RT3606BC Datasheet, PDF (39/72 Pages) Richtek Technology Corporation – Dual Channel PWM Controller

RT3606BC
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.
L
V_IN
Q1
Q2
Gate
Driver
Ai
Induced charge
current signal
CCRCOT
VIN
VID
t_ON
COMP _-
+
Charge current
C_O1 C_O2
R_ESR
CPU
C2
R2
C1
R1
-
EA
+
I_DROOP
VID
Output voltage
VID Transition
Figure 18. Droop Effect in VID transition
DVID_Threshold
(SET1)
DVID_Width
(SET2)
Figure 19. Definition of Virtual Charge Current Signal
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.
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
DS3606BC-04 June 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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