ECT 2440 Final: Operational Amplifiers - Positive Feedback - Schmitt Trigger
Document Summary
The basic comparator circuit is an op-amp arranged in the open-loop configuration as shown on the circuit of figure 1. The op-amp is characterized by an open-loop gain a and let"s assume that the output voltage vo can go all the way to vdd and vee. Vo = a v + v ) (1. 1) Where v+ and v correspond to the voltages at the non-inverting and the inverting terminals respectively. For the circuit on figure 1, v+ = vin and v = vref . For vref = 0 , the voltage transfer characteristic vo versus vin is as shown on figure 2. saturation inv linear region ov. When vin > v + , vo = vdd and for vin < v , vo = vee . The values v + and v is inversely proportional to the open-loop gain a. Operation in the linear region is restricted to v < vin amp is driven to saturation.
