1.2MHz, Low-Cost,

High-Performance Chargers

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11

CSA

A = 17.5V/V

CSSN

CSSP

Gm =

2.8

μA/mV

IINP

GMS

CSIN

CSIP

GMI

ISET

26mV

CHARGER

SHUTDOWN

CELL

SELECT

LOGIC

BATT

VCTL

GMV

CC

LOWEST

VOLTAGE

CLAMP

CSI

60mV

PWM

FILTER

DHI

DLO

PGND

LX

BST

LEVEL

SHIFT

HIGH-SIDE

DRIVER

LOW-SIDE

DRIVER

CCMP

IMIN

IMAX

IZX

10mV

OVP

DC-DC

CONVERTER

110mV

10mV

BDIV

BDIV

VCTL + 100mV

5.4V LINEAR

REGULATOR

4.2V

REFERENCE

DCIN

LDO

POWER

FAIL

LDO

AGND

BATT

ACOK

LDO

ACIN

MAX17005A

MAX17006A

MAX17015A

CSA

A = 17.5V/V

Figure 2. Functional Diagram

The MAX17005A/MAX17006A/MAX17015A feature a

voltage-regulation loop (CCV) and two current-regula-

tion loops (CCI and CCS). The loops operate indepen-

dently of each other. The CCV voltage-regulation loop

monitors BATT to ensure that its voltage never exceeds

the voltage set by VCTL. The CCI battery charge cur-

rent-regulation loop monitors current delivered to BATT

to ensure that it never exceeds the current limit set by

ISET. The charge current-regulation loop is in control as

long as the battery voltage is below the set point. When

the battery voltage reaches its set point, the voltage-

regulation loop takes control and maintains the battery

voltage at the set point. A third loop (CCS) takes control

and reduces the charge current when the adapter cur-

rent exceeds the input current limit.

The MAX17005A/MAX17006A/MAX17015A have single-

point compensation. The two current loops are internal-

ly compensated while the voltage loop is compensated

with a series RC network at CC pin. See the

CC Loop

Compensation section for the resistor and capacitor

selection. A functional diagram is shown in Figure 2.