TPS40090
TPS40091
SLUS578A 鈭?OCTOBER 2003 鈭?REVISED JUNE 2004
HIGH FREQUENCY,
MULTIPHASE CONTROLLER
FEATURES
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Two-, Three-, or Four-Phase Operation
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5-V to 15-V Operating Range
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Programmable Switching Frequency Up to
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D
D
D
D
D
D
D
D
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1-MHz/Phase
Current Mode Control With Forced Current
Sharing
(1)
1% Internal 0.7-V Reference
Resistive Divider Set Output Voltage
True Remote Sensing Differential Amplifier
Resistive or DCR Current Sensing
Current Sense Fault Protection
Programmable Load Line
Compatible with UCC37222 Predictive Gate
Drive錚?Technology Drivers
24-Pin Space-Saving TSSOP Package
TPS40090: Binary Output
TPS40091: Tri鈭扴tate Output
DESCRIPTION
The TPS4009x family are two-, three-, or
four-phase programmable synchronous buck
controllers, optimized for low-voltage, high-
current applications powered by a 5-V to 15-V
distributed supply. A multi-phase converter offers
several advantages over a single power stage
including lower current ripple on the input and
output capacitors, faster transient response to
load steps, improved power handling capabilities,
and higher system efficiency.
Each phase can be operated at a switching
frequency up to 1-MHz, resulting in an effective
ripple frequency of up to 4-MHz at the input and the
output in a four-phase application. A two phase
design operates 180 degrees out-of- phase, a
three-phase design operates 120 degrees out of
phase, and a four-phase design operates 90
degrees out of phase as shown in Figure 1.
The number of phases is programmed by con鈭?/div>
necting the de-activated phase PWM output to the
output of the internal 5-V LDO. In two-phase
operation the even phase outputs should be
de-activated.
The TPS4009x uses fixed frequency, peak current
mode control with forced phase current balancing.
When compared to voltage mode control, current
mode results in a simplified feedback network and
reduced input line sensitivity. Phase current is
sensed by using either current sense resistors
installed in series with output inductors or, for
improved efficiency, by using the DCR (direct
current resistance) of the filter inductors. The
latter method involves generation of a current
proportional signal with an R-C circuit (shown in
Figure 10.
The R-C values are selected by matching the time
constants of the R-C circuit and the inductor;
R-C = L/DCR. With either current sense method,
the current signal is amplified and superimposed
on the amplified voltage error signal to provide
current mode PWM control.
Copyright
錚?/div>
1999 鈭?2003, Texas Instruments Incorporated
APPLICATIONS
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Internet Servers
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Network Equipment
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Telecommunications Equipment
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DC Power Distributed Systems
PW PACKAGE
(TOP VIEW)
CS1
CS2
CS3
CS4
CSCN
ILIM
DROOP
REF
COMP
FB
DIFFO
VOUT
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
EN/SYNC
VIN
BP5
PWM1
PWM2
PWM3
PWM4
GND
RT
SS
PGOOD
GNDS
(1) Patent pending
Predictive Gate Drive is a trademark of Texas Instruments Incorporated.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
www.ti.com
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