Maxim’s MAX17690ATE+ is a peak current mode, fixed-frequency switching controller specifically designed for the isolated flyback topology operating in discontinuous conduction mode (DCM). The device senses the isolated output voltage directly from the primary-side flyback waveform during the off-time of the primary switch. No auxiliary winding or optocoupler is required for output voltage regulation.

This controller is designed to operate over a wide supply range of 4.5 V to 60 V. The switching frequency is programmable from 50 kHz to 250 kHz. An EN/UVLO pin allows the user to turn on/off the power supply precisely at the desired input voltage. The MAX17690ATE+ provides an input overvoltage protection through the OVI pin. The 7 V internal LDO output of the device makes it suitable for switching both logic-level and standard MOSFETs used in flyback converters. With 2 A/4 A source/sink currents, the MAX17690ATE+ is ideal for driving low R_DS(ON) power MOSFETs with fast gate transition times. The MAX17690ATE+ provides an adjustable soft-start feature to limit the inrush current during startup.