下载
Document Number: MC34674
Rev. 2.0, 11/2008
Freescale Semiconductor
Advance Information
This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
© Freescale Semiconductor, Inc., 2007-8. All rights reserved.
High Input Voltage Travel
Charger for Single-cell Li-Ion
Batteries
The MC34674 is a fully integrated single-cell Li-Ion and Li-Polymer
battery charger optimized for travel charger applications. The few
external components required include a dual-color LED for charge-
status indication, a negative temperature coefficient (NTC) thermistor
circuit for setting the charge temperature window, and two decoupling
capacitors. The high input voltage, up to 28
V, allows low-cost AC/DC
converters to be used for further system cost reduction. A typical
charge cycle of the MC34674 includes trickle, constant-current (CC)
and constant-voltage (CV) charge modes. The CC-mode current is
selectable from 50
mA to 1.05 A with 8% accuracy and the constant-
output voltage in the CV-mode is fixed at 4.2
V with 0.4% accuracy over
-20°C to 70°C temperature range.
The MC34674 has all the features such as trickle charging for a
deeply discharged battery, an internal timer for termination to prevent
charging a failed battery, charger current thermal foldback for thermal
protection, and smart battery connection verification to prevent
charging in case there is no battery connected. It also protects the
system with its input over-voltage protection (OVP) feature. In addition,
it has a 2.6
V falling power-on-reset (POR) threshold, making it perfect
to work with current limited power supplies. When the charger is
disabled, the BAT pin leaks less than 1.0 μA current from the battery.
All the above functions are fit into a small 8-lead 2X3 UDFN package.
Features
• No external MOSFET, reverse-blocking diode or current-
sense resistor are required
•28 V maximum input voltage rating with 11 V over-voltage
protection threshold
• Factory programmable charge current
• Trickle charge for fully discharged batteries
• ±0.4% voltage accuracy over -20°C to 70°C
• Driving a dual-color LED and smart battery connection
verification optimized for travel charger applications
• Interface to NTC thermistor
• Internal timer and thermal current limit
• Small 2X3 mm
2
thermally enhanced UDFN package
• Pb-free packaging designated by suffix code EP
Figure 1. 34674 Simplified Application Diagram
POWER MANAGEMENT IC
EP SUFFIX (PB-FREE)
98ASA10774D
8-PIN UDFN
34674
ORDERING INFORMATION
Device
Temperature
Range (T
A
)
Package
Refer to Table 1,
Device Variations
-40°C to 85°C 8 UDFN-EP
VIN
GND
RED
GRN
EN
BAT
VREF
TEMP
R
PU
34674
R
S
V
IN
TO BATTERY
TO BATTERY NTC
(THERMISTOR)
C
IN
C
OUT
ON
OFF
页面指南
