ISL6388

The ISL6388 is a smart and smallest 6-Phase Green PWM controller, designed to be compliant to Intel VR12. 5/VR12 specifications and control the microprocessor core or memory voltage regulator. It includes programmable functions and telemetries for easy use, system flexibility and over-clocking applications using SMBus, PMBus, or I²C interface, which is designed to be conflict free with CPU’s SVID bus and to program NVM banks up to 8 different compensations and system parameters. This minimizes external components and significantly reduces design complexity and PCB area, and simplifies the manufacturing process. The ISL6388 utilizes Renesas' proprietary Advanced Linear EAPP (Enhanced Active Pulse Positioning) Digital control scheme to achieve the extremely fast linear transient response with fewer output capacitors and overcomes many hurdles of the traditional digital approach, which uses non-linear, discrete control method for both voltage loop and current balance loop and runs into beat frequency oscillation and non-linear response. The ISL6388 accurately monitors the load current via the IMON pin and reports this information via the I_OUT register to the microprocessor, which sends a PSI# signal to the controller at low power mode via SVID bus. The controller enters 1- or 2-phase operation in low power mode (PSI1); in the ultra-low power mode (PSI2, PSI3), it operates in single phase with diode emulation option. In low power modes, the magnetic core and switching losses are significantly reduced, yielding high efficiency at light load. After the PSI# signal is de-asserted, the dropped phase(s) are added back to sustain heavy load transient response and efficiency. In addition, the ISL6388 features auto-phase shedding to optimize the efficiency from light to full load for Greener Environment without sacrificing the transient performance. The ISL6388 senses the output current continuously by a dedicated current sense resistor or the DCR of the output inductor. The sensed current flows through a digitally programmable 1% droop resistor for precision load-line control. Current sensing circuits also provide the needed signals for channel-current balancing, average overcurrent protection and individual phase current limiting. The TM pin senses an NTC thermistor’s temperature, which is internally digitized for thermal monitoring and for integrated thermal compensation of the current sense elements of the regulator. The ISL6388 features remote voltage sensing and completely eliminates any potential difference between remote and local grounds. This improves regulation and protection accuracy. The threshold-sensitive enable input is available to accurately coordinate the start-up of the ISL6388 with other voltage rails.