Rectifiers increase electronic charge efficiency

4th March 2015

Nat Bowers

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Enabling higher integration and efficiency in portable chargers, two synchronous rectifiers combining a driver circuit with an internal MOSFET have been released by Diodes Incorporated. Providing cost effective rectification with reduced power dissipation and using fewer external components, the APR3415 and APR34330 are suitable for applications including adapters/chargers for cellular and cordless phones, ADSL modems and MP3 players.

The APR3415 and APR34330 are synchronous rectification switchers for 5V output-voltage applications operating in discontinuous conduction mode. Synchronous rectification can reduce secondary-side power dissipation, while the devices’ ability to sense the MOSFET drain-to-source voltage enables an optimised drive signal using fewer external components. The internal N-channel MOSFET has been optimised for low gate charge, low RDS(ON), fast switching speed and reverse recovery, which helps these devices provide a fast response to secondary-side voltage and can also improve the transient performance of a primary-side control system.

The APR3415 is aimed at designs requiring output currents up to 2A and is supplied in a standard SO-8 package. The APR34330 is intended for output currents up to 1.5A and is offered in an SO 8EP exposed-pad package. Both devices feature over-voltage protection and VCC under voltage lock out, which is not typically available on competitive devices. This not only aids system safety and reliability, but also extends their use in additional application areas, such as standby and auxiliary power supplies.

The APR3415 is priced at $0.40 while the APR34330 is priced at $0.38, each in 1,000 unit quantities.