TPS40400_1110 Datasheet, PDF (57/72 Pages) Texas Instruments – 3.0-V TO 20-V PMBus SYNCHRONOUS BUCK CONTROLLER

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TPS40400
SLUS930B – APRIL 2011 – REVISED OCTOBER 2011
Remote Sensing
Remote sensing can be accomplished with the differential amplifier as shown in Figure 22. Resistors RS1 and
RS2 (R7 and R18 in the schematic above) are used if the sense connections fail or get damaged. The values of
RS1 and RS2 are bound by an upper value such that the voltage drop across them does not introduce
appreciable voltage regulation error from the bias current, and a lower value such that the voltage drop in the
load wires which appears across these resistors does not dissipate appreciable power. Values between 10 Ω to
50 Ω are usually chosen.
U1
TPS40400
1 CLK
DATA 24
2 CNTL SMBALT 23
C2
3 PG
ADDR1 22
R2 C1
4 SYNC ADDR0 21
Rbias
C3 ^R3
R1
5 TRACK VDD 20
6 COMP HDRV 19
7 FB
BOOT 18
VOUT
+SENSE
Rs 1
LOAD
PGND
-SENSE
Rs2
8 DIFFO
9 VSNS+
10 VSNS-
11 ISNS-
SW 17
LDRV 16
GND 15
BP6 14
12 ISNS+
BP3 13
SGND
PAD
Figure 22. Remote Sense Schematic
Copyright © 2011, Texas Instruments Incorporated
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