Patent ID: 6294947
Filing Date: 2001-09-25
Classification: H03K

Abstract:
A current output circuit comprising:first and second output nodes;a separate load resistance connectable to said first and second output nodes;a current driver connected to at least one of said first and second output nodes and supplying a total and substantially constant current I; andat least one bypass resistor connected between said first and second output nodes, each bypass resistor being switchable between a non-conducting state and a conducting state having a predetermined resistance, the states of said at least one bypass resistor providing a plurality of discretely selectable output current states of particular current magnitudes through said load resistance when said load resistance is connected to said output nodes;wherein, when the load resistance is connected to said first and second output nodes, the total current flow from the first output node to the second output node through said load resistance and any conducting bypass resistors is substantially I for each of the discretely selectable output current states.