PIFE32251B-R47MS datasheet(38/96 Pages) TI1

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OUT

IN(MIN)

OUT

ripple(min)

max

IN(MIN)

sw(max)

)

ripple(min)

DSON

LIM

ILIM

LIMREF

1.3

u u

u ¨

TPS65094

SWCS133C – SEPTEMBER 2015 – REVISED FEBRUARY 2019

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Detailed Description

6.3.3.4

Current Limit

The buck controllers (BUCK1, BUCK2, and BUCK6) have inductor-valley current-limit architecture and the

current limit is programmable by an external resistor at the ILIMx pin. Equation 1 shows the calculation for

a desired resistor value, depending on specific application conditions. ILIMREF is the current source out of

the ILIMx pin that is typically 50 µA, and RDSON is the maximum channel resistance of the low-side FET.

The scaling factor is 1.3 to take into account all errors and temperature variations of RDSON, ILIMREF, and

RILIM. Finally, 8 is another scaling factor associated with ILIMREF.

where

•

ILIM is the target current limit. An appropriate margin must be allowed when determining ILIM from

maximum output DC load current.

•

Iripple(min) is the minimum peak-to-peak inductor ripple current for a given VOUT.

(1)

where

•

Lmax is maximum inductance

•

fsw(max) is maximum switching frequency

•

VIN(MIN) minimum input voltage to the external power stage

(2)

The buck converter limit inductor peak current cycle-by-cycle to IIND_LIM is specified in Section 5.8,

Electrical Characteristics: Synchronous Buck Converters.

PIFE32251B-R47MS 数据表(PDF) 38 Page - Texas Instruments

PIFE32251B-R47MS 数据表(HTML) 38 Page - Texas Instruments

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