Datasheet

bq24640
SLUSA44 –MARCH 2010 www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
5.0 V ≤ V(VCC) ≤28 V, 0°C < T < +125°C, typical values are at T
A
= 25°C, with respect to GND (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
THERMISTOR COMPARATOR
V
LTF
Cold temperature rising threshold As percentage to V
VREF
72.5% 73.5% 74.5%
V
LTF_HYS
Rising hysteresis As percentage to V
VREF
0.2% 0.4% 0.6%
V
HTF
Hot temperature rising threshold As percentage to V
VREF
36.4% 37% 37.6%
V
TCO
Cut-off temperature rising threshold As percentage to V
VREF
33.7% 34.4% 35.1%
Deglitch time for temperature out of
V
TS
< V
LTF
, or V
TS
< V
TCO
, or V
TS
< V
HTF
400 ms
range detection
Deglitch time for temperature in V
TS
> V
LTF
– V
LTF_HYS
or V
TS
>V
TCO
, or V
TS
20 ms
valid range detection > V
HTF
CHARGE OVER-CURRENT COMPARATOR (CYCLE-BY-CYCLE)
Current rising, in non-synchronous mode,
45.5 mV
measure on V
(SRP-SRN)
, V
SRP
< 2V
Charge over-current rising threshold
Current rising, as percentage of V
(IREG_CHG)
,
160%
in synchronous mode, V
SRP
> 2.2V
V
OC
Minimum OCP threshold in synchronous
Charge over-current threshold floor 50 mV
mode, measure on V
(SRP-SRN)
, V
SRP
> 2.2V
Charge over-current threshold Maximum OCP threshold in synchronous
180 mV
ceiling mode, measure on V
(SRP-SRN)
, V
SRP
> 2.2V
CHARGE UNDER-CURRENT COMPARATOR (CYCLE-BY-CYCLE)
Charge under-current falling
V
ISYNSET
Switch from CCM to DCM, V
SRP
>2.2V 1 5 9 mV
threshold
LOW CHARGE CURRENT COMPARATOR
Low charge current (average) falling
V
LC
threshold to force into Measure V
(SRP-SRN)
1.25 mV
non-synchronous mode
V
LC_HYS
Low charge current rising hysteresis 1.25 mV
V
LC_DEG
Deglitch on both edge 1 µs
VREF REGULATOR
V
VREF_REG
VREF regulator voltage V
VCC
> V
UVLO
(0–35 mA load) 3.267 3.3 3.333 V
I
VREF_LIM
VREF current limit V
VREF
= 0 V, V
VCC
> V
UVLO
35 mA
REGN REGULATOR
V
REGN_REG
REGN regulator voltage V
VCC
> 10V, CE = HIGH (0–40mA load) 5.7 6.0 6.3 V
I
REGN_LIM
REGN current limit V
REGN
= 0V, V
VCC
> V
UVLO
, CE = HIGH 40 mA
PWM HIGH SIDE DRIVER (HIDRV)
High side driver (HSD) turn-on
R
DS_HI_ON
V
BTST
– V
PH
= 5.5 V 3.3 6 Ω
resistance
R
DS_HI_OFF
High side driver turn-off resistance V
BTST
– V
PH
= 5.5 V 1 1.3 Ω
Bootstrap refresh comparator VBTST – VPH when low side refresh pulse
V
BTST_REFRESH
4.0 4.2 V
threshold voltage is requested
PWM LOW SIDE DRIVER (LODRV)
Low side driver (LSD) turn-on
R
DS_LO_ON
4.1 7 Ω
resistance
R
DS_LO_OFF
Low side driver turn-off resistance 1 1.4 Ω
PWM DRIVERS TIMING
Dead time when switching between LSD and
Driver Dead-Time 30 ns
HSD, no load at LSD and HSD
PWM OSCILLATOR
V
RAMP_HEIGHT
PWM ramp height As percentage of VCC 7%
PWM switching frequency 510 600 690 kHz
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