Programmable Integrator Circuit With Variable Integration Reference
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-27
The integrator circuit uses a multiplying digital-to-analog converter to digitally program the integration gain. A pair of differential amplifiers is used to re-reference signals and allow integration with respect to voltages other than ground. The circuit is shown in the figure and includes Diff Amp 1 which finds the difference between Vin and Vref (the new integration reference), and re-references that difference to GND. Normal integration takes place, then with R1, C1, and the Op Amp 8. The non-inverting Multiplying D->A converter 10, when programmed for zero output voltage, does not contribute to the integration time constant, but when it is programmed for output other than zero, it contributes current to the integration process. The greater the programmed multiplication factor, the greater the integrator's gain.