Power supply and electronic ballast with high efficiency voltage converter

• US 5,969,481 A
• Filed: 09/30/1997
• Issued: 10/19/1999
• Est. Priority Date: 09/30/1997
• Status: Expired due to Term

• Current Assignee: OSRAM Sylvania Inc. (Ams-Osram AG)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Konopka, John G.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Malos, Jennifer H.
• Application Number:
  US08/941,140
• Time in Patent Office: 749 Days
• Field of Search: 315/209 R, 315/246, 315/283, 315/205, 315/219
• US Class Current: 315/209.00R
• CPC Class Codes: H05B 41/28 using static converters

Abstract

An electronic power supply (10) comprising a rectifier circuit (100) and a voltage converter circuit (200). Voltage converter circuit (200) comprises a first inductor (220), a second inductor (230), an electronic switch (240), a control circuit (300), a first rectifier (250), a second rectifier (260), a first capacitor (270), and a second capacitor (280). First inductor (220) and second inductor (230) may be implemented either as separate inductors or as coupled inductors. Power supply (10) efficiently provides a high output voltage with greater efficiency than conventional boost converters.

Claims

1. A power supply, comprising:

a rectifier circuit having a pair of input connections adapted to receive a source of alternating current, and a pair of output connections; and

a voltage converter circuit, comprising;

first and second input terminals coupled to the output connections of the rectifier circuit;

first and second output terminals;

a first inductor coupled between the first input terminal and a first node;

an electronic switch coupled between the first node and a second node;

a control circuit coupled to the electronic switch and operable to turn the electronic switch on and off;

a second inductor coupled between the second node and the second input terminal, wherein the first inductor is magnetically coupled to the second inductor, and the first inductor and the second inductor are oriented in relation to each other such that the presence of a positive voltage across the first inductor from the first input terminal to the first node substantially coincides with the presence of a positive voltage across the second inductor from the second node to the second input terminal;

a first rectifier having an anode coupled to the first node and a cathode coupled to the first output terminal;

a second rectifier having a cathode coupled to the second node and an anode coupled to the second output terminal;

a first capacitor coupled between the first output terminal and a third node, wherein the third node is coupled to one of the input connections of the rectifier circuit; and

a second capacitor coupled between the third node and the second output terminal.

2. The power supply of claim 1, wherein the second inductor has an inductance that is approximately equal to that of the first inductor.

3. The power supply of claim 1, wherein the first inductor and the second inductor have an approximately equal number of turns.

4. The power supply of claim 1, wherein the first inductor and the second inductor share a common magnetic core.

5. The power supply of claim 1, wherein the electronic switch comprises a field-effect transistor having a drain lead coupled to the first node, a source lead coupled to the second node, and a gate lead coupled to the control circuit.

6. The power supply of claim 5, wherein the control circuit comprises a current-mode type controller.

7. The power supply of claim 1, wherein the rectifier circuit comprises a full-wave diode bridge coupled between the input connections and the output connections of the rectifier circuit.

8. The power supply of claim 7, wherein the rectifier circuit further comprises a high frequency bypass capacitor coupled between the input connections of the rectifier circuit.

9. The power supply of claim 1, further comprising an inverter coupled across the output terminals.

10. The power supply of claim 9, wherein the inverter is operable to power at least one gas discharge lamp.

11. A power supply, comprising:

a rectifier circuit, comprising;

a pair of input connections adapted to receive a source of alternating current;

a pair of output connections;

a full-wave diode bridge coupled between the input connections and the output connections; and

a high frequency bypass capacitor coupled between the input connections of the rectifier circuit; and

a voltage converter circuit, comprising;

first and second input terminals coupled to the output connections of the rectifier circuit;

first and second output terminals;

a first inductor coupled between the first input terminal and a first node;

an electronic switch coupled between the first node and a second node;

a control circuit coupled to the electronic switch and operable to turn the electronic switch on and off in a periodic manner;

a second inductor coupled between the second node and the second input terminal, wherein the second inductor has an inductance that is approximately equal to that of the first inductor, the first inductor is magnetically coupled to the second inductor, and the first inductor and the second inductor are oriented in relation to each other such that the presence of a positive voltage across the first inductor from the first input terminal to the first node substantially coincides with the presence of a positive voltage across the second inductor from the second node to the second input terminal;

a first diode having an anode coupled to the first node and a cathode coupled to the first output terminal;

a second diode having an anode coupled to the second output terminal and a cathode coupled to the second node;

a first capacitor coupled between the first output terminal and a third node, wherein the third node is coupled to one of the input connections of the rectifier circuit; and

a second capacitor coupled between the third node and the second output terminal.

12. The power supply of claim 11, wherein the first inductor and the second inductor have an approximately equal number of turns.

13. The power supply of claim 11, wherein the first inductor and the second inductor share a common magnetic core.

14. The power supply of claim 11, wherein the electronic switch comprises a field-effect transistor having a drain lead coupled to the first node, a source lead coupled to the second node, and a gate lead coupled to the control circuit.

15. The power supply of claim 14, wherein the control circuit comprises a current-mode type controller.

16. The power supply of claim 11, further comprising an inverter coupled across the output terminals.

17. The power supply of claim 16, wherein the inverter is operable to power at least one gas discharge lamp.

18. An electronic ballast, comprising:

a rectifier circuit, comprising;

a pair of input connections adapted to receive a source of alternating current;

a pair of output connections;

a full-wave diode bridge coupled between the input, connections and the output connections; and

a high frequency bypass capacitor coupled between the input connections of the rectifier circuit;

a voltage converter circuit, comprising;

first and second input terminals coupled to the output connections of the rectifier circuit;

first and second output terminals;

a first inductor coupled between the first input terminal and a first node; and

a field-effect transistor (FET) having a drain lead coupled to the first node, a source lead coupled to a second node, and a gate lead;

a control circuit coupled to the gate of the FET and operable to turn the FET on and off at a high frequency rate;

a second inductor coupled between the second input terminal and the second node, wherein the first inductor and the second inductor are oriented in relation to each other such that the presence of a positive voltage across the first inductor from the first input terminal to the first node substantially coincides with the presence of a positive voltage across the second inductor from the second node to the second input terminal;

a first diode having an anode coupled to the first node and a cathode coupled to the first output terminal;

a second diode having a cathode coupled to the second node and an anode coupled to the second output terminal;

a first capacitor coupled between the first output terminal and a third node, wherein the third node is coupled to one of the input connections of the rectifier circuit; and

a second capacitor coupled between the third node and the second output terminal; and

an inverter coupled across the output terminals of the voltage converter circuit and adapted to provide operating power to at least one gas discharge lamp.

19. The power supply of claim 18, wherein the first inductor and the second inductor have an approximately equal number of turns.

20. The power supply of claim 18, wherein the second inductor is magnetically coupled to the first inductor.

21. The power supply of claim 20, wherein the first inductor and the second inductor share a common magnetic core.