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US 8,896,209 B2Granted
Programmed start circuit for ballast
AssigneeGeneral Electric Company
InventorsGang Yao, Bo Zhang, Ting Zhang
Life of this patent
Estimating the term…
Abstract
A programmed start ballast circuit is presented having a mode control circuit to selectively switch an inverter output load to control operation for cathode preheating, step dimming and/or anti-arcing operation.
Claims20
A programmed start ballast circuit for powering at least one light source, the ballast circuit comprising:
- a DC circuit operative to provide a DC output at first and second DC output terminals;
- an inverter circuit operatively coupled to the DC circuit to convert the DC output to produce an AC output to power at least one light source, the inverter comprising:
- a first capacitance and a second capacitance coupled in series between the first and second DC output terminals and joined with one another at a first intermediate node,
- a first switching device and a second switching device coupled in series between the first and second DC output terminals and joined with one another at a second intermediate node, and
- a first transformer with a first primary winding coupled between the second intermediate node and a third intermediate node;
- a second transformer with a second primary winding coupled between the first and third intermediate nodes;
- and
- a mode control circuit operative in a first mode to selectively couple the third intermediate node with one of the first and second DC output terminals to reduce a voltage potential across the second primary winding, and in a second mode to disconnect the third intermediate node from the second DC output terminal.
5 more elements
A programmed start ballast circuit, comprising:
- an inverter circuit having a resonant circuit and operative to produce an AC output to power at least one light source at a first output power level in a first mode or to power the at least one light source at a second lower output power level in a second mode, the inverter comprising:
- first and second DC input terminals,
- a first capacitance and a second capacitance coupled in series between the first and second DC input terminals and joined with one another at a first intermediate node,
- a first switching device and a second switching device coupled in series between the first and second DC input terminals and joined with one another at a second intermediate node, and
- a first transformer with a first primary winding coupled between the second intermediate node and a third intermediate node;
- a second transformer with a second primary winding coupled between the first and third intermediate nodes;
- a preheat circuit operative in the second mode to provide heat to at least one light source cathode;
- and
- a mode control circuit comprising a switching device operative according to a mode control input to set the inverter circuit in the first mode or the second mode using two equal potential nodes to change an impedance of the inverter resonant circuit, the mode control circuit operative in the first mode to cause the switching device to selectively couple the third intermediate node with one of the first and second DC input terminals to reduce a voltage potential across the second primary winding, and in the second mode to disconnect the third intermediate node from the one of the first and second DC input terminals.
6 more elements
Dependencies are inferred from the claim text.