Delco Electronics Corporation

Delphi Technologies, Inc.

Wayne A Madsen

Gregory J Manlove

Vineet Gupta

James L Kohler

Paul M Werking

Andrew R Betts

James N Athans

Todd M Poole

Jeremy A King

Brian W Johnson

A VFD drive apparatus in which the filament of a VFD is coupled at a first terminal to an input voltage derived from a voltage source, and at a second terminal to a shunt voltage regulator that establishes a regulated filament current and a regulated cutoff voltage with respect to ground potential. Other electrical loads such as drive circuitry for the anodes and grid of the display are coupled between the second terminal of the filament and ground potential so that at least a portion of the filament current is supplied to such other electrical loads. Power dissipated by the shunt voltage regulator is thereby reduced, and the cost associated with providing additional voltage regulators for the other electrical loads is avoided.

Drive apparatus for a vacuum fluorescent display

A filter board for filtering electromagnetic emissions from an electronic device couples to a conductive housing in the device. The filter board includes a plurality of filter components connected to a substrate, which is coupled to a continuous ground plane. Signal lines from the electronic device are coupled to the filter components and pass through the substrate and ground plane before being connected to other circuits. The filter board prevents high frequency noise and excessive emissions from exceeding required limits.

Electromagnetic filtering structure

Circuitry (100, 100') for determining actuator position includes four MOS transistors (T1-T4) connected to each side of a bi-directional motor (10). The current flowing through the motor (10) at any given time is proportional to voltages developed across the internal impedances of the transistors (T1-T4). The resulting motor voltages are amplified and high-pass filtered to remove any DC offsets due to the signal amplification. The conditioned motor voltages are then compared to one or more threshold voltages and passed through a one shot circuit (120) to provide detectable pulses for each motor commutation event. Circuitry (106,107) is provided for counting pulses provided by the one shot circuit (120) and, based on a desired motor position, for providing a number of digital control signals to a digital control circuit (104). Digital control circuit (104) is responsive to the number of digital control signals to control the gate voltages of the four transistors (T1-T4) to thereby control the position of the motor (10).

Circuitry for determining actuator position

An actuator for automotive HVAC control is coupled to a remote controller by two wires. The controller applies power to the actuator in a high current or a low current mode. A variable resistance driven by the actuator generates a voltage proportional to position in the low current mode. Zener diodes in the actuator circuit prevent motor operation in the low current mode and permit motor operation in the high current mode. A microprocessor in the controller selects the mode and reads the voltage in low mode to determine position. It controls the motor for a duration required to reach a desired position and then checks the new position to verify that the target has been reached. If not, another iteration is employed to reach the target.

Control method and apparatus for two-wire motor actuator

A coolant shutoff valve is closed when a motor-operated temperature door is moved to full cold position to prevent heating of air due to radiation, conduction, convection, or leakage around the door. The motor moves the door to hot or cold limit positions and remains in a stall condition to maintain such positions. A motor control responsive to operator selected temperature moves the door to such limit positions. A shutoff circuit associated with the motor control senses whether a hot or cold mode is selected and detects from the motor current whether the motor is stalled. When the circuit determines both a cold mode and motor stall current an actuation signal is sent to the shutoff valve.

Coolant control method and apparatus for vehicle air conditioning system

An efficient power supply for a vacuum fluorescent display having a battery or other unregulated source supplies the grid voltage directly from the battery and supplies the anode voltage via a step-up regulator. To eliminate apparent display brightness changes upon variation of battery voltage, the battery voltage and the anode voltage are fed back to the regulator, adjusting the regulated anode voltage inversely to the battery voltage. The direct coupling of battery to the grid eliminates the necessity of regulating or converting the grid voltage, allowing a smaller power supply to be used and minimizing heat losses.

Method and apparatus for VF tube power supply

A power supply for a VF display generates a DC filament voltage from a battery by either a switched transformer supply or a monolithic regulator circuit. Where a higher-than-battery voltage is needed for anode and grid voltages, another monolithic regulator circuit or the switched transformer is used. An H-switch develops an alternating voltage from the DC voltage and applies it to the display filament. A controller for the H-switch is a logic circuit including flip-flops which toggle in response to a low frequency pulsed dimmer signal to synchronize the filament half cycles with the dimmer phases. Slew rate control ramps the H-switch control signal to produce a trapezoidal waveform in the filament current having reduced radio frequency emissions.

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Kokomo, IN, United States of America

Wayne A Madsen