Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

BQ2000T Datasheet(PDF) 5 Page - Texas Instruments

Click here to check the latest version.
Part No. BQ2000T
Description  Programmable Multi-Chemistry Fast-Charge Management IC
Download  16 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  TI [Texas Instruments]
Homepage  http://www.ti.com
Logo 

BQ2000T Datasheet(HTML) 5 Page - Texas Instruments

 
Zoom Inzoom in Zoom Outzoom out
 5 / 16 page
background image
with a trickle maintenance-charge that continues as
long as the voltage on pin BAT remains below VMCV.
Lithium-Ion Batteries
The bq2000T uses a two-phase fast-charge algorithm for
Li-Ion batteries (Figure 3). In phase one, the bq2000T
regulates constant current until VBAT rises to VMCV. The
bq2000T then moves to phase two, regulates the battery
with constant voltage of VMCV, and terminates when the
charging current falls below the IMIN threshold. A new
charge cycle is started if the cell voltage falls below the
VRCH threshold.
During the current-regulation phase, the bq2000T
monitors charge time, battery temperature, and battery
voltage for adherence to the termination criteria. During
the final constant-voltage stage, in addition to the
charge time and temperature, it monitors the charge
current as a termination criterion. There is no
post-charge maintenance mode for Li-Ion batteries.
Charge Termination
Maximum Charge Time (NiCD, NiMH, and
Li-Ion)
The bq2000T sets the maximum charge-time through
pin RC. With the proper selection of external resistor
and capacitor, various time-out values may be achieved.
Figure 4 shows a typical connection.
The following equation shows the relationship between
the RMTO and CMTO values and the maximum charge
time (MTO) for the bq2000T:
MTO = RMTO
∗ CMTO ∗ 35,988
MTO is measured in minutes, RMTO in ohms, and CMTO
in farads. (Note: RMTO and CMTO values also determine
other features of the device. See Tables 2 and 3 for de-
tails.)
For Li-Ion cells, the bq2000T resets the MTO when the
battery reaches the constant-voltage phase of the
charge. This feature provides the additional charge time
required for Li-Ion cells.
Maximum Temperature (NiCd, NiMH, Li-Ion)
A negative-coefficient thermistor, referenced to VSS and
placed in thermal contact with the battery, may be used
as a temperature-sensing device. Figure 5 shows a typi-
cal temperature-sensing circuit.
During fast charge, the bq2000T compares the battery
temperature to an internal high-temperature cutoff
threshold, VTCO. As shown in Table 4, high-temperature
termination occurs when voltage at pin TS is less than
this threshold.
∆T/∆t (NiCd, NiMH)
When fast charging, the bq2000T monitors the voltage
at pin TS for rate of temperature change detection,
∆T/∆t. The bq2000T samples the voltage at the TS pin
every 16s and compares it to the value measured 2 sam-
ples earlier. This feature terminates fast charge if this
voltage declines at a rate of
V
161
V
Min
CC


Figure 5 shows a typical connection diagram.
Minimum Current (Li-Ion Only)
The bq2000T monitors the charging current during the
voltage-regulation phase of Li-Ion batteries. Fast charge
is terminated when the current is tapered off to 7% of
the maximum charging current. Please note that this
threshold is different for the bq2000.
Initial Hold-Off Period
The values of the external resistor and capacitor con-
nected to pin RC set the initial hold-off period. During
this period, the bq2000T avoids early termination by
disabling the
∆T/∆t feature. This period is fixed at the
5
Battery Chemistry
Charge Algorithm
NiCd or NiMH
1. Charge qualification
2. Trickle charge, if required
3. Fast charge (constant current)
4. Charge termination (
∆T/∆t, time)
5. Top-off (optional)
6. Trickle charge
Li-Ion
1. Charge qualification
2. Trickle charge, if required
3. Two-step fast charge (constant current followed by constant voltage)
4. Charge termination (minimum current, time)
Table 1. Charge Algorithm
bq2000T


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16 


Datasheet Download




Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Alldatasheet API   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn