LX2207
PRODUCTION DATA SHEET
Microsemi
Analog Mixed Signal Group
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 10
Copyright © 2007
Rev. 1.0a, 2007-10-08
WWW.Microsemi .COM
Three Level Lithium Ion Battery Charger
TM
®
APPLICATION NOTE
POWER STATUS INDICATORS
The STAT pin is designed to source or sink current.
LEDs can be configured to indicate charging or battery full.
The battery full indicator can be connected to DCOK rather
than GND to insure it is off when the input power is
removed and the STAT pin and DCOK pin go to a high
impedance state.
Conditions STAT
Charge in process Low
Charge completed High
I
NPUT POWER SOURCE DETECTION
In order to detect when the input power source has been
removed, the LX2207 requires that a small current (up to
200uA) momentarily flow out of the IN pin (in the reverse
direction). Once detected, the reverse IN current is shut off
(the IN pin becomes a very high impedance until an input
power source is later reapplied). In most applications, there
is sufficient loading on the IN pin from external circuitry to
accomplish this, which includes the “Full” and/or “Power
On” LED loads and the TFB resistor string. If there is no
external load on the IN pin, then it is recommended to
provide a 15k resistor from IN to GND as shown below.
Adapter or USB
0.47uF1k
IN
CMP
LX2207
15k
CHARGING PROFILE
CONDITIONING CURRENT
Battery Charging USB High Level
3.90
3.95
4.00
4.05
4.10
4.15
4.20
4.25
0.0 60.0 120.0
Time in minutes
Battery Voltage
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
Battery Cuurent
Vbat
Ibat
Conditioning Current vs IHCP
0
10
20
30
40
50
60
0.00 50.00 100.00 150.00
IHCP (in uA)
Conditioning Current (in mA)
C
C
H
H
A
A
R
R
T
T
S
S
