Richtek RT8856GQW Schematic [ru]
®
RT8856
Multi-Phase PWM Controller for CPU Core Power Supply
General Description
The RT8856 is a single/dual pha se PWM controller with
two integrated MOSFET drivers. Moreover, it is compli ant
with Intel IMVP6.5 V oltage Regulator Specification to fulfill
its mobile CPU Vcore power supply requirements. The
TM
RT8856 adopts NAVP
proprietary topology derived from finite DC gain
compensator peak current mode, ma king it an ea sy 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 accuracy DAC converts the VID code
ranging from 0V to 1.5V with 12.5mV per step. The system
accuracy of the controller can reach 1.5%. The part
supports VID on-the-fly and mode change on-the-fly
functions that are fully compliant with IMVP6.5
specification. It operates in single pha se, dual pha se and
RFM. It can rea ch up to 90% efficiency in different modes
according to different loa ding conditions. The droop load
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 tra nsition slew rate vi a
a capacitor. It supports both DCR and sense resistor
current sensing. The current mode NA VPTM topology with
high accura cy current sensing a mplifier well balances the
RT8856's channel currents.
The RT8856 provides power good, clock enabling and
thermal throttling output signals for IMVP6.5 specification.
It also features complete fault protection functions
including over voltage, under voltage, negative voltage, over
current, thermal shutdown, and under voltage lockout.
The RT8856 is available in a WQFN-40L 6x6 small foot
print package.
(Native AVP) which is Richtek's
Features
1/2 Phase PWM Controller with 2 Integrated
MOSFET Drivers
IMVP6.5 Compatible Power Management States
(DPSRLVR, PSI, Extended Deeper Sleep Mode)
NAVP (Native AVP) Topology
7-bit DAC
0.8% DAC Accuracy
Fixed V
Differential Remote Voltage Sensing
Programma ble Output Tra nsition Slew Rate Control
Accurate Current and Thermal Balance
System Thermal Compensation AVP
Ringing Free Mode at Light Load Conditions
Fast T ran sient Respon se
Power Good
Clock Enable Output
Thermal Throttling
Current Monitor Output
Switching Frequency up to 1MHz Per Phase
OVP, UVP, NVP, OCP, OTP, UVLO
40-Lead WQFN Package
RoHS Compliant and Halogen Free
BOOT
(1.1V)
Ordering Information
RT8856
Package Type
QW : WQFN-40L 6X6 (W-Type)
(Exposed Pad-Option 1)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Applications
IMVP6.5 Core Supply
Multi-phase CPU Core Supply
A VP Step-Down Converter
Notebook/ Des ktop Computer/ Servers
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
DS8856-04 August 2014 www.richtek.com
©
1
RT8856
Marking Information
RT8856GQW : Product Number
RT8856
YMDNN : Date Code
GQW
YMDNN
Typical Application Circuit
V
C
C
C
3
V
I
0
D
V
I
D
1
V
I
D
2
V
I
D
.
V
3
3
R
R
7
V
p
c
c
R
1
1
P
W
R
G
D
L
C
K
E
N
T
V
R
T
C
M
C
1
2
C
U
P
S
V
E
N
S
E
S
S
R
2
0
R
V
U
O
T
C
U
P
S
V
E
N
S
E
C
C
2
R
8
D
1
R
5
C
1
4
1
R
2
2
T
N
C
2
4
3
V
I
D
4
V
I
D
5
V
I
D
6
P
S
I
R
P
L
S
V
P
R
V
R
O
N
1
R
8
C
R
2
3
1
C
1
8
Pin Configurations
(TOP VIEW)
2
C
P
V
T
2
E
N
S
E
C
S
O
I
41
SOFT
RGND
L
R
6
1
V
L
R
1
4
V
U
C
C
1
2
S
N
_
2
N
E
S
I
ISEN1
C
C
S
S
2
T
O
O
B
31323334353637383940
30
UGATE2
29
PHASE2
28
PGND2
27
LGATE2
26
PVCC
25
LGATE1
24
PGND1
PHASE1
23
22
UGATE1
21
BOOT1
20191817161514131211
ISEN1_N
6
C
7
V
O
U
1
0
C
1
6
E
N
S
E
T
1
C
1
D
N
DPRSLPVR
VRON
FS
CM
M
C
S
VID6
VID5
VID4
VID3
VID2
O
E
O
K
G
L
P
C
1
2
3
4
5
T
E
6
7
8
9
10
VID1
VID0
C
C
V
I
S
P
T
N
T
R
O
T
V
GND
FB
COMP
C
T
N
VSEN
WQFN-40L 6x6
V
I
5
R
1
8
8
T
R
5
3
8
V
C
C
1
2
V
D
I
1
1
V
D
I
1
0
D
V
I
9
D
V
I
8
D
V
I
7
D
V
I
6
D
V
I
1
3
P
I
S
1
P
D
R
2
V
R
O
4
0
P
G
O
3
9
L
C
K
3
6
V
R
T
4
M
C
5
S
M
C
1
6
E
S
V
1
5
B
F
1
5
1
4
O
C
M
3
F
S
2
R
5
6
0
1
U
2
P
3
4
5
6
L
S
I
S
L
P
V
R
U
N
P
D
O
E
N
L
T
T
E
N
I
S
P
G
D
N
4
1
(
E
2
6
P
V
C
C
2
B
G
H
G
P
E
B
G
H
G
P
E
O
x
1
O
T
O
1
2
2
T
A
1
E
2
3
A
S
E
1
2
5
T
A
E
1
2
4
N
G
1
D
1
9
I
E
S
1
N
2
0
N
1
_
N
3
1
O
T
2
O
3
0
T
A
E
2
2
9
A
S
E
2
2
7
A
T
2
E
2
8
N
G
2
D
3
7
T
N
O
3
3
I
E
S
2
N
3
2
2
N
_
N
1
8
O
S
F
T
1
7
G
N
R
D
3
5
N
T
C
3
4
C
S
T
E
p
o
s
e
d
p
a
d
)
V
C
1
R
2
C
R
3
R
4
C
R
9
1
R
0
R
1
2
R
1
6
C
C
1
7
R
2
6
R
2
9
N
7
V
o
t
2
4
V
C
4
1
Q
Q
2
9
3
Q
Q
4
1
R
7
1
3
R
2
7
2
5
R
C
R
C
V
N
I
R
1
9
R
2
N
T
1
D
5
V
I
N
7
V
o
t
C
8
1
3
2
D
9
8
2
C
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2
Table 1. IMVP6.5 VID code table
RT8856
VID6 VID5 VID4 VID3 VID2 VID1 VID0 Output
0 0 0 0 0 0 0 1.5000V
0 0 0 0 0 0 1 1.4875V
0 0 0 0 0 1 0 1.4750V
0 0 0 0 0 1 1 1.4625V
0 0 0 0 1 0 0 1.4500V
0 0 0 0 1 0 1 1.4375V
0 0 0 0 1 1 0 1.4250V
0 0 0 0 1 1 1 1.4125V
0 0 0 1 0 0 0 1.4000V
0 0 0 1 0 0 1 1.3875V
0 0 0 1 0 1 0 1.3750V
0 0 0 1 0 1 1 1.3625V
0 0 0 1 1 0 0 1.3500V
0 0 0 1 1 0 1 1.3375V
0 0 0 1 1 1 0 1.3250V
VID6 VID5 VID4 VID3 VID2 VID1 VID0 Output
0 1 0 0 0 0 1 1.0875V
0 1 0 0 0 1 0 1.0750V
0 1 0 0 0 1 1 1.0625V
0 1 0 0 1 0 0 1.0500V
0 1 0 0 1 0 1 1.0375V
0 1 0 0 1 1 0 1.0250V
0 1 0 0 1 1 1 1.0125V
0 1 0 1 0 0 0 1.0000V
0 1 0 1 0 0 1 0.9875V
0 1 0 1 0 1 0 0.9750V
0 1 0 1 0 1 1 0.9625V
0 1 0 1 1 0 0 0.9500V
0 1 0 1 1 0 1 0.9375V
0 1 0 1 1 1 0 0.9250V
0 1 0 1 1 1 1 0.9125V
0 0 0 1 1 1 1 1.3125V
0 0 1 0 0 0 0 1.3000V
0 0 1 0 0 0 1 1.2875V
0 0 1 0 0 1 0 1.2750V
0 0 1 0 0 1 1 1.2625V
0 0 1 0 1 0 0 1.2500V
0 0 1 0 1 0 1 1.2375V
0 0 1 0 1 1 0 1.2250V
0 0 1 0 1 1 1 1.2125V
0 0 1 1 0 0 0 1.2000V
0 0 1 1 0 0 1 1.1875V
0 0 1 1 0 1 0 1.1750V
0 0 1 1 0 1 1 1.1625V
0 0 1 1 1 0 0 1.1500V
0 0 1 1 1 0 1 1.1375V
0 0 1 1 1 1 0 1.1250V
0 1 1 0 0 0 0 0.9000V
0 1 1 0 0 0 1 0.8875V
0 1 1 0 0 1 0 0.8750V
0 1 1 0 0 1 1 0.8625V
0 1 1 0 1 0 0 0.8500V
0 1 1 0 1 0 1 0.8375V
0 1 1 0 1 1 0 0.8250V
0 1 1 0 1 1 1 0.8125V
0 1 1 1 0 0 0 0.8000V
0 1 1 1 0 0 1 0.7875V
0 1 1 1 0 1 0 0.7750V
0 1 1 1 0 1 1 0.7625V
0 1 1 1 1 0 0 0.7500V
0 1 1 1 1 0 1 0.7375V
0 1 1 1 1 1 0 0.7250V
0 1 1 1 1 1 1 0.7125V
0 0 1 1 1 1 1 1.1125V
0 1 0 0 0 0 0 1.1000V
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1 0 0 0 0 0 0 0.7000V
1 0 0 0 0 0 1 0.6875V
3
RT8856
VID6 VID5 VID4 VID3 VID2 VID1 VID0 Output
1 0 0 0 0 1 0 0.6750V
1 0 0 0 0 1 1 0.6625V
1 0 0 0 1 0 0 0.6500V
1 0 0 0 1 0 1 0.6375V
1 0 0 0 1 1 0 0.6250V
1 0 0 0 1 1 1 0.6125V
1 0 0 1 0 0 0 0.6000V
1 0 0 1 0 0 1 0.5875V
1 0 0 1 0 1 0 0.5750V
1 0 0 1 0 1 1 0.5625V
1 0 0 1 1 0 0 0.5500V
1 0 0 1 1 0 1 0.5375V
1 0 0 1 1 1 0 0.5250V
1 0 0 1 1 1 1 0.5125V
1 0 1 0 0 0 0 0.5000V
VID6 VID5 VID4 VID3 VID2 VID1 VID0 Output
1 1 0 0 0 0 1 0.2875V
1 1 0 0 0 1 0 0.2750V
1 1 0 0 0 1 1 0.2625V
1 1 0 0 1 0 0 0.2500V
1 1 0 0 1 0 1 0.2375V
1 1 0 0 1 1 0 0.2250V
1 1 0 0 1 1 1 0.2125V
1 1 0 1 0 0 0 0.2000V
1 1 0 1 0 0 1 0.1875V
1 1 0 1 0 1 0 0.1750V
1 1 0 1 0 1 1 0.1625V
1 1 0 1 1 0 0 0.1500V
1 1 0 1 1 0 1 0.1375V
1 1 0 1 1 1 0 0.1250V
1 1 0 1 1 1 1 0.1125V
1 0 1 0 0 0 1 0.4875V
1 0 1 0 0 1 0 0.4750V
1 0 1 0 0 1 1 0.4625V
1 0 1 0 1 0 0 0.4500V
1 0 1 0 1 0 1 0.4375V
1 0 1 0 1 1 0 0.4250V
1 0 1 0 1 1 1 0.4125V
1 0 1 1 0 0 0 0.4000V
1 0 1 1 0 0 1 0.3875V
1 0 1 1 0 1 0 0.3750V
1 0 1 1 0 1 1 0.3625V
1 0 1 1 1 0 0 0.3500V
1 0 1 1 1 0 1 0.3375V
1 0 1 1 1 1 0 0.3250V
1 0 1 1 1 1 1 0.3125V
1 1 0 0 0 0 0 0.3000V
1 1 1 0 0 0 0 0.1000V
1 1 1 0 0 0 1 0.0875V
1 1 1 0 0 1 0 0.0750V
1 1 1 0 0 1 1 0.0625V
1 1 1 0 1 0 0 0.0500V
1 1 1 0 1 0 1 0.0375V
1 1 1 0 1 1 0 0.0250V
1 1 1 0 1 1 1 0.0125V
1 1 1 1 0 0 0 0.0000V
1 1 1 1 0 0 1 0.0000V
1 1 1 1 0 1 0 0.0000V
1 1 1 1 0 1 1 0.0000V
1 1 1 1 1 0 0 0.0000V
1 1 1 1 1 0 1 0.0000V
1 1 1 1 1 1 0 0.0000V
1 1 1 1 1 1 1 0.0000V
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Functional Pin Description
Pin No. Pin Name Pin Function
1 DPRSLPVR
2 VRON Voltage Regulator Enabler.
3 FS
4 CM
5 CMSET
6 to 12 VID[6:0]
13
14 COMP Compensation. This pin is the output node of the error amplifier.
15 FB Feedback. This is the negative input node of the error amplifier.
16 VSEN
17 RGND
18 SOFT
19 ISEN1 Positive Input of Phase1 Current Sense.
20 ISEN1_N Negative Input of Phase1 Current Sense.
21 BOOT1
22 UGATE1 Upper Gate Drive of Phase1. This pin drives the gate of the high side MOSFETs.
23 PHASE1
24 PGND1 Dr ive r Ground of Phase1.
25 LGATE1 Lower Gate Drive of Phase1. This pin drives the gate of the low side MOSFETs.
26 PVCC Driver Power.
27 LGATE2 Lower Gate Drive of Phase2. This pin drives the gate of the low side MOSFETs.
28 PGND2 Dr ive r Ground of Phase2.
29 PHASE2
PSI
Deep er Sle ep Mod e S ig nal . Togeth er wit h PSI, the com b ination o f the se t wo pin s
indicates the power management states.
Fre quen c y Se t ting . C on nec t t h is p in w ith a res is tor t o g r oun d to set the oper ati ng
frequency.
Current Monitor Output. This pin outputs a voltage proportional to the output
current.
Curr e nt Mo nit or Ou tpu t Ga in Ex t ern all y S et ting . Conn ec t this pin wit h o ne res is tor
to VSE N while C M pin is connec ted to grou nd wit h a not her resis tor. Th e curre nt
mo nitor ou tput gain can be set by the ratio of these two resist ors.
Voltage ID. DAC voltage identification inputs for IMVP6.5.
The logic threshold is 30% of VCCP as the maximum value for low state and 70%
of VCCP as the minimum value for the high state. VCCP is 1.05V.
Power Status Indicator II. Together with DPRSLPVR, the combination of these two
pins indicates the power management states.
Positive Voltage Sensing Pin. This pin is the positive node of the differential
v oltage sensing.
Return Gro und. This pin is the n egative node of the differential remote voltage
sensing.
Soft-Start. This pin provides soft-start function and slew rate control. The
capac it an ce of t he s le w rat e c on trol ca paci t or is restrict ed to be lar g er than 10n F.
The feedback voltage of the converter follows the ramping voltage on the SOFT pin
during soft-start and other voltage transitions according to different modes of
operation and VID change.
Boo tstra p Power Pin of Phase1 . T his p in powe rs the high s ide MOSFE T drivers .
Conn ec t this pin t o t he j unc tio n of the boo t st rap c ap ac itor wi th t he c ath ode of the
bootstrap diode. Connect the anode of the bootstrap diode to the PVCC pin.
Retu r n Node o f P ha se 1 H ig h Sid e D ri ver . C onn ect thi s pin to h i gh si de MO SFE T
sources together with the low side MOSFET drains and the inductor.
Retu r n Node o f P ha se 2 H ig h Sid e D ri ver . C onn ect thi s pin to h i gh si de MO SFE T
sources together with the low side MOSFET drains and the inductor.
RT8856
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5
RT8856
Pin No. Pin Name Pin Function
30 UGATE2
31 BOOT2
32 ISEN2_N Negative Input of Phase2 Current Sense.
33 ISEN2 Positive input of Phase2 Curr ent Sense.
34 OCSET
35 NTC
36
37 TON
38 VCC Chip Power.
39
40 PGOOD Power Good Indicator.
41 (Exposed Pad) GND
VRTT
CLKEN
Upper Gate Drive of Phase2. This pin drives the gate of the high side
MOSFETs.
Bootstrap Power Pin of Phase2. This pin powers the high side MOSFET drivers.
Connect this pin to the junction of the bootstrap capacitor with the cathode of the
bootstrap diode. Connect the anode of the bootstrap diode to the PVCC pin.
Over Current Protection Setting. Connect a resistive voltage divider from VCC to
ground and connect the joint of the voltage divider to the OCSET pin. The
voltage, V
Thermal Detection Input for VRTT Circuit. Connect this pin with a resistive
voltage divider from VCC using NTC on the top to set the thermal management
thre s h old le ve l.
Voltage Regul ator Thermal Throttling. This open-dr ain output pin indi cates the
tem per ature exceeding the preset level when it is pulled low.
Connect this pin to VIN with one resistor. This resistor value sets the ripple size
in ringing free mode.
In verted Clock Enable. This open-drain pi n is an output indic ating the start of the
PLL locking of the clock chip.
Ground. The exposed pad m ust be soldered to a larg e PCB and connected to
GND for maximum power dissipation.
, determines the over current threshold, I
OCSE T
LIM
.
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Function Block Diagram
RT8856
FS
TON
OCSET
I
S
P
DPRSLPVR
VRON
FB
Ringing
OCP
Mode
Power On Reset
OSC
Free
Setting
Selection
&
Mode
Central Logic
BOOT1
PHASE1
UGATE1
-
+
LGATE1
PVCC
PGND1
Driver
+
Logic
-
UGATE2
BOOT2
Control
+
OTP
-
PHASE2
PWMCP
LGATE2
PWMCP
-
+
ISEN1
ISEN2_N
-
+
20
1/2
+
ONE_PHASE
ISEN1_N
PGND2
ISEN2
-
20
CM
CMSET
CM
+
Offset Cancellation
PGOOD VCC
N
E
K
L
C
T
T
R
V
NTC
-
-
+
Point
OVP Trip
MUX
VID0
VID1
+
AMP
ERROR
-
UVP Trip
VID2
Point
DAC
VID3
VID4
VID5
VID6
SOFT
RGND
+
START
FB
SOFT
VSEN
COMP
-
+
Point
NVP Trip
-
+
1.2V
VCC
GND
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RT8856
Absolute Maximum Ratings (Note 1)
VCC to GND ------------------------------------------------------------------------------------------------ −0.3V to 6.5V
RGND, PGNDx to GND ---------------------------------------------------------------------------------- −0.3V to 0.3V
VIDx to GND------------------------------------------------------------------------------------------------ −0.3V to (V
PSI, VRON to GN D --------------------------------------------------------------------------------------- −0.3V to (V
PGOOD, CLKEN, VRTT to GND----------------------------------------------------------------------- −0.3V to (V
VSEN, FB, COMP, SOFT , FS, OCSET, CM, CMSET, NTC to GND--------------------------- −0.3V to (V
ISENx, ISEN1_N, ISEN2_N to GND ----------------------------------------------------------------- −0.3V to (V
PVCC to PGNDx ------------------------------------------------------------------------------------------ −0.3V to 6.5V
LGA TEx to PGNDx --------------------------------------------------------------------------------------- −0.3V to (PVCC + 0.3V)
PHASEx to PGNDx -------------------------------------------------------------------------------------- −3V to 28V
BOOTx to PHASEx--------------------------------------------------------------------------------------- −0.3V to 6.5V
UGATEx to PHASEx ------------------------------------------------------------------------------------- −0.3V to (BOOTx − PHASEx)
PGOOD------------------------------------------------------------------------------------------------------ −0.3V to (V
Power Dissipation, P
@ T
D
= 25°C
A
WQFN−40L 6x6-------------------------------------------------------------------------------------------- 2.941W
Package Thermal Re sistance (Note 2)
WQF N-40L 6x6, θJA--------------------------------------------------------------------------------------- 34°C/W
WQFN-40L 6x6, θJC-------------------------------------------------------------------------------------- 6°C/W
Junction T emperature------------------------------------------------------------------------------------- 150°C
Lead T e mperature (Soldering, 10 sec.)--------------------------------------------------------------- 26 0°C
Storage T emperature Range ---------------------------------------------------------------------------- −65°C to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode) ------------------------------------------------------------------------------ 2kV
MM (Ma chine Mode)-------------------------------------------------------------------------------------- 200V
+ 0.3V)
CC
+ 0.3V)
CC
+ 0.3V)
CC
+ 0.3V)
CC
+ 0.3V)
CC
+ 0.3V)
CC
Recommended Operating Conditions (Note 4)
Supply Voltage, V
Battery Voltage, V
Junction T emperature Range---------------------------------------------------------------------------- −40°C to 125°C
Ambient T emperature Range----------------------------------------------------------------------------
-------------------------------------------------------------------------------------- 4.5V to 5.5V
CC
-------------------------------------------------------------------------------------- 7V to 24V
IN
−40°C to 85°C
Electrical Characteristics
(V
= 5V, TA = 25°C, unless otherwise specified)
CC
Parameter Symbol Test Conditions Min Typ Max Unit
Supply Input
R
= 33k, V
Supply Current I
Shutdown Curr ent I
VCC
CC
+ I
+ I
PVCC
PVCC
FS
Not Switching
V
VRON
= 0V -- -- 5 A
Soft-Start/Slew Rate Control (based on 10nF CSS)
Soft-Start / Soft-Shutdown I
Deeper Sleep Exit/VID
Change Slew Current
V
SS1
I
V
SS2
SOFT
SOFT
= 1.5V 16 20 24 A
= 1.5V 80 100 120 A
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VRON
= 3.3V,
-- -- 10 mA
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