

A method for controlling an off-line dc power supply circuit as claimed in claim 2 further comprising step (f) of monitoring the input power for said dc power supply circuit to prevent operation of said power supply circuit unless said input power is at a minimum operating voltage level.

Claim 5

Dependent Claim 58 words

A method for controlling an off-line dc power supply circuit as claimed in claim 3 wherein step (e) comprises step (g) of repetitively connecting said unregulated dc input power supply to said primary winding, and step (h) of disconnecting said input power supply before the next connection time with the disconnection times being determined by said error signal.

Claim 6

Dependent Claim 46 words

A method for controlling an off-line dc power supply circuit as claimed in claim 4 wherein step (g) is performed at transitions of a signal generated by an oscillator circuit, the operation of which is controlled by the results of the monitoring operation of step (f).

Claim 7

Dependent Claim 174 words

An off-line dc power supply circuit including a printed circuit board supporting components of said power supply circuit which comprises: a source of unregulated dc input power; a power transformer having at least one primary winding and at least one secondary winding separates said power supply circuit into a primary side and a secondary side; comparator means for comparing an output dc voltage generated at a secondary winding of said power transformer to a reference voltage to generate an error signal representative of the difference error therebetween; primary/secondary isolation means for coupling said error signal from the secondary side of said power supply circuit to the primary side of said power supply circuit and comprising a capacitor formed from traces on opposite sides of the printed circuit board; and power supply control means for selectively connecting said unregulated dc input power to a primary winding of said power transformer to regulate said power supply circuit in the primary side thereof in response to said error signal which is generated in the secondary side thereof.

Claim 8

Dependent Claim 174 words

An off-line dc power supply circuit including a printed circuit board supporting components of said power supply circuit which comprises: a source of unregulated dc input power; a power transformer having at least one primary winding and at least one secondary winding separates said power supply circuit into a primary side and a secondary side; comparator means for comparing an output dc voltage generated at a secondary winding of said power transformer to a reference voltage to generate an error signal representative of the difference error therebetween; primary/secondary isolation means for coupling said error signal from the secondary side of said power supply circuit to the primary side of said power supply circuit and comprising a capacitor formed from traces on opposite sides of the printed circuit board; and power supply control means for selectively connecting said unregulated dc input power to a primary winding of said power transformer to regulate said power supply circuit in the primary side thereof in response to said error signal which is generated in the secondary side thereof.

Claim 9

Dependent Claim 45 words

An off-line dc power supply circuit as claimed in claim 6 wherein the voltage level of said error signal is representative of said difference error and said primary/secondary isolation means further comprises a voltage to frequency converter circuit for generating a varying frequency output signal.

Claim 10

Dependent Claim 23 words

An off-line dc power supply circuit as claimed in claim 7 wherein said voltage to frequency converter circuit comprises a voltage controlled oscillator.

Claim 11

Dependent Claim 24 words

An off-line dc power supply circuit as claimed in claim 7 wherein said primary/secondary isolation means further comprises a one-shot circuit including said capacitor.

Claim 12

Dependent Claim 60 words

An off-line dc power supply circuit as claimed in claim 9 further comprising lockout means connected to said source of unregulated dc input power and to said power supply control means for monitoring the input power for said power supply circuit to prevent operation of said power supply circuit unless said input power is at a minimum operating voltage level.

Claim 13

Dependent Claim 43 words

An off-line dc power supply circuit as claimed in claim 10 wherein said power supply control means comprises switch means connected to said primary winding for selectively connecting said unregulated dc input power thereto and switch controller means for activating said switch means.

Claim 14

Dependent Claim 123 words

An off-line dc power supply circuit as claimed in claim 11 further comprising a filter circuit connected to said one-shot circuit for generating an output signal connected to the switch controller means and having a voltage level proportional to the frequency of the signal generated by said voltage to frequency converter and hence said difference error, and wherein said power supply control means comprises an oscillator circuit for generating a repetitive output signal which is connected to said switch controller means such that said switch means is activated at transitions of the output signal of said oscillator circuit and deactivated at a point in each cycle of the output signal of said oscillator circuit determined by the output signal of said filter circuit.

Claim 15

Dependent Claim 25 words

An off-line dc power supply circuit as claimed in claim 12 wherein said lockout means is connected to control the operation of said oscillator circuit.

Claim 16

Dependent Claim 20 words

An off-line dc power supply circuit as claimed in claim 13 wherein said switch means comprises a cascode power switch.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-06-05	1992-12-05	1993-06-06	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-06-05	1996-12-05	1997-06-06	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-06-05	2000-12-05	2001-06-06	$7700.00	Window Closed / Lapsed

Off-line dc power supply

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