DESCRIPTION (CONTINUED)

VREF

0.010 Ω

0.010 Ω

Q2 (ACFET)

SI4435

Q3(BATFET)

SI4435

P

P

ACN

ACP

ACDRV

ACDET

/ACGOOD

SRSET

ACSET

VREF

CELLS

CHGEN

VDAC

VADJ

ADC

IADAPT

HOST

PVCC

BATDRV

HIDRV

PH

BTST

REGN

LODRV

PGND

SRP

SRN

P

PACK+

PACK-

SYSTEM

ADAPTER +

ADAPTER -

ACGOOD

AGND

bq24751

2.2 µF

C1

432 kΩ

1%

66.5 kΩ

1%

R1

R2

10 kΩ

R5

1 µF

C4

100 pF

C5

0.1 µF

C8

Q4

FDS6680A

Q5

FDS6680A

0.1 µF

C9

L1

8.2 µH

D1

BAT54

1 µF

C10

BAT

OVPSET

422 kΩ

1%

R3

71 kΩ

1%

R4

LEARN

ACOP

Q1 (ACFET)

SI4435

10 µF

C6

C15

0.1 µF

C16

0.47 µF

0.1 µF

C2

C3

2 Ω

R10

0.1 µF

PowerPad

10 µF

C7

10 µF

C12

C14

0.1 µF

C13

0.1 µF

C11

10 µF

GPIO

DAC

DAC

bq24751

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 bq24751 controls external switches to prevent battery discharge back to the input, connect the adapter to

the system, and to connect the battery to the system using 6-V gate drives for better system efficiency. For

maximum system safety, inrush-power limiting provides instantaneous response to high input voltage multiplied

by current. This AC Over-Power protection (ACOP) feature limits the input-switch power to the programmed level

on the ACOP pin, and latches off if the high-power condition persists to prevent overheating.

The bq24751 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.

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

2

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