AME2056 Datasheet, PDF (13/26 Pages) Analog Microelectronics – 1A Single Cell Li-ion

AME
AME2056
1A Single Cell Li-ion
Battery Linear Charger
Battery Temperature Fault Monitoring
In the battery over-temperature condition, the charger will turn off the internal pass device. Two internal compared
voltage references V_TEMP-H and V_TEMP-L are 80%*V_CC and 45%*V_CC, respectively. When the voltage at TEMP pin rises
above V_TEMP-H or falls below V_TEMP-L, AME2056 stops charging. After the system recover from a temperature fault, the
charger will resume operation. If applications do not need the function, short the TEMP pin to ground.
The resistance of R1 and R2 are set according to the battery temperature range and the value of thermal sensitive
resistor. Assume the battery is equipped with NTC thermistor and the temperature range is T_L to T_H (T_L<T_H). The
thermistor resistance R_T decreases as temperature increases from T_L to T_H.
The TEMP pin voltage can be calculated as:
V_TEMP
=
R2 // R_T
R1 + R2 // R_T
× V_CC
The V_TEMP decreases as the temperature increase from T_L to T_H.
R1 and R2 resistance are set for temperature:
0.8 ×V_CC
= V_{TEMP −H}
=
R2 // R_TL
R1 + R2 // R_TL
× V_CC
at T_L
0.45 ×V_CC
= V_TEMP−L
=
R2 // R_TH
R1 + R2 // R_TH
× V_CC
at T_H
Where R_TL and R_TH are the thermistor resistances at T_L and T_H, respectively.
The R1 and R2 can be derived as following:
R₁
=
R_TL × R_TH × (0.8 − 0.45)
(R_TL − R_TH )× 0.8× 0.45
R₂
=
R_TL
R_TL × R_TH × (0.8 − 0.45)
× (0.45 − 0.8× 0.45)− R_TH × (0.8 − 0.8× 0.45)
Rev. B.01
13