1243 results about "Voltage sensing" patented technology

An organic light emitting diode (OLED) display includes an array of OLEDs, each OLED having two terminals; a voltage sensing circuit for each OLED including a transistor in each circuit connected to one of the terminals of a corresponding OLED for sensing the voltage across the OLED to produce feedback signals representing the voltage across the OLEDs; and a controller responsive to the feedback signals for calculating a correction signal for each OLED and applying the correction signal to data used to drive each OLED to compensate for the changes in the output of each OLED.

A PWM controller has a line voltage input that allows using a start-up resistor for both start-up and power-limit compensations so that it can save the power consumption, ease the PCB layout, and shrink the power supply size. In the integrated circuit, a current switch used for both start-up and line voltage sensing is composed of a diode and a switch transistor. A current multiplier is used to improve the precise by canceling the impact of the integrated resistor's absolute value, which is composed of a transistor loop, a constant current and a reference current. Thus, by properly selecting the value of the start-up resistor, an identical output power limit for low line and high line voltage input can be achieved.

A clamping current and voltage sensor provides an isolated and convenient technique for measuring current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a body formed from two handle portions that contain the current and voltage sensors within an aperture at the distal end, which may be a ferrite cylinder with a hall effect sensor disposed in a gap along the circumference to measure current, or alternatively a winding provided through the cylinder along its axis and a capacitive plate or wire disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage. When the handles are compressed the aperture is opened to permit insertion of a wire for measurement.

A primary side controlled power converter having a voltage sensing means coupled to a transformer of the power converter and configured to provide a voltage feedback waveform representative of an output of the transformer is provided. A primary switching circuit operates to control energy storage of a primary side of the transformer. The primary switching circuit is operable during an on time and inoperable during an off time. The on and off time is switched at a system frequency. A feedback amplifier generates an error signal indicative of a difference between the voltage feedback waveform and a reference voltage. A sample and hold circuit samples the error signal at a periodic frequency during the off time. An error signal amplifier is configured to provide the sampled value to the primary switching circuit wherein the primary switching circuit controls the transformer and thereby regulates an output of the power converter.

Provided herein are methods and apparatus for stroke volume determination by bioimpedance from a patient's upper arm, or brachium, utilizing pulsations of the brachial artery contained therein. The apparatus includes two or more spaced apart alternating current flow electrodes positioned on the patient's arm proximate the brachial artery and two or more spaced apart voltage sensing electrodes positioned on the patient's arm proximate the brachial artery. The voltage sensing electrodes are positioned between the alternating current flow electrodes on the arm. An alternating current source is electrically connected to the alternating current flow electrodes and a voltmeter electrically is connected to the voltage sensing electrodes. A data input device is provided along with a processing unit in communication with the data input device, the alternating current source, alternating current flow electrodes, the voltmeter, and voltage sensing electrodes. The processing unit is capable of using data from the data input device and voltage sensing electrodes to calculate the stroke volume of the patient.

A power conversion circuit senses an output voltage to detect shorted lamp conditions in a backlight system. The power conversion circuit can drive at least one fluorescent lamp. A voltage sensing feedback circuit, such as a capacitive voltage divider or a resistive voltage divider, senses the output voltage at an output of the power conversion circuit and generates a voltage feedback signal for a shorted lamp detector. The shorted lamp detector reliably detects a shorted lamp condition of one fluorescent lamp in a multi-lamp configuration or detects a short circuit condition of the output voltage line coupling the output voltage of the power conversion circuit to the fluorescent lamps.

A boost type power supply circuit for providing a DC output voltage comprising first and second semiconductor switches coupled between respective input lines and a common connection; an AC input voltage from an AC source being supplied across the input lines; first and second diodes coupled in series with respective ones of the switches; third and fourth diodes coupled across respective ones of the switches in a free-wheeling relationship with the switches; an inductance coupled in at least one of the input lines; a controller for controlling the conduction times of the switches by providing a pulse width control signal to each of the switches; wherein the controller turns on at least one of the switches during a positive half cycle of the AC voltage to allow energy storage in the inductance and turns off the at least one switch to allow the energy stored in the inductance to be supplied to an attached load through one of the first and second diodes and one of the third or fourth diodes; and the controller turns on at least one of the switches during a negative half cycle of the AC voltage to allow energy storage in the inductance and turns off at least one switch to allow the energy stored in the inductance to be supplied to the attached load through one of the first and second diodes and one of the third and fourth diodes. The controller determines an on-time and an off-time of a pulse of the pulse width modulated control signal during each half cycle of the AC voltage, the on-time and off-time of the pulse being controlled to regulate said output voltage and to provide power factor correction of said AC input voltage, based on either voltage sensing or current sensing.

A power supply for plural loads coupled in parallel comprises a voltage regulator, a plurality of current regulators, and an error control circuit. The voltage regulator provides a common output voltage to the plural loads. The voltage regulator comprises a sensor circuit providing a voltage sense signal corresponding to the output voltage, which provides feedback to regulate the output voltage at a selected level. The plurality of current regulators are coupled to respective ones of the plural loads. Each of the plurality of current regulators regulates current drawn by respective ones of the plural loads to within a desired regulation range. The plurality of current regulators each further provide a respective error signal corresponding to an ability to remain within the desired regulation range. The error control circuit is operatively coupled to the voltage regulator and to the plurality of current regulators. The error control circuit receives the error signals from the plurality of current regulators and provides a common error signal to the voltage regulator. The voltage regulator thereby changes the selected level of the output voltage in response to the common error signal. Accordingly, the selected level of the output voltage remains at a minimum voltage necessary to keep the plural loads in the desired regulation range.

An automatic transfer switch (ATS) controller is disclosed which includes a power supply circuit to regulate and filter input power, a transformer to convert utility and generator power sources into power supply voltages and voltage sensing sources and a voltage sense signal conditioning circuit. Controller further implements a solenoid driver circuit to drive automatic transfer switch solenoids, an embedded microcontroller configured to monitor utility and generator voltages and a user interface interfaced to said microcontroller for operator entry of instructions. A LED indicator is included and is configured to verify user interface entries and overall operation of the controller and ATS system.

Provided are a charge equalization apparatus and method for a battery string connected in series, and more particularly, are a charge equalization apparatus and method that efficiently perform charge equalization while reducing entire complexity and volume and lowering production costs through a configuration that an individual battery included in a battery string shares a single voltage sensing module and a single charge equalizing module; a switch block of a two-stage structure forms a current path for measuring voltage of individual batteries included in the battery string, and at the same time, forms a charging or discharding path of a low-charged or over-charged battery among the battery strings; and a switch device having low withstand voltage is used.

A tamper detection arrangement in a meter having a service disconnect switch employs a voltage sense circuit that requires only a single connection to digital processing circuitry for the feeder lines of typical residential service. In one embodiment, the voltage sense circuit includes an isolation device that electrically isolates the processing device from the line voltages. The voltage sense circuit senses a voltage on the feeder lines and is operable to generate a voltage detection signal having a characteristic representative of whether line voltage from the electrical power lines is present on the feeder lines. A processing circuit is operably connected to the voltage sense circuit to receive the voltage detection signal and to selectively generate a tamper flag based on whether the characteristic of the voltage detection signal indicates the presence of voltage on the first and second feeder lines when the service disconnect switch has disconnected the electrical power lines from the first and second feeder lines.

A fast buffer and switching regulator are combined in parallel in a master-slave loop topology to form a voltage regulator. The buffer circuit has a voltage sensing amplifier that senses the difference between the voltage at the output of the voltage regulator and a reference voltage. This voltage difference is amplified, and then input to a buffer that sources current to or sinks current from the output of the voltage regulator. The output of the buffer circuit is coupled to the switching converter which senses the changing buffer circuit output current. The switching converter changes its duty cycle to oppose the current from the buffer circuit. This is a master-slave loop topology wherein the buffer circuit is the master loop that quickly provides high levels of current to compensate for a voltage transient at the output of the voltage regulator, and the switching converter is the slave loop which eventually takes over from the master loop to meet the current output requirements of the voltage regulator.

A method and system for providing a mixed-mode (current- and voltage-source) audio amplifier is disclosed. The mixed-mode amplifier includes a voltage sensing feedback path including a first network comprising at least one circuit; and a current sensing feedback path including a second network comprising at least one circuit. According to the method and system disclosed herein, the first and second networks vary an output impedance or transconductance of the amplifier as a function of frequency of the input voltage signal, such that at a first frequency range, the amplifier operates substantially as a current amplifier, and at a second frequency range, the amplifier operates substantially as a voltage amplifier, thereby inheriting distortion reduction of the current amplifier and stability of the voltage amplifier.