Texas Instruments TPS40090EVM-002 - Manuals

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 ...

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) ...

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...

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...

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...

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...

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...

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 ...

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%....

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...

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,...

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...

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 ...

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

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)

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

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...