Smart fuel pump controller
First Claim
1. A pressure responsive motor drive circuit for fluid delivery systems comprising:
- a pressure transducer which provides an electrical signal in response to a sensed pressure condition;
an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal;
an oscillator circuit producing an alternating signal of predetermined frequency;
a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each time said alternating signal rises above and falls below the level of said amplified signal;
a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition;
wherein said amplifier circuit includes programmable bias means for the programmable controlling the gain of said amplifier.
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Accused Products
Abstract
The motor drive circuit has an instrumentation amplifier with a programmable gain set by selectively blowing fuses during initial circuit calibration. The quasi-sawtooth waveform of a relaxation oscillator is compared with the amplified and conditioned signal produced by a pressure responsive Wheatstone bridge circuit. The result of this comparison is a drive signal which controls the pump motor speed. Radio frequency interference is minimized by storing the motor drive current in a capacitor located near the motor. Further interference is minimized by a reactive matching circuit which combines with the motor impedance to result in a purely resistive load.
26 Citations
21 Claims
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1. A pressure responsive motor drive circuit for fluid delivery systems comprising:
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a pressure transducer which provides an electrical signal in response to a sensed pressure condition; an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal; an oscillator circuit producing an alternating signal of predetermined frequency; a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each time said alternating signal rises above and falls below the level of said amplified signal; a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition; wherein said amplifier circuit includes programmable bias means for the programmable controlling the gain of said amplifier. - View Dependent Claims (2, 3, 4)
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5. A pressure responsive motor drive circuit for fluid delivery systems comprising:
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a pressure transducer which provides an electrical signal in response to a sensed pressure condition; an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal; an oscillator circuit producing an alternating signal of predetermined frequency; a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each time said alternating signal rises above and falls below the level of said amplified signal; a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition; wherein said amplifier circuit includes an integrator stage to subdue rapid changes in motion of said motor.
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6. A pressure responsive motor drive circuit for fluid delivery systems comprising:
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a pressure transducer which provides an electrical signal in response to a sensed pressure condition; an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal; an oscillator circuit producing an alternating signal of predetermined frequency; a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each time said alternating signal rises above and falls below the level of said amplified signal; a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition; further comprising regulated DC voltage reference source coupled to said amplifier circuit for providing said predetermined DC offset. - View Dependent Claims (7, 8, 9)
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10. A pressure responsive motor drive circuit for fluid delivery systems comprising:
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a pressure transducer which provides an electrical signal in response to a sensed pressure condition; an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal; an oscillator circuit producing an alternating signal of predetermined frequency; a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each time said alternating signal rises above and falls below the level of said amplified signal; a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition; wherein said oscillator circuit employs a negative resistance device. - View Dependent Claims (13, 14, 15)
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11. A pressure responsive motor drive circuit for fluid delivery systems comprising:
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a pressure transducer which provides an electrical signal in response to a sensed pressure condition; an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal; an oscillator circuit producing an alternating signal of predetermined frequency; a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each time said alternating signal rises above and falls below the level of said amplified signal; a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition; wherein said oscillator circuit comprises a relaxation oscillator. - View Dependent Claims (12, 17, 18)
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16. A pressure responsive motor drive circuit for fluid delivery systems comprising:
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a pressure transducer which provides an electrical signal in response to a sensed pressure condition; an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal; an oscillator circuit producing an alternating signal of predetermined frequency; a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each time said alternating signal rises above and falls below the level of said amplified signal; a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition; wherein said power transistor circuit includes a field effect transistor device.
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19. A pressure responsive motor drive circuit for fluid delivery systems comprising:
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a pressure transducer which provides an electrical signal in response to a sensed pressure condition; an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal; an oscillator circuit producing an alternating signal of predetermined frequency; a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each time said alternating signal rises above and falls below the level of said amplified signal; a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition; wherein said power transistor circuit includes reactance means coupled across said motor substantially null the inductance of said motor and thereby reduce ringing overshoot of the motor drive current.
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20. A pressure responsive motor drive circuit for fluid delivery systems comprising:
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a pressure transducer which provides an electrical signal in response to a sensed pressure condition; an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal; an oscillator circuit producing an alternating signal of predetermined frequency; a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each time said alternating signal rises above and falls below the level of said amplified signal; a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition; further comprising energy storage means for receiving electrical energy through a transmission line from a remote power source; said energy storage means being coupled to said power transistor circuit to supply energy from which said pulse width modulated current is produced; said energy storage means being of sufficient capacity to minimize rapid voltage changes over said transmission line and thereby reduce radio frequency radiation by said transmission line.
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21. A pressure responsive motor drive circuit for fluid delivery systems comprising:
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a pressure transducer which provides an electrical signal in response to a sensed pressure condition; an amplifier circuit coupled to said pressure transducer for amplifying said electrical signal to produce an amplified signal; an oscillator circuit producing an alternating signal of predetermined frequency; a comparator circuit coupled to said oscillator circuit and to said amplifier circuit for producing a pulse train which changes state each tim said alternating signal rises above and falls below the level of said amplified signal, a power transistor circuit coupled to said comparator circuit for providing a pulsed current to drive a motor such that the motion of said motor is controlled by said sensed pressure condition; and further comprising regulated DC voltage reference source for receiving electrical energy from a vehicular electrical energy source, said reference source being coupled to said amplifier circuit for providing said predetermined DC offset and also being coupled to said pressure transducer to supply electrical energy from which said electrical signal is developed, said motor drive circuit thereby being ratiometric and accurate over a range of supply voltages of said vehicular electrical energy source.
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Specification