UC3843AD中文资料Flyback, Forward and Isolated数据手册Microchip规格书

描述 Description

The UC3843AD controller provides all the necessary features to implement off-line fixed-frequency, current-mode switching power supplies with a minimum of external components. The current mode architecturedemonstrates improved load regulation, pulseby-pulse current limiting and inherent protection of the power supply output switch. The IC includes: A bandgap reference trimmed to ±1% accuracy, an error amplifier, a current sense comparator with internal clamp to 1V, a high current totem pole output stage for fast switching of power MOSFET's, and an externally programmable oscillator to set frequency and maximum duty cycle. The undervoltage lock-out is designed to operate with 250?A typ. start-up current, allowing an efficient bootstrap supply voltage design. The UC3843AD has 8.4V startup voltage and 0.8V hiseresys, operating at any duty cycle up to 100%. The UC3843AD has a 14-pin SOIC package which makes the Power Output Stage Collector and Ground pins available.