RT8113 RICHTEK [Richtek Technology Corporation], RT8113 Datasheet - Page 15

• Manufacturer Part Number: RT8113
• Description: Single Phase VR11.1 PWM Controller with 7-bit VID
• Manufacturer: RICHTEK [Richtek Technology Corporation]

Load Transient Quick Response
In steady state, the voltage of V
close to V
light load to heavy load could cause V
V
design (without non-linear control) for CPU VR application,
due to limited control bandwidth, it is hard for the VR to
prevent V
light load to heavy load. Hence, the RT8113 builds in a
state-of-the-art quick response function which detects load
DS8113-02 April 2011
EAP
by several tens of mV. In conventional buck converter
OUT
EAP
. However While a load step transient from
undershoot during quick load transient from
V
V
OUT
EAP
Figure 5. Circuit for V
Sense Pin of CPU)
= V
(Negative Remote
Sense Pin of CPU)
(Positive Remote
DAC
V
FB
V
CC_SNS
C
SS_SNS
R
- V
FB
is controlled to be very
FB
ADJ
FB
Figure 6. Load Transient Quick Response
to be lower than
FB
-
+
EA
R1
C2
OUT
C1
C
R
FB
FB
R
Differential Sensing and No Load Offset
COMP
ADJ
FB
FBRTN
ADJ
QR Circuit
V
transient by comparing V
drops below “V
voltage (~40mV), the quick response indicator QR rises
up. When QR = high, the RT8113 turns on all high side
MOSFETs and turns off all low side MOSFETs. The
sensitivity of quick response can be adjusted by varying
the values of C
will make QR easier to be triggered. Figure 6 is the circuit
and typical waveforms.
DAC
+
-
I
I
OFSP
OFSP
+ -
V
I
OUT
OUT
EAP
QR
FB
EAP
and R
+
-
− V
QR
FB
”where V
COMP
R1
. Smaller R
FB
C2
and V
C1
QR
EAP
FB
is a predetermined
. If V
and/or larger C
RT8113
www.richtek.com
FB
suddenly
15
FB