RT8856

RT8856 Multi-Phase PWM Controller f or CPU Core Power Supply General D escription The RT8856 is a single/dual phase PWM controller with two integrated MOSFETdrivers. Moreover , it is compli ant with Intel IMVP6.5Voltage Regulator Spe cification to ful fill its mobile CPU Vcore power supply requirements. The RT8856 adopts NAVPTM (Native AVP) which is Richtek's proprietary topology derived from f inite DC gain compensator peak current mode, ma king it a n easy setting PWM controller that meets all Intel AVP (Active Voltage Positioning) mobile CPU requirements. The output voltage of the RT8856 is set by 7-bit VID code. The built-in high a ccuracy DAC converts the VID code ranging from 0Vto 1.5Vwith 12.5mVper step.The syste m accuracy of the controller ca n rea ch 1.5%. The part supports VID on-the-fly a nd mode cha nge on-the-fly function s that are fully compli ant with IMVP6.5 specification. It operates in single pha se, dual phase and RFM. It ca n reach up to 90% ef ficiency in different modes according to different loading conditions. The droop loa d line can be easily programmed by setting the DC gain of the error amplifier. With proper compensation, the load transient can achieve optimized AVP performance. This chip controls soft-start and output transition slew rate via a capacitor. It supports both DCR a nd sen se re sistor current sensing.The current modeNAVPTM topology with high accuracy current sen sing amplifier well bala nces the RT8856's channel currents. Features...