Converter/inverter full bridge ballast circuit

• US 6,281,638 B1
• Filed: 01/28/2000
• Issued: 08/28/2001
• Est. Priority Date: 10/10/1997
• Status: Expired due to Fees

• Current Assignee: Chicago Miniature Optoelectronic Technologies, Inc.
• Original Assignee: Electro-Mag International, Inc.
• Inventors: Moisin, Mihail S.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): TRAN, THUY V
• Application Number:
  US09/493,543
• Time in Patent Office: 578 Days
• Field of Search: 315/244, 315/209.R, 315/224, 315/209.T, 315/209.CD, 315/276, 315/283, 315/291, 315/307, 315/297, 363/65, 363/68, 363/69
• US Class Current: 315/244
• CPC Class Codes: H02M 1/425 using a single converter stage both for correction of AC input power factor and generation of a high frequency AC output voltage
• CPC Class Codes: H02M 7/538 in a push-pull configuration H02M7/5375 takes precedence ; with oscillating arrangements H02M7/53832, H02M7/53846
• CPC Class Codes: H02M 7/5383 in a self-oscillating arrangement H02M7/538 takes precedence
• CPC Class Codes: H02M 7/53832 in a push-pull arrangement
• CPC Class Codes: H05B 41/28 using static converters
• CPC Class Codes: H05B 41/2856 against internal abnormal circuit conditions
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A circuit for driving a load. In one embodiment, the load is driven by an inverter circuit having a full bridge circuit divided by inductive elements to provide cross conduction protection. In another embodiment, first and second converter circuits are coupled to the inverter circuit with the inverter and converter circuits having common circuit elements. In a further embodiment, a common mode inducter is inductively coupled to a power circuit for detecting a common mode signal generated by a load current return path disruption. The common mode inductor is coupled to a control circuit for limiting current to the load.

Claims

1. A circuit for driving a load, comprising:

a first converter circuit for coupling to a power circuit including a first switching element and a first converter inductive element, wherein the first switching element forms a portion of the power circuit; and

a second converter circuit for coupling to the power circuit including a second switching element and a second converter inductive element, wherein the second switching element forms a portion of the power circuit.

2. The circuit of claim 1, wherein the first and second converter circuits charge a common charge storage element.

3. The circuit of claim 1, wherein the first converter circuit includes the first converter inductive element, a first current switch, a first capacitive element, and the first switching element.

4. The circuit of claim 1, wherein the power circuit is a resonant inverter circuit.

5. The circuit according to claim 1, wherein the first switching element is controlled by a switch inductor element inductively coupled to the first converter inductor.

6. A circuit for driving a load, comprising:

a first converter circuit for coupling to a power circuit including a first switching element and a first converter inductive element, the first switching element forming a portion of the power circuit,

a second converter circuit for coupling to the power circuit including a second switching element and a second converter inductive element, the second element forming a portion of the power circuit,

wherein the first converter circuit includes the first converter inductive element, a first current switch, a first capactive element, and the first switching element, and the second converter circuit includes the second converter inductive element, a second current switch, the first capactive element, and the second switching element.

7. A ballast circuit for driving a lamp, comprising:

a pair of terminals for coupling the ballast circuit to a source of ac voltage,

a resonant full bridge circuit having a first portion formed from a first switching element and a first diode and a second portion formed from a second switching element and a second diode with first and second inductive elements dividing the bridge into the first and second portions, wherein the load is coupled between the first and second inductive elements;

a capacitive element coupling the first and second portions of the bridge circuit;

a first converter circuit including a first converter inductor, wherein the first switching element forms a portion of the first converter circuit; and

a second converter circuit including a second converter inductor, wherein the second switching element forms a portion of the second converter circuit.

8. The circuit according to claim 7, wherein the first and second switching elements are controlled by the first and second converter inductors and/or the first and second inductive elements.