Typical application circuit of NE5565

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

Photocoupler

The NE5565 is a highly integrated controller designed for switching power supply applications, particularly in electronic ballasts. It combines two essential control circuits into one chip: a PFC (Power Factor Correction) boost converter and a half-bridge oscillator. The PFC section improves the power factor to over 0.99, minimizes AC current harmonic distortion, and provides protection against transient voltage spikes. Meanwhile, the half-bridge oscillator converts the DC output from the PFC stage into high-frequency AC, which is then used for lamp operation.

The NE5565 also features a built-in half-bridge controller that drives two external high-voltage MOSFETs. This allows precise regulation of the lamp current, limits peak lamp voltage, and ensures safe operation under various load conditions. The device operates within a wide temperature range of 0°C to 85°C, making it suitable for industrial and commercial applications.

Some key features of the NE5565 include:

• Integrated PFC and dimming control on a single chip
• Ultra-low AC current harmonic distortion
• Supports variable frequency operation
• Programmable preheating and ignition for smooth three-step startup
• Lamp overvoltage protection
• Eliminates voltage overshoot during load disconnection

The typical application circuit for the NE5565 is shown above. In this configuration, T1 is a high-frequency transformer used in the half-bridge oscillator, while T2 serves as a current-sensing transformer for the lamp. This setup ensures efficient and stable performance in a variety of lighting systems, especially those requiring high power factor and low distortion.