NCP1234AD100R2G

The purpose of the Dynamic Self-Supply (DSS) feature in the NCP1234 fixed-frequency current-mode controller is to simplify the design of the auxiliary supply and V CC capacitor by activating the internal startup current source to supply the controller during transients. It helps maintain the V CC voltage between V CC(on) and V CC(min) by turning the HV start-up current source on and off, ensuring the controller stays alive during light load conditions or load transients when V CC might drop. The DSS function is useful in latch conditions or to prevent the controller from stopping during load transients.

The NCP1234 controller can be used in applications where low part count is a key parameter without sacrificing safety. It is particularly well suited for building a safe and efficient power supply based on a fixed-frequency flyback converter .

Some key features of the NCP1234 controller mentioned in the document include: 1. Current-Mode Operation with slope compensation for maximum safety and ease of design of the feedback loop . 2. Fixed-Frequency Oscillator with Jittering available in different frequency options for application flexibility . 3. Frequency foldback and skip mode for high efficiency under all load conditions . 4. Extended VCC range accepting supply voltage up to 28V with overvoltage threshold for safety . 5. Clamped Driver Stage ensuring voltage on DRV pin is safely below 16V for reduced current consumption . 6. Dual Latch-off Input for latching off by voltage increase or decrease for precise control . 7. Dynamic Self-Supply (DSS) simplifying auxiliary supply design and VCC capacitor activation during transients . 8. Timer-based fault detection for overload protection and detection of faults in applications . Fixed Frequency Current Mode Controller for Flyback Converters.