The MP3900 is a boost controller that drives an external MOSFET capable of handling 10A current. It has an operational current of typically 180µA and can accommodate off-line, Telecom and non-isolated applications. Internal undervoltage lockout, slope compensation and peak current limiting are all provided to minimize the external component count. In a boost application, with an output voltage of less than 30V, the current sense pin can connect directly to the drain of the external switch. This eliminates the requirement for an additional current sensing element and its associated efficiency loss. While designed for boost applications, the MP3900 can also be used for other topologies including Forward, Flyback and Sepic. The 10V gate driver voltage minimizes the power loss of the external MOSFET while allowing the use of a wide variety of standard threshold devices. The MP3900 is available in 8-pin MSOP and SOIC packages.
The EV3900DK-00B is an evaluation board for the MP3900DK. It is configured to provide a regulated 25V output at up to 2A load current from a 12V input. The output is adjustable by changing feedback resistors on the evaluation board. MOSFET Rds,on can be directly used for current sense purpose without an external sense resistor.
Although the demo board uses the external 10mW to sense the current, it also provides the stuffing option for users who want to use the Rds,on as the sense element.