Abstract: A power system for powering a load including a power converter and a control circuit coupled to the power converter. The power converter includes an input terminal for receiving an input voltage and an input current, and output terminal for outputting an output voltage and an output current to a load. The control circuit is configured to monitor the output voltage and the output current of the power converter and shut down the power converter in response to the output voltage being less than or equal to a defined voltage threshold and the output current being greater than or equal to a defined current threshold for a defined period of time. Other example power systems, control circuits, and methods of controlling power converters are also disclosed.
Abstract: Apparatus and methods operate to disable a dynamically biased apparatus and a dynamic bias current source providing dynamic bias current to the apparatus at the beginning of a static bias startup period shortly after power-on. The dynamically biased apparatus is then gradually enabled in a static bias mode of operation during the static bias startup period. Following the end of the static bias startup period, operation of the dynamically biased apparatus in a dynamic transconductance mode is gradually enabled during a dynamic bias startup period. Such startup sequence operates to prevent damaging in-rush currents in a system employing the dynamically biased apparatus in a feedback control loop.
Abstract: Methods and circuits related to power regulator start-up are disclosed. In one embodiment, a start-up circuit can include: (i) a delay circuit having a resistor and a capacitor, where the capacitor is coupled between ground and a common node; and (ii) a control chip that receives a reference voltage, and includes an input pin coupled to an input source, an output pin supplying power for a device, and a multiplexed pin coupled to the resistor at the common node to receive an enable signal. The start-up circuit outputs an electrical signal at the output pin based on a comparison of a voltage at the multiplexed pin against the reference voltage, and after a delay time determined by the capacitor and the reference voltage. The voltage at the multiplexed pin can increase continuously with a rising slope determined by input current flowing through the multiplexed pin during a start-up process.
Abstract: A multi-phase power source device capable of easily changing the number of phases is realized. For example, a plurality of drive units POL-POL corresponding to the number of phases are provided, wherein each POL[n] receives a phase input signal PHI[n] serving as a pulse signal, and generates a phase output signal PHO[n] by delaying PHI[n] by a predetermined cycles of a clock signal CLK. PHI[n] and PHO[n] of each POL[n] are coupled in a ring, wherein each POL[n] performs a switching operation with PHI[n] or PHO[n] as a starting point. In this case, each POL[n] charges and discharges a capacitor Cct commonly coupled to each POL[n] with an equal current, and a frequency of CLK is determined based on this charge and discharge rate. That is, if the number of phases increases n times, the frequency of CLK will be automatically controlled to n times.
Abstract: Systems and methods for providing variable-frequency soft start of an AC load are disclosed. In one exemplary embodiment, a method for starting an alternating current (AC) load with a variable-frequency AC power output includes receiving an indication of a duty cycle for chopping the AC power output during starting of the AC load, and determining a frequency of the AC power output. The method further includes chopping the AC power output at the duty cycle, based on the determined frequency of the AC power output, and providing the chopped AC power output to start the AC load.
Abstract: A method and structure for preventing operation of a circuit in a high current operating region by disabling a start-up circuit until a power supply headroom is detected at a predetermined voltage level.
June 11, 2007
Date of Patent:
April 26, 2011
International Business Machines Corporation
Abstract: A polyphase AC induction motor is connected to a power supply through a soft starter having three sets of inverse parallel connected silicon controlled rectifiers with each set corresponding to one particular phase. Low speed starting and operation of the motor can be accomplished through triggering circuits controlling the phases of the triggering pulses in relation to the phases of the supply. The low motor speeds are developed by a gating sequence that generates a low frequency waveform that is less than the main supply frequency to the motor. This low frequency waveform is current and voltage controlled by the gating sequence to permit the AC motor to smoothly operate at speeds less than 100% of rated while developing net positive torque at the low controlled operating frequency.
August 29, 2005
Date of Patent:
March 18, 2008
Walter G. Barie, Ronald E. Vines, Harold D. Hagerty
Abstract: A circuit arrangement for limiting the current to be switched of an electrical load, with the power input of the electrical load being controlled by means of a Triac, said Triac being connected in series with the electrical load, with a Diac being connected to the gate terminal of the Triac, said Diac being connected in series with a resistor arrangement whose resistance value is variable for the purpose of controlling the Triac, said Triac being disconnectible from the power supply by means of a first switch, wherein a second switch is provided by means of which the series arrangement comprised of the resistor arrangement and the Diac is disconnectible from the power supply, and wherein, on turning the electrical load on, the first switch is closed first, while the second switch is closed with a time delay. Advantageously, on turning the electrical load off, the second switch is opened first, while opening of the first switch occurs with a time delay.
Abstract: A power control system in a DIN rail mount assembly for switching power in a low cost, compact, and solid state for controlling electric heaters. The system can be used for single phase, three phase-two leg, and three phase-three leg. Current switching capabilities range from 30A to 50A. Variable time base, 4-20 mA process control or VAC/DC input contactor configurations can be utilized. The DIN Rail back plate includes a sliding mechanical configuration. A potting fence provides for potting of the electrical substrate and also provides a heat sink. A large cover covers finger palm safer terminals. The DIN rail assembly can also be used for supporting electrical, electromechanical, optical or other types of assemblies.
Abstract: The present invention provides a electronic switch suitable for fading on/off control of electrical equipment like lamps and motors. The main circuit comprises a rectifier bridge circuit and a thyristor. A control circuit includes a fast discharging synchronic integrator and a trigger pulse integrator, the former acts as a pulse phase shifter to provide a self-adapting magnitude variable sawtooth waveform, while the latter acts as a dynamic phase variation memory so as to provide a variable reference for comparison. Trigger pulses which are feed back via the main circuit causes the synchronic integrator to fast discharge. If a control switch is closed, the voltage on the integral capacitor and the trigger angle decreases gradually to produce the fade on. In the fade off process, the conditions are just the opposite. Fading on/off time can be independently set.
Abstract: In a method and device for limiting the starting current of a DC converter, at least one buffer capacitor is initially charged through a load resistor. The current going through the load resistor is measured with a monitor. The monitor switches on a DC converter and bridges the load resistor once a switching threshold is reached. A predetermined minimum current is used as the switching threshold.
September 20, 1988
Date of Patent:
January 1, 1991
Adam-Istvan Koroncai, Alexander Lechner
Abstract: A compensation circuit includes a circuit for monitoring the current delivered to a load and for producing a switching signal whenever a current spike is detected. A control signal representative of the desired voltage across the load is produced. A power supply supplies voltage to the load in response to the control signal. The circuit for generating the control signal is responsive to the switching signal for adjusting the control signal such that when a current spike is detected the voltage delivered to the load is substantially instantaneously reduced.
Abstract: Electrical control apparatus including a power supply, a regulating element, a manually-operable control device which can be set to provide a preset output from the regulating element, and an automatic control circuit for modifying the operation of the control elements in the event of a power failure. The automatic control circuit is so arranged as to rapidly reduce the output to zero when the absolute supply voltage falls below a predetermined level, and to progressively raise the output to the preset level when the supply voltage is restored.
Abstract: A circuit for controlling the initiation and operation of a phase control circuit employed in voltage regulation to a load such as dimming lights. The circuit uses a power semi-conductor which is triggered by a "walk-in" circuit. The "walk-in" circuit includes a regulator diode across a diode bridge which stabilizes the output of the load, such as a level of lighting.
Abstract: The present invention provides a power supply for lighting an incandescent lamp with high-brightness, comprising connecting a time constant circuit, rectifier, switching device so that the output of the rectifier is supplied to an incandescent lamp through the impedance for a period, determined by the time constant circuit, and that the switching device conducts and shorts the impedance after a lapse of the period to allow the incandescent lamp to receive the output of the rectifier by bypassing the impedance.
Abstract: An electrical control system controls an electrical load device, particularly an inductive load such as the ballast of a gas discharge lamp which generates a back EMF when power is removed therefrom. The control system includes a first electronic switch for controlling the application of power to and withdrawal of power from the load and a second electronic switch which controls the first electronic switch. The second switch is responsive to a command signal preferably occurring between 90.degree. and 180.degree. of the AC power half wave to turn on and thus switch off the first switch which in turn withdraws power from the load. The circuit remains in this state until a predetermined circuit condition occurs at which point the potentials on the load and the AC power supply are at predetermined levels. The equal potential turns the second switch off, whereupon power is reapplied to the load by the first electronic switch.
Abstract: A system of controlling the operation of an AC load with a switch placed in series with the load, which switch is itself operated by dc control logic powered by power loss experienced by the switch which the logic controls. Numerous elements in the control system perform multiple functions allowing the control logic to remain alive during both the on and off mode of the switch without power being provided to the logic by separate conductors to the AC power source, such that the control system is completely self powered and self regulated by simply placing the system, with two wires, into a series loop with the AC power source and the load.
Abstract: Current inrush limiting apparatus is disclosed including a power supply circuit (32) which regulates the transmission of power from a source (12) to a load (14). A soft start control (36) controls the power supply to prevent excessive current inrush to the load by causing it to apply power to the load gradually when the power first comes on. A dropout timer (38) monitors the power signal and rapidly resets the soft start control circuit if a power dropout exceeds a predetermined minimum duration. This ensures that excessive current inrush also does not occur following brief power dropouts.