Voltage regulated power supply providing a constant output voltage

• US 5,254,878 A
• Filed: 12/31/1991
• Issued: 10/19/1993
• Est. Priority Date: 12/31/1991
• Status: Expired due to Fees

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Olsen, Lawrence H.
• Primary Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US07/815,673
• Time in Patent Office: 658 Days
• Field of Search: 307/4, 307/5, 307/75, 307/77, 323/266, 323/268, 323/349, 323/351, 363/43
• US Class Current: 307/75
• CPC Class Codes: G05F 1/59 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: G05F 1/648 being plural resistors among which a selection is made
• CPC Class Codes: H02J 1/00 Circuit arrangements for dc mains or dc distribution networks
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit

Abstract

A voltage regulator is provided for producing a predetermined output voltage level. The voltage regulator has a voltage source for providing a plurality of successively increasing voltage levels at a corresponding plurality of output terminals, or taps. A controller is provided for automatically selecting, in response to an electrical control signal, the one of the taps providing a voltage level above the predetermined output voltage level. In a preferred embodiment of the invention, the selected tap is the one of the plurality of taps producing a voltage level closest to, and greater than, the predetermined output voltage level. With such an arrangement, the electronic control signal allows a convenient way to select an output voltage level closest to, and greater in magnitude than, the predetermined voltage level, thereby improving the efficiency of the regulator.

Claims

1. A regulated power supply comprising:

a) a voltage source having a plurality of outputs, each output having a successive increasing voltage level;

b) means, responsive to a control voltage signal, for selecting one of the plurality of outputs of the voltage source, the selecting means comprising;

(i) a plurality of switches, each switch coupled to a corresponding one of the outputs of the voltage source; and

(ii) comparator means, responsive to the control voltage signal and each one of the outputs of the voltage source, for selecting one of the outputs of the voltage source, the selected one of the outputs of the voltage source having a voltage level greater than the control voltage signal, the comparator means comprising;

a first and a second transistor, each transistor having a base, an emitter and a collector, the emitter of the first transistor connected to a first one of the outputs of the voltage source, the emitter of the second transistor connected to the second successive output from the first one of the outputs of the voltage source;

a first resistor disposed between the base of the second transistor and the second successive voltage source output and a second resistor disposed between the base of the second transistor and the collector of the first transistor;

a third resistor having a first terminal and a second terminal, the first terminal connected to the base of the first transistor; and

a diode disposed between the second terminal of the third resistor and the control voltage signal; and

c) smoothing regulator means, responsive to the control voltage signal and the selected one of the outputs of the voltage source, for providing a predetermined voltage level signal.

2. The regulated power supply as recited in claim 1 wherein each switch comprises:

(a) a transistor having a gate, a source and a drain, the drain connected to a corresponding one of the outputs of the voltage source;

(b) a first resistor having a first terminal and a second terminal, the first terminal connected to the gate of the transistor, a second resistor connected between the source of the transistor and the second terminal of the first resistor and a third resistor connected between the second terminal of the first resistor and the comparator means.

3. The regulated power supply as recited in claim 1 wherein the smoothing regulating means comprises:

(a) a transistor having a gate, a source and a drain, the drain connected to the selected one of the outputs of the voltage source and the source providing the predetermined voltage signal;

(b) a first resistor connected between the gate of the transistor and the control voltage signal and a second resistor connected between the control voltage signal and the source;

(c) a zener diode connected between the control voltage signal and the source; and

(d) a capacitor connected between the control voltage signal and a ground potential.

4. A power supply comprising:

means, in response to a control signal, for coupling a selected one of a plurality of successively increasing voltage level sources to an output, such coupling means comprising;

a) a plurality of comparators, each comparator having a pair of inputs and an output, a first one of the pair of inputs coupled to the control signal, a second one of the pair inputs coupled to a corresponding, different one of the plurality of successively increasing voltage level sources, each comparator comprising;

(i) a first and a second transistor, each transistor having a base, an emitter and a collector, the emitter of the first transistor connected to a first one of the successively increasing voltage level sources, the emitter of the second transistor connected to a second successive one of the successively increasing voltage level sources from the first one of the successively increasing voltage level sources of the voltage source;

(ii) a first resistor disposed between the base of the second transistor and the second successive one of the successively increasing voltage level sources and a second resistor disposed between the base of the second transistor and the collector of the first transistor;

(iii) a third resistor having a first terminal and a second terminal, the first terminal connected to the base of the first transistor; and

(iv) a diode disposed between the second terminal of the third resistor and the control voltage signal;

b) a plurality of switches, each switch having an input, an output and a control port, the input coupled to that next successive one of the plurality of successively increasing voltage level sources having a voltage level less than a voltage level of the second one of the inputs of the one of the plurality of comparators corresponding thereto, the control port coupled to the output of a corresponding comparator, each one of the plurality of switches selectively coupling, or decoupling, the input thereof to the output thereof in accordance with the output of the corresponding one of the plurality of comparators; and

smoothing regulator means, responsive to the control signal and the selected one of the plurality of successively increasing voltage level sources, for providing a predetermined voltage level signal.

5. The power supply as recited in claim 4 wherein each one of the plurality of switches comprises:

(a) a transistor having a gate, a source and a drain, the drain connected to a corresponding one of the successively increasing voltage level sources;

(b) a first resistor having a first terminal and a second terminal, the first terminal connected to the gate of the transistor, a second resistor connected between the source of the transistor and the second terminal of the first resistor and a third resistor connected between the second terminal of the first resistor and the output of the corresponding one of the plurality of comparators.

6. The power supply as recited in claim 4 wherein the smoothing regulator means comprises:

(a) a transistor having a gate, a source and a drain, the drain connected to the selected one of the plurality of successively increasing voltage level sources and the source providing the predetermined voltage signal;

(b) a first resistor connected between the gate of the transistor and the control signal and a second resistor connected between the control signal and the source;

(c) a zener diode connected between the control signal and the source; and

(d) a capacitor connected between the control signal and a ground potential.

7. A power supply comprising:

a) a voltage source having a plurality of different voltage level outputs;

b) a plurality of switches, each switch having an input, an output and a control port, the input of each switch coupled to a corresponding one of the different voltage level outputs of the voltage source;

c) a plurality of comparators, each comparator having a first and second input and an output, the first input coupled to a control voltage signal, the second input coupled to a corresponding one of the different voltage level outputs of the voltage source and the output of each comparator coupled to the control port of a corresponding switch, each comparator comprising;

(i) a first and a second transistor, each transistor having a base, an emitter and a collector, the emitter of the first transistor connected to a first one of the different voltage level outputs of the voltage source, the emitter of the second transistor connected to a second successive one of the different voltage level outputs from the first one of the different voltage level outputs of the voltage source;

(ii) a first resistor disposed between the base of the second transistor and the second successive one of the different voltage level outputs and a second resistor disposed between the base of the second transistor and the collector of the first transistor;

(iii) a third resistor having a first terminal and a second terminal, the first terminal connected to the base of the first transistor; and

(iv) a diode disposed between the second terminal of the third resistor and the control voltage signal; and

d) a smoothing regulator having an input, an output and a control port, the input coupled to the outputs of the switches and the control port coupled to the control voltage signal.

8. The power supply as recited in claim 7 wherein the smoothing regulator comprises:

(a) a transistor having a gate, a source and a drain, the drain connected to the selected one of the different voltage level outputs of the voltage source and the source providing a predetermined voltage signal;

(b) a first resistor connected between the gate of the transistor and the control voltage signal and a second resistor connected between the control voltage signal and the source;

(c) a zener diode connected between the control voltage signal and the source; and

(d) a capacitor connected between the control voltage signal and a ground potential.