Analog computing method of solving a second order differential equation
OwnerHung C. Lin, Hwey C. Chieninventors
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Abstract
A method of measuring the depletion layer width and electric field of a semiconductor junction or barrier with a particular impurity distribution profile in the semiconductor. With analog computation technique, a time-varying signal is used to simulate the impurity profile. Automatic generation of the constants of integration for the solution of Poisson's differential equation is achieved by adjusting pulse repetition rate or by iterative bisection method.
Claims13
A method of solving a second order differential equation using an analog computation circuit technique, said differential equation having a derivative of an unknown quantity V with respect to a variable X, comprising the steps of
- first integrating said second derivative of the differential equation to obtain a first integral with an electronic integrator,
- deriving a constant of integration based on first boundary conditions of said unknown quantity at a certain value of said variable using sample-hold circuit technique with a switched capacitor,
- summing said first integral with said constant of integration to obtain a sum with a summing amplifier,
- integrating said sum to obtain a second integral using a second electronic integrator,
- setting said second integral to a second boundary condition of said unknown quantity and another value of said variable by means of electronic adjustment.
Dependencies are inferred from the claim text.