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DESCRIPTION (CONTINUED)

VREF

R

AC

0.010 W

(1) Pull-uprailcouldbeeitherVREForothersystemrail .

(2) SRSET/ACSET couldcomefromeitherDACorresistordividers .

Q1 (ACFET)

SI4435

Q3(BATFET)

SI4435

Controlledby

HOST

P

P

ACN

ACP

ACDET

EXTPWR

SRSET

ACSET

VREF

DAC

CELLS

CHGEN

VDAC

VADJ

DAC

ADC

IADAPT

HOST

PVCC

HIDRV

PH

BTST

REGN

LODRV

PGND

SRP

SRN

P

PACK+

PACK-

SYSTEM

ADAPTER+

ADAPTER-

EXTPWR

AGND

bq24740

C3

0.1 F

m

100pF

C5

Q4

FDS6680A

Q5

FDS6680A

L1

D1

BAT54

C14

BAT

IADSLP

ISYNSET

DPMDET

LPMD

VREF

LPREF

R91.8MW

Q2 (ACFET)

SI4435

Controlledby

HOST

C2

0.1 F

m

C8

1 F

m

C6

10 F

m

C7

10 F

m

0.010 W

8.2 H

m

C11

10 F

m

C1

10 F

m

C12

10 F

m

C13

0.1 F

m

0.1 F

m

C9

0.1 F

m

C10

1 F

m

C15

0.1 F

m

R7

200kW

R8

24.9kW

R6

33kW

R4

10kW

R5

10kW

C4

1 F

m

R2

66.5k

1%

W

R3

10kW

R1

432k

1%

W

PowerPad

C18

10 F

m

C17

10 F

m

C16

10 F

m

bq24740

SLUS736 – DECEMBER 2006

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

The bq24740 features Dynamic Power Management (DPM) and input power limiting. These features reduce

battery charge current when the input power limit is reached to avoid overloading the AC adapter when

supplying the load and the battery charger simultaneously. A highly-accurate current-sense amplifier enables

precise measurement of input current from the AC adapter to monitor the overall system power. If the adapter

current is above the programmed low-power threshold, a signal is sent to host so that the system optimizes its

power performance according to what is available from the adapter.

TYPICAL APPLICATION

Figure 1. Typical System Schematic, Voltage and Current Programmed by DAC

2

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