Constant current driving apparatus and constant current driving semiconductor integrated circuit

A constant current driving semiconductor integrated circuit, integrated on a single semiconductor chip, for driving a plurality of loads at output currents which are constant and of a same value, comprising:

• a constant current driving circuit having one or more reference current input terminals and a plurality of driving output terminals, for deriving outputs for driving each of the plurality of loads at the same value of constant current from the individual driving output terminals in accordance with a reference current inputted to the reference current input terminals;
• a reference current producing circuit connected to the constant current driving circuit, having a plurality of reference current output terminals, for producing output currents of a same value from the individual current output terminals;
• a shift register circuit, having a serial input terminal to which signals for carrying out on-off control of outputs of the constant current driving circuits are inputted serially, for outputting in parallel the signals inputted to the serial input terminal;
• and
• a latch circuit, having a latching input terminal, for latching the parallel outputs of the shift register circuit in accordance with the signals inputted to the latching input terminal, to carry out on-off control of outputs of the constant current driving circuits by the latched outputs.

A constant current driving apparatus for driving each of a plurality of loads with a constant drive current, comprising:

• a reference current generation circuit generating a plurality of reference currents each having a reference current value;
• and
• at least two constant current driver circuits each controlled by an associated control circuit, each of said at least two constant current driver circuits driving a subset of the plurality of loads with the constant drive current in accordance with the reference current value,
• wherein each of the associated control circuits converts a serial control signal into a parallel signal to control the driving of each of the subset of the plurality of loads by said at least two constant current driver circuits.