The NCP1212 is a high performance current mode PWM controller designed for off-line DC-DC converter applications. The device requires very few external components, providing additional protection for the designer for better system reliability. The device features a trimmed oscillator with precise duty cycle control, an accurate bandgap voltage reference, a high gain error amplifier, a current sense comparator and a high current output totem pole gate driver ideal for driving external power MOSFETs. In addition, the device has built-in programmable brownout detection and soft-start functions to improve system reliability. Additionally, 48%/82% selectable duty cycle control and externally programmable maximum turn-on switching frequency capability make this device ideal for controller forward and flyback configurations. This device is available in both PDIP-8 and space saving SOIC-8 packages.

Features • Lead-free package is available • Trimmed oscillator charge and discharge current for precise duty cycle control • Internal high precision bandgap voltage reference • Current mode operation up to 200 kHz • Inherent feed-forward compensation • Cycle-by-cycle current limit locked to PWM cycle High current totem pole output gate driver Low startup and operating current Internal hysteretic undervoltage lockout Internal leading edge blanking current feedback Functions programmable through external capacitors • User programmable 48%/82% maximum duty cycle selection • Output overvoltage protection against open loop • AC line undervoltage detection protection • Output overload protection regardless of auxiliary voltage level