Page 2 - EVM IMPORTANT NOTICE
2 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 EVALUATIONPURPOSES ONLY and is not considered by TI to be fit for commercial use. As such, the goods ...
Page 3 - DYNAMIC WARNINGS AND RESTRICTIONS
3 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 f...
Page 4 - Systems Power; Introduction
SLUU195 − June 2004 4 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A Systems Power Contents 1 Introduction 4 . . . . . . . . . . . . . . . . . . . . . . . . ...
Page 7 - Component Selection; Frequency of Operation; PH
SLUU195 − June 2004 7 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A + + + 1.5V/100A + + + + + Figure 3. TPS40090EVM−002 Schematic Part 3 − Power Stage 4 Component Selection 4.1 Frequency of Operation The clock oscillator frequency for the TPS40090 is ...
Page 8 - Inductance Value; RIPPLE; Input Capacitor Selection; floor
SLUU195 − June 2004 8 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 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). L + V OUT f I RIPPLE ǒ 1 * V OUT V IN(max) ...
Page 9 - Figure 4. Input Ripple Current RMS Value Overload Current; The maximum input ripple RMS current can be estimated as shown in (4).; ESR; Output Ripple Cancellation and Capacitor Selection; ǒŤ; if
SLUU195 − June 2004 9 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 0 0.1 0.2 0.5 0.6 0.4 0.3 0 10 20 30 40 50 60 70 80 90 100 Duty Cycle − % I RMS_CIN(nom) − Normalized RMS Input − A NPH = 1 NPH = 2 NPH = 3 NPH = 4 NPH = 6 Figure 4. Input Ripple Curr...
Page 10 - Figure 5. Output Ripple Current Cancellation
SLUU195 − June 2004 10 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A where • D is the duty cycle for a single phase • N PH is the number of active phases • K (N PH ) is the intermediate function for calculation In this case, N PH =4 and D min =0.107 w...
Page 11 - OH; MOSFET Selection; DCR
SLUU195 − June 2004 11 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 3. Transient consideration. An additional consideration in the selection of the output inductor and capacitance value can be derived from examining the transient voltage overshootwhi...
Page 12 - NTC; Overcurrent Limit Protection; If the threshold of V; ILIM; where
SLUU195 − June 2004 12 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A With the chosen inductor described in Inductance Value, (section 4.2, of this document) thefollowing values are used. • R=19.6 k Ω • C=10 nF • R NTC =100 k Ω • R1=124 k Ω • R2=22.6 k...
Page 13 - Compensation Components; The ESR zero of the power stage is:; The resulting values selected for this design are:
SLUU195 − June 2004 13 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 4.8 Compensation Components The TPS40090 uses peak current mode control. Type II network is used here, which isimplemented to provide one zero and two poles. The first pole is placed...
Page 14 - Test Setup; Figure 7. Connections for the Test
SLUU195 − June 2004 14 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 5 Test Setup The HPA072 has the following input/output connections: 12-V input J1 (VIN) and J2 (GND),1.5-V output J9 (VOUT) and J10 (GND). A diagram showing the connection points is ...
Page 15 - Test Results and Performance Data; Efficiency and Power Loss
SLUU195 − June 2004 15 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 6 Test Results and Performance Data 6.1 Efficiency and Power Loss Figure 8 shows the efficiency as the load varies from 10 A to over 100 A. The efficiency at fullload is about 84.3%....
Page 16 - Closed-Loop Performance; GAIN AND PHASE; Output Ripple and Noise; Figure 11 shows typical output noise where V; IN; Figure 11. Output Noise
SLUU195 − June 2004 16 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 6.2 Closed-Loop Performance The TPS40090 uses peak current-mode control. Figure 10 shows the bode plots at 100 A ofload current, where no droop function is implemented. The crossover...
Page 17 - Transient Response; s for; Figure 12. Transient Response
SLUU195 − June 2004 17 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 6.4 Transient Response The on-board load transient circuit enables to check the step load transient response on thesame board. Simply by putting a jumper to connect Pin1 and 2 of J3,...
Page 18 - Start up with Pre-Biased Output; Figure 13. J11 Short Circuit
SLUU195 − June 2004 18 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 6.5 Start up with Pre-Biased Output In synchronous buck converter, the bottom FET discharges the pre-biased output duringstart-up. To avoid this, a comparator U9 and surround compone...
Page 19 - Layout Considerations
SLUU195 − June 2004 19 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 7 Layout Considerations The PCB layout plays a critical role in the performance in a high frequency switching powersupply design. Following the suggestions listed below will help to ...
Page 20 - EVM Assembly Drawing and PCB Layout; Figure 15. Top Side Component Assembly
SLUU195 − June 2004 20 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 8 EVM Assembly Drawing and PCB Layout Figure 15. Top Side Component Assembly Figure 16. Bottom Assembly
Page 21 - Figure 17. Top Side Copper
SLUU195 − June 2004 21 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A Figure 17. Top Side Copper Figure 18. Internal 1 (Ground Plane)
Page 22 - Figure 20. Internal 3
SLUU195 − June 2004 22 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A Figure 19. Internal 2 (Power Plane) Figure 20. Internal 3
Page 24 - List of Materials; Table 2. List of Materials
SLUU195 − June 2004 24 TPS40090 Multi-Phase Buck Converter and TPS2834 Drivers Steps-Down from 12-V to 1.5-V at 100 A 9 List of Materials The following table lists the TPS40090EVM−002 components corresponding to the schematicshown in Figure 1. Table 2. List of Materials Reference Designator QTY Desc...
