Abstract A control circuit for maintaining a detected condition at a maximum level. The condition, for example, the speed of an automobile, is detected by a sensor which includes a rotating magnet and a sensing coil. The rotation of the magnetic field is proportional to the velocity of the automobile and therefore the output frequency of the sensing coil is directly proportional to the speed of the vehicle. As the sensor output increases due to increases in the condition the limiting circuit actuates a counting circuit. The counting circuit then actuates a differential circuit which yields an output proportional to the detected condition. When the output of the difference circuit is above a predetermined level the current in an actuating coil is reduced to zero and full control is realized. When the output of the sensor is below a set level, current in the coil is a maximum and no limiting occurs. For conditions between the two extremes partial control is realized.
A control circuit for use in a vehicle top speed limiting system comprising: means for generating a signal proportional to the speed of said vehicle; means for receiving said signal and generating an output when said signal is above a predetermined level; means for generating a biasing voltage; a capacitor network connected between said means for generating a biasing voltage and said means for receiving said proportional signal, said capacitor network being charged by said biasing voltage and being discharged by said output to produce a net charge proportional to said speed of said vehicle; means for detecting said net charge and generating a voltage proportional thereto; means controlled by said output for generating a time varying signal, said time varying signal having a period and a maximum amplitude, said period and maximum amplitude being proportional to said speed, the proportionality of said time varying signal being of opposite sense to the proportionality of said voltage proportional to said net charge; comparator means for receiving said time varying signal and said voltage proportional to said net charge, said comparator means providing a comparator output when the amplitude of said time varying signal exceeds said proportional voltage level; and means for receiving said comparator output and generating a magnetic field proportional thereto and consequently to the speed of said vehicle.
Claim 2
Dependent Claim
219 words
A control circuit for use in a vehicle top speed limiting system comprising: means for generating a signal proportional to the speed of said vehicle; means for receiving said signal and generating an output when said signal is above a predetermined level; means for generating a biasing voltage; a capacitor network connected between said means for generating a biasing voltage and said means for receiving said proportional signal, said capacitor network being charged by said biasing voltage and being discharged by said output to produce a net charge proportional to said speed of said vehicle; means for detecting said net charge and generating a voltage proportional thereto; means controlled by said output for generating a time varying signal, said time varying signal having a period and a maximum amplitude, said period and maximum amplitude being proportional to said speed, the proportionality of said time varying signal being of opposite sense to the proportionality of said voltage proportional to said net charge; comparator means for receiving said time varying signal and said voltage proportional to said net charge, said comparator means providing a comparator output when the amplitude of said time varying signal exceeds said proportional voltage level; and means for receiving said comparator output and generating a magnetic field proportional thereto and consequently to the speed of said vehicle.