SLUS553D − MAY 2003 − REVISED JULY 2005
Programming the Battery Charge Current
The battery charge current is programmed via a voltage on the SRSET pin. This voltage can be derived from
a resistor divider from the 5-V VREF or by means of an DAC. The voltage is converted to a current source that
is used to develop a voltage drop across an internal offset resistor at one input of the SR gm amplifier. The charge
current is then a function of this voltage drop and the sense resistor (RS), refer to Figure 5.
Figure 5. Battery Charge Current Input Threshold Function
The battery charge current can be defined as:
where VSRSET is the programming voltage on the SRSET pin. VSRSET maximum is 2.5 V.
Programming the Adapter Current
Like the battery charge current described previously, the adapter current is programmed via a voltage on the
ACSET pin. That voltage can either be from an external resistor divider from the 5-V VREF or from an external
DAC. The adapter current is defined as: