RT3612EB datasheet(38/47 Pages) RICHTEK

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RT3612EB

DS3612EB-02 December 2019

www.richtek.com

is a registered trademark of Richtek Technology Corporation.

System Input Power Monitoring (PSYS)

RT3612EB provides PSYS function to monitor total

platform system power and report to the CPU via SVID

interface. The PSYS function can be illustrated as in Figure

24. PSYS meter measures system input current and

outputs a proportional current signal IPSYS. RPSYS is

designed for the PSYS voltage = 1.6V with maximum

IPSYS for 100% system input power. 1.6V is a full-scale

analog signal for FFh digitized code.

Figure 24. PSYS Function Block Diagram

Zero Loadline

RT3612EB also can support zero loadline function. It can

be enabled by PIN-SETTING of Zero LL_EN = 1. When

zero loadline function is enabled, the output voltage is

determined only by VID and does not vary with the loading

current like loadline system behavior. RT3612EB adopts

a new feature, i.e. AC-droop, to effectively suppress load

transient ring back and to control overshoot well for zero

loadline application. Figure 25 shows the condition without

AC-droop control. The output voltage without AC-droop

control has extra ring back

ΔV2 due to C area charge.

Figure 26 shows the condition with AC-droop control. While

loading occurs, controller temporarily changes VID target

to short-term voltage target. Short-term voltage target is

related to transient loading current

ΔICC and can be

represented as the following :

Short_Term_Voltage_Target = VID

− ΔICC x RLL

The setting method of RLL is the same as loadline system.

The short-term voltage target reverts to VID target slowly

after a period of time. The short-term voltage target can

help inductor current not to exceed loading current too

much and then the ring back can be suppressed. The

overshoot amplitude is reduced to only

ΔV3.

Input Power

Source

PSYS "Meter"

RT3612EB

PSYS

CPU

IPSYS

SVID

Analog Current Signal

(Indicates system total

power)

VPSYS

RPSYS

RT3612EB Datasheet(PDF) 38 Page - Richtek Technology Corporation

RT3612EB Datasheet(HTML) 38 Page - Richtek Technology Corporation

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