Optical sensor system for a bill validator
AssigneeMars, Incorporated
InventorEdward M. Zoladz, Jr.
Life of this patent
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Abstract
An optical sensor system for use in a currency validator is described. The system includes a controller, a plurality of light transmitters, a plurality of light receivers and a variable gain amplifier circuit connected to the receivers and to the microcontroller. The microcontroller controls the gain of the variable gain amplifier circuit. The variable gain amplifier circuit includes dual transconductance amplifiers connected together in such a manner to compensate for leakage current over a wide range of temperatures.
Claims12
An optical sensor system for use in a currency validator, comprising:
- a microcontroller;
- a plurality of light transmitters connected to the microcontroller;
- a plurality of light receivers connected to the microcontroller for producing signals;
- and
- a variable gain amplifier circuit connected to the receivers and to the microcontroller, wherein the microcontroller controls the gain of each light transmitter, and wherein the variable gain amplifier includes dual transconductance amplifiers having an input signal applied to a bias current input and having their differential inputs inversely connected together to compensate for leakage current over a wide range of temperatures.
A variable gain amplifier circuit, comprising:
- an operational transconductance amplifier circuit having dual transconductance amplifiers having an input signal applied to a bias current input and having their differential inputs inversely connected together to compensate for leakage current over a wide range of temperatures.
Dependencies are inferred from the claim text.