RT8885A

® RT8885A Dual Output 3-Phase + 2-Phase PWM Controller For CPU and GPU Core Power Supply General Description The RT8885A is a dual output 3-phase + 2-phase PWM controller with 3 integrated MOSFET gate drivers and a single SVID interface for CPU and GPU core power supply. This part complies with Intel VR12/IMVP7 Pulse Width Modulation Specification. The RT8885A adopts G-NAVPTM (Green-Native AVP), which is a Richtek proprietary topology derived from finite DC gain compensator in constant ontime control mode. G-NAVPTM makes this part an easysetting PWM controller to meet all Intel mobile CPU/GPU AVP (Active Voltage Positioning) requirements. The RT8885A uses SVID interface to control an internal 8-bit DAC for output voltage programming. The built-in high accuracy DAC converts the VID code to a reference voltage ranging from 0V to 1.52V with 5mV step voltage. The system accuracy of the controller reaches 0.8%. Each output channel of the RT8885A can operate in multi-phase continuous conduction mode or in single-phase diode emulation mode to reach a maximum of 90% efficiency in different load conditions. The droop function (load line) is selectable and the load line is easily programmed by setting the DC gain of the error amplifier. With proper compensation, the load transient response can achieve optimized AVP performance. The output voltage transition slew rate is programmed via the SVID interface. The RT8885A supports inductor DCR and sense-resistor current sensing. This devic...