TPS51120 Datasheet, PDF (1/34 Pages) Texas Instruments – DUAL CURRENT MODE, SYNCHRONOUS STEP-DOWN CONTROLLER WITH 100-mA STANDBY REGULATORS FOR NOTEBOOK SYSTEM POWER

TPS51120
www.ti.com
SLUS670A – JULY 2005 – REVISED AUGUST 2005
DUAL CURRENT MODE, SYNCHRONOUS STEP-DOWN CONTROLLER WITH 100-mA
STANDBY REGULATORS FOR NOTEBOOK SYSTEM POWER
FEATURES
• 3.3-V and 5-V 100-mA Bootstrapped Standby
Regulators with Independent Enables
• Selectable D-CAP^® Mode Enables Fast
Transient Response Less than 100 ns
• Selectable Low Ripple Current Mode
• Less than 1% Internal Reference Accuracy
• Selectable PWM-only/Auto-skip Modes
• Low-side R_DS(on) Loss-less Current Sensing
• R_SENSE Accurate Current Sense Option
• Internal Soft-start and Integrated V_OUT
Discharge Transistors
• Integrated 2-V Reference
• Adaptive Gate Drivers with Integrated Boost
Diode
• Power Good for Each Channel with Delay
Timer
• Fault Disable Mode
• Supply Input Voltage Range: 4.5 V to 28 V
APPLICATIONS
• Notebook Computers System Bus and I/O
C31
1 nF
DESCRIPTION
The TPS51120 is a highly sophisticated dual current
mode synchronous step-down controller. It is a full
featured controller designed to run directly off a three-
or four-cell Li-ion battery and provide high-power and
5-V and/or 3.3-V standby regulation for all the down-
stream circuitry in a notebook computer system. High
current, 100-mA, 5-V or 3.3-V on-board linear regu-
lators have glitch-free switch over function to SMPS
and can be kept alive independently during standby
state. The pseudo-constant frequency adaptive
on-time control scheme supports full range of current
mode operation including simplified loop compen-
sation, ceramic output capacitors as well as seamless
transition to reduced frequency operation at light-load
condition. Optional D-CAP™ mode operation
optimized for SP-CAP or POSCAP output capacitors
allows further reduction of external compensation
parts. Dynamic UVP supports VIN line sag without
latch off by hitting 5V UVP. No negative voltage
appears at output voltage node during UVLO, UVP,
and OCP, OTP or loss of VIN.
The TPS51120 32-pin QFN package is specified from
–40°C to 85°C ambient temperature.
V5FILT
VO2
3.3V/6A
+
C2B
150 µF
R21
100 kΩ
EN_LDO5
P_GOOD2
EN_LDO3
VBAT
GND
8
7
6
5
4
3
2
1
R11
100 kΩ
9
EN5
10 EN3
32
SKIPSEL
TONSEL 31
GND
P_GOOD1
VBAT
11 PGOOD2
PGOOD1 30
C10
20 µF
L2
2.2 µH
C2A
150 µF
EN_2
12 EN2
Q3
IRF7821
C21
0.1 µF
13 VBST2
14 DRVH2
Q4
IRF7832
15 LL2
DRVL2
16
TPS51120RHB
(QFN−32)
PowerPAD
EN1 29
VBST1 28
DRVH1 27
LL1 26
DRVL1
25
EN_1
C11
0.1 µF
C10
20 µF
Q1
IRF7821
L1
4.7 µH
Q2
IRF7832
C1A
150 µF
+
VO1
5V/6A
C1B
150 µF
VO2_GND −
PGND2
17 18 19 20 21 22 23 24
R22
3.3 kΩ
C30
10 µF
R50
5.1W
C51
1 µF
R12
3.6 kΩ
C30
C50
NA
10 µF
VBAT
− ^VO1_GND
PGND1
UDG−05074
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
D-CAP is a registered trademark of Texas Instruments.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2005, Texas Instruments Incorporated