Nisshinbo NJW1871 boost/flyback switching regulator controller

The NJW1871A model operates as a current mode boost/fly-back switching regulator controller, featuring a broad operating voltage range from 4.5 to 40V. It is equipped with an N-channel MOSFET driver circuit, making it ideal for applications requiring high output currents.

Users can set the operating clock frequency between 1 and 2MHz by attaching an external resistor to the FREQ pin. Additionally, an external clock signal can be fed to the SYNC pin for synchronisation with other clock circuits, enhancing flexibility in complex systems. The device's high switching frequency not only mitigates AM band interference but also facilitates the use of compact inductors, contributing to reduced system size.

Phase compensation is employed to enhance the stability of the feedback loop, allowing for adjustment of the phase margin through the connection of a capacitor and resistor between the ITH (current sense) and GND pins. This adjustment helps maintain stability and prevents feedback loop oscillations. The inclusion of a soft start feature ensures a gradual increase in output voltage upon activation, reducing the risk of inrush currents and voltage spikes that could compromise component integrity or system stability. The RUN pin offers multiple functionalities, including power management and standby mode activation, with startup voltage adjustable via two divider resistors.

To ensure operational safety, the NJW1871A incorporates several protective measures against overvoltage, overcurrent, undervoltage lockout, and thermal overload conditions. Its Hiccup overcurrent protection mechanism facilitates automatic recovery post-overload, enhancing durability and preventing overheating. This makes the NJW1871A a robust solution for boost/fly-back applications in environments such as automotive and industrial settings.