LM27964SQ-A/NOPB

The LM27964SQ-A/NOPB (OFF-Line LED Drivers) is a Pre-Regulated flyback LED Driver IC designed for LED backlight applications. It provides LED current solutions in the range of 2mA to 3A. This IC is a high-voltage, high-current switching device with a synchronous rectifier and a high-accuracy error amplifier. This IC is a high-performance, economical IC for AC/DC power conversion in off-line LED lighting applications.

Application Field

The ON Semiconductor LM27964SQ-A/NOPB is a comprehensive solution for controlling backlighting current in LCD displays, which can be applied to industrial, consumer and automotive environments. This IC integrates all the necessary components for efficient conversion of AC/DC power, such as: a primary-side controller, a synchronous rectifier, a high-frequency transformer, a hysteretic approach and a high-accuracy dual error amplifier.

The LM27964SQ-A/NOPB is designed to provide trend-setting functionality, reliability, and flexibility when controlling backlight current. This IC requires minimum external components and offers enhanced system performance, such as: low MTBF and isolated feedback. The IC also supports a wide range of operating parameters, such as: dimming range, frequency, off-time compensation and over-voltage protection.

Working Principle

The LM27964SQ-A/NOPB half-bridge controller provides The primary side with a controlled output voltage for driving an external MOSFET. The power switching is based on an oscillating frequency hysterisis. The driver creates a pulsed voltage on the primary side for controlling a MOSFET to drive the load. The input to the driver is an error signal generated by a dual error amplifier. This error signal is a function of the Dimming input voltage and the LED current. The dynamic parameters are determined by two external components, a resistor and a capacitor. The hysteretic controller provides soft-start, frequency jitter and over-temperature protection.

The IC also has a synchronous rectification control circuitry and a soft turn-off. The power consumption efficiency is greatly increased by the synchronous rectification. The soft turn-off helps to limit the primary current. The driver also provides an over-voltage protection against input voltage rising and LED current runaway conditions.

Conclusion

The LM27964SQ-A/NOPB is a comprehensive and high performance LED driver IC for AC/DC power conversion in off-line LED lighting applications. This IC integrates all the necessary components for efficient conversion and offers enhanced system performance, such as: low MTBF and isolated feedback. The IC also supports a wide range of operating parameters, such as: dimming range, frequency, off-time compensation and over-voltage protection.