Dual-Phase Buck Controller targets Graphics CardsJune 26, 2014 by Jeff Shepard
Diodes Incorporated has released a dual-phase synchronous rectified buck controller, optimized for use in high-performance GPU and CPU core power supplies. Providing pwm VID output voltage control, the AP3598A assures the fast, high-current response demanded by the inherently large variations in output loading. The device includes a pwm controller, a pair of MOSFET drivers with internal bootstrap diodes, channel-current balance and comprehensive protection features in the compact, low pin-count U-QFN4040-24 package. Designed for 12V systems, it delivers an output current as high as 60A and harnesses external compensation to minimize output voltage ripple and optimize transient response.
Accurate phase current balance is maintained through lossless RDS(ON) current sensing, while inductor current sampling ensures a dependable current limit. To help maximize efficiency, the AP3598A offers a power-save mode, which enables it to switch automatically between dual- and single-phase operation when subject to light loading.
For safe high-current operation, the controller provides a full complement of protection functions including over-current, over-temperature, and under- and over-voltage protection. Other features include adjustable soft-start, adjustable operating frequency selection, and a power-good indicator and enable control. The AP3598A dual-phase pwm-VID buck controller is priced at $0.7USD each in 1k quantities.