Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies

The MAX5014/MAX5015 integrate all the building blocks necessary for implementing DC-DC fixed-frequency isolated power supplies. These devices are current-mode controllers with an integrated high-voltage startup circuit suitable for isolated telecom/industrial voltage range power supplies. Current-mode control with leading-edge blanking simplifies control-loop design and internal ramp compensation circuitry stabilizes the current loop when operating at duty cycles above 50% (MAX5014). The MAX5014 allows 85% operating duty cycle and could be used to implement flyback converters, whereas the MAX5015 limits the operating duty cycle to less than 50% and can be used in single-ended forward converters. A high-voltage startup circuit allows these devices to draw power directly from the 18V to 110V input supply during startup. The switching frequency is internally trimmed to 275kHz ±10%, thus reducing magnetics and filter component costs.

The MAX5014/MAX5015 are available in 8-pin SO packages. An evaluation kit (MAX5015EVKIT) is also available.

Warning: The MAX5014/MAX5015 are designed to operate with high voltages. Exercise caution.

Applications

* Industrial Power Supplies * Isolated Power Supplies * Networking Power Supplies * Telecom Power Supplies

* Wide Input Range: (18V to 110V) or (13V to 36V)

* Current-Mode Control

* Leading-Edge Blanking

* Internally Trimmed 275kHz ±10% Oscillator

* Low External Component Count

* Soft-Start

* High-Voltage Startup Circuit

* Pulse-by-Pulse Current Limiting

* Thermal Shutdown

* SO-8 Package