Voltage-regulated power supply unit

• US 3,886,438 A
• Filed: 09/24/1973
• Issued: 05/27/1975
• Est. Priority Date: 09/26/1972
• Status: Expired due to Term

• Current Assignee: Antonius Fredericus Mattias Bouman
• Original Assignee: Antonius Fredericus Mattias Bouman
• Inventors: Bouman, Antonius Fredericus Mattias
• Primary Examiner(s): Pellinen, A. D.
• Application Number:
  US05/399,857
• Time in Patent Office: 610 Days
• Field of Search: 307/43,44,69 321/18 323/22T,23,25
• US Class Current: 323/275
• CPC Class Codes: G05F 1/563 including two stages of regulation at least one of which is output level responsive, e.g. coarse and fine regulation

Abstract

Voltage-regulated power supply unit provided with first and second d.c. voltage sources of different voltage levels and first and second regulators. The first regulator delivers a stabilised output voltage. In general, the input voltage of the first regulator is derived from the first source. However, if the output voltage of the first source drops below the working voltage of the first regulator, an additional supply of energy is provided by the second source via the second regulator. A smoothing filter having a certain ripple factor, is inserted in the first source, thus increasing the efficiency of the supply unit.

Claims

1. Voltage-regulated power supply unit a first and second voltage source producing a fluctuating d.c. voltage, a first and second regulator connected to the first and second voltage sources, respectively, a feedback circuit connected to the output of said first regulator, which feedback circuit comprises a first comparator providing a control voltage related to the difference between the output voltage of said first regulator and a first fixed reference voltage for regulating the output voltage, means including a power transistor whereby the second regulator establishes a connection between the second voltage source and the first regulator during the time when the second regulator is registering a voltage generated by the first voltage source, which voltage is below the sum value of the required minimum operating voltage of the first regulator and said output voltage, for the purpose of maintaining a d.c. voltage which is at least equal to said sum value and to be supplied to the first regulator, and a differential amplifier which supplies a control voltage to said power transistor which is derived from the difference voltage between the voltage applied to the input of the first regulator and a second fixed reference voltage.

2. Voltage-regulated power supply unit as claimed in claim 1 including means for maintaining the level of the instantaneous terminal voltage supplied by the second voltage source higher than that of the voltage generated by the first voltage source, said first voltage source including a rectifier and a filter dimensioned so that the variation in the efficiency of the supply unit is approximately inversely proportional to the dimensions of said filter with respect to the ripple factor.

3. Voltage-regulated power supply unit as claimed in claim 1, wherein said second reference voltage is derived direct from the output voltage of said supply unit.

4. Voltage-regulated power supply unit as claimed in claim 1, wherein the second regulator comprises a control amplifier, by means of which the control voltage derived from the differential amplifier is transformed to a control voltage for the power transistor of the second regulator.

5. A voltage regulated power supply comprising, a first DC voltage source that produces a fluctuating DC voltage with a given ripple factor, a second DC voltage source of a higher voltage than said first source, a first voltage regulator with its input connected to the output of the first voltage source and its output connected to a feedback circuit comprising a first comparator which compares the first regulator output voltage with a first fixed reference voltage to provide a first control voltage that adjusts the impedance of the first regulator to regulate the output voltage, a second voltage regulator with its input connected to the output of the second voltage source and including a second comparator for comparing the input voltage to the first regulator with a second reference voltage to provide a second control voltage which establishes a connection between the output of the second voltage source and the input of the first regulator via an amplifier element of the second regulator only at a time when the second comparator receives a voltage below a given voltage level required by the first regulator for proper operation thereof.

6. A power supply as claimed in claim 5 wherein the circuit parameters of the first voltage source are chosen so that the ripple factor of the fluctuating DC voltage produced by the first voltage source is approximately 14 percent.

7. A power supply as claimed in claim 5 wherein said second reference voltage is derived from the output voltage of the first voltage regulator and is applied to the second comparator via an integrating circuit.

8. A power supply as claimed in claim 5 wherein the first reference voltage is derived directly from the output of the second voltage source.

9. A power supply as claimed in claim 5 wherein the DC voltage supply for the second comparator is derived exclusively from the output of the second voltage source.

10. A power supply as claimed in claim 5 wherein the second voltage regulator includes a control amplifier supplied with first and second DC operating voltages derived from said first and second voltage sources, respectively, and means for coupling the second control voltage derived by the second comparator to a control input of said control amplifier.