TPS51125_16 Datasheet, PDF (23/33 Pages) Texas Instruments – Dual-Synchronous, Step-Down Controller With Out-of-Audio Operation and 100-mA LDOS for Notebook System Power

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8 Application and Implementation
TPS51125
SLUS786H – OCTOBER 2007 – REVISED JANUARY 2015
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The TPS51125 is typically used as a dual-synchronous buck controller, which convert an input voltage ranging
from 5.5 V to 28 V, to output voltage 5 V and 3.3 V respectively, targeted for notebook system-power supply
solutions.
8.2 Typical Application
3.3V/100mA
SGND
R1
13kW
R5
130kW
SGND
R2
20kW
R3
20kW
VREF
C6
0.22mF
R4
30kW
R6
130kW
SGND
VIN
VIN
6
5
4
3
2
1
VO2
3.3V/8A
VO2_GND
EN0
C1
10mF
C2
10mF
PGND
L1
3.3mH
C3
10mF
PGND
Q1
IRF7821
C4
0.1mF
C5
POSCAP
330mF
Q2
FDS6690AS
7 VO2
8 VREG3
R7
5.1W
9 VBST2
10 DRVH2
11 LL2
12 DRVL2
TPS51125RGE
(QFN24)
PowerPAD
VO1 24
PGOOD 23
R8
100kW VREG5
VBST1 22
DRVH1 21
R9
5.1W
C7
0.1mF
LL1 20
DRVL1 19
C8
10mF
C9
10mF
PGND
Q3
IRF7821 ^L2
3.3mH
Q4
FDS6690AS
C10
POSCAP
330mF
PGND
PGND
SGND
13 14 15 16 17 18
PGND
PGND
VREG5
S1
R10
620kW
SGND
VREF
C11
33mF
PGND
PGND
VO1
C13
100nF
D1
D2
C12
100nF
D3
C14
100nF
C15
100nF
D4
C16
1uF
PGND
Figure 34. 5-V/8-A, 3.3-V/8-A Application Circuit (245-kHz/305-kHz Setting)
VIN
5.5 ~ 28V
VO1
5V/8A
VO1_GND
5V/100mA
15V/10mA
8.2.1 Design Requirements
Table 3. Design Parameters
PARAMETER
Input voltage range
Channel 1 output voltage
Channel 1 output current
Channel 2 output voltage
Channel 2 output current
VALUE
5.5 V to 28 V
5V
8A
3.3 V
8A
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