TPS51513 datasheet(21/37 Pages) TI

21 / 37 page

–25

1.05

1.00

1.15

1.10

1.40

1.35

1.50

1.45

1.25

1.20

1.30

125

100

CS(eff)

– Temperature – °C

P _ N

CS(eff )

DCR

SEQU

P _ N

(

)

PAR

NTC

SERIES

P _ N

PAR

NTC

SERIES

( )

RIPPLE

MAX

TRIPSEL min

CS eff

TPS51513

www.ti.com ...................................................................................................................................................................................................... SLUS956 – JUNE 2009

EFFECTIVE OUTPUT RESISTANCE

TEMPERATURE

Figure 11.

In this case, the nearest standard values are:

• R

SEQU = 2.61 kΩ;

• R

SERIES = 3.16 kΩ;

• R

PAR = 12.7 kΩ

• C

SENSE =180 nF

Note the effective divider ratio for the inductor DCR. The effective current sense resistance (RCS_Eff) is:

RP_N is the series/parallel combination of RNTC, RSERIES and RPAR.

RCS_Eff is 1.31mΩ. Choose the value of TRIPSEL so the minimum TRIPSEL voltage is just above the voltage

across the current sense pins at the valley point of the current waveform. Maximize the value of RCS_Eff for

improved circuit performance.

In this case, the TRIPSEL minimum value needs to be greater than 29.8 mV; the next highest value in the

parameter table is 31.4 mV. This value corresponds to connecting TRIPSEL to VREF and RSLEW to VREF.

Step Six: Determine the output capacitor configuration. In general, for a system with a load-line, the ESR of the

output capacitors should be equal to or less than the load-line value. The magnitude and slew rate of the

dynamic load also drives the capacitor choice, as does the inductor selection. For highly dynamic systems, a

successful design has a combination of bulk and ceramic capacitance totaling approximately 1000

µF.

Submit Documentation Feedback

Product Folder Link(s) :TPS51513

TPS51513 Datasheet(PDF) 21 Page - Texas Instruments

TPS51513 Datasheet(HTML) 21 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37

Datasheet Download

Link URL