Diodes Incorporated – High-voltage DC-DC controller provides for very low stand-by power losses


The AP3108L from Diodes Inc is a current-mode PWM DC-DC converter controller which supports high- voltage start-up operation. The device is intended for use in offline power supplies that require very low stand-by power consumption, high power density and a comprehensive set of protection functions.

When used in secondary-side USB Power Delivery and rapid charger controllers, it provides a versatile solution which supports a wide dynamic output- power range.

The AP3108L integrates a high- voltage start-up function through its HV pin, which removes the need for an external start-up resistor and reduces losses in stand-by mode. An X-CAP discharge function is also available through this HV pin, saving power by automatically discharging a connected X-CAP when the AC line voltage is off.

The AP3108L includes a 100V low drop-out regulator, which helps to provide for high output-voltage accuracy in applications which produce a wide range of output voltages.

The AP3108L offers versatile system- protection functions. These include constant output-current limitation, to maintain the same over-current limit over a wide output-voltage range.

The AP3108L is available in an SSOP-9 package, which has a small footprint.


  • Secondary-side over- and under-voltage protections
  • Cycle-by-cycle primary current limiting
  • Brown-out protection
  • Programmable external over-temperature protection
  • 1.5μA start-up current
  • 500mA maximum gate output current


  • USB Power Delivery circuits
  • Rapid chargers
  • AC-DC power adaptors