The AP3103A is a low startup current, current mode ofline PWM controller with green-mode power-saving operation. The PWM switching frequency at normal operation is externally programmable and is trimmed to a tight range. The dithering of frequency will also improve the EMI feature. When the load decreases, the frequency will reduce and when at a very low load, the IC will enter the „burst mode‟ to minimize switching loss.

 

About 20kHz frequency switching is to avoid the audible noise as well as reducing the standby loss. The skip mode point can be adjusted through the external resistor connected to the current sense resistor.

 

The AP3103A features a lot of functions such as the Leading-Edge Blanking (LEB) of the current sensing, internal slope compensation and several protection functions including cycle-by-cycle current limit (OCP), VCC Over Voltage Protection (VOVP) and OLP protection.

 

This IC is available in SOT26 package.