12W 5V SMPS evaluation board with ICE3AR4780VJZ

Circuit description

Application Note

6

Revision 1.2, 2015-05-12

5.8

Peak current control of primary current

The CoolMOS™ drain source current is sensed via external shunt resistors R14 and R14A which determine the

tolerance of the current limit control. Since ICE3AR4780VJZ is a current mode controller, it would have a

cycle-by-cycle primary current and feedback voltage control which can make sure the maximum power of

the converter is controlled in every switching cycle. Besides, the patented propagation delay compensation

is implemented to ensure the maximum input power can be controlled in an even tighter manner. The

evaluation board shows approximately ±2.2% of average maximum input power (refer to Figure 11).

5.9

Output stage

On the secondary side the power is coupled out by a schottky diode D21. The capacitor C22 & C23 provides

energy buffering following with the LC filter L21 and C24 to reduce the output voltage ripple considerably.

Storage capacitors C22 & C23 are selected to have a very small internal resistance (ESR) to minimize the

output voltage ripple.