A multi-channel current regulator includes two or more channels, each
channel acting as a current source or sink for a respective load. Each
channel regulates its load current so that the load current is
proportional to an input voltage supplied to the channel. An operational
amplifier is shared between the channels. Each channel is selected in a
rotating sequence for connection to the amplifier. As each channel is
selected, a two-phase refresh cycle is initiated. During the first phase,
the output of the amplifier is charged until it substantially matches the
drive voltage of the selected channel. This is followed by the second
phase where the output of the amplifier is adjusted until the load
current of the selected channel is proportional to a set voltage
V.sub.set.