Current mirror digital to analog converter

A nonlinear current mirror digital to analog converter for providing an analog output signal from binary data signals in accordance with the ".mu.225" law, said binary data signals including a first set of signals defining a chord and a second set of signals defining a step, said converter comprising:

• a first input transistor connected to a current source;
• a second transistor, the current flowing through said second transistor being proportional to the current from said current source;
• a first set of linear logic gates, each having a first input lead connected to said current source and a second input lead connected to a data source for designating steps of the ".mu.255" law curve, each gate within said first set of linear logic gates providing an output signal on an output lead;
• a first set of transistors, each corresponding to one of said linear logic gates, the current through each transistor within said said first set of transistors being proportional to the current through said first transistor in response to the output signal from said associated linear logic gate;
• a second set of transistors;
• a second set of linear logic gates, each linear logic gate within said second set having a first digital input lead and a second digital input lead for receiving data signals designating the chords of the ".mu.255" law curve, each of said logic gates within said second set of logic gates corresponding to a transistor within said second set of transistors, each transistor within said second set of transistors conducting a current proportional to the current from said current source when the signal at the first digital input lead of said corresponding linear logic gate is in a first binary state, each transistor within said second set of transistors conducting a current proportional to the total amount of current through said first set of transistors when the signal present at the second digital input lead of said corresponding logic gate is in said first binary state;
• and
• an output lead for conducting an amount of current equal to the total current flowing through said second set of transistors.