MAX17409 데이터 시트보기 (PDF) - Maxim Integrated

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MAX17409

1-Phase Quick-PWM GPU Controller

Maxim Integrated 

1-Phase Quick-PWM GPU Controller

DH

NH

LX

MAX17409 DL

NL

PGND

INPUT (VIN)

CIN

L

DL

SENSE RESISTOR

LESL

RSENSE

R1

CEQ

COUT

CEQR1 =

LSENSE

RSENSE

CSP

CSN

A) OUTPUT SERIES RESISTOR SENSING

DH

NH

LX

MAX17409 DL

NL

PGND

CSP

CSN

B) LOSSLESS INDUCTOR SENSING

Figure 3. Current-Sense Methods

INPUT (VIN)

CIN

INDUCTOR

L

RDCR

DL

R1

R2

CEQ

COUT

RCS

=

R2

R1 + R2

RDCR

[ ] L

RDCR = CEQ

1

R1

+

1

R2

FOR THERMAL COMPENSATION:

R2 SHOULD CONSIST OF AN NTC RESISTOR IN

SERIES WITH A STANDARD THIN-FILM RESISTOR.

Feedback Adjustment Amplifiers

Voltage-Positioning Amplifier

(Steady-State DC Droop)

The MAX17409 includes a transconductance amplifier

for adding gain to the voltage-positioning sense path.

The amplifier’s input is generated by the differential cur-

rent-sense inputs, which sense the inductor current by

measuring the voltage across either current-sense

resistors or the inductor’s DCR. The amplifier’s output

connects directly to the regulator’s voltage-positioned

feedback input (FB), so the resistance between FB and

the output-voltage sense point determines the voltage-

positioning gain:

VOUT = VTARGET - RFBIFB

where the target voltage (VTARGET) is defined in the

Nominal Output-Voltage Selection section, and the FB

amplifier’s output current (IFB) is determined by the cur-

rent-sense voltages:

IFB = Gm(FB) x (VCSP - VCSN)

where VCSP - VCSN is the differential current-sense volt-

age, and Gm(FB) is typically 600µS, as defined in the

Electrical Characteristics table.

Differential Remote Sense

The MAX17409 includes differential, remote-sense

inputs to eliminate the effects of voltage drops along the

PCB traces and through the processor’s power pins.

The feedback-sense node connects to the voltage-posi-

tioning resistor (RFB). The ground-sense (GNDS) input

connects to an amplifier that adds an offset directly to

the target voltage, effectively adjusting the output volt-

age to counteract the voltage drop in the ground path.

Connect the voltage-positioning resistor (RFB) and

ground-sense (GNDS) input directly to the processor’s

remote-sense outputs as shown in Figure 1.

Integrator Amplifier

An integrator amplifier forces the DC average of the FB

voltage to equal the target voltage. This transconduc-

tance amplifier integrates the feedback voltage and

provides a fine adjustment to the regulation voltage

18 ______________________________________________________________________________________

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