Triple-loop fluorescent lamp driver

A driver circuit for providing electrical energy from a power source to a fluorescent lamp producing a light having a brightness, the circuit comprising:

• a transformer having a primary winding and a secondary winding, wherein each of the primary and secondary windings have a first and a second end and are configured to conduct an electrical current, wherein the primary winding comprises a center tap, and wherein the ends of the secondary winding are coupled to the fluorescent lamp;
• a current steering module configured to provide a drive output signal to the center tap of the transformer in response to a current steering input signal;
• and
• a lamp frequency control loop comprising:
• a filter circuit configured to receive and filter the drive output signal to produce a filtered drive signal;
• a flip-flop having a clock input, a signal input, an inverting output, and a non-inverting output, and wherein the inverting input is coupled to the signal input and the clock input is configured to receive the filtered drive signal;
• a first switch coupled to the inverting input, to a reference voltage, and to the first end of the primary winding;
• and
• a second switch coupled to the non-inverting input, to the reference voltage, and to the second end of the primary winding;
• wherein the lamp frequency control loop is configured to automatically toggle the first and second switches to switchably couple the first and second ends of the primary winding, respectively, to the reference voltage and to thereby adjust the electrical polarity of the electrical current in the primary winding of the transformer in response to a signal received from the transformer to thereby adjust the frequency of the lamp drive current applied to the fluorescent lamp.

A system comprising:

• a power source;
• a fluorescent lamp producing a light having a brightness;
• a driver circuit configured to provide electrical energy from the power source to the fluorescent lamp, the driver circuit comprising:
• a transformer having a primary winding and a secondary winding, wherein each of the primary and secondary windings have a first and a second end and are configured to conduct an electrical current, wherein the primary winding comprises a center tap, and wherein the ends of the secondary winding are coupled to the fluorescent lamp;
• a current steering module configured to provide a drive output from the power source to the center tap of the transformer in response to a current steering input;
• a lamp frequency control loop comprising:
• a flip-flop having a clock input, a signal input, an inverting output, and a non-inverting output, and wherein the inverting input is coupled to the signal input;
• a first switch coupled to the inverting input, to a reference voltage, and to the first end of the primary winding;
• and
• a second switch coupled to the non-inverting input, to the reference voltage, and to the second end of the primary winding;
• wherein the lamp frequency control loop is configured to automatically toggle the first and second switches to switchably couple the first and second ends of the primary winding, respectively, to the reference voltage and to thereby adjust the electrical polarity of the primary winding of the transformer in response to a signal received from the transformer to thereby adjust the frequency of the lamp drive current applied to the fluorescent lamp.