TPS51221 Datasheet, PDF (1/36 Pages) Texas Instruments – Fixed Frequency, 99% Duty Cycle Peak Current Mode Notebook System Power Controller

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TPS51221
SLVS786 – NOVEMBER 2007
Fixed Frequency, 99% Duty Cycle Peak Current Mode
Notebook System Power Controller
FEATURES
1
•2 Input Voltage Range: 4.5 V to 28 V
• Output Voltage Range: 1 V to 12 V
• Selectable Light Load Operation (Continuous /
Auto Skip / Out-Of-Audio™ Skip)
• Programmable Droop Compensation
• Voltage Servo Adjustable Soft Start
• 200 kHz to 1 MHz Fixed Frequency PWM
• Current Mode Architecture
• 180° Phase Shift Between Channels
• Resistor or Inductor DCR Current Sensing
• Powergood Output for each channel
• OCL/OVP/UVP/UVLO protections
• Current Monitor Output for CH1
• Thermal Shutdown (Non-latch)
• Output Discharge Function (Disable option)
• Integrated Boot Strap MOSFET Switch
• QFN32 (RTV)
APPLICATIONS
• Notebook Computer System and I/O Bus
• Point of load in LCD TV, MFP
DESCRIPTION
The TPS51221 is a dual synchronous buck regulator
controller with 2 LDOs. It is optimized for 5V/3.3V
system controller, enabling designers to cost
effectively complete 2-cells to 4-cells notebook
system power supply. The TPS51221 supports high
efficiency, fast transient response and 99% duty cycle
operation. It supports supply input voltages ranging
from 4.5V to 28V, and output voltages from 1V to
12V. Peak current mode supports stability operation
with lower ESR capacitor and output accuracy. The
high duty (99%) operation and wide input/ output
voltage range supports flexible design for small
mobile PCs and a wide variety of other applications.
The fixed frequency can be adjusted from 200 kHz to
1MHz by a resistor, and each channel runs 180° out
of phase. The TPS51221 can also synchronize to the
external clock, and the interleaving ratio can be
adjusted by its duty. The TPS51221 is available in the
32 pin 5×5 QFN package and is specified from –40°C
to 85°C.
TYPICAL APPLICATION CIRCUIT
VO1
5.0V
VBAT
L1
C11
PGND
Q11
C12
PGND
Q12
PGND
VO1
R01
VREG5
5V/100mA
C01
C14
C24
PGND
GND
PGND
32 31 30 29 28 27 26 25
1 _DRVH1
2 V5SW
3 RF
DRVH2 ²⁴
VIN 23
VREG3 22
GND EN1
PGOOD1
4 EN1
5 PGOOD1
TPS51221RTV
(QFN32)
EN2 21
PGOOD2 20
SKIPSEL1
R14
6 SKIPSEL1
7 CSP1
C13
8
CSN1
PowerPAD
SKIPSEL2 19
CSP2 18
CSN2 ₁₇
VBAT
Q21 C22
L2
PGND
Q22
C21
VO2
3.3V
PGND
PGND
C03
EN2
PGOOD2
GND
SKIPSEL2
R24
C23
VBAT
VREG3
3.3V/10mA
IMON1
R02 ^EN
VO1
C04
GND
GND
R11
R12
GND
9 10 11 12 13 14 15 16
R23
R21
R13
C02
GND
R22
GND
VREG5
VO2
1
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.
Out-Of-Audio, D-CAP, PowerPAD are trademarks of Texas Instruments.
2
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 © 2007, Texas Instruments Incorporated