An amplifier (1) adapted to receive an input signal and to generate an
output signal at an amplifier output (7) according to the input signal,
the amplifier (1) comprising: a feedback circuit arranged to provide a
feedback signal indicative of the output signal; an error signal
generating circuit (12, 44) arranged to receive the feedback signal and
generate a digital error signal according to the feedback signal; and an
output signal generating circuit arranged to generate the output signal
and to receive the digital error signal and to adjust the output signal
according to the digital error signal; the amplifier (1) further
comprising: a fault detection circuit (50) arranged to receive the
digital error signal and to determine the presence or absence of a fault
condition at the amplifier output (7) according to the digital error
signal and to provide a signal (54) indicative of the presence or absence
of the fault condition.