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US 4,721,344 AGranted
Electric brake controller
AssigneeKelsey-Hayes Company
InventorsJohn S. Frait, Michael D. Warner, David T. Ayers
Life of this patent
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AssigneeKelsey-Hayes Company
InventorsJohn S. Frait, Michael D. Warner, David T. Ayers
Estimating the term…
An electric brake control circuit is responsive to an activation signal and a vehicle deceleration signal for generating a brake control signal representing a predetermined amount of braking. A comparator compares the voltage level of the brake control signal with the voltage level of a sawtooth waveform to produce a pluse width modulated signal having a duty cycle corresponding to the predetermined amount of braking. This pulse width modulated signal is supplied to an output driver for generating a brake driving signal to energize the brakes. The activation signal is generated at the voltage level of the vehicle power supply when the driver actuates the vehicle stop light switch. The circuit is responsive to the activation signal for disabling the output driver when the voltage level of the activation signal is below a predetermined level. The circuit also senses the current load on the brake driving signal to protect the output driver in the event of a full or partial short circuit condition. As the sensed current load progressively exceeds a predetermined level, the circuit progressively increases the average voltage level of the sawtooth waveform, thus causing the comparator to reduce the duty cycle of the pulse width modulated signal.
An electronic controller for generating a pulse width modulated signal having a desired duty cycle comprising:
An improved electronic controller for energizing electrically operated brakes in a towed vehicle in response to a demand by a driver in a towing vehicle having at least one brake light for connection to a vehicle power supply through a normally open brake light switch, the brake light switch operable by the vehicle driver to close and generate an activation signal having a magnitude substantially equal to the voltage level of the vehicle power supply, the activation signal being generated at a junction between the brake light and the brake light switch, said controller comprising:
An improved electronic brake control system for energizing electrically operated brakes in a towed vehicle in response to a demand by a driver in a towing vehicle, said system comprising:
Dependencies are inferred from the claim text.