NE8629 is a highly integrated flyback power PWM control chip. Its built-in NLDMOS power transistor is on the same wafer as the control circuit, and the current of the power transistor is sensed through a "lossless current sampling circuit", resulting in high efficiency; It can operate in CCM and DCM modes, operating at the maximum frequency built into the chip of 330kHz during heavy loads, and gradually decreasing in frequency during light loads to improve light load efficiency and reduce no-load power consumption; The chip has built-in feedforward compensation, soft start, slope compensation, and RC compensation integrated at the COM pin, which can be directly connected to the optocoupler, making the peripheral circuit of the chip extremely simple.
The NE8629 integrates multiple control and protection functions, with simple peripherals that can be designed according to actual needs. Three functions are achieved through a resistor, including startup, feedforward compensation, and programming the turn-off speed of the built-in power transistor; Both input undervoltage protection and input overvoltage protection thresholds can be designed simultaneously through two resistors. Integrating functions such as over power protection, output short circuit protection, output overvoltage protection, and over temperature protection, it can achieve self recovery after abnormal situations are cancelled, maximizing the reliability of the switching power supply system.