A voltage regulator circuit arrangement limits the DC voltage applied to a
tip and ring amplifiers of a subscriber line interface circuit (SLIC),
each of which has a first polarity input coupled to a first current flow
path to which a DC input (battery) voltage is coupled. A first current
source supplies a first current derived via a low pass filter path from
that flowing through the first current flow path to a second polarity
input node of the tip amplifier, while a second current source supplies a
similarly low pass filter path-derived second current to a second
polarity input node of the ring amplifier. A voltage regulator is coupled
with the first current flow path and is operative to regulate the voltage
at the first polarity inputs of the tip and ring amplifiers to a
regulated voltage value Vreg, so that the magnitudes of the first and
second currents are based upon the regulated voltage value Vreg.