Abstract: A power converter includes a DC power supply bus having a positive power supply line (10) and negative power supply line (11). A limiting resistor (RL) is connected in series with the negative power supply line (11) of the DC power supply bus and is designed to limit the charging current of the bus capacitor (Cbus). An inverter module has upper transistors (T2, T4, T6) and lower transistors (T1, T3, T5) in series of the normally ON field-effect type, and several Grid control devices (CT1-CT6) allow each to apply a Grid voltage to the transistors for controlling each transistor so as to turn off or to turn on. A start-up source (Sd) is connected in parallel with the limiting resistor and to each Grid control device (CT1, CT3, CT5) for the lower transistors, and is configured for charging with a negative voltage when the power converter starts up.

Abstract: Provided is a switching regulator capable of performing stable start-up with a soft-start operation without causing excessive extension of a soft-start time period. In a start-up period, a voltage approximating a feedback voltage (FB) is provided as an initial value of a soft-start reference voltage. The feedback voltage (FB) and the soft-start reference voltage become substantially equal to each other at a moment when the start-up is completed, to thereby realize a smooth transition of an operating state from the start-up to normal control.

Abstract: A feedback circuit for an isolated power converter includes an opto-coupler and a reversed polarity regulator. The opto-coupler provides a current related to an output voltage of the isolated power converter. When the isolated power converter enters light load, the output voltage rises and the reversed polarity regulator reduces the current to decrease the power consumption and thus improve the light load efficiency of the isolated power converter.

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[1]-POL[4] 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: The present invention provides a voltage converter circuit for the clocked supply of energy to an energy storage based on an input voltage applied at an input applied at an input of the voltage converter circuit. The voltage converter circuit includes an energy storage and a switch arrangement, wherein the switch arrangement has a first switch and a second switch which are connected in parallel to each other and coupled to the energy storage. The first switch of the switch arrangement has a smaller turn-on voltage according to amount than the second switch, wherein a control terminal of the first switch is wired up such that the first switch is active in a startup phase of the voltage converter circuit to supply energy to the energy storage, and wherein a control terminal of the second switch is wired up such that the second switch is active after the startup phase to supply energy to the energy storage in a clocked way.

Abstract: A capacitor discharging circuit and a power converter having the capacitor discharging circuit are disclosed. The capacitor discharging circuit comprises a conversion module connected with the two terminals of the capacitor, an AC power-off detecting unit used to detect on-off state of AC power, and a control unit. The conversion module comprises an energy consumption unit. When AC power is disconnected, the AC power-off signal generated by the AC power-off detecting unit intervenes the control unit to control the energy consumption unit to consume the energy stored in the capacitor.

Abstract: A power control system provides immunity from power supply dropout for a controller without compromising a startup time of the controller. In at least one embodiment, the power control system includes separate startup and dropout immunity capacitors. In at least one embodiment, selection of the capacitance of the startup capacitor is independent of selection of the capacitance of the dropout immunity capacitance. In at least one embodiment, the startup capacitance can be minimized to provide sufficient energy for the controller to normally operate during one missed cycle of an input voltage and, thus, provide a minimum startup time for the controller. The capacitance of the dropout immunity capacitor can be maximized to provide sufficient energy for the controller to operate normally during a time period longer than one cycle of the input voltage.

Abstract: A start-up circuit to discharge EMI filter is developed for power saving. It includes a detection circuit detecting a power source for generating a sample signal. A sample circuit is coupled to the detection circuit for generating a reset signal in response to the sample signal. The reset signal is utilized for discharging a stored voltage of the EMI filter.

Abstract: A circuit arrangement includes a switching element that switches a load current, a current-limiting element connected in series to the switching element, a bistable first relay connected in parallel to the switching element and the current-limiting element, and a control circuit that switches the power-supply unit from a first operating state to a second operating state in which a load current for generating a DC voltage flows from the power grid to the power-supply unit, such that the control circuit turns on the switching element for a first time period during switching of the power-supply unit from the first to the second operating state, to turn the bistable relay on during the first time period, and to turn the switching element off at the end of the first time period.

Abstract: A start-up circuit to discharge EMI filter is developed for power saving. It includes a detection circuit detecting a power source for generating a sample signal. A sample circuit is coupled to the detection circuit for generating a reset signal in response to the sample signal. The reset signal is utilized for discharging a stored voltage of the EMI filter.

Abstract: An isolated switched mode power supply (SMPS) is disclosed. The SMPS comprises a switching controller to generate start-up and operational switching control signals. The SMPS further includes a transformer, having a primary winding, and a full-bridge drive circuit to drive the primary winding. The full-bridge drive circuit comprises a first switching element, a boot-strap dnving circuit, and a second switching element. The switching controller is further used to start up isolated SMPS by determining a duty cycle for operational control signals and generating the start-up switching control signals.

Abstract: A switching power supply includes a switching unit, a driving signal generator, and a control circuit. The driving signal generator is configured for providing a driving signal including a plurality of acting voltage parts. The plurality of acting voltage parts is used to turn on the switching unit. Each of the acting voltage parts may be one of a high level voltage and a low level voltage. The control circuit is connected between the driving signal generator and the switching unit. The control circuit turns off the switching unit when a duration of one of the plurality of acting voltage parts is longer than a preset time period.

Abstract: A method and a control device control a switching device for providing a resonant circuit with a switching voltage for generating a resonant current in order to provide a required output power at an output of a resonant power converter.

Abstract: A switching mode power supply (SMPS) usable with an image forming apparatus receives an alternating current (AC) power from an external electric power supply source and outputs a direct current (DC) power. When a supply state of an electric power to the image forming apparatus is turned off, electric charges charged in a capacitor of the SMPS are discharged.

Abstract: Integrated AC regenerative motor drives and operating methods are presented in which a precharging circuit is provided with an IGBT, a diode and a parallel current limiting component in an intermediate DC circuit between a switching rectifier and an output inverter, and the drive is operated in one of three modes for motoring, regenerating and precharging.

Abstract: A power starting circuit used in a DC power supply circuit has a double-pole, double-throw switch electrically connected to a positive pole of a DC power supply and controls a conducting state of the circuit. A first capacitor provides a voltage signal for a first switch circuit and controls the conducting state of the first switch circuit in a continuous charging and discharging process. The first switch circuit controls the conducting state of the DC power supply circuit. A maintaining signal input end provides a maintaining signal for the first capacitor. The power starting circuit can achieve an over discharge protection function for the control circuit. Moreover, when the switch is turned on, it can automatically switch the circuit off so as to save power if the electrical product does not need to continue to work.

Abstract: A start-up circuit includes a switching-device control circuit arranged to receive an input voltage and to provide a switching-device control signal, a switching device arranged to be controlled by the switching-device control signal and to provide a start-up signal, a power-converter control circuit arranged to receive the start-up signal and to provide a power-converter control signal, and a power converter arranged to receive the power-converter control signal and to provide an auxiliary output signal. The switching control circuit is arranged to receive the auxiliary output signal such that, when the auxiliary output signal reaches a predetermined level, the switching-device control circuit stops providing the switching-device control signal.

Abstract: Provided is a DC-DC converter including a soft start circuit capable of prolonging a soft start time without increasing a capacitance used in the soft start circuit. A soft start is implemented by gradually increasing a limiting level of an inductor current or a reference voltage. The soft start time is adjusted by varying a frequency of CLOCK signals supplied to switch circuits. The soft start time may be prolonged without increasing a chip size because the capacitance does not need to be increased to prolong the soft start time.

Abstract: A circuit for boosting the voltage from a very low level voltage source to a higher level voltage output utilizing self-oscillation.

Abstract: Disclosed is an electronic circuit with a first load terminal, a second load terminal, a supply terminal configured for having a charge storage arrangement connected thereto, and a load transistor, a current sense circuit with a sense transistor, and a start-up circuit with a start-up transistor.

Abstract: A power circuit for protecting against high pulse load current and inrush current is disclosed. The power circuit comprises a buck-boost module and a PFC controller operatively coupled with the buck-boost module. The PFC controller is configured to receive an input voltage feedback, an output voltage feedback, and a current feedback, and is configured to utilize one of an Integral Gain Compensation (IGC) and an Integral Value Compensation (IVC) to control the high pulse load current and inrush current in the power circuit.

Abstract: A power conversion system with zero-voltage start-up mechanism and a zero-voltage start-up device are disclosed. The system includes a power conversion circuit, a power factor correction unit, a storage capacitor, a storage switching unit, and a zero-voltage detection module. The storage switching unit is serially connected with the storage capacitor, and particularly controlled by the zero-voltage detection module. The zero-voltage detection module detects a timing as an input voltage is at low level, and then outputs a control signal to turn on the storage switching unit. Therefore, the present invention assures that the power conversion system is turned on when the input voltage is at the low level, in order to suppress the system from a surge current.

Abstract: An embodiment apparatus comprises a secondary synchronous rectifier and a secondary gate drive controller. The secondary gate drive controller coupled to a transformer winding comprises a secondary synchronous rectifier soft start signal generator configured to generate a plurality of soft start pulses, a pulse width modulation generator configured to generate a forward switch drive signal and a freewheeling switch drive signal based upon a signal across the transformer winding and a soft transition generator configured to generate a soft start freewheeling switch drive signal by gradually releasing the freewheeling switch drive signal during a soft start process.

Abstract: A power converter arrangement configured to convert a direct voltage into an alternating voltage to be supplied to a grid includes a photovoltaic generator configured to generate the direct voltage, a voltage intermediate circuit, a main power converter connected in series with a bypass switch, a maximum power point controller configured to set a maximum power point voltage, and at least one voltage-limited additional circuit configured to be active during a start-up phase of the photovoltaic generator. The at least one voltage-limited additional circuit and the main power converter are configured as a voltage divider in parallel with the photovoltaic generator. The at least one voltage-limited additional circuit is configured as a capacitive voltage divider having a first capacitor and an intermediate circuit capacitor connected in series.

Abstract: A power transistor chip with built-in enhancement mode metal oxide semiconductor field effect transistor and application circuit thereof provides an enhancement mode metal oxide semiconductor field effect transistor in association with two series connected resistors to act as a start-up circuit for the AC/DC voltage converter. The start-up circuit can be shut off after the pulse width modulation circuit of the AC/DC voltage converter circuit works normally and still capable of offering a function of brown out detection for the pulse width modulation circuit as well. Besides, the enhancement mode metal oxide semiconductor field effect transistor is built in the power transistor chip without additional masks and processes during the power transistor chip being fabricated such that the entire manufacturing process is simplified substantively with the economical production cost.

Abstract: A switching power supply apparatus including an AC-to-DC conversion circuit, a hysteretic relay and a relay control circuit is provided. The AC-to-DC conversion circuit includes a current limit resistor, and the current limit resistor is configured to suppress an inrush current generated during the AC-to-DC conversion circuit converts an AC input voltage into a DC output voltage. The hysteretic relay is coupled with the current limit resistor in parallel. The relay control circuit is coupled to the AC-to-DC conversion circuit and the hysteretic relay, and configured to control the hysteretic relay to turn on in response to one of an over drive pulse signal and a holding modulation signal when the DC output voltage reaches to a predetermined value, so as to bypass the current limit resistor, wherein an enabling time of the over drive pulse signal is different from that of the holding modulation signal.

Abstract: Disclosed include switching-mode power supplies and control methods thereof. A disclosed switching-mode power supply is coupled to an input power node and a ground node, comprising a controller, a first inductor, and a bootstrap circuit. The controller is for controlling a power switch coupled to the input power node and a connection node. The controller is powered by the connection node and an operation power node. The first inductor is coupled between the connection node and a discharge node. The bootstrap circuit is coupled between the discharge node, the operation power node and the connection node, to make an operation voltage at the operation power node substantially not less than a discharge voltage at the discharge node. The discharge node is coupled to power an output load.

Abstract: A start up circuit constituted of: a first alternating current lead; a second alternating current lead, said second alternating current lead exhibiting an opposing phase of said first alternating current lead; a first capacitor, a first end of said first capacitor coupled to said first alternating current lead; a second capacitor, a first end of said second capacitor coupled to said second alternating current lead; a breakdown diode coupled between a second end of said first capacitor and a second end of said second capacitor; and a third capacitor coupled in parallel with said breakdown diode. A direct current power is developed across the breakdown diode without requiring dissipative elements.

Abstract: A digital device generates a fixed duty cycle signal with an internal oscillator after a Power-On-Reset (POR). This fixed duty cycle signal is output on a signal pin that normally is used for a PWM control signal. The fixed duty cycle signal is used to stimulate the voltage generation circuits so as to power up the digital device for initialization thereof. Once the digital device has powered-up and initialized, the digital device switches over to normal operation for control of the power system.

Abstract: The invention relates to a power converter comprising: a DC power supply bus comprising a positive power supply line (10) and negative power supply line (11), a limiting resistor (RL) connected in series with the negative power supply line (11) of the DC power supply bus, designed to limit the charging current of the bus capacitor (Cbus), an inverter module comprising upper transistors (T2, T4, T6) and lower transistors (T1, T3, T5) in series of the normally ON field-effect type, several Grid control devices (CT1-CT6) allowing each to apply a Grid voltage to the transistors for controlling each transistor so as to turn off or to turn on, a start-up source (Sd) connected in parallel with the limiting resistor (RL) and to each Grid control device (CT1, CT3, CT5) for the lower transistors (T1, T3, T5) and configured for charging with a negative voltage when the power converter starts up.

Abstract: An exemplary power supply system is used to provide one or more operation voltages to a plurality of loads individually. The power supply system includes a timing circuit configured to control a starting time that the corresponding loads start to receive their corresponding operation voltages. The timing circuit includes a first capacitor arranged to be charged by the corresponding DC voltage, and the starting time is determined according to a charging characteristic of the first capacitor.

Abstract: A switching power supply device includes a transformer, a switching unit which is connected with a primary winding of the transformer and configured to switch a current flowing to the primary winding, a start unit configured to start the switching unit, a voltage drop unit configured to lower output voltage from a secondary winding of the transform, and a current control unit configured to control an amount of a current flowing in the start unit when the switching unit is in an off state by lowering output voltage by the voltage drop unit.

Abstract: An offline power supply includes a power supply circuit including a primary-side circuit for connecting to a first power source, a secondary-side circuit for connecting to a load, and a transformer connecting the primary-side circuit and the secondary-side circuit. A switch operates to selectively connect the primary-side circuit to the first power source. A second power source is charged during operation of the power supply circuit. A controller powered by the second power source has at least one input, and an output to selectively operate the switch based on the at least one input.

Abstract: A method for initializing a power inverter of a photovoltaic system includes: opening an AC mains switch and a DC switch to disconnect the power inverter from an electrical grid and to disconnect a capacitor bank associated with the inverter from a solar cell array; closing the AC mains switch to allow power to flow from an electrical grid to the DC capacitor bank to charge the DC capacitor bank; monitoring the DC capacitor bank until a desired voltage is reached; initiating the operation of the power inverter; stabilizing the DC voltage received from the DC capacitor bank at a predetermined power up voltage for the power inverter; waiting for an inverter initialization period to elapse; and adjusting DC voltage received by the power inverter to a voltage associated with a maximum power output level of the solar cell array.

Abstract: An embodiment of a self-supply circuit, for a voltage converter that converts an input voltage into an output voltage and has a main switch and a controller, designed to control switching of the main switch for controlling the output voltage; the self-supply circuit is provided with: a charge accumulator, which is connected to the controller and supplies a self-supply voltage to the same controller; a generator, which supplies a charge current to the charge accumulator; and an auxiliary switch, which has a first conduction terminal in common with a respective conduction terminal of the main switch and is operable so as to control transfer of the charge current to the charge accumulator. In particular, the self-supply circuit is provided with a precharge stage, connected to the auxiliary switch, which carries out a precharging of an intrinsic capacitance of the auxiliary switch before a turning-off transient of the main switch ends.

Abstract: A power management (PM) system architecture for a controlled SoC detects availability of power supply for signal-driving at a given node inside a chip, and uses a timer, a discharge mechanism with trigger for starting/stopping a discharge process, and a comparator for monitoring a measured voltage of an intended node during the discharge process. Enabling the discharge mechanism for a known time period helps detection. Power supply can be internally generated in the chip or from a source on board. The architecture detects if the node is driven or floating, an undriven floating node causing a dip in the measured voltage. The measured voltage does not have a dip when the node is driven. The architecture is also configured so that when there is a required on-board external power supply, an internal power supply is disabled to avoid a race-condition. The architecture obviates a dedicated IO pin for mode-indication.

Abstract: A system including a power transistor configured to receive an alternating current (AC) line voltage and a control circuit. During a rising portion of a half cycle of the AC line voltage, the control circuit is configured to turn on the power transistor when the AC line voltage reaches a first value and turn off the power transistor when the AC line voltage reaches a second value. The second value is greater than the first value. During a falling portion of the half cycle, the control circuit is configured to turn on the power transistor when the AC line voltage reaches the second value and turn off the power transistor when the AC line voltage reaches the first value.

Abstract: The power conversion module includes a power converter coupled to provide a DC output voltage from an input voltage source. The power converter may have primary and secondary stages, and the power converter may also provide a DC output voltage that is electrically isolated from the input voltage source. Additionally, the power conversion module also includes a voltage controller configured to measure a pre-bias value of the output voltage prior to start-up of the power converter and provide a start-up control signal, wherein the start-up control signal corresponds to an initial output voltage that is greater than the pre-bias value of the output voltage. The initial output voltage includes a start-up voltage margin above the pre-bias value and is maintained for a margin hold time. A method of operating a power conversion module is also provided.

Abstract: The present abstract discloses a CMOS bandgap reference source circuit, comprising a startup circuit, a power-off control circuit, a reference voltage generating circuit and an operational amplifier. The positive and a negative input terminal of the operational amplifier both consist of two same field effect transistors and both are provided with an input controlled switch; by doing so, two field effect transistors in the positive terminal and two field effect transistors in the negative terminal work alternately between their strong inversion and cut-off region so as to drastically reduce the noises of the reference circuit, which results originally from the flicker noises of two input transistors of the operational amplifier.

Abstract: A converter may include a transformer; a first circuit arrangement coupled to a first transformer side; a second circuit arrangement coupled to a second transformer side, wherein the second circuit arrangement is configured to provide an output voltage; a first coupler configured to provide information about the output voltage to the first circuit arrangement; wherein the first circuit arrangement is configured to determine a state of the secondary side based on the received information about the output voltage, and to generate a switch control signal dependent on the determined state; a switch circuit arranged on the second side; and a second coupler configured to provide a switch control signal from the first circuit arrangement to the switch circuit; wherein the switch circuit is coupled to the first circuit arrangement to provide a first circuit arrangement control signal to the first circuit arrangement depending on the switch control signal.

Abstract: A converter may include a start-up circuit having a switch circuit coupled to a reference potential terminal and an input circuit coupled to an input voltage, wherein the input circuit is coupled to the start-up circuit such that in case that at least one of the input voltage is lower than a predetermined threshold and that the input voltage is substantially constant for a predefined time period, electrical charges stored in the input circuit are flowing through the switch circuit to the reference potential terminal.

Abstract: A light-emitting diode driver circuit includes: a first-rectifier circuit to output a first-rectified voltage; a transformer including primary and secondary coils and an auxiliary coil inductively coupled to the primary or secondary coils, the primary coil being applied with the first-rectified voltage; a transistor connected in series to the primary coil; a second-rectifier circuit to output a second-rectified voltage obtained by rectifying a voltage generated in the auxiliary coil; a capacitor to be charged with the second-rectified voltage; and a control circuit to control on and off of the transistor based on a charging voltage of the capacitor so that the charging voltage becomes equal to a predetermined voltage, the secondary coil outputting a voltage that varies with a frequency corresponding to a frequency of the first-rectified voltage and that corresponds to a turns ratio between the primary and secondary coils, as a voltage for driving a light-emitting diode.

Abstract: An HVDC transmission system including a rectifier station and an inverter station each having a series connection of at least two converters. A by-pass DC breaker is connected in parallel with each converter. A control device is adapted to deblock a blocked converter by starting to control the converter at high delay angle and gradually decreasing the delay angle until substantially all DC current flows through the converter and to then control the by-pass breaker to open at substantially zero current, and to stop the operation of a converter by controlling the converter at gradually increasing delay angle until the voltage across the converter is substantially zero and to then control the converter to be blocked by firing a by-pass pair thereof and to then control the by-pass breaker to close for taking over all the DC current when the voltage between a neutral bus and a pole of a transmission line between the stations is to be increased and reduced, respectively.

Abstract: The AC adapter with automatic built-in power switch comprises of an AC power supply circuit, an AC control circuit, and a monitoring circuit. The monitoring circuit further comprises of a standby power supply, a microcontroller, a circuit for device detection, and a current monitor circuit. The AC power supply circuit is electrically connected to the alternating current source and converts the alternating current to direct current for charging the rechargeable battery of an electronic device. The AC control circuit acts as a switch to turn the AC power supply on and off. The monitor circuit detects whether an electronic device is connected to the adapter and also whether the charging process is completed.

Abstract: An AC-DC power converter has a phase-shifting autotransformer based rectifiers and DC capacitors. Soft start of the AC-DC power converter is achieved by designing the autotransformer to operate at a low peak flux density at a point of AC voltage step application (initial turn on). The addition of a controlled impedance segregates capacitor charging from the initial magnetizing process of the autotransformer.

Abstract: A motor control device is electrically connected with a motor. The motor control device includes a controller and a driving circuit. The controller has a default value of time and generates a first driving signal and a second driving signal. The driving circuit includes a first switching element and a second switching element, the first switching element and the second switching element receive the first driving signal and the second driving signal respectively, and the first switching element and the second switching element are switched on or switched off alternately according to the first driving signal and the second driving signal respectively, so as to drive the motor to operate.

Abstract: A DC/DC converter including an inductor and a capacitor is started by connecting an input voltage to the inductor and shunting a current around the inductor so as to pre-charge the capacitor to a predetermined voltage.

Abstract: An integrated circuit includes a threshold detection circuit that is coupled to measure a signal from a first resistive external circuit coupled between a fourth external terminal of the integrated circuit and a first external terminal of the integrated circuit during a duration of an initialization period after the fourth external terminal has been charged to a supply threshold value. A regulator circuit is coupled to charge the fourth external terminal to the supply threshold value during the initialization period of the integrated circuit. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode of the integrated circuit in response to the signal measured from the first resistive external circuit during the duration of the initialization period after the fourth external terminal has been charged to the supply threshold value.

Abstract: A resonant mode power converter is controlled with a control unit including a current limiting circuit coupled to receive a first current representative of a power converter output and a second current generated in response to a reference voltage. The current limiting circuit is coupled to limit the first current in response to the second current. An oscillator is coupled to receive the first current to generate a control signal having a control frequency in response to the first current. The power converter output is controlled in response to the control frequency of the control signal.

Abstract: Disclosed is an apparatus for reducing standby power, which is capable of minimizing standby power losses by using an electric double layer capacitor (ELDC). The apparatus includes: an electric double layer capacitor for converting electrical energy supplied from the AC power source into DC power and storing the converted electrical energy; a charging circuit for charging the electrical energy in the electric double layer capacitor; a voltage conversion circuit for converting the electrical energy charged in the electrical double layer capacitor into a stable voltage; a voltage detection circuit for detecting a charged voltage of the electric double layer capacitor; and a power supply control circuit for turning on/off a power switch in response to a command from the voltage detection circuit, wherein the power supply control circuit uses the electrical energy charged in the electrical double layer capacitor to turn on/off the power switch.