LX2201CLQ Microsemi Analog Mixed Signal Group, LX2201CLQ Datasheet - Page 9

• Manufacturer Part Number: LX2201CLQ
• Description: IC CHARGER BATT USB LI-ION 20MLP
• Manufacturer: Microsemi Analog Mixed Signal Group

Specifications of LX2201CLQ

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 4.5 V ~ 6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 20-MLP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Copyright © 2000
Rev. 1.3, 2006-02-09
C
or have high source impedance, the battery charging current
and/or load current can pull the VDD pin down very close
to the battery terminal voltage. This may cause the LX2201
to enter an indeterminate state where it switches between
charge and discharge modes. To prevent this, the PNP
differential amplifier circuit of figure 4 can be added; this
circuit adds an additional control loop that regulates the
charger headroom to 300mV by scaling back the battery
charging current.
the power supply have a minimal level of strength to switch
from discharge mode to charge mode. If the power source is
severely current limited, the LX2201 may not open the
discharge switch. In this case, a small amount of current
will be allowed to flow into the battery unregulated. If left
in this state indefinitely, the current will eventually raise the
battery terminal voltage to the point where the batteries
internal protection circuitry will open the circuit. Typically,
the LX2201 requires a minimum of 80mA in USB mode
and 200mA using the VDD input to force the switchover to
charge mode. Alternatively, if weak power sources are
used, the switchover from discharge to charge mode can be
forced by momentarily setting VID0 and VID1 to a low
state, which will open the discharge switch allowing the
VDD voltage to rise so the LX2201 can enter charge mode.
URRENT
When using input power supplies that are current limited
The internal power switch within the LX2201 requires
TM
L
IMITED
P
OWER
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
S
UPPLIES
A P P L I C A T I O N N O T E
Integrated Products Division
®
Microsemi
Not Recommended for New Design:
USB C
current must be less than 100mA in the low power mode
and less than 500mA in the high power mode. If the
LX2201 is configured as shown in Figure 3, it is possible
for the system to consume more than the maximum
allowed USB current (in which case the battery charging
current will have been fully scaled back). If it is not
possible to regulate the load current when charging from a
USB power source and strict adherence to the USB power
budget is required. In this case the system load can be
applied directly to the battery and the LX2201 will prevent
the load + battery from drawing more power than is
allowed for USB compliance. A better approach that
provides battery isolation may be used; in this approach,
the op amp circuit provides a current limiter that prevents
the system from exceeding the USB power limits. The
battery is only discharged if the AC adapter or USB inputs
are removed or current limited.
L
AYOUT
To be compliant with the USB specification, the +5V
•
•
OMPLIANCE
place 10µF ceramic capacitors close to the VDD
and V
path from the thermal pad on the bottom of the
LX2201 package to the ground plane of the circuit
board to maximize the heat dissipation.
It is important when laying out the LX2201 to
It is important to provide a low thermal impedance
USB Li-Ion Battery Charger
G
UIDELINES
P
BAT
RODUCTION
IC terminals to filter switching transients.
D
ATA
S
HEET
See the LX2202
LX2201
Page 9