RT3606BC datasheet(39/72 Pages) RICHTEK

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RT3606BC

DS3606BC-04 June 2016

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is a registered trademark of Richtek Technology Corporation.

Dynamic VID (DVID) Compensation

When VID transition event occurs, a charger current will be generated in the loop to cause DVID performance. However,

the DVID performance will be deteriorated by this induced charger current, this phenomenon is called droop effect. The

droop effect is shown in Figure 18, when VID up transition occurs, the output capacitor will be charged by inductor

current. Since current signal is sensed in inductor, an induced charge current will appear in control loop. The induced

charge current will produce a voltage drop in R1 to cause output voltage to have a droop effect. Due to this, VID transition

performance will be deteriorated.

VIN

Gate

Driver

RESR

CO2

CPU

Charge current

Induced charge

current signal

CO1

COMP

CCRCOT

tON

VID Transition

IDROOP

VID

Output voltage

VIN

VID

Figure 18. Droop Effect in VID transition

RT3606BC provide a DVID compensation function. A virtual charge current signal can be established by the SET1/SET2

pins to cancel the real induced charge current signal and the virtual charge current signal is defined in Figure 19. Figure

20 shows the operation of canceling droop effect. A virtual charge current signal is established first and then VID signal

plus virtual charge current signal to be generated on the FB pin. Hence, an induced charge current signal flows to R1

and is cancelled to reduce droop effect.

Figure 19. Definition of Virtual Charge Current Signal

DVID_Threshold

(SET1)

DVID_Width

(SET2)

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