1.2MHz, Low-Cost,

High-Performance Chargers

10

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BATT

ADAPTER

BST

CSSP

CSSN

DHI

LX

DLO

PGND

RS1

15m

Ω

CSIN

CSIP

BATT

BATTERY

CC

VCTL

ISET

LDO

AGND

IINP

ADAPTER

PWM SIGNAL

R1

22.6k

Ω

C4

0.68

μF

C2

0.1

μF

C5

0.01

μF

R2

R3

R4

200k

Ω

R6

200k

Ω

RS2

10m

Ω

N1

N2

N3

N4

Q1b

C3

1

μF

C1

4.7

μF

R7

R8

ONLY FOR MAX17015B

L1

SYSTEM LOAD

D1

C6

1

μF

μF

μF

L1 = 2

μH

R9

2M

Ω

Q1a

DCIN

C7

0.1

μF

ACIN

ACOK

LDO

10k

Ω

MAX17005B

MAX17006B

MAX17015B

Figure 1. Typical Operating Circuit

Detailed Description

The MAX17005B/MAX17006B/MAX17015B include all

the functions necessary to charge Li+, NiMH, and NiCd

batteries. An all n-channel synchronous-rectified step-

down DC-DC converter is used to implement a preci-

sion constant-current, constant-voltage charger. The

charge current and input current-limit sense amplifiers

have low-input offset errors (250μV typ), allowing the

use of small-value sense resistors.

The MAX17005B/MAX17006B/MAX17015B use a new

thermally optimized high-frequency architecture. With this

new architecture, the switching frequency is adjusted to

control the power dissipation in the high-side

MOSFET. Benefits of the new architecture include

reduced output capacitance and inductance, resulting in

smaller PCB area and lower cost.