LM2601MTCEVAL National Semiconductor Corporation, LM2601MTCEVAL Datasheet - Page 4

• Manufacturer Part Number: LM2601MTCEVAL
• Description: LM2601 - Adapter Interface Circuit Not Recommended For Designs , Package: Tssop, Pin Nb=14
• Manufacturer: National Semiconductor Corporation

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Electrical Characteristics
Note 5: Adapter Enable input is used to change the state of Disconnect, Direction Sense input is used to change the state of Backfeed.
a. Fall time is measured as the time it takes Backfeed or Disconnect voltage to go from a high level (approx. V
is initiated at Adapter Enable or Direction Sense.
b. Rise time is measured as the time it takes Backfeed or Disconnect voltage to go from a low level (approx. 0.5V) to (V
at Adapter Enable or Direction Sense.
Typical Application
Notes
1. R
2. Internal and external circuits associated with Direction
3. Voltage difference (V
4. R5 and R6 prevent the FETs from turning on unless
programmed over current will cause a voltage drop
across R
R
should be used to scale the voltage drop down.
Sense and Backfeed FET pins allow to emulate a Schot-
tky diode functionality with much lower forward voltage
drop and, therefore, with much lower power dissipation.
R2/R4 resistor divider programs the backfeed current
protection threshold. The backfeed FET Q1 turns off
when the backfeed current pulse level causes more than
9 mV (typical value) voltage drop between V
and Direction Sense pin.
be higher than 20mV to reliably isolate the adapter in
case of leakage.
driven by LM2601.
SENSE
SENSE
has to be selected then R1/R3 resistor divider
value should be selected to guarantee that a
SENSE
of approx. 135mV. If a higher value of
DIRECTION SENSE
- V
(Continued)
ADAPTER
adapter
) must
pin
4
5. C
6. T
7. Pin Master Power Source (MPS) should be connected to
mula:
also the Typical Delay Time vs. Temperature graph.
System Management Controller’s (SMC) and battery
packs’ GPIOs. When SMC detects a powered AC
adapter via active signals at Charger Present or Adapter
Present outputs, it asserts Adapter Enable signal and
isolates the battery pack(s). Adapter Enable signal turns
the Disconnect FET on. When the AC adapter is un-
plugged or powered off, SMC enables one of the system
battery packs. The battery packs’ embedded controller
starts driving the logic MPS signal high that turns the
Disconnect FET off.
C
DELAY
DELAY
DELAY
(nF) = T
temperature coefficient equals 4000ppm/˚C. See
value can be calculated from the following for-
ADAPTER
DELAY
(µs)/90 at 25˚C
− 0.5V) to (V
ADAPTER
10130903
− 2V) after the signal is initiated
ADAPTER
− 4V) after the signal