Ford Motor Company Limited

Lectron Products, Inc.

Harold R Macks

Paul A Michaels

Henry J Ewald

Kenneth G Slotkowski

Gregory J Dygert

Steven P Nimer

Michael R Smith

Alan E Sartori

A detector and battery switch control energy flow from a battery in a vehicle to an electronic module. The vehicle ignition switch controls battery energy flow when the ignition switch is on and the detector and battery switch control battery energy flow when the ignition switch is off. A dimming circuit provides a dimming signal when a demand for energy is made, such as when the headlights are turned on with the ignition switch turned off. The detector senses the dimming signal and operates a battery switch to power up a microprocessor controller from an unpowered state to control operation of the module when the demand for energy is made. There is no sleep mode. A response is made directly to the demand for energy and there is no battery power used until a demand is made for battery energy.

Activation control for an automotive electronic module

Two electronic modules are connected to share and to independently read the sensed value from a single environmental sensor element, by communicating between each other when a particular module is reading the sensor output signal. The sensor output signal is a function of the value of the reference voltage being applied by the reading module and the characteristics of the environment being sensed. A module provides a toggle signal when it completes its reading of the sensor so that the other (non-reading) module will know when it may apply its reference voltage to the sensor and complete its reading of the sensor. The modules alternate the reading of the sensor in order to eliminate the need for a plurality of corresponding sensors.

Method and apparatus for a plurality of modules to independently read a

A low cost, less complex microcomputer power supply circuit with temperature stability and low current consumption in which a single voltage regulating element is used to provide the supply voltage, power-on reset (POR) and low voltage inhibitor (LVI) functions to the microcomputer (12). In an exemplary embodiment, the power supply circuit (10) includes a regulating circuit with a zener diode (30) that is conductive when the voltage level of the DC source (14) is above a threshold value and nonconductive when the voltage level of the DC source (14) is below a threshold value. The regulator circuit provides a regulated supply voltage to the microcomputer from the DC source (14). The regulator circuit also provides a regulation signal, whose state depends on the conductivity of the zener diode (30), to a reset circuit. The reset circuit of the power supply circuit is responsive to the regulation signal for providing a reset signal to the microcomputer (12). The state of the reset signal similarly depends upon the conductivity of the zener diode (30). Accordingly, when the zener diode (30) is nonconductive, operation of the microcomputer (12) is inhibited. Alternatively, when the zener diode (30) is conductive, operation of the microcomputer (12) is enabled. In one embodiment, the power supply (10) further includes a time delay circuit (28, 32 and 34) for delaying initialization of the microcomputer to a known operating state until the DC source voltage rises above the threshold value for a period of time.

Low cost microcomputer power supply with power on reset and low voltage

A short circuit protection system that reacts to a voltage across an electrical load to prevent overdissipation of a semiconductor switch in the event of a short circuit. The system includes a capacitor having a charge state. When the capacitor is charged, the electrical load is turned ON via a transistor. The system automatically latches the electrical load ON until a short circuit occurs or until the capacitor discharges. When a short circuit occurs, the system automatically turns the load OFF.

Short circuit protection for high side driver

A DC power supply 44 for providing a desired filament voltage to a static filament in a vacuum fluorescent display 16 includes a voltage regulator 46 with an input and an output. The input couples to a source of ignition voltage 10 while the output couples to the base of a transistor 50. A first dropping resistor 52 connects between the source of ignition voltage 10 and the collector of the transistor 50. A second dropping resistor 54 connects between the emitter of the transistor 50 and the filament 20 of the VF display 16. Accordingly, a first current path to the filament 20 is defined through the first dropping resistor 52, the collector-emitter junction of the transistor 50, and the second dropping resistor 54. A second current path to the filament 20 is defined through the voltage regulator 46, the base-emitter junction of the transistor 50, and the second dropping resistor 54. In operation, therefore, filament current flows through the first current path when the source of ignition voltage 10 is operating in an upper portion of its range dissipating a significant amount of power across the first dropping resistor 52. Alternatively, filament current flows through the second current path when the source of ignition voltage 10 is operating in a lower portion of its voltage fluctuation range.

Filament power supply for static vacuum fluorescent display

In two embodiments of the present invention, the speed of a DC motor is determined by examining the signal at the negative terminal of the motor. The signal is high-pass-filtered to extract the AC component of the signal. The frequency of this signal is, in almost all cases, proportional to the speed of the motor. This signal is then fed into a comparator, which converts the signal into a square wave, which is then input into a microprocessor. The microprocessor determines the frequency of the square wave. If the frequency of the square wave is below a threshold of acceptable motor speed, the microprocessor can turn off the motor and provide a malfunction indication. If the frequency of the square wave is above a second threshold of acceptable motor speed, the microprocessor can likewise turn off the motor and provide a malfunction indication.

Method and apparatus for DC motor speed monitoring

An automatic headlamp dimmer system for switching a vehicle's headlamps from high beam to low beam when lights from another vehicle are detected in front of the vehicle. To prevent spurious responses to reflected light from signs and other sources, the dimmer system includes a light detector which is responsive only to infrared light. Also, unwanted responses to flashing lights are avoided by detecting the presence of a periodically varying light signal, and inhibiting switching between high and low beams in response thereto. The system is also capable of sensing the activation of windshield wipers and preventing headlamp switching caused by interruption of light to the system's light sensor by action of the wiper blades.

Automatic headlamp dimmer having improved signal discrimination and

A low voltage inhibiting circuit for use with a microcomputer in which a reset signal is applied during power-up or whenever the voltage of an unregulated source to a regulated supply drops below a predetermined threshold level. The reset signal is removed whenever the voltage from the unregulated source is restored to a value which is above a second predetermined threshold value defined as being above the first threshold value and after a predetermined period of time.

Low voltage inhibiting circuit for a microcomputer

Automatic headlamp dimmer

A vehicle light sensor for controlling light responsive systems such as an automatic headlamp dimmer. The sensor includes an enclosure containing a lens and a photo responsive detector. An optical chamber within the enclosure permits unwanted light from reaching the detector. A series of baffles within the chamber prevent light from outside a desired entrance angle from reaching the detector. A thin-film aperture is attached to the detector for controlling the size and shape of the detector's field of view. Gray scale shading may also be incorporated into the aperture to reduce the intensity of incoming light in selected portions of the field of view. An adjustment mechanism provides very fine angular view adjustments, beyond what is practical by simple assembly of molded parts.

Automatic headlamp dimmer with optical baffle

A vehicle lamp control sensor for switching a lamp on or off depending on ambient levels. The device employs a silicon photodetector in combination with a filter chosen to give the detector a response curve that peaks at about 550 nanometers. This gives the control sensor the same proximate spectral response as the human eye. The photo detector transmits an electrical signal in response to the ambient light. The electrical signal is sensed by a lamp switching circuit to switch the vehicle lamp at predetermined light levels. The vehicle lamp control sensor will thus respond to changes in the ambient light levels in a manner which matches the perceived light levels of a human observer.

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Detroit, MI, United States of America

Harold R Macks