ISL9502

® ISL9502 Data Sheet July 17, 2006 FN9275.1 Two-Phase PWM Controller for Graphics Processor Units (GPU) Increase in GPU clock frequency is accompanied by associated increase in the demand for power and transientcurrent slew rate. At the same time, the voltage tolerance requirement during steady-state and transient operation is becoming more stringent of advanced GPU. The ISL9502 is a two-phase PWM controller with embedded gate drivers, which is tailored to meet the power and dynamic requirements. The two-phase buck converter uses two interleaved channels to effectively double the output voltage ripple frequency and thereby reduce output voltage ripple amplitude with fewer components, lower component cost, reduced power dissipation, and smaller real estate area. The heart of the ISL9502 is the patented R3 (Robust Ripple Regulator®) modulator. Compared with the traditional multiphase buck regulator, R3 technology has the fastest transient response. This is due to the R3 modulator commanding variable switching frequency during a load transient. At heavy load operation of the active mode, ISL9502 commands the two phase continuous conduction mode (CCM) operation. While the pin SET3 is asserted at the medium or light load, the ISL9502 smoothly disables one phase and operates in a one-phase operation. Once in onephase operation, when the GPU further lowers the load current, the ISL9502 enables diode emulation to maximize efficiency at light load depending on the logic of SET1 and ...