Input circuit for an electronic vehicle speed control unit
First Claim
1. An input circuit to an electronic speed control unit for a vehicle having an ignition system adapted to generate pulses of electrical current at a frequency proportional to engine speed comprising:
- means responsive to each ignition system current pulse for generating a voltage differential signal;
biasing means for generating bias signals defining a predetermined voltage differential range;
differential amplifier means connected to said voltage differential signal generating means and said biasing means for generating an output signal when said voltage differential signal exceeds said predetermined voltage differential range; and
capacitive means connected to said voltage differential signal generating means for rejecting common mode signals superimposed on said voltage differential signal.
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Accused Products
Abstract
An improved input circuit for an electronic vehicle speed control unit is disclosed. An ignition current sensor coil is adapted to have a voltage differential signal induced therein each time an ignition pulse is generated by the vehicle engine. Electrical noise signals generated by the vehicle engine appear as common mode signals across the ignition current sensor coil. The ignition current sensor coil is connected at each end to a capacitor, both of which are connected to ground potential. The ends of the ignition current sensor coil are further connected to the inputs of a differential amplifier. The capacitors appear in a series loop with the ignition current sensor coil for the differential voltage signals and, consequently, provide tuning for inductance. However, the capacitors appear in parallel with one another to ground potential with respect to the common mode noise signals, thereby providing high frequency noise rejection for the input circuit. The differential amplifier further rejects the common mode noise signal applied to the inputs thereof.
23 Citations
36 Claims
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1. An input circuit to an electronic speed control unit for a vehicle having an ignition system adapted to generate pulses of electrical current at a frequency proportional to engine speed comprising:
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means responsive to each ignition system current pulse for generating a voltage differential signal; biasing means for generating bias signals defining a predetermined voltage differential range; differential amplifier means connected to said voltage differential signal generating means and said biasing means for generating an output signal when said voltage differential signal exceeds said predetermined voltage differential range; and capacitive means connected to said voltage differential signal generating means for rejecting common mode signals superimposed on said voltage differential signal. - View Dependent Claims (4, 5, 6, 8, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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2. An input circuit to an electronic speed control system for a vehicle having an ignition system adapted to generate pulses of electrical current to an engine comprising:
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an inductive ignition current sensor responsive to each of the ignition system current pulses for generating a voltage differential signal; a first capacitor connected between an end of said ignition current sensor and a ground potential; a second capacitor connected between another end of said ignition current sensor and the ground potential; a resistive voltage divider network connected between a source of voltage at a predetermined level and the ground potential, and further connected to said ignition current sensor for generating bias signals defining a predetermined voltage differential range; and differential amplifier means responsive to said voltage differential signal and said bias signals for generating an output signal when said voltage differential signal exceeds said predetermined voltage differential range. - View Dependent Claims (7, 9, 10)
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3. An input circuit to an electronic speed control unit for a vehicle having an ignition system adapted to generate pulses of electrical current at a frequency proportional to engine speed comprising:
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means responsive to each ignition system current pulse for generating a voltage differential signal; biasing means for generating bias signals defining a predetermined voltage differential range; differential amplifier means connected to said voltage differential signal generating means and said biasing means for generating an output signal when said voltage differential signal exceeds said predetermined voltage differential range; and diode means connected between said differential amplifier means and said biasing means for limiting the magnitude of the signals applied to said differential amplifier means. - View Dependent Claims (11, 12)
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Specification