AN1476低成本家电电源

AN1476低成本家电电源

AN1476
APPLICATION NOTE

LOW-COST POWER SUPPLY FOR HOME APPLIANCES

INTRODUCTION
In most non-battery applications, the power to the microcontroller is supplied by using a step-
down transformer, which is then rectified, filtered and regulated. However, in many smaller
low-cost applications, the cost of the transformer becomes the key factor in the system. Under
these circumstances, the step-down transformer is normally not used in order to reduce the
cost as well as the size. The power supply is a simple one-way rectifier with very few compo-
nents. The output voltage is regulated by using a 5.6V zener diode. Despite its simplicity and
low cost, it i