LNK6669V

The LNK6669V is a cost-effective, 3-A, main-side synchronous PWM Controller IC with an integrated diode. Together with an external MOSFET, it is capable of driving AC-DC converters, offline switchers, as well as other applications.

Application Field

The LNK6669V has a wide range of applications in AC-DC power conversion and control, including notebook and desktop computer adaptors, computer printers and other office electronics, mobile appliances, telecom, industrial equipment, and many other consumer applications. It is especially suitable for low-power, low-cost AC-DC converters.

Working Principle

The LNK6669V is a synchronous controller, which means that the power from the input to the output is synchronously controlled by a pulse-width modulation (PWM) waveform, generated by the control IC. The controller IC provides up to 3 amps peak current in normal operation. To convert an AC input voltage to a DC output voltage, an external high-voltage MOSFET is used. The MOSFET is triggered by a signal from the controller IC, and it will conduct when the PWM signal is active. The on-time of the PWM waveform is adjusted to regulate the output voltage. The LNK6669V also has protections against DC input overvoltage, over-current, over-temperature, and power limits.

The controller IC also integrates several features that reduce external parts counts and radio frequency interference (RFI) issues. An external Schottky diode is used as a catch diode to improve output power usage. The diode takes advantage of the natural inductivitiy behavior of the input energy source, allowing the voltage across it to alternately peak in each polarity, thus providing a rectified input. The controller IC also uses an internal pull-down resistor to minimize EMI and the output voltage ripple.

The LNK6669V can also be used in offline switchers. An offline switcher is essentially a power converter from AC mains input to DC output with no isolation transformer. This simpler and low-cost power architecture avoids high volume, labor-intensive winding and insulation work for the isolation transformer. In addition, it allows for a smaller design, with increased space savings and low cost. With the LNK6669V, the power conversion from AC mains input to DC output is controlled by the same PWM signal as above, with output voltage and current limiting protection.

Conclusion

Overall, the LNK6669V is a versatile, low cost, and low power integrated controller IC that is ideal for a wide range of AC-DC converters and offline switchers. With its broad feature set and high efficiency, the LNK6669V is a great choice for power designs.