An apparatus and methods for balancing current in multiple negative
impedance gas discharge lamp loads. Embodiments advantageously include
balancing transformer configurations that are relatively cost-effective,
reliable, efficient, and good performing. Embodiments include
configurations that are applicable to any number of gas discharge tubes,
such as cold cathode fluorescent lamps. The balancing transformer
configuration techniques permit a relatively small number of power
inverters, such as one power inverter, to power multiple lamps in
parallel. One embodiment of a balancing transformer includes a safety
winding which can be used to protect the balancing transformer in the
event of a lamp failure and can be used to provide an indication of a
failed lamp.