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PDF LP4060A Data sheet ( Hoja de datos )
| Número de pieza | LP4060A | |
| Descripción | 800mA Standalone Linear Li-Ion Battery Charger | |
| Fabricantes | Lowpowersemi | |
| Logotipo |  |
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Preliminary Datasheet
LP4060A
800mA Standalone Linear Li-Ion Battery Charger with
Thermal Regulation in ThinSOT
General Description
The LP4060A is a complete constant-current/constant-
voltage linear charger for single cell lithium-ion batteries.
Its ThinSOT package and low external component count
make the LP4060A ideally suited for portable applications.
Furthermore, the LP4060A is specifically designed to work
within USB power specifications. No external sense resistor
is needed, and no blocking diode is required due to the
internal MOSFET architecture. Thermal feedback regulates
the charge current to limit the die temperature during high
power operation or high ambient temperature. The charge
voltage is fixed at 4.2V, and the charge current can be
programmed externally with a single resistor. The
LP4060A automatically terminates the charge cycle when
the charge current drops to 1/10th the programmed value
after the final float voltage is reached. Other features
include charge current monitor, undervoltage lockout,
automatic recharge and a status pin to indicate charge
termination and the presence of an input voltage.
Features
Programmable Charge Current Up to
800mA
No MOSFET, Sense Resistor or Blocking Diode
Required
Complete Linear Charger in ThinSOT
Package for Single Cell Lithium-ion Batteries
Constant-Current/Constant-Voltage Operation
with Thermal Regulation to Maximize
Charge Rate Without Risk of Overheating
Charges Single Cell Li-Ion Batteries Directly from
USB Port
Preset 4.2V Charge Voltage with ± 1% Accuracy
Available in SOT23-5 Package
Charge Current Monitor Output for Gas
Gauging
Automatic Recharge
2.9V Trickle Charge Threshold
C/10 Charge Termination
Order Information
LP4060A - □ □ □ □ □
F: Pb-Free
Package Type
B5: SOT23-5
Applications
Portable Media Players/MP3 players
Cellular and Smart mobile phone
PDA/DSC
Bluetooth Applications
Typical Application Circuit
Vin
1uF +
LED R
4 VCC BAT 3
1 CHRG
2 GND PROG 5
LLPP44006600JB55FF
+
10K 1uF BATT
Marking Information
Please see website.
LP4060A – Ver. 1.0 Datasheet Nov.-2007
Page 1 of 13
1 page  
Preliminary Datasheet
Typical Operating Characteristics
LP4060
LP4060A
LP4060
LP4060
LP4060
LP4060
LP4060A – Ver. 1.0 Datasheet Nov.-2007
LP4060
Page 5 of 13
5 Page 
Preliminary Datasheet
LP4060A
By dropping voltage across a resistor in series with a
5V wall adapter (shown in Figure 9), the on-chip
power dissipation can be decreased, thus increasing the
thermally regulated charge current.:
Solving for IBAT using the quadratic formaula
Using RCC = 0.25Ω, VS = 5V, VBAT = 3.75V,
TA = 25℃ and θJA = 125℃/W we can calculate the
thermally regulated charge current to be:
While this application delivers more energy to the
battery and reduces charge time in thermal mode, it
may actually lengthen charge time in voltage mode if
VCC becomes low enough to put the LP4060A into
dropout. This technique works best when RCC values
are minimized to keep component size small and avoid
dropout. Remember to choose a resistor with adequate
power handling capability.
VCC Bypass Capacitor
Many types of capacitors can be used for input
bypassing, however, caution must be exercised when
using multilayer ceramic capacitors. Because of the
self-resonant and high Q characteristics of some types
of ceramic capacitors, high voltage transients can be
generated under some start-up conditions, such as
connecting the charger input to a live power
source .Adding a 1.5Ω resistor in series with an
X5R ceramic capacitor will minimize start-up
voltage transients.
Charge Current Soft-Start
The LP4060A includes a soft-start circuit to
minimize the inrush current at the start of a charge
cycle. When a charge cycle is initiated, the charge
current ramps from zero to the full-scale current
over a period of approximately 100µs. This has
the effect of minimizing the transient current load on
the power supply during start-up.
CHRG Status Output Pin
The CHRG pin can provide an indication that the input
voltage is greater than the undervoltage lockout
threshold level. A weak pull-down current of
approximately 12µA indicates that sufficient voltage is
applied to VCC to begin charging. When a discharged
battery is connected to the charger, the constant current
portion of the charge cycle begins and the CHRG pin
pulls to ground. The CHRG pin can sink up to 10mA
to drive an LED that indicates that a charge cycle is in
progress. When the battery is nearing full charge, the
charger enters the constant-voltage portion of the
charge cycle and the charge current begins to drop.
When the charge current drops below 1/10 of the
programmed current, the charge cycle ends and the
strong pull-down is replaced by the 12µA pull-down,
indicating that the charge cycle has ended. If the input
voltage is removed or drops below the under voltage
lockout threshold, the CHRG pin becomes high
impedance. Figure 10 shows that by using two
different value pull-up resistors, a micro-processor can
detect all three states from this pin.
To detect when the LP4060A is in charge mode, force the
digital output pin (OUT) high and measure the voltage at
the CHRG pin. The N-channel MOSFET will pull the pin
voltage low even with the 2k pull-up resistor. Once the
charge cycle terminates, the N-channel MOSFET is
turned off and a 12µA current source is connected to the
CHRG pin. The IN pin will then be pulled high by the 2k
pull-up resistor. To determine if there is a weak pull-down
current, the OUT pin should be forced to a high
impedance state. The weak current source will pull the IN
pin low through the 800k resistor; if CHRG is high
impedance, the IN pin will be pulled high, indicating that
the part is in a UVLO state.
LP4060A – Ver. 1.0 Datasheet Nov.-2007
Page 11 of 13
11 Page | ||
| Páginas | Total 13 Páginas | |
| PDF Descargar | [ Datasheet LP4060A.PDF ] | |
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