An erasing method for the memory cells of a non-volatile memory is provided. Each memory cell comprises a gate, a source, a drain, an electron-trapping layer and a substrate. The data within the memory cell is erased by applying a first voltage to the control gate, applying a second voltage to the source, applying a third voltage to the drain and applying a fourth voltage to the substrate. The electrons are pulled from the electron-trapping layer into the channel by negative gate F-N tunneling effect.

Erasing method for non-volatile memory

This invention relates to a circuit arrangement and the associated mechanism for slaving the angles of rotation of the slats of a plurality of centrally controlled sun or window blinds. The driving motor of each blind is provided with current via a corresponding operational amplifier and related circuit. The motor operates the slats to achieve balance between an input control voltage and a voltage depending on the angular position of the slats. An automatic version in which the control voltage is generated by a photoelectric sensor and several circuit variations are shown.

Apparatus for synchronizing the slats of motor driven window blinds

An apparatus for driving a plurality of motors at different variable speeds. The apparatus includes a rectifier for supplying direct current power to a dc bus circuit. A plurality of inverters are connected to the dc bus circuit and each inverter drives a respective motor. Each inverter is controlled by an individual controller connected thereto for controlling the frequency of the output of the inverter to thereby control the speed of the associated motor. The inverters are preferably mounted on a common heat sink to reduce electrical and mechanical complexity. The apparatus permits the rectifier and the dc bus circuit to be sized to handle a maximum rating of less than the sum total of maximum loads of each of the motors. The dc bus circuit also serves to distribute energy generated by a slowing motor, for example, to other motors driven from the bus circuit. A chopper resistor may be included and switched across the dc bus circuit to provide braking to the motors.

Frequency inverting apparatus

A control system for a linear actuator having an electric motor drawing a variable current level during operation. The control system includes a current level sensor for determining an operational current level of the linear actuator and a controller for generating a drive signal and a force request signal representative of a desired current level of the linear actuator. The drive signal remains constant during a predetermined time interval of the controller. The control system further includes a current limiting component for receiving the force request signal, the current level of the linear actuator and the drive signal. The current limiting component minimizes the current level of the electric motor in response to a comparison between the force request signal and the desired current level within a time interval substantially smaller than the predetermined time interval of the controller.

Linear actuator control structure

A quick-calibrate control module for use in a heating and cooling system is provided which responds to setpoint signals from a control potentiometer to drive a remote actuator to corresponding positions. The control module comprises a motor coupled to the actuator and a feedback potentiometer coupled to the motor for producing a feedback signal relating to the actuator position. Operational amplifiers combine the setpoint signal and the feedback signal to produce an error signal, and a comparator responds to the error signal and drives the motor to minimize the error signal. A reference supply is connected to the control potentiometer, the reference supply having a zero setting potentiometer which calibrates the closed position of the actuator to a corresponding zero setting of the control potentiometer. A stroke adjustment potentiometer scales the feedback signal to calibrate a desired open position of the actuator with a corresponding setting of the control potentiometer. The amplifiers also prevent cross-loading of the reference supply and the stroke adjustment potentiometer, so that stroke adjustments can be made without altering the zero setting of the actuator.

Non-bridge type electronic actuator control

A motor actuator circuit for use in heating and air conditioning and process control systems to selectively rotate a motor shaft which positions a damper or valve. A command signal, such as a voltage, or a potentiometer controlled by a sensing element of the system provides a signal representing the desired position for the damper and a sense potentiometer provides a signal representing the actual shaft position; a signal comparator circuit including a differential amplifier having an output switching stage is responsive to a potential difference between the signals to effect energization of one of a pair of motor windings, the energized one of the pair being determined by the polarity of the difference signal; and detent circuits derive a detent signal from the voltage across the other one of the motor windings for coupling to the amplifier input to increase the potential difference, the sense potentiometer wiper being linked to the motor shaft so that the potential difference decreases as the shaft rotates to the desired position, and the motor is deenergized when the desired position is reached.

R Nettles

Papers

Proportional motor actuator circuit