Patent ID: 7944152

Claim:
A two-stage balancer for a multi-lamp backlight electrically connected to a driving unit through a driving transformer, and the two-stage balancer comprising: a first balancing transformer group having a plurality of first balancing transformers; wherein each of the first balancing transformers has a primary winding and a secondary winding, and the secondary windings are coupled in series in a closed loop; a second balancing transformer group having a plurality of second balancing transformers, and each of the second balancing transformers having a primary winding and has a secondary winding; wherein a second terminal of the primary winding of each second balancing transformer is electrically connected to a first terminal of the secondary winding of each second balancing transformer to form a common node, and the common node is electrically connected to a second terminal of the primary winding of the corresponding first balancing transformer; a lighting unit group having a plurality of lighting units; wherein a first terminal of the primary winding of each second balancing transformer is electrically connected to a first terminal of the lighting unit, and a second terminal of the secondary winding of each second balancing transformer is electrically connected to a first terminal of each lighting unit so that each of the second balancing transformer is electrically connected to two lighting units; wherein a first terminal of the primary winding of each first balancing transformer is electrically connected to a first terminal of a secondary winding of the driving transformer, and a second terminal of the lighting unit is electrically connected to a second terminal of the secondary winding of the driving transformer; whereby each of the second balancing transformers is electrically connected in series to one corresponding first balancing transformers and two corresponding lighting units to form a plurality of circuit loops, and each of the circuit loops is electrically connected in parallel.