The NCP1370 is a PWM current mode controller targeting isolatedflyback and non−isolated constant current topologies. The controlleroperates in a quasi−resonant mode to provide high efficiency. Thanksto a novel control method, the device is able to precisely regulate aconstant LED current from the primary side. This removes the needfor secondary side feedback circuitry, biasing and an opto−coupler.The device is highly integrated with a minimum number of externalcomponents. A robust suite of safety protection is built in to simplifythe design. This device supports analog/digital dimming and bothmodes can be combined to enhance dimming precision. The NCP1370has a programmable peak current limit to optimize designcompatibility over a wide range of applications. The controllerfeatures a standby mode with reduced current consumption.

• Accurate Primary Side Sensing
• Quasi−resonant Peak Current−mode Control Operation
• Line Feed−forward
• Programmable Cycle−by−Cycle Peak Current Limit
• Analog and/or PWM dimming
• Secondary Diode Short Protection
• V
• Undervoltage and overvoltage protection
• Open and Shorted Output LED Protection
• Brown−out