NE5565

The Electronic Ballast controller chip NE5565 has been designed in a bipolar process. NE5565 is housed in a 20-lead dual-in-line plastic package. The control chip contains the equivalent of two (2) switched mode power supply control circuits. The first SMPS controller is a DC-to-DC converter operating in the discontinuous current conduction mode. It is used as a PFC in the ballast system to provide a DC voltage step-up function, good AC power factor, low AC current harmonic distortion, and circuit protection against some types of AC voltage transients. The PFC uses pulse width modulation to control the power transfer with an external MOS power transistor. The second SMPS circuit is a half-bridge oscillator circuit. NE5565 converts the DC output voltage of the PFC into a high frequency AC voltage for operating lamps. Power transfer in this circuit is controlled by changing the switch frequency. The half-bridge controller circuit is capable of driving two external high voltage MOS power transistors and NE5565 has circuits to regulate the lamp current, limit the peak lamp voltage, and protect the power switches during fault conditions. This electronic ballast controller circuit has the capability of being used in a dimming application.