A4051
BATTERY MANAGEMENT
AiT Semiconductor Inc.
www.ait-ic.com
1A LINEAR LI-ION BATTERY CHARGER
PIN DESCRIPTION
Top View
Pin # Symbol
Function
Battery temperature detection input. TEMP pin to receive the battery NTC sensor output. If
the TEMP pin voltage is less than the input voltage is greater than 45% or 80% of the input
voltage means the battery temperature is too low or too high, then the charge has been
suspended.
If the TEMP direct access GND, battery temperature detection canceled, the other
charged and functioning properly.
1
TEMP
Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current
is programmed by connecting a 1% resistor, RPROG, to ground. When charging in
trickle-current mode, this pin servos to 0.1V. When charging in constant-current mode, this
pin servos to 1V. In all modes, the voltage on this pin can be used to measure the charge
current using the following formula: IBAT = (VPROG/RPROG) •1000.
The PROG pin can also be used to shut down the charger. Disconnecting the program
resistor from ground allows a 3uA current to pull the PROG pin high. When it reaches the
1.21V shutdown threshold voltage, the charger enters shutdown mode, charging stops and
the input supply current drops to 50uA. This pin is also clamped to approximately 2.4V.
Driving this pin to voltages beyond the clamp voltage will draw currents as high as 1.5mA.
Reconnecting RPROG to ground will return the charger to normal operation.
Ground
2
PROG
3
4
GND
VCC
Positive Input Supply Voltage. Provides power to the charger, VCC can range from 4.25V to
6.5V and should be bypassed with at least a 10uF capacitor. When VCC drops to within
30mV of the BAT pin voltage, the A4051 enters shutdown mode, dropping IBAT to less than
2uA.
Charge Current Output. Provides charge current to the battery and regulates the final float
voltage to 4.2V. An internal precision resistor divider from this pin sets the float voltage
which is disconnected in shutdown mode
5
6
7
BAT
The completion of battery charging instructions side. When the battery charge is complete,
STDBY STDBY pulled low by internal switches, indicating the completion of charging. In addition,
STDBY pin will be in a high-impedance state.
Open-Drain Charge Status Output. When the battery is charging, the CHRG pin is pulled
low by an internal N-channel MOSFET. When the charge cycle is completed, CHRG pin
will be in a high-impedance state.
CHRG
Chip enable input High input level would A4051 is in normal working condition; low input
level so that A4051 is prohibited charging status. CE pin can be TTL or CMOS level-level
driver
8
CE
REV1.3
- JUN 2010 RELEASED, APR 2017 UPDATED -
- 2 -
AITSEMI [ AiT Semiconductor ]
