How it Works
Texas Instruments
Loading...
TPS40090EVM-002
User Manual
26 pgs734.31 Kb0

Texas Instruments TPS40090EVM-002 User Manual

User’s Guide
  
User’ s Gu ide
1
EVM IMPORTANT NOTICE
Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION
Should this evaluation kit not meet the specifications indicated in the EVM User’s Guide, the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR S TA TUTOR Y, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user indemnifies TI from all claims arising from the handling or use of the goods. Please be aware that the products received may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge.
EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
TI currently deals with a variety of customers for products, and therefore our arrangement with the user is not exclusive.
TI assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or services described herein.
Please read the EVM User’s Guide and, specifically, the EVM Warnings and Restrictions notice in the EVM User’s Guide prior to handling the product. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact the TI application engineer.
Persons handling the product must have electronics training and observe good laboratory practice standards. No license is granted under any patent right or other intellectual property right of TI covering or relating to any
machine, process, or combination in which such TI products or services might be or are used.
Mailing Address:
Texas Instruments Post Office Box 655303 Dallas, Texas 75265
Copyright 2003, Texas Instruments Incorporated
2
DYNAMIC WARNINGS AND RESTRICTIONS
It is important to operate this EVM within the input voltage range of 0 Vdc to100 Vdc. Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM.
If there are questions concerning the input range, please contact a TI field representative prior to connecting the input power.
Applying loads outside of the specified output range may result in unintended operation and/or possible permanent damage to the EVM. Please consult the EVM User’s Guide prior to connecting any load to the EVM output. If there is uncertainty as to the load specification, please contact a TI field representative.
During normal operation, some circuit components may have case temperatures greater than 50°C. The EVM is designed to operate properly with certain components above 50°C as long as the input and output ranges are maintained. These components include but are not limited to linear regulators, switching transistors, pass transistors, and current sense resistors. These types of devices can be identified using the EVM schematic located in the EVM User’s Guide. When placing measurement probes near these devices during operation, please be aware that these devices may be very warm to the touch.
Mailing Address:
Texas Instruments Post Office Box 655303 Dallas, Texas 75265
Copyright 2004, Texas Instruments Incorporated
3
SLUU195 − June 2004
r
TPS40090 Multi-Phase Buck Converter and TPS2834
Drivers Steps-Down from 12-V to 1.5-V at 100 A
Systems Powe
Contents
1 Introduction 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Features 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Schematic 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Component Selection 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Test Setup 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 Test Results/Performance Data 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 Layout Considerations 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 EVM Assembly Drawing and PCB Layout 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 List of Materials 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Introduction
The TPS40090EVM−002 multi-phase dc-to-dc converter utilizes the TPS40090 multi-phase controller and TPS2834 adaptive driver to step down a 12-V input to 1.5-V at 420 kHz. The output current can exceed 100 A. The TPS40090 provides fixed-frequency, peak current-mode control with forced-phase current balancing. Phase currents are sensed by the voltage drop across the DC resistance (DCR) of inductors. Other features include a single voltage operation, true differential output voltage sense, user programmable current limit, capacitor-programmable soft-start and a power good indicator. Device operation is specified in the TPS40090 datasheet
TPS40090EVM-002 can be configured into 2-, 3− or 4-phase operation. For 2-phase operation, populate R65 and R66 to tie PWM2 and PWM4 up to internal 5-V and leave components in related phases unpopulated. For 3-phase operation, tie PWM4 to BP5 through R66 only. For 4-phase operation, leave both R65 and R66 unpopulated.
In this user’s guide, all the tests are conducted under 4 phase operation.
[1]
.
4
TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A
2 Features
Load transient response voltage
Load transient response voltage Load transient response recovery
Load transient response recovery
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Input voltage range 10.5 12.0 14.0 Output voltage set point 1.477 1.508 1.540 Output current range VIN = 12 V 0 100 120 A
Line regulation Load regulation I
change
time Loop bandwidth I
Phase margin I Input ripple voltage 80 200 Output ripple voltage 15 25 Output rise time ms Operating frequency 370 418 454 kHz
Full load efficiency
Current sharing tolerance
Table 1. TPS40090EVM−002 Performance Summary
I
rising from 10 A to 100 A,
(1)
OUT
10.5 V ≤ VIN ≤ 14 V rising from 10 A to 100 A ±0.3%
OUT
I
rising from 10 A to 100 A −160
OUT
I
falling from 100 A to 10 A 200
OUT
I
rising from 10 A to 100 A < 10
OUT
I
falling from 100 A to 10 A < 15
OUT
= 100 A, I
OUT
= 100 A 40 °
OUT
VIN = 12 V, V I
= 100 A
OUT
VIN = 12 V, V I
= 100 A
OUT
= 10 A 89 kHz
OUT
= 1.5 V,
OUT
= 1.5 V,
OUT
SLUU195 − June 2004
±0.1%
84.3%
±5% ±10%
mV
mV
V
PK
µs
PK
3 Schematic
12V
+
+
Phase Programming R65 R66 4−phase open open 3−phase open 1k 2−phase 1k 1k
Figure 1. TPS40090EVM−002 Schematic Part 1 − TPS40090 Controller and Pre-Bias Circuit
TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A
5
SLUU195 − June 2004
TRANS_EN
Figure 2. TPS40090EVM−002 Schematic Part 2 − Driver Circuit and Load Transient Generator
6
TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A
SLUU195 − June 2004
(1)
+ +
+ +
Figure 3. TPS40090EVM−002 Schematic Part 3 − Power Stage
4 Component Selection
4.1 Frequency of Operation
+ + +
+
1.5V/100A
The clock oscillator frequency for the TPS40090 is programmed with a single resistor from RT (pin 16) to signal ground. Equation (1) from the datasheet allows selection of the R
resistor in
T
kΩ for a given switching frequency in kHz.
+ R12 + K
R
T
PH
ǒ
39.2 103 f
*1.024
PH
* 7
Ǔ
(kW)
where
• K
• f
• for 2-phase and 3-phase configurations K
• for 4-phase K
The R
T
is the coefficient that depends on the number of active phases
PH
is the single phase frequency, in kHz
PH
=1.333
PH
=1.0 is a single phase frequency, kHz.
PH
resistor value is returned by the last expression in kΩ. For 420 kHz, RT is calculated as
65.8 kΩ and a resistor with a 64.9-kΩ standard value is used.
TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A
7
SLUU195 − June 2004
(2)
(3)
4.2 Inductance Value
The output inductor value for each phase can be calculated from the volt-second during off time, shown in equation (2).
V
L +
where
• I
RIPPLE
With I
RIPPLE
to be 0.63 µH. Using SPM12550−R62M300 inductors from TDK, each had inductance of 0.6µH and resistance of 1.75-mΩ.
In multi-phase high current buck converter design, due to the ripple cancellation factor from interleaving, the inductor value could be smaller than that in a single phase operation. But from conduction loss point of view, the inductor value tends to be big to reduce the ripple current, thus losses.
4.3 Input Capacitor Selection
The bulk input capacitor selection is based on the input voltage ripple requirements. Due to the interleaving of multi phase, the input RMS current is reduced. The input ripple current RMS value over load current is calculated in equation (3).
D I
IN(nom)
OUT
f I
RIPPLE
is usually chosen to be between 10% and 40% of maximum phase current I
= 20% of I
ǒ
NPH,D
ǒ1*
PH(max)
Ǔ
+
V
OUT
V
IN(max)
Ǔ
PH(max)
, there is a ripple current of 5 A, and the inductance value is found
.
2
D *
ǒ
NPH,D
k
ȱ ȧ
ǒ
Ȳ ȱ
ǒ
kǒNPH,DǓ) 1
ȧ Ȳ
where
ǒ
• k
NPH,DǓ+ floorǒNPH D
• floor(x) is the function to return the greatest integer less than N
• N
Figure 4 shows the input ripple current RMS value over the load current versus duty cycle with different number of active phases.
is the number of active phases
PH
Ǔ
N
Ǔ ǒ
PH
2
Ǔ
kǒNPH,DǓ) 1
D *
ǒ
N
PH
ǒ
NPH,D
k
N
Ǔ
Ǔ
Ǔ
PH
ȳ
* D
Ǔ
ȧ
)
ȴ
3
) kǒNPH,D
N
ǒ
12 D
Ǔ
PH
Ǔ
2
kǒNPH,DǓ) 1
2
ǒ
V
ƪ
L f
N
OUT
PH
PH
× D
(
1 * D
ǒ
I
OUT
* D
Ǔ
Ǔ
)
ƫ
3
ȳ ȧ ȴ
8
TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A
Loading...
+ 18 hidden pages
Buy Points How it Works FAQ Contact Us Questions and Suggestions Privacy Policy Cookie Policy Terms of Use