Electronic Components Datasheet Search
English 中文版
Manufacturer Upload
Part Name:
 
Description:
BQ2011SN Gas Gauge IC for High Discharge Rates
Prototype PCB
Part No.:   BQ2011SN
Download: Download   Right selection Save Target As
View Datasheet (Html)   No need to install PDF reader software
Description:   Gas Gauge IC for High Discharge Rates
File Size :   195 K    
Page : 21 Pages
Logo:   
Maker   TI [ TEXAS INSTRUMENTS ]http://www.ti.com
Buy Now :   
  BQ2011SN Datasheet PDF page 3 BQ2011SN Datasheet PDF page 4 BQ2011SN Datasheet PDF page 5 BQ2011SN Datasheet PDF page 6 BQ2011SN Datasheet PDF page 8 BQ2011SN Datasheet PDF page 9 BQ2011SN Datasheet PDF page 10 BQ2011SN Datasheet PDF page 11  
100%
bq2011
3.
Nominal Available Charge (NAC):
NAC counts up during charge to a maximum value
of LMD and down during discharge and self dis-
charge to 0. NAC is reset to 0 on initialization and
on the first valid charge following discharge to EDV.
To prevent overstatement of charge during periods
of overcharge, NAC stops incrementing when NAC
= LMD.
Note:
NAC is set to the value in LMD when SEG
5
is pulled low during a reset.
4.
Discharge Count Register (DCR):
The DCR counts up during discharge independent
of NAC and could continue increasing after NAC
has decremented to 0. Prior to NAC = 0 (empty
battery), both discharge and self-discharge incre-
ment the DCR. After NAC = 0, only discharge in-
crements the DCR. The DCR resets to 0 when NAC
= LMD. The DCR does not roll over but stops
counting when it reaches FFFFh.
The DCR value becomes the new LMD value on the
first charge after a valid discharge to V
EDV
if:
n
Discharge Counting
All discharge counts where V
SRO
> 500µV cause the
NAC register to decrement and the DCR to increment.
Exceeding the fast discharge threshold (FDQ) if the rate
is equivalent to V
SRO
> 2mV activates the display, if en-
abled. The display becomes inactive after V
SRO
falls be-
low 2mV.
Self-Discharge Estimation
The bq2011 continuously decrements NAC and incre-
ments DCR for self-discharge based on time and tempera-
ture. The self-discharge count rate is programmed to be a
nominal
1 80
* NAC rate per day. This is the rate for a bat-
tery whose temperature is between 20°–30°C. The NAC
register cannot be decremented below 0.
Count Compensations
The bq2011 determines fast charge when the NAC up-
dates at a rate of
≥2
counts/sec. Charge and discharge
activity is compensated for temperature and charge/dis-
charge rate before updating the NAC and/or DCR. Self-
discharge estimation is compensated for temperature
before updating the NAC or DCR.
No valid charge initiations (charges greater than
256 NAC counts; or 0.006 – 0.01C) occurred dur-
ing the period between NAC = LMD and EDV
detected.
The self-discharge count is not more than 4096
counts (8% to 18% of PFC, specific percentage
threshold determined by PFC).
The temperature is
0°C when the EDV level is
reached during discharge.
Charge Compensation
Two charge efficiency factors are used for trickle charge
and fast charge. Fast charge is defined as a rate of
charge resulting in
2 NAC counts/sec (≥ 0.15C to 0.32C
depending on PFC selections; see Table 2). The compen-
sation defaults to the fast charge factor until the actual
charge rate is determined.
Temperature adapts the charge rate compensation fac-
tors over three ranges between nominal, warm, and hot
temperatures. The compensation factors are shown below.
Charge
Temperature
<40°C
40°C
Trickle Charge
Compensation
0.80
0.75
Fast Charge
Compensation
0.95
0.90
n
n
The valid discharge flag (VDQ) indicates whether
the present discharge is valid for LMD update.
Charge Counting
Charge activity is detected based on a negative voltage
on the V
SR
input. If charge activity is detected, the
bq2011 increments NAC at a rate proportional to V
SRO
(V
SR
+ V
OS
) and, if enabled, activates an LED display
if V
SRO
< -1mV. Charge actions increment the NAC af-
ter compensation for charge rate and temperature.
The bq2011 determines a valid charge activity sustained
at a continuous rate equivalent to V
SRO
< -400µV. A
valid charge equates to a sustained charge activity
greater than 256 NAC counts. Once a valid charge is de-
tected, charge counting continues until V
SRO
rises
above -400µV.
7
Home - IC Supply - Link
Copyright© 2001 - 2014 ICPDF All Rights Reserved ICPDF.COM

粤公网安备 44030402000629号


粤ICP备13051289号-7