UC3842开关电源系列频率计算pdf,5-1.2 5-2.8 ( e Rt Rt 查表Id的值如下: UC284XB UC384XB, XBV Characteristics Symbol Min Typ Max Min TypMaxUnit Discharge Current (Vosc=2.0v A T=25°C 7.88388788388 TA= Ton to Thigh (UC284XB, UC384XB) 8.8 88 (UC384XBV) 8.8 ld取8.3mA,可得: ld=