BQ2040SN-C408 BENCHMARQ, BQ2040SN-C408 Datasheet - Page 24

• Manufacturer Part Number: BQ2040SN-C408
• Description: BATTERY CHARGE MONITOR, SMD, 2040
• Manufacturer: BENCHMARQ

Specifications of BQ2040SN-C408

• Battery Management Function: Charger, Status Monitor
• Battery Type: Li-Ion / NiCd / NiMH
• Supply Voltage Range: 3V To 6.5V
• Battery Ic Case Style: SOIC
• No. Of Pins: 16
• Operating Temperature Range: 0°C
• Interface Type: 2-Wire, Serial

bq2040
Note:
Temperature
offset
Maximum
temperature
and T step
Charge
efficiency
Full-charge
percentage
Reserved
Li-Ion taper
current
M a xim u m
overch a rge
limit
Reserved
Access protect
FLAGS1
FLAGS2
Current
measurement
gain
Battery voltage
offset
Description
1
1
1
1. Can be adjusted to calibrate the battery pack.
0x3d
Byte
0x38
0x3a
0x3c
0x3e
0x46
0x48
0x49
0x4a
0x4b
0x4c
Low
0x2f
0x3f
EEPROM
Address
High
Byte
0x39
0x3b
0x47
Table 10. Example Register Contents (Continued)
Byte
Low
EEPROM
Contents
00
00
10
b0
00
b0
00
8a
9c
5f
9c
fe
ff
Hex
High
Byte
0f
ff
ff
SBD access only
Li-Ion chemistry
Relative display
compensation =
Fast compensa-
bq2040 charge
temperature =
Maintenance
T step = 4.6 C
tion = 100%
Maximum
Example
100mAh
240mA
Values
control
13.8 C
61.0 C
100%
-2mV
100%
3840
0
0
0
24
Not currently used by the bq2040.
Sets the upper taper limit for Li-Ion charge termina-
tion. Stored in 2’s complement.
Sets the maximum amount of overcharge before a
maximum overcharge charge suspend occurs.
Stored in 2’s complement.
Must be programmed to 0.
If the bq2040 is reset and bit 3 of this location is 0, the
bq2040 locks access to any command outside of the SBS
data set. Program to 0xb8 for full R/W access, 0xb0 for
SBD access only.
Initializes FLAGS1
Initializes FLAGS2.
The current gain measurement and current integra-
tion gain are related and defined for the bq2040 cur-
rent measurement. This word equals 192/sense re-
sistor value in ohms.
Used to adjust the battery voltage offset according to
the following:
Voltage = (V
The default value (zero adjustment) for the offset is
12.8 C or 0x80.
TOFF
(TEMP
Maximum charge temperature is 69- (mt
= upper nibble). The T step is (dT
(dT = lower nibble).
Sets the fast-charge (high) and maintenance charge
(low) efficiencies. The upper nibbles sets the low effi-
ciency and the lower nibble adjusts the high effi-
ciency according to the equation:
Nibble = (efficiency%
This packed field is the two’s complement of the de-
sired value in RM when the bq2040 determines a
full-charge termination. If RM is below this value,
RM is set to this value. If RM is above this value,
then RM is not adjusted.
NEW
ACTUAL
= TOFF
SB
(mV) + V
- TEMP
CURRENT
REPORTED
256 - 196)/4
OFF
Notes
)
+
Voltage gain
) 10
2 + 16)/10 C
1.6) C (mt