基于UC3842的三路输出小功率开关电源设计

针对通信供电系统高效率、小型化、集成化、智能化以及高可靠性的发展趋势，本文以UC3842为PWM 控制器，采用电阻，TL431和线性光耦等元器件构成电压采样反馈电路，设计了一种48V转+5V， 15V开关稳压电源，主输出（+5VDC@2A）：电压精度为0.5%，纹波为0.4％（峰峰值20mV）；辅助输出1（+15VDC@500mA）：电压精度为2％（14.7V），纹波为0.13％（峰峰值20mV）；辅助输出2（-15VDC@500mA）：电压精度为2％（-14.7V），纹波为0.33％（峰峰值50mV）；具有精度高，纹波小，效率高，性能可靠等优点，可广泛应用于各类小功率变换场合。

Design of a three output Small-Power Switching Power-Supply Based on UC3842

Aimed at the development trend of the communications power supply system with high efficiency, miniaturization, integration, intelligence and high reliability, this paper taked UC3842 as PWM controller, useingresistance, TL431 and linear optocoupler components constitute a voltage sampling feedback circuit,design a 48V switch to the +5 V, 15V switching power supply. The main output voltage (+5VDC@2A): the precision is 0.5%, the ripple of voltage is 0.4% (the value of peak voltage is 20mV); the auxiliary output voltage 1 (+15VDC@500mA): the accuracy of voltage is 2% (14.7V), the ripple of voltage is 0.13% (the value peak to peak is 20mV); the auxiliary output voltage 2 (-15VDC@500mA): the accuracy of voltage is 2% (-14.7V), the ripple of voltage is 0.33% (the value peak to peak value is 50mV); this switching power supply has high precision, small ripple, high efficiency and high reliable, which can be widely used in all kinds of small power conversion applications.