The S1F77500 from Epson combines battery-charging functions to make charging and discharging of lithium ion batteries. The device offers varied charging functions, depending on the battery voltage. Using an integrated constant-voltage supply, connecting a constant voltage can recharge a partly charged lithium-ion battery, or a special charging process for low battery voltages can first preliminarily charge an almost fully discharged battery. The integrated constant-voltage supply also regulates a FET transistor, which ensures controlled discharging of lithium-ion batteries. Using a FET transistor means that a diode does not have to be used for the discharge process and enables the use of lithium-ion batteries even at the lowest voltages.
Additionally, the S1F77500 provides protection functions such as detecting the battery voltage of a fully-charged battery, surge protection, protection against a too high charging current, battery temperature measurement, voltage supply detection and timer functions. If required, the S1F77500 also measures the charge and discharge current of lithium-ion batteries. This function can be controlled via external pins.
Features
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Maximum charging precision using constant voltage of 4.1V/4.2V +/-1%
Maximum output current precision of +/-3%
Constant charging current (various charging functions, depending on battery voltage)
Detection of max. allowed battery charging voltage
Surge voltage detection
Excessive current protection function
FET transistor-regulated discharge function
Automatic charging functions (”Preliminary Charge / Full charge”)
Automatic battery recharging possible
Supply voltage detection
Battery temperature measurement using external temperature sensor
Timer function
Power on Reset function
Available in SSOP3-24 package
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Specification
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Supply voltage level 4.5 - 5.5V
Battery voltage 2.0 - 4.2V
Internal voltage supply 2.0 - 5.5V
Output current (ERR, CLK, Vccerr, FC) Max. 2.0mA
Output current (LEDR, LEDG) Max. 10.0mA
Output current (EXT1, EXT2) 10.0mA (typ.)
Output current (Vref) Max. 200µA
Output current (Imon) Max. 20µA
Temperature range -20°C to 70°C
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Samples of the S1F77500 are available. Epson provides on request an evaluation board.
