Isolated No-Opto Synchronous Flyback Controller

The LT3837 is an isolated switching regulator controller designed for medium power flyback topologies. A typical application is 10W to 60W with the part powered from a DC supply.

The LT3837 is a current mode controller that regulates an output voltage based on sensing the secondary voltage via a transformer winding during flyback. This allows for tight output regulation without the use of an optoisolator, improving dynamic response and reliability. Synchronous rectification increases converter efficiency and improves output cross regulation in multiple output converters.

The LT3837 operates in forced continuous conduction mode which improves cross regulation in multiple winding applications. Switching frequency is user programmable and can be externally synchronized. The part also has load compensation, undervoltage lockout and soft-start circuitry.

The LT3837 is available in a thermally enhanced 16-pin TSSOP package.

Applications

* Isolated Medium Power (10W to 60W) Supplies

* Instrumentation Power Supplies

* Isolated Medical Supplies

* Senses Output Voltage Directly from Primary Side Winding—No Optoisolator Required

* Synchronous Driver for High Efficiency

* Supply Voltage Range 4.5V to 20V

* Accurate Regulation Without User Trims

* Programmable Switching Frequency from 50kHz to 250kHz

* Synchronizable

* Load Compensation

* Undervoltage Lockout

* Available in a Thermally Enhanced 16-Lead TSSOP Package