The main role of the power chip is to provide drive signal, pulse width control, overvoltage and overcurrent protection functions, some power chips integrated with a power tube in the interior, can directly drive the high-frequency transformer, this chip is generally a power limit, such as VIp22a maximum power is 12W!
There is another kind of power chip without power tube inside, need external power tube, this chip can make high-power power, can make much power depends on the selected power tube and other external components, such as KA3842 can be used for more than 100 watts of electric car charger and so on! All power chips can be designed to output multiple voltages at the same time!