d.c. To d.c. voltage regulator having an input protection circuit, a d.c. to d.c. inverter, a saturable reactor regulator, and main and auxiliary rectifying and filtering circuits

• US 4,462,069 A
• Filed: 08/14/1981
• Issued: 07/24/1984
• Est. Priority Date: 08/14/1981
• Status: Expired due to Term

• Current Assignee: Union Switch & Signal, Inc. (Hitachi, Ltd.)
• Original Assignee: American Standard Inc. (Trane Technologies plc)
• Inventors: Becky, Raymond
• Primary Examiner(s): Beha, Jr., William H.
• Application Number:
  US06/293,042
• Time in Patent Office: 1,075 Days
• Field of Search: 363/15, 363/16, 363/22, 363/23, 363/28, 363/40, 363/49, 363/50, 363/55, 363/56, 363/82, 363/91, 363/95, 363/133, 363/21, 323/253, 323/281, 361/55, 361/56, 361/91
• US Class Current: 363/23
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 3/3384 of the parallel type

Abstract

A multiple output d.c. to d.c. regulating circuit including an input protection circuit for providing protection against input overcurrent, input transient voltages, sustained input overvoltage and input polarity reversal. The protection circuit powers a d.c. to a.c. inverter which generates high frequency square-wave signals. The square-wave signals are fed to a magnetic saturable reactor regulator which has its controlled windings connected by a rectifying filtering network to a pair of main output terminals and connected by transformer rectifier filter circuits to a plurality of auxiliary output terminals. The d.c. output voltage across the main output terminals is sampled and is compared to a reference voltage of an integrated circuit operational amplifier. The output of the integrated circuit operational amplifier is connected to the control winding of the saturable reactor for controlling the controlled windings so that the square-wave signals are pulse width modulated to regulate the d.c. voltages developed across the pair of main output terminals and the plurality of auxiliary output terminals. A soft starting circuit prevents high in-rushing currents from damaging the d.c. to a.c. inverter. An overload protection circuit senses overloads on the input and main output terminals and causes removal of power from the regulating circuit.

Claims

1. A d.c. to d.c. voltage regulator comprising, a pair of input terminals connectable to a source of d.c. voltage, a protection circuit including transient suppressing means connected to said pair of input terminals, a d.c. to a.c. inverting circuit connected to the output of said protection circuit, said d.c. to a.c. inverting circuit producing a.c. signals which are transformer coupled to the input of a saturable reactor regulating circuit, said saturable reactor regulating circuit having its output coupled to a pair of main output terminals by a rectifying circuit and coupled to a plurality of auxiliary output terminals by a transformer rectifying circuit, and said saturable reactor regulating circuit having a sampling circuit coupled to said pair of main output terminals for sensing the output voltage and for controlling said saturable reactor regulating circuit whereby the output voltage across said pair of main output terminals as well as the output voltages across the plurality of auxiliary output terminals are maintained at a constant level, and an overvoltage protection circuit including a switching transistor and a two-input OR gate, said two-input OR gate includes a first zener diode and pair of resistors for sensing an overvoltage condition across said pair of input terminals and includes a second zener diode and pair of resistors for sensing an overvoltage condition across said pair of main output terminals and for rendering said switching transistor conductive to energize a circuit breaker which opens electrical contacts connected to said pair of input terminals for deenergizing the d.c. to d.c. voltage regulator when an overvoltage condition exists across said pair of input terminals or exists across said pair of output terminals.

2. The d.c. to d.c. voltage regulator as defined in claim 1, wherein said protection circuit includes an L-C network, a varistor and a suppressor for absorbing the energy of transient voltages and includes a reverse voltage protection diode for preventing damage due to reverse polarity connection of the source of d.c. voltage across said pair of said input terminals.

3. The d.c. to d.c. voltage regulator as defined in claim 1, wherein said d.c. to a.c. inverting circuit includes a saturable reactor transformer having a primary winding and a center-tapped secondary winding for driving a pair of push-pull oscillating transistors which produce square-wave output signals.

4. The d.c. to d.c. voltage regulator as defined in claim 1, wherein said d.c. to a.c. inverting circuit is connected to the output of said protection circuit by a four-terminal capacitor which supplies operating potential to said d.c. to a.c. inverting circuit.

5. The d.c. to d.c. voltage regulator as defined in claim 1, wherein said saturable reactor regulating circuit includes a pair of cores and controlled windings and a control winding.

6. The d.c. to a.c. voltage regulator as defined in claim 1, wherein said sampling circuit includes an integrated circuit operation amplifier which compares the output voltage developed across said pair of main output terminals with a reference voltage to control the current to said control windings.

7. The d.c. to d.c. voltage regulator as defined in claim 1, wherein a soft starting circuit is connected to said sampling circuit for controlling said sampling circuit upon start-up to prevent high in-rushing surges from damaging said d.c. to a.c. inverting circuit.

8. The d.c. to d.c. voltage regulator as defined in claim 6, wherein a voltage divider includes a plurality of resistors which may be shorted to provide a calibration of the output voltage developed across said pair of main output terminals with the reference voltage.