MAX15034BAUI 데이터 시트보기 (PDF) - Maxim Integrated

부품명

상세내역

제조사

MAX15034BAUI

Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications

Maxim Integrated 

Configurable, Single-/Dual-Output, Synchronous

Buck Controller for High-Current Applications

LX_

MAX15034

SENSE RESISTOR (INDUCTIVE)

LOUT

ESL

RSENSE

VOUT

R1

C1

CSP_

C2

CSN_

R2

C3

Figure 10. Inductive Sense Resistor

The MAX15034 provides precision average current-limit

programmability while using standard sense resistors

or shunts. Use the equation below to determine the

appropriate VAVGLIMIT external reference voltage at

AVGLIMIT:

( ) VAVGLIMIT = 56 × RSENSE[mΩ] × ILOAD(MAX)[A] + 612.5mV

For example, assuming the desired average current

limit is 18A, and RSENSE = 2mΩ.

VAVGLIMIT = (2mΩ × 36 × 18A) + 612.5mV

= 1910mV = 1.91V

where RSENSE is determined from maximum load cur-

rent, wattage rating, and circuit parasitics (see above)

and ILOAD(MAX) from circuit requirements. VAVGLIMIT is

the average current-limit reference voltage selected for

a desired ILOAD(MAX) and is set by a resistive voltage-

divider from REG to AGND. See the Programming the

Average Current Limit section.

The second current-protection circuit is the hiccup fault

protection as explained in the Hiccup Fault Protection

section. The average current during a short at the out-

put is given by:

IAVG(SHORT) = 0.0625 × ILOAD(MAX)

Programming the Average Current Limit

The MAX15034 average current-limit reference voltage

is set by connecting a resistor-divider network from

REG to AGND, the center node is connected to

AVGLIMIT. The resistive divider’s upper resistor, R1, is

connected between REG and the AVGLIMIT. The resis-

tive divider’s lower resistor, R2, is connected between

the AVGLIMIT and AGND.

The resistor-divider values are determined by first,

choosing R2. To minimize reference noise select R2

such that (R1 + R2) < 100kΩ; a typical value is 10kΩ.

Next, determine R1 from:

R1 =

R2

×

⎛

⎝⎜

VREG

VAVGLIMIT

−

⎞

1⎠⎟

=

10kΩ

×

⎛

⎜

⎝

5V

VAVGLIMT(MAX) [V]

−

⎞

1⎟

⎠

From the example above, assuming VAVGLIMIT = 1.91V:

R1 =

10kΩ

×

⎛

⎝⎜

5V

1.91V

− 1⎞⎠⎟

=

16.18kΩ

A standard value for R1 is 16.2kΩ. Connect AVGLIMIT

to AGND for default current limit

⎛

⎝⎜

20.4mV

RSENSE

⎞

⎠⎟

.

22 ______________________________________________________________________________________

Share Link: