Circuit and method for temperature and process independent transimpedance amplifier arrangement

A method comprising:

• providing a plurality of internal matched resistors within an integrated circuit;
• multiplying a current to provide a signal whose value is a function of an input current signal, an external resistor and a first set of said provided plurality of internal matched resistors;
• and
• providing an output transimpedance amplifier coupled to provided signal, said provided output transimpedance amplifier exhibiting a gain whose value is a function of a second set of said provided plurality of internal matched resistors,
• wherein the output of said provided output transimpedance amplifier is a function of the input current signal, an external resistor, said first set of said provided plurality of internal matched resistors and said second set of said provided plurality of internal matched resistors, wherein the variations with temperature of said first set of said provided plurality of internal matched resistors and said second set of said provided plurality of internal matched resistors cancel.

A light sensor comprising:

• a plurality of internal matched resistors;
• a first photo-diode exposed to a target light;
• a second photo-diode not exposed to the target light;
• an input difference circuit arranged to output a signal representing the difference between the current of said first photo-diode and said second photo-diode;
• a current multiplier coupled to the output of said input difference circuit, said current multiplier arranged to output a signal whose value is a function of said signal representing the difference output by said input difference circuit, an external resistor and a first set of said plurality of internal matched resistors;
• and
• an output transimpedance amplifier coupled to the output of said current multiplier, said output transimpedance amplifier exhibiting a gain whose value is a function of a second set of said plurality of internal matched resistors,
• wherein the output of said output transimpedance amplifier is a function of said signal representing the difference output by said input difference circuit, the external resistor, said first set of said plurality of internal matched resistors and said second set of said plurality of internal matched resistors, wherein the variations with temperature of said first set of said plurality of internal matched resistors and said second set of said plurality of internal matched resistors cancel.