资 源 简 介
UC3842/UC3843/UC3844/UC3845 SMPS Controller
Features• Low Start up Current• Maximum Duty Clamp• UVLO With Hysteresis• OperaTIng Frequency up to 500KHz
DescripTIonThe UC3842/UC3843/UC3844/UC3845 are fixedfrequencycurrent-mode PWM controller. They are speciallydesigned for Off-Line and DC to DC converter applicaTIonswith minimum external components. These integratedcircuits feature a trimmed oscillator for precise duty cyclecontrol, a temperature compensated reference, high gainerror amplifier, current sensing comparator and a highcurrent totempole output for driving a Power MOSFET. TheUC3842 and UC3844 have UVLO thresholds of 16V (on)and 10V (off). The UC3843 and UC3845 are 8.5V(on) and7.9V (off). The UC3842 and UC3843 can operate within100% duty cycle. The UC3844 and UC3845 can operatewith 50% duty cycle.
