Datasheet
bq77PL900
www.ti.com
...................................................................................................................................................... SLUS844B – JUNE 2008 – REVISED JANUARY 2009
Table 2. Host Control Summary
MODE TRANSITION FUNCTION AND FIRMWARE PROCEDURE
Normal to current protection Vsr > Voc or Vsc for period of toc or tsc
Automatically, DSG and CHG turn off, SCD or OCD status changes = 1, XALERT = L
Current protection to normal 1. Send commands to transition LTCLR from 0 to 1 to 0
2. Read status bit. XALERT would change to H.
3. Set CHG and DSG FET ON to enable normal operation
Vcell > Vov for period of tov
Normal to overvoltage protection
Automatically, CHG turns off, UV status changes = 1, XALERT = L
Overvoltage protection to normal 1. Confirm the OVP protection status is cleared
2. Send command LTCLR from 1 to 0
3. Read status bit. XALERT changes to H.
4. Set CHG FET ON to enable normal operation
Vcell < Vuv for period of tuv
UVFET_DIS = 0
Automatically, DSG turns off, UV status changes = 1, XALERT = L
Normal to undervoltage
protection 1. Vcell < Vuv or for period of tuv, UV status changes = 1, XALERT = L
UVFET_DIS = 1
2. Send commands to turn off DSG.
Undervoltage protection 1. Confirm the OVP protection status is cleared
to normal
2. Send command LTCLR from 1 to 0
UVFET_DIS = X
3. Set DSG FET ON to enable normal operation
4. Read status bit. XALERT changes to H.
Normal to overtemperature 1. Send commands to turn on TOUT
2. If TIN voltage < 0.975 V, DSG and CHG turn off, OVTEMP status changes = 1,
XALERT = L
Overtemperature to normal 1. Send commands to turn on TOUT (To return to normal mode, bq77PL900 must
acknowledge Vth > 1.075 V)
2. Send commands to transition LTCLR from 1 to 0
3. Set CHG and DSG FET ON
4. Read status bit. XALERT changes to H.
Any mode to shutdown 1. Set DSG FET OFF
2. Wait until PACK voltage decreases to 0 V
3. SET shutdown bit to 1
ORDERING INFORMATION
T
A
PACKAGED
SSOP48
– 40 ° C to 100 ° C bq77PL900DL
(1)
(1) The bq77PL900 can be ordered in tape and reel by adding the suffix
R to the orderable part number, I.e., bq77PL900DLR.
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