TPS51120_15 Datasheet, PDF (1/41 Pages) Texas Instruments – TPS51120 Dual, Synchronous Step-Down Controller With 100-mA Standby Regulators for Notebook System Power

Product
Folder
Sample &
Buy
Technical
Documents
Tools &
Software
Support &
Community
TPS51120
SLUS670C – JULY 2005 – REVISED JANUARY 2015
TPS51120 Dual, Synchronous Step-Down Controller With 100-mA Standby Regulators for
Notebook System Power
1 Features
•1 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
• Powergood for Each Channel with Delay Timer
• Fault Disable Mode
• Supply Input Voltage Range: 4.5 V to 28 V
2 Applications
Notebook Computers System Bus and I/O
3 Description
The TPS51120 is a highly sophisticated dual,
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
downstream circuitry in a notebook computer system.
High-current, 100-mA, 5-V or 3.3-V on-board linear
regulators 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
compensation, 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 5-V 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.
Device Information⁽¹⁾
PART NUMBER PACKAGE
BODY SIZE (NOM)
TPS51120
VQFN (32)
5.00 mm × 5.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Reference Design for D-CAP Mode Converter
C31
1 nF
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
5.1Ω
C51
1 µF
R12
3.6 kΩ
C30
C50
NA
10 µF
VBAT
− VO1_GND
PGND1
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.