Abstract: An electrostatic discharge (ESD) protection circuit is provided. The ESD protection circuit includes a transient-state detection circuit configured to generate a dynamic triggering signal based on a voltage change rate of a voltage on a first power rail; a voltage detection circuit configured to generate a static triggering signal based on the voltage on the first power rail; a trigger circuit configured to generate a discharge control signal based on the dynamic triggering signal and the static triggering signal; and a main discharge circuit configured to discharge an electric charge from the first power rail to a second power rail based on the discharge control signal.

Abstract: A controller outputs pulse signals to a first switch and a second switch based on a circuit current flowing through a power conversion circuit and a voltage of an AC power supply. The first switch is opened and closed alternately to the second switch. According to the opening and closing, a current in which a high frequency component is mixed with a low frequency component of the AC power supply flows through the power conversion circuit.

Abstract: When an image forming apparatus shifts to a power saving mode, a controller unit further reduces power consumption by switching AC current on/off every predetermined amount of time. When AC current input from a commercial AC power supply is turned off, a DC voltage generating circuit normally can no longer supply a DC voltage, rendering the controller unit unable to operate. Accordingly, the controller unit operates using a charge accumulated in a smoothing capacitor while the AC current is not being supplied. An AC cutting circuit is switched on before a both-end voltage at the smoothing capacitor drops below a lower limit of operation voltage of the DC voltage generating circuit, and the smoothing capacitor is recharged.

Abstract: A control circuit for controlling one or more power switches of a power converter includes a voltage control loop and a current control loop. The control circuit is configured to generate a current reference for the current control loop using the voltage control loop and an AC reference signal. The control circuit is configured to operate in at least a first mode in which a parameter of the voltage control loop is sampled only at every other zero crossing of the AC reference signal and the sampled parameter is used to generate the current reference for the current control loop. The power converter may be an AC-DC converter or a DC-AC converter (i.e., inverter). Alternatively, the voltage control loop may be sampled at every zero crossing of the AC reference signal, and/or more frequently during transient load conditions.

Abstract: The present invention discloses an off-line regulator. The off-line regulator comprises a rectification circuit configured to rectify an AC line voltage into a rectified line voltage; a pass device coupled between the rectified line voltage and a first capacitor, the pass device is configured to be turned ON or OFF according to a comparison signal indicating whether the rectified line voltage is over a threshold voltage. The first capacitor delivers an interim voltage into a converter which supplies power to a load. Wherein a second capacitor coupled across a driver which driving the pass device is charged by the first capacitor when the comparison signal is at a first state, and the driver is boosted when the comparison signal is at a second state.

Abstract: Method and apparatus for controlling an apparatus transmitting power between two electricity networks or between an electricity network and a polyphase electric machine), and including low-voltage power cells (C), which include a single-phase input/output connection (IN/OUT). The power cells are arranged into groups (G1-GN, GP1-GPN1, GS1-GSN2, G1??-GN??) such that at least one power cell per each phase of the electricity network or of the electric machine belongs to each group, and the input terminals (IN) of all the power cells belonging to the same group are connected to a common transformer, the transformer including its own separate winding that is galvanically isolated. The controllable power semiconductor switches connected to the input connectors (IN) of all the power cells supplying power to the same transformer are controlled cophasally with a 50% pulse ratio.

Abstract: A DC motor is provided. The DC motor prevents rush or overload of current in the DC motor during and/or after power input irregularities to the DC motor. A control circuit of the DC motor is configured to control current provided to the DC motor. When power irregularities in the power input to the DC motor are detected by the control circuit, the control circuit stops generating PWM (Pulse Width Modulated) signals and stops the current provided to the DC motor. After the stoppage of PWM signals, the control circuit can perform a soft-start of the PWM signals when the power irregularities are no longer detected. The soft starting of the PWM signals generates gradual increase in current to the DC motor, thus, preventing sudden rush of current that cause malfunction of the DC motor.

Abstract: The present invention provides a transient suppression circuit for use with a rectifier coupled to a transformer. In one embodiment, the transient suppression circuit includes a triggering section configured to provide a timing signal corresponding to a dead time of the rectifier. Additionally, the transient suppression circuit also includes a biasing section coupled to the triggering section and configured to apply a reverse bias voltage to the rectifier based on the timing signal.

Abstract: A method and an arrangement for controlling phase-specific thyristors of a half-controlled network bridge. The method comprises the steps of identifying continuously a thyristor to be controlled on the basis of magnitudes of supplying phase voltages; controlling the thyristor by enabling a current flow to its gate current circuit through an inductive component of a constant current regulator, which constant current regulator is common to all the gate current circuits, the thyristor control comprising the steps of determining a magnitude of the gate current at the potential of the gate conductor in the constant current regulator, alternately switching the voltage producing the gate current off from the gate current circuit when the gate current is higher than a predetermined limit, and switching the voltage producing the gate current on in the gate current circuit when the gate current is lower than a predetermined limit.

Abstract: An instantaneous voltage-drop compensation circuit including: a first voltage detector detecting three-phase voltages to be input to a power converter converting three-phase AC to DC based on control pulse signals, and outputting three-phase voltage signals; a first three-phase to two-phase converter converting the detected signals to two-phase voltage signals; a first current detector detecting three-phase currents to be input to the power converter and outputting three-phase current signals; a second three-phase to two-phase converter converting the detected current signals to two-phase current signals; a first subtracter generating a first deviation signal from input current command signals and the two-phase current signals; an input current controller generating input current control signals based on the first deviation signal; and a first adder adding the two-phase voltage signals to the input current control signals, to generate control pulse signals for the power converter.

Abstract: An electronic monitor for monitoring characteristics of an AC power line for swells, sags, RMS voltage, impulses, total harmonic distortion (THD) and frequency. The waveform is received at the monitor, scaled to a lower magnitude, rectified by an op amp with zero offset voltage, converted a digital form which is representative of the waveform and processed to determine the occurrence of any irregularity in the AC power waveform. Two DMA channels are used to store each cycle, or groups of cycles, of the waveform into two buffers for further processing. An input surge protective circuit limits impulse voltage to the power supply. Related methods are also disclosed.

Abstract: A variable speed drive with a converter that is controllable to precharge a DC link is provided. The variable speed drive also includes an inverter. The converter converts a fixed line frequency, fixed line voltage AC power from an AC power source into DC power. The DC link filters the DC power from the converter. Finally, the inverter is connected in parallel with the DC link and converts the DC power from the DC link into a variable frequency, variable voltage AC power. The converter includes a plurality of pairs of power switches, wherein each pair of power switches includes a reverse blocking power switch connected in anti-parallel to another reverse blocking power switch. Alternatively, each pair of power switches includes a reverse blocking power switch connected in anti-parallel with a silicon carbide controlled rectifier.

Abstract: A switching regulator that performs voltage regulation using synchronous rectification in step-up and step-down modes includes input and output terminals, an inductor, first through fourth transistors, an overcurrent detection unit, and a control unit. The input terminal receives an input voltage. The inductor generates an output voltage. The output terminal provides the output voltage. The first and second transistors perform switching in the step-down mode. The third and fourth transistors perform switching in the step-up mode. The overcurrent detection unit detects an overcurrent condition. The control unit controls operation of the transistors, causes the first and third transistors to be off and the second and fourth transistors to be on when the overcurrent condition is detected in a first state, and causes the first and fourth transistors to be on and the second and third transistors to be off when the overcurrent condition is detected in a second state.

Abstract: The present invention provides a method and apparatus for detecting a continuous current of a switching current. A current signal is produced in response to a switching current of the magnetic device. By sampling the waveform of the current signal in response to the enabling of a switching signal, a first current signal and a second current signal are generated. A continuous current signal is produced according to the first current signal and the second current signal. The continuous current signal is corrected to the continuous current of the switching current.

Abstract: In one embodiment of the present invention, an output control device is disclosed capable of reducing a chip size and realizing a low cost. An output control device includes a switching transistor controlling an output voltage by having an on/off time ratio controlled and a control IC controlling the on/off time ratio of the switching transistor on the basis of the output voltage controlled by the switching transistor. The switching transistor is made of a lateral power MOSFET.

Abstract: A switching power supply apparatus 10 controls a main switching element Q1 by a control circuit 12 so that a direct-current voltage obtained by rectifying an input alternating-current voltage is stabilized and outputted as a target direct current output. A starting current of the control circuit 12 is obtained via a first starting resistor R1 and a second starting resistor R2 from the direct-current voltage. Moreover, the switching power supply apparatus 10 includes a voltage detection circuit 14 and a switching circuit 13. The voltage detection circuit 14 detects a voltage of the direct current input with the use of a Zener diode ZD1. The switching circuit 13 stops the main switching element Q1 in a case where a voltage value of the direct current input becomes equal to or less than a predetermined value. The voltage detection circuit 14 detects a direct current voltage at a point connecting two of the plurality of starting resistors with the use of the Zener diode ZD1.

Abstract: DC power for low power loads is provided for vehicles such as snowmobiles where the electrical system includes primarily AC power. DC voltage is provided for gauges and similar loads even though the peak value of the AC is below a desired level. Rectification and regulation of some energy from the alternator is used for supplying the DC power at a desired DC voltage that is above an alternator zero to peak value. A capacitor and a diode are connected in parallel from the alternator with rectifying circuit portions for supplying power to the DC load. A DC voltage monitor senses the DC voltage supplied to the DC load and prevents the DC voltage from rising above the desired voltage by controlling the first rectification, the second rectification, or both.

Abstract: A variable speed drive with a converter that is controllable to precharge a DC link is provided. The variable speed drive also includes an inverter. The converter converts a fixed line frequency, fixed line voltage AC power from an AC power source into DC power. The DC link filters the DC power from the converter. Finally, the inverter is connected in parallel with the DC link and converts the DC power from the DC link into a variable frequency, variable voltage AC power. The converter includes a plurality of pairs of power switches, wherein each pair of power switches includes a reverse blocking power switch connected in anti-parallel to another reverse blocking power switch.

Abstract: A circuit for lowering the effective voltage drop of a semi-conductor diode. The circuit includes a first Metal Oxide Semi-conductor (MOS) device connected in parallel with the diode. A bias voltage which is close to but lower than the threshold voltage is applied to the MOS device. When a forward voltage is applied to the diode, this voltage is added to the source to drain voltage of the MOS device which turns it on. The MOS device then bypasses the diode to effectively overcome the inherent forward voltage drop of the diode. The circuit is advantageously applied to a rectifier circuit to reduce input voltage requirements and improve the efficiency of the rectifier.

Abstract: A device for providing a high d.c. voltage supply and a low d.c. voltage supply. The device includes, in parallel, a first diode connected in series with a capacitor, a rectifier having a polarity opposite to that of the first diode, and a breakover voltage limiter. The terminals of the low d.c. voltage source correspond to the terminals of the capacitor.

Abstract: A portable radio receiver powered by a battery includes an RF amplifier, an IF amplifier and an audio amplifier powered by a first regulated, switched, DC power converter that derives a first DC voltage. A frequency synthesizer, including varactor diodes, is powered by a second regulated, switched DC power converter that derives a second DC voltage. Digital circuitry included in the synthesizer is powered by opposite polarity, third and fourth power converters. A synchronizing source for switching all of the power converters simultaneously has a fundamental and harmonics outside of the bandpasses of the audio and IF amplifiers to minimize the injection of spurious signals by the power converters into the amplifiers. The synchronizing source is FM modulated by an audio source so that harmonics of the synchronizing source are spread over a predetermined spectrum and the harmonics have noise-like characteristics spread over relatively wide frequency ranges.