Motorola Corporation

Eaton Corporation

Ranco Inc. of Delaware

Other

Robertshaw Controls Company

Eac Technologies Corp.

Bay E Estes

Leonard Latasiewicz

Leonard W Jenski

Patrick S Roberts

Robert J Crawford

Rolf Ernst Kowalewski

Richard H Noens

Kevin G Nowobilski

Joseph S Calabrese

Felix B Melikian

A defrost heater relay control circuit having reduced power consumption during a de-energized mode of operation is provided. The relay drive circuit utilizes a series connected capacitor to introduce a phase shift in the AC current waveform such that the amount of real power dissipated in the circuit during periods when the defrost heater control relay is de-energized is greatly reduced. This effectively shorts out the relay drive voltage without generating heat due to real power dissipation through the switched circuitry that disables the relay.

Adaptive defrost control circuit with relay power saving feature

A water temperature control circuit for a washing machine includes window detector and dual water valve drivers to modulate the hot and cold water valves to maintain the water temperature at a desired level. A temperature selector switch provides hot, regulated hot, warm, regulated warm, and cold temperature settings for the washing machine. During regulated temperature operation the window detector modulates one of the water valves to maintain the water temperature within a narrow temperature band. The window comparator includes two comparators that receive a common temperature input from a temperature sensing element. As such, no shunt resistor is required for one or the other comparators, thus improving accuracy. The control circuit operates open loop with respect to the hot and cold water valves that it controls, utilizing instead only the temperature input for controlling the proper water valve when enabled.

Automatic fluid temperature controller and washing machine incorporating same

A driver circuit for a latching type valve is provided which utilizes an electronic switch assembly to provide the dual polarity necessary to actuate the latching type valve to both its open and closed states. The driver circuitry includes a microprocessor and a slope detector circuit for monitoring the coil current used to energize the valve solenoid to determine when the valve armature has moved to its fully actuated position. The driver circuit preferably utilizes power MOSFET devices in the switch assembly configured into an H-bridge to drive the solenoid coil. Advantageously, the user of power MOSFET devices eliminates the necessity for a current sense resistor in the control circuitry, thereby decreasing power dissipation and increasing efficiency of the drive circuit, thereby prolonging the battery life used to drive the valve. A pulse of fixed duration may be utilized to transition the valve to an OFF position, or a second slope detector may be implemented to control the transition to the OFF position in like manner. Monitoring of the actual time required to actuate the valve may be utilized to signal low battery voltage or a failed valve, if desired.

Driver circuitry for latching type valve and the like

An electronic selector knob circuit (10) which uses a tapped potentiometer (POT1) to provide accurate operation without requiring factory calibration. The potentiometer (POT1) is calibrated through on-board circuitry which includes a tap voltage biasing device and which monitors operation on a continual basis through both a current monitor (16) and a voltage monitor (18). A redundant disable circuit (14) provides a redundant hardware means for shutting off all oven heating elements.

Tapped variable potentiometer resistor with current sense and safety

A precharged capacitor connected in parallel with the contacts of an open switch discharges through the switch upon closure. Oxides on the switch contacts are broken through upon closure of the switch to produce a good electrical connection. The capacitor provides sufficient voltage and transient current to clean the switch contacts. A microprocessor having signals of only 5 volts can interrogate a plurality of such switches by multiplexing some semiconductor switching circuits that energize the interrogated switches and by synchronously multiplexing some microprocessor input circuits. The microprocessor's input circuits therefore receive signals indicating the status of each switch in turn.

Computer-checking of the position of a switch whose contacts where

A controller for a relay controls the pull-in time of the armature of the relay by controlling the power applied to the relay coil. To determine the actual pull-in time, the time of closure of the contacts is sensed and the time at which power is applied to the coil is subtracted from it. The actual pull-in time is then compared with a stored value of ideal pull-in time to produce an error signal. The error signal corrects the level of power applied to the relay coil upon the next actuation of the relay, to make the actual pull-in time approximately equal to the ideal pull-in time. In some embodiments to control the level of power on the coil, a Gray-code counter samples a duty-cycle register in a micro-computer and produces a train of pulses that is filtered to provide a DC control signal. The DC control signal controls the duty cycle of a pulse-width-modulated oscillator that rapidly switches (modulates) the power to the relay coil.

Controller for fixed-time pull-in of a relay

Disclosed are two arrangements for remotely indicating the status of a washing machine and/or a dryer. In one arrangement, a current sense circuit is employed along with an optional vibration sense circuit to detect whether or not the washing machine or the dryer are on or off. At a change from on-to-off or from off-to-on, the status of the washing machine or dryer is transmitted over the air to a receiver for status display to the operator. In the second arrangement, detection of the status is internal to the washing machine and the dryer and the status includes additional information such as the type of cycle and the amount of time left before the cycle finishes. To avoid constant transmission of such information, the receiver includes a timer which is synchronized to the washing machine/dryer timing circuits.

Remote display arrangement for appliances

Disclosed is an arrangement for controlling the current in a solenoid. A microcomputer is used to control three states of a 3-state output device (high impedance, high and low) which are designed to correspond to three current modes of the solenoid: no current, full current and reduced current. The 3-state output device produces a signal which is used to control a solenoid drive circuit. The drive circuit includes first means for generating a first drive signal in response to the 3-state signal being in the high impedance state or the low state, and second means for generating a second drive signal in response to the 3-state signal being in the high impedance state or the high state. The circuit further includes third means for coupling the first and second drive signals to the solenoid such that the current in the solenoid is controlled according to the states of the 3-state signal.

Current drive circuit

Apparatus and method for retaining an electronic device having an encapsulated body portion of a generally uniform cross section by means of a socket assembly having a plurality of deformable ribs extending medially therein. The electronic device, in particular an LED is inserted into the cavity for frictional retention therein by deformably engaging the ribs of the socket assembly. Critical height spacing of the LED is retained yet the deformable ribs allow for thermal expansion and contraction of the device body and leads without placing undue stress on its lead/die interface.

Apparatus and method for retaining an electronic device

A visual display mounting assembly is provided wherein a substantially rectangular parallelopiped central body 18 of a display module 17 is sandwiched between a planar surface 29 of a printed circuit board 23 and a substantially planar chassis wall 15 having a rectangular opening 16 therein for a front viewing surface 19 of the display module. The chassis wall opening 16 is formed with two opposing planar edge portions 32 of the chassis wall and two opposing nonplanar edge portions 33 of the wall comprising bent portions of the wall projecting towards the module. Peripheral portions 34 of the front surface 19 of the display module are positioned in pressure contact with the planar edge portions 32, and the front surface 19 is positioned between the non-planar edge portions 33 of the chassis wall. The display module 17 is held in place by retaining twist tabs 24 fixing the circuit board to the chassis wall and thereby having the circuit board press the display module body against the chassis wall.

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Palatine, IL, United States of America

Bay E Estes