Diodes – Dual Phase Buck Controller for High Current Applications
With an operating frequency adjustable over the range of 50Hz to 1MHz per phase, the buck controller can deliver an output current of up to 60A and suits the power needs of high end GPU and memory cores. The AP3595, available in the standard QFN4x4-24 package, integrates 12V+12V bootstrapped MOSFET drivers to ensure highest efficiency power conversion. In addition, the bootstrap diode is itself built into the device, simplifying circuit design and reducing the external part count and PCB size. To optimize system performance, the AP3595’s gate drive voltage is fully configurable, regulated via a reference input set using external voltage divider.
By tuning the duty cycle of each channel in response to internal MOSFET on-resistance sensing, the controller ensures phase currents are always balanced. With a power saving interface (PSI), the controller can switch between single and dual mode to help reduce losses. Dual phase mode is entered with the VPSI pin at greater than 1.2V, single phase mode is selected at less than 0.4V. To ensure high reliability operation at high currents, the AP3595 buck controller features a comprehensive range of in-built protection features, including over current, input/output undervoltage, over voltage and over temperature protection. An adjustable soft start facility is integrated.