Wednesday, April 25, 2018
Publication Date: 08/1/2008
Archive >  August 2008 Issue >  New Products > 

Zero Point Detector Driver from Zetex
Zero point detector driver.
Hauppauge, NY — Zetex Semiconductors is introducing the ZXGD3101 Zero Point Detector Driver (ZPDD). A dedicated rectifier controller, it enables designers to replace lossy Schottky diodes with surface mount MOSFETs, which will now function as "ideal diodes" in synchronous flyback converters ranging from 50W to 150W. Benefits include reduced power supply size, weight and heat generation, a simplification of overall circuit design, and improved efficiency.

The ZXGD3101 incorporates a high-voltage differential amplifier stage, and a high-current driver, into a compact SM8 package. It ensures that a MOSFET performs the same function as the diode it replaces, accurately sensing the point at which the secondary current reaches zero. Monitoring MOSFET drain-source reverse voltage, it produces a positive gate voltage to turn the MOSFET on when body diode conduction occurs. Being proportional to the MOSFET drain-source reverse voltage, the drive voltage to the gate is progressively backed off, thereby ensuring rapid MOSFET turn-off at the zero voltage switching point, and that reverse conduction does not occur.

Simpler and more robust than synchronous controller ICs, the new device needs only three external, passive components to produce source and sink currents of up to 2.5A. Simple to implement, it requires no timing information to be transferred from the primary side, and no timing components are needed on the secondary side.

Contact: Zetex Inc. 700 Veterans Hwy. Hauppauge, NY 11788 631-360-2222 fax: 631-360-8222 E-mail: Web:

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