ZSPM4521

High-Efficiency Charger for Li-Ion Batteries with Photovoltaic Sources

© 2013 Zentrum Mikroelektronik Dresden AG

— Rev.1.00 — February 14, 2013. All rights reserved. The material contained herein may not be reproduced, adapted, merged,

translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.

For more information, contact ZMDI via analog@zmdi.com.

Photovoltaic Cells

Battery

(optional)

VDD

(optional)

VDD

GND

EN

VTHERM

SW

NFLT

VBAT

SCL

PGND

VIN

SDA

VTH_REF

VSENSE

VDD

ZSPM4521

Brief Description

The ZSPM4521 is a DC/DC synchronous switching

lithium-ion (Li-Ion) battery charger with fully inte-

grated power switches, internal compensation, and

full fault protection. It uses a temperature-indepen-

dent photovoltaic maximum power point tracking

(MPPT) function to optimize power output from the

source during Full-Charge Constant-Current (CC)

Mode. Its switching frequency of 1MHz enables the

use of small filter components, resulting in smaller

board space and reduced bill-of material costs.

During Full-Charge Constant-Current Mode, the duty

cycle is controlled by the MPPT regulator. Once the

battery’s termination voltage is reached, the regula-

tor operates in Constant Voltage Mode. In this mode,

the ZSPM4521 modulates the charging current until

the battery reaches full charge. When the regulator

is disabled (the EN pin is low), the device draws

10µA (typical) quiescent current (Disabled Mode).

The

ZSPM4521

includes

supervisory

reporting

through the NFLT (inverted fault) open-drain output

to interface other components in the system. Device

programming is achieved by an I²C

™* interface

through the SCL and SDA pins.

Benefits



Up to 1.5A of continuous output current in Full-

Charge Constant Current (CC) Mode



High efficiency

– up to 92% with typical loads

Available Support



Evaluation Kit



Documentation

* I

Features



Temperature-independent photovoltaic maximum

power tracking (MPPT) regulator



VBAT reverse-current blocking



Programmable temperature-compensated

termination voltage: 3.94V to 4.18V ± 1%



User programmable maximum charge current:

50mA to 1500mA





Input supply under-voltage lockout



Full protection for VBAT over-current, over-

temperature, VBAT over-voltage, and charging

timeout



Charge status indication



I

Related ZMDI Smart Power Products



ZSPM4523 DC/DC Synchronous Switching

Super Capacitor Charger With MPPT Regulator



ZSPM4551 High-Efficiency Li-Ion Battery Charger



ZSPM4121 Ultra-low Power Under-Voltage Switch



ZSPM4141 Ultra-Low-Power Linear Regulator

Physical Characteristics



Wide input voltage range: 4.0V to 7.2V



Junction operating temperature: -40°C to 125°C



Package: 16-pin PQFN (4mm x 4mm)

ZSPM4521 Application Circuit