Datasheet

No
Yes
Yes
No
No
Yes
V
I(BAT)
<
V
(RCH)
Enable
I
(DETECT)
for
t
(DETECT)
V
I(BAT)
<
V
(LOWV)
BATTERY
PRESENT
BeginCharge
BATTERY
PRESENT
Begin
Charge
Apply
I
O(PRECHG)
for
t
(DETECT)
V
I(BAT)
>
V
(RCH)
BATTERY
ABSENT
Charge Done
or
TimerFault
bq24010, bq24012
bq24013, bq24014, bq24018
www.ti.com SLUS530K –SEPTEMBER 2002–REVISED JANUARY 2014
BATTERY ABSENT DETECTION
For applications with removable battery packs, bqTINY provides a battery absent detection scheme to reliably
detect insertion or removal of battery packs, or both.
The voltage at the BAT pin is held above the battery recharge threshold, V
(RCH)
, by the charged battery following
fast charging. When the voltage at the BAT pin falls to the recharge threshold, either by a load on the battery or
due to battery removal, the bqTINY begins a battery absent detection test. This test involves enabling a detection
current, I
(DETECT)
, for a period of t
(DETECT)
and checking to see if the battery voltage is below the pre-charge
threshold, V
(LOWV)
. Following this, the pre-charge current, I
O(PRECHG)
is applied for a period of t
(DETECT)
and the
battery voltage checked again to be above the recharge threshold. The purpose is to attempt to close a battery
pack with an open protector, if one is connected to the bqTINY. Passing both of the discharge and charging tests
indicates a battery absent fault at the STAT pins. Failure of either test starts a new charge cycle. For the absent
battery condition the voltage on the BAT pin rises and falls between the V
(LOWV)
and V
O(REG)
thresholds
indefinitely. See Figure 7.
Figure 7. Battery Absent Detection
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