Voltage Mode PWM Controller 2.5A/1A 16-Pin SOIC T/R

The NCP1282 is a voltage mode controller designed for ac--dc or dc--dc converters requiring high--efficiency and low parts count. This controller incorporates two in phase outputs with an overlap delay to prevent simultaneous conduction and facilitates soft switching. The main output is designed for driving a forward converter primary MOSFET. The secondary output is designed for driving an active clamp circuit MOSFET, a synchronous rectifier on the secondary side, or an asymmetric half bridge circuit. The NCP1282 reduces component count and system size by incorporating high accuracy on critical specifications such as maximum duty cycle limit, under voltage detector and overcurrent threshold. Two distinctive features of the NCP1282 are soft--stop and a cycle skip current limit with a time threshold. Soft--stop circuitry powers down the converter in a controlled manner if a severe fault is detected. The cycle skip detector enables a soft--stop sequence if a continuous overcurrent condition is present. Additional features found in the NCP1282 include line feed-- forward, frequency synchronization up to 1.0 MHz, cycle--by--cycle current limit with leading edge blanking (LEB), independent under and overvoltage detectors, adjustable output overlap delay, programmable maximum duty cycle, internal startup circuit and soft--start. Dual Control Outputs with Adjustable Overlap Delay >2.0 A Output Drive Capability Soft-Stop Powers Down Converter in a Controlled Manner Cycle-by-Cycle Current Limit Cycle Skip Initiated if Continuous Current Limit Condition Exists Voltage Mode Operation with Input Voltage Feedforward Fixed Frequency Operation up to 1.0 MHz Bidirectional Frequency Synchronization Independent Line Under voltage and Overvoltage Detectors Minimum Operating Voltage of 8.5 V Ensures Enough Voltage is Available for Driving High Voltage MOSFETs Accurate Programmable Maximum Duty Cycle Limit Programmable Maximum Volt-Second Product Programmable Soft-Start Internal 500 V Startup Circuit Precision 5.0 V Reference This is a Pb-Free Device