Patent ID: 6014685
Filing Date: 2000-01-11
Classification: G06G

Abstract:
An electronic circuit for providing an analog output that is proportional to one of a substantially quadratic function and a substantially exponential function of the difference between an input voltage and a reference voltage with which the circuit has been programmed, said circuit comprising:(a) a first transistor having a channel conductivity, said first transistor having: a current input; an output; a control input; and a programmable threshold, said first transistor threshold programmed by a stored charge defining a transistor current operating regime when a voltage on said first transistor control input exceeds said reference voltage;(b) a second transistor having a like channel conductivity, said second transistor having: a current input; an output; a control input; and a programmable threshold, said second transistor threshold programmed by a stored charge defining a transistor current operating regime when a voltage on said second transistor control input exceeds a complementary voltage to said reference voltage, said regime for said first and second transistors is one of a relatively high transistor current operating regime and a relatively low transistor current operating regime corresponding to said substantially quadratic function and a substantially exponential function, respectively;(c) said input voltage being supplied to said control input of said first transistor and the complement of said input voltage being supplied to the control input of said second transistor; and(d) said outputs of said two transistors connected together to provide said analog output.