Abstract: An on-board charger is provided with a first stage for converting an alternating current (AC) voltage from an external power supply to a direct current (DC) voltage. A capacitor is coupled to the first stage to receive the DC voltage and to provide a DC-Link voltage. A second stage is coupled to the capacitor to boost the DC-Link voltage and to supply the boosted DC-Link voltage to charge a battery. A processor is programmed to adjust the DC-Link voltage between a first setpoint and a second setpoint based on a battery voltage value.

Abstract: A memory sub-system comprises a power management component comprising a plurality of regulators configured to output respective operating voltages for the memory sub-system. The power management component comprises a power management integrated circuit (PMIC) and is configured to monitor voltage levels of the plurality of regulators and prevent an event of the memory sub-system from occurring until the monitored voltage levels of a set of the plurality of regulators are determined to have reached respective threshold voltage levels.

Abstract: The present invention is directed to Bidirectional Multimode Power Converter which employs a high frequency dynamically varying amplitude modulation and voltage steering method to convert the source AC or DC voltages to output AC or DC voltages with programmable output voltage levels, output voltage frequency and duration. The Bidirectional Multimode Power Converters of the present invention support: inrush current control, turning off the idle converter, line voltage brown out protection, soft start, high pre-charge voltage generation, soft shut down of converter, dimming operation, programmable time of the day operation and operation for specified duration of time. The Bidirectional Multimode Power Converters of the present invention support coupling of multiple power sources for bidirectional power conversion.

Abstract: A power supply device includes a switching converter, an inductor, and a linear voltage regulator. The inductor is electrically connected between a first switching node and a second switching node of the switching converter. The power supply device is configured such that when the switching converter is in an ON state the inductor is charged with a charging current. The power supply device is further configured such that when the switching converter is in an OFF state, the switching converter modulates an input voltage to generate a positive-bias output voltage at a positive-bias output node, the charging current flows from the inductor such that a negative input voltage is generated at a linear voltage regulator input node, and the linear voltage regulator regulates the negative input voltage to generate a negative-bias output voltage at a negative-bias output node.

Abstract: There is provided a power supply device configured to boost an input voltage to output an output voltage, the power supply device including: an oscillator circuit configured to receive the input voltage and to output an oscillation signal; a step-up circuit configured to output a boost voltage based on the oscillation signal; a first hysteresis comparator and a second hysteresis comparator configured to compare boost voltages with threshold values; a first switch that is connected between the oscillator circuit and the step-up circuit and that is controlled based on a comparison result of the first hysteresis comparator; and a second switch that is connected to an output terminal configured to output the output voltage and that is controlled based on a comparison result of the second hysteresis comparator.

Abstract: A startup circuit adapted to be coupled to an input voltage supply and operable to supply an output voltage at an output terminal, the startup circuit including: a first transistor having a first control terminal, a first current terminal and a second current terminal, the first current terminal adapted to be coupled to the input voltage supply and the second current terminal coupled to the output terminal; a precharge circuit having a first terminal, a second terminal and a third terminal, the second terminal adapted to be coupled to the input voltage supply and the third terminal coupled to the first control terminal; a current limiter coupled to the precharge circuit, the first control terminal and the second current terminal; a second transistor having a second control terminal, a third current terminal and a fourth current terminal, the third current terminal coupled to the precharge circuit and the second control terminal adapted to be coupled to a control signal; and a third transistor having a third c

Abstract: A method comprising activating an internal switch within a packaged electronic device to connect to a reference ground of an internal voltage source to a first input of an analog front end, receiving an external ground potential voltage at a first package pin of the packaged electronic device, generating a zero detector output signal for the packaged electronic device at a second package pin, activating the internal switch to connect the first input of the analog front end to the internal voltage source, receiving a second voltage level at the first package pin that generates a second output signal that matches the zero detector output signal, and receiving trim instructions to trim an internal voltage generated by the internal voltage source to a voltage level that is closer to a target voltage level.

Abstract: A control unit is provided. The control unit is configured to provide a control signal for controlling a power unit. The power unit includes a first positive voltage terminal, a second positive voltage terminal, a first negative voltage terminal, a second negative voltage terminal, and a switching element. The first negative voltage terminal and the second positive voltage terminal are coupled to each other in a short circuit manner. One terminal of the switching element is electrically connected to the first negative voltage terminal. The control unit is configured to: receive a pulse width modulation signal; receive a first power supply signal; receive a second positive voltage terminal signal; output a second power supply signal; and output the control signal for controlling the switching element to be turned on or turned off.

Abstract: A memory sub-system comprises a power management component comprising a plurality of regulators configured to output respective operating voltages for the memory sub-system. The power management component comprises a power management integrated circuit (PMIC) and is configured to monitor voltage levels of the plurality of regulators and prevent an event of the memory sub-system from occurring until the monitored voltage levels of a set of the plurality of regulators are determined to have reached respective threshold voltage levels.

Abstract: A buffer stage for amplifying a clock signal generated by a current controlled oscillator that receives a first current at a first supply voltage from a first current source. The buffer stage comprises an input terminal configured to receive the clock signal; an output terminal configured to output a buffered signal; at least one buffer, coupled between the input and output terminal, configured to receive a second current at a second supply voltage and buffer the clock signal to generate the buffered signal; a clamping circuit that receives the first current and the second current, and generates a first supply voltage and a second supply voltage. The clamping circuit clamps the second supply voltage equal to the first supply voltage.

Abstract: A system includes a transformer having an auxiliary coil to provide a flyback voltage to a primary side of an alternating current to direct current (AC-DC) converter. A primary side controller includes an auxiliary pin coupled to the transformer and to an external capacitor, the auxiliary pin to receive the flyback voltage after startup. a junction gate field-effect transistor (JFET) coupled to a supply voltage. A first FET is coupled in series between the JFET and the auxiliary pin, the JFET to charge the external capacitor from the supply voltage during startup. One or more depletion region diodes are coupled to a gate of the first FET, the one or more depletion region diodes to bias a voltage of the gate of the first FET to a specific voltage.

Abstract: A power control circuit includes a detection device, a first control device, and a second control device. When the detection signal is changed from lower to higher than the first voltage, the first control device's output is changed to the second potential. When the detection signal is changed from higher to lower than the second voltage, the first control device's output is changed to the first potential. When the detection signal is changed from lower to higher than the third voltage, the second control device's output is changed to the fourth potential. When the detection signal is changed from higher to lower than the fourth voltage, the second control device's output is changed to the third potential. According to the first or second potentials, the circuit device turns on/off the first function. According to the third or fourth potentials, the circuit device turns on/off the second function.

Abstract: A device for supplying electric power to an electronic component, including a DC-to-DC converter able to operate using pulse width modulation with high states and low states, with an input and an output, the output being intended to supply power to the electrical component; and a protective circuit connected to the input of the DC-to-DC converter, with a storage capacitive component connected to a diode for protecting against polarity reversals. The protective circuit furthermore includes a bypass for bypassing the protective diode so as to allow the storage capacitive component to discharge during the low states of the pulse width modulation.

Abstract: Provided is a premagnetization device for a converter system that is connectable to a three-phase electrical grid that has a three-phase power transformer, a converter connected to the power transformer and a circuit-breaker on the grid side of the power transformer. The premagnetization device is premagnetizes the power transformer in a state isolated from the grid. The premagnetization device uses a single-phase reference voltage (Uref) that has a fixed relationship to the grid voltage (Ugrid) with regard to the voltage parameters, in order to generate, based on the measured instantaneous reference voltage (Uref) and the known fixed parameter relationships, by actuating the converter, a three-phase alternating voltage synchronous to the grid voltage (Ugrid) on the grid side of the power transformer.

Abstract: A method of controlling an isolated DC-DC converter includes switching the primary side switching devices of the converter at a fixed first switching period and variable duty cycle during non-transient load conditions so as to transfer energy across the transformer of the converter during first energy transfer intervals separated by energy circulation intervals, such that the ratio of each first energy transfer interval to the first switching period is less than unity. The method also includes switching the primary side switching devices at a second switching period different than the first switching period during a transient load condition so as to transfer energy across the transformer during second energy transfer intervals of a duration determined so as to avoid saturation of the transformer core, and such that any energy circulation interval separating the second energy transfer intervals is shorter than the energy circulation intervals separating the first energy transfer intervals.

Abstract: A method and system includes receiving, at a computing device including a design tool application, design parameters indicative of a plurality of power supply loads to be powered. The method further includes generating power supply solutions that do not include multi-channel voltage regulators and generating power supply solutions that do include multi-channel voltage regulators. The method also includes ranking all power supply solutions and providing the ranked power supply solutions to a user.

Abstract: The power supply apparatus includes a transformer, at least one switching element provided on a primary side of the transformer and configured to perform a switching operation to output an output voltage from a secondary side of the transformer, and a control unit configured to determine a turn-on time of a pulse signal for controlling the switching element for each of first cycles, and perform a predetermined control in which a change value of the turn-on time of the pulse signal for each of second cycles each including the first cycles becomes smaller than a change value of the turn-on time of the pulse signal for each of the first cycles, to change the second cycle depending on operation states.

Abstract: Embodiments are directed to power conversion circuits including a bypass circuit for bypassing an inrush current limiting resistor. In one embodiment, a power conversion circuit is provided that includes a bridge rectifier, a current limiting resistor, a controllable current switching device, and a driver. The current limiting resistor has a first terminal coupled to an output terminal of the bridge rectifier and a second terminal coupled to an electrical ground. The controllable current switching device has conduction terminals coupled in parallel with respect to the current limiting resistor. The driver is coupled between the first terminal of the current limiting resistor and a control terminal of the current switching device, and the driver controls an operation of the current switching device based on a current through the current limiting resistor.

Abstract: A power converter circuit includes a plurality of first converter cells, a plurality of second converter cells, and a plurality of DC link capacitors. Each of the plurality of first converter cells is coupled to a corresponding one of the plurality of DC link capacitors. Each of the plurality of second converter cells is coupled to a corresponding one of the plurality of DC link capacitors. At least one of the plurality of second converter cells is configured to, during start-up of the power converter, internally dissipate power received from the corresponding DC link capacitor while a cell output power of the at least one of the plurality of second converter cells is substantially zero.

Abstract: A power converter as disclosed herein includes circuitry to reduce switching current spikes as conventionally appear at startup, and control the current spikes in a predictable way, thereby improving reliability of the power converter. A controller generates drive signals to half-bridge switching elements, an output therefrom corresponding to a frequency of the gate drive signals. A resonant tank comprises a resonant capacitor, DC blocking capacitor, a resonant inductor, and a load. Pre-charge circuitry is coupled to the resonant tank and, after initially receiving power from the DC power source and prior to controller startup, pre-charges at least the DC blocking capacitor to a steady state operating value. By pre-charging the DC blocking capacitor to its steady state voltage even before startup of the controller, AC current is introduced into the resonant inductor after the low-side switching element is first turned on and soft switching is provided throughout.

Abstract: An AC/DC converter includes a first terminal and a second terminal to receive an AC voltage and a third terminal and a fourth terminal to deliver a DC voltage. A rectifying bridge is provided in the converter. A controllable switching or rectifying element has a control terminal configured to receive a control current. A first switch is coupled between a supply voltage and the control terminal to inject the control current. A second switch is coupled between the control terminal and a reference voltage to extract the control current. The first and second switches are selectively actuated by a control circuit.

Abstract: A circuit and method for regulating an internal power supply of a switching converter is presented. A switching converter with a depletion mode power switch coupled to an enhancement mode power switch via a switching node and an energy storing element coupled to the depletion mode power switch is provided. The energy storing element may be adapted to provide energy to the switching converter. For instance, the energy storing element may be a capacitor. Optionally, the switching converter may comprise an inductor coupled to the depletion mode transistor, the inductor being adapted to provide an inductor current.

Abstract: A DC-to-DC power converter includes a transformer having a primary side and a secondary side, and a primary circuit electrically coupled to the primary side of the transformer. The primary circuit includes a primary microcontroller configured to generate a first energizing signal that energizes a portion of the primary circuit. The DC-to-DC power converter also includes a secondary circuit electrically coupled to the secondary side of the transformer. The secondary circuit includes a secondary microcontroller communicatively coupled to the primary microcontroller, wherein the secondary microcontroller is configured to provide an instruction to the primary microcontroller that causes the primary microcontroller to relinquish control of the primary circuit to the secondary microcontroller, and wherein the secondary microcontroller is further configured to provide a second energizing signal to the portion of the primary circuit.

Abstract: A supply circuit includes a rectifying bridge arranged in series between two high voltage capacitors. An AC line provides an intermediate voltage to a low voltage capacitor through the two high voltage capacitors. A plurality of resistors mounted in series with the two high voltage capacitors. A voltage clamping device limits the intermediate voltage at the low voltage capacitor and a linear series regulator provides an output DC voltage.

Abstract: An ACF power converter uses a soft start operation to reduce overheating and stress on components. The power converter includes a first transistor and second transistor. A high side driver controls the first transistor, and low side driver controls the second transistor. A first operating potential is provided to the low side driver during a first period of time. The second transistor switches based on an oscillator signal having a first rate of frequency change to generate a second operating potential for the high side driver, while attempting to hold the first transistor in the non-conductive state during a second time period. The first and second transistors switch based on the oscillator signal having a second rate of frequency change during a third time period. The power converter is held in ACF mode and inhibited from changing state for a period of time post soft start.

Abstract: A current control apparatus arranged to regulate an electric current flowing between a load and an external electric circuit includes a current control loop having a current regulator arranged to manipulate an amount of the electric current flowing between the load and the external electric circuit; and a voltage control loop having a voltage regulator arranged to manipulate a voltage across the current regulator.

Abstract: A load control device for controlling the amount of power delivered to an electrical load may include a rectifier circuit configured to receive a phase-control voltage and produce a rectified voltage. A power converter may be configured to receive the rectified voltage at an input and generate a bus voltage. An input capacitor may be coupled across the input of the power converter. The input capacitor may be adapted to charge when the magnitude of the phase control voltage is approximately zero volts. The power converter may be configured to operate in a boost mode, such that the magnitude of the bus voltage is greater than a peak magnitude of the input voltage. The power converter may be configured to operate in a buck mode to charge the input capacitor from the bus voltage when the magnitude of the phase-control voltage is approximately zero volts.

Abstract: An electronic device is provided. The electronic device includes a power supply module, a system load, a soft start unit, a unidirectional conducting unit and a connector. The system load is electrically coupled with the power supply module. The soft start unit is electrically coupled with the system load and the power supply module. The unidirectional conducting unit is electrically coupled between the soft start unit and the power supply module, so as to prevent the energy from the power supply module from entering the soft start unit. The connector has a power input terminal. The power input terminal is electrically coupled with the soft start unit.

Abstract: An energy efficient apparatus includes a switching device, a frequency dependent reactive device, and a control element is provided. The switching device is coupled to a source of electrical power and includes a pair of transistors and is adapted to receive a control signal and to produce an alternating current power signal. The frequency of the alternating current power signal is responsive to the control signal. The frequency dependent reactive device is electrically coupled to the pair of transistors for receiving the alternating current power signal and producing an output power signal. The frequency dependent reactive device is chosen to achieve a desired voltage of the output power signal relative to the frequency of the alternating current power signal. The control element senses an actual voltage of the direct current power signal and modifies the control signal delivered to achieve the desired voltage of the direct current power signal.

Abstract: A method of regulating an output voltage of a buck converter during a startup period in which the buck converter is first enabled includes regulating the output voltage of the buck converter to a reference voltage under current-mode control during a first part of the startup period, and regulating the output voltage of the buck converter to the reference voltage under voltage-mode control during a second, later part of the startup period. The reference voltage ramps up from an initial voltage at the beginning of the startup period to a target voltage at the end of the startup period. Buck converter embodiments are also described.

Abstract: An ultra high voltage regulator includes a rectifying circuit, a first transistor, a second transistor, an output capacitor, a bootstrap diode, a bootstrap capacitor, and a gate driver circuit. The ultra high voltage regulator converts a received alternative current into a direct voltage to an electrical component. The ultra high voltage regulator is capable of providing a larger current becomes more compact and thinner in size without cooperating with a mass transformer/high voltage capacitor, which satisfies the request for miniaturization of the electrical components.

Abstract: An apparatus for controlling paralleled inverter is disclosed. In the apparatus for controlling paralleled inverter, one synchronization signal is shaped by at least two inverters to respectively transmit a voltage command and an operation command.

Abstract: An OVP circuit includes a voltage boost circuit, for boosting an input voltage into an output voltage in need and providing the output voltage to a load, a voltage control module for controlling the voltage boost circuit to boost an input voltage into an output voltage in need and for providing the output voltage to the load, an overvoltage protection module for monitoring a voltage of a positive terminal of the load to enable or disable the voltage control module, and an overvoltage adjusting module for monitoring an operation voltage of the load to adjust the overvoltage. It effectively prevents from the abnormal operation attributed by over practical operation voltage or prevents components from damage attributed by tardy protection. The present invention also proposes an LED backlight driving circuit using the OVP circuit and an LCD having the LED backlight driving circuit.

Abstract: An apparatus for controlling paralleled inverter is disclosed. In the apparatus for controlling paralleled inverter, one synchronization signal is shaped by at least two inverters to respectively transmit a voltage command and an operation command.

Abstract: A user device is provided. The device includes a main power supply, and an auxiliary power supply. The main power supply provides a main power. The auxiliary power supply cuts off the main power according to a power level of the main power supply and provides an auxiliary power upon Sudden Power-Off (SPO).

Abstract: Embodiments described herein describe a power supply controller configured to control a power supply that provides power to an output load via a power supply transformer. The power supply controller includes a first terminal that provides supply voltage to the controller. The controller also includes a second terminal coupled to a switch external to the controller, the switch is part of a power converter controlled by the controller, wherein the second terminal is used for an initial power up of the power converter when the switch is turned on and used for a second functionality when the switch is turned off.

Abstract: An OVP circuit includes a voltage boost circuit, for boosting an input voltage into an output voltage in need and providing the output voltage to a load, a voltage control module for controlling the voltage boost circuit to boost an input voltage into an output voltage in need and for providing the output voltage to the load, an overvoltage protection module for monitoring a voltage of a positive terminal of the load to enable or disable the voltage control module, and an overvoltage adjusting module for monitoring an operation voltage of the load to adjust the overvoltage. It effectively prevents from the abnormal operation attributed by over practical operation voltage or prevents components from damage attributed by tardy protection. The present invention also proposes an LED backlight driving circuit using the OVP circuit and an LCD having the LED backlight driving circuit.

Abstract: An apparatus includes a voltage regulation module that controls output voltage of a bidirectional DC to DC converter to an output voltage reference over an output current range between a positive power reference and a negative power reference. A positive power regulation module controls output power of the converter to the positive power reference over a positive constant power range between the output voltage reference and a positive output current reference. A negative power regulation module controls output power of the converter to the negative power reference over a constant power range between the output voltage reference and a maximum negative power limit, and a constant current module limits output current to a positive output current reference in a range between a minimum output voltage and output power of the converter reaching the positive power reference.

Abstract: A DCDC converter includes a transconductance amplifier, a comparator, a current driving component, an output impedance, a switch, a clamp resistor and a p-channel FET. The transconductance amplifier outputs a transconductance current and a switch control signal. The comparator has a two n-channel FET inputs forming a differential pair and outputs a compared signal. The current driving component generates an output current based on the compared signal. The output impedance component generates an output DC voltage based on the output current. The switch is between the two n-channel FETs and can open and close based on the switch control signal. The clamp resistor is arranged in series with the switch. The p-channel FET is in series with the clamp resistor and is controlled by the output DC voltage.

Abstract: A power conversion apparatus includes a switch circuit which drives switching elements based on a control signal, a feedback section which performs feedback control, a signal output section which outputs the control signal based on a controlled variable of the feedback control, an output value detecting section which detects an output value outputted from the switch circuit, and an operation determining unit which has an operation stop determination section which determines whether to stop operation of the switching elements based on a rate of change of the output value, and an operation start determination section which determines whether to start operation of the switching elements based on the controlled variable.

Abstract: A quick discharge circuit includes a reference voltage source, a power supply voltage monitoring circuit, a control circuit, and a discharge circuit. The reference voltage source provides a threshold voltage for quick discharge; the power supply voltage monitoring circuit collects change conditions of a power supply voltage; the control circuit performs logical control according to the power supply voltage collected by the power supply voltage monitoring circuit and the threshold voltage provided by the reference voltage source to determine whether the discharge circuit is ON. With the quick discharge circuit, when a terminal product is powered off, an input bulk capacitor of a DC-DC circuit is discharged quickly so that the voltage thereof rapidly drops to a safe voltage range. When the terminal product is powered on again quickly, it is guaranteed that a soft start circuit works normally so as to implement slow increase of power-on voltage and current.

Abstract: A method of controlling a start-up sequence of a DC/DC Buck converter includes continuously comparing the Buck converter's output voltage with an internal reference voltage and continuously monitoring for a Buck converter start-up signal. If the output voltage is greater than the reference voltage when a Buck converter start-up signal is detected, the Buck converter is switched off and an output capacitor of the Buck converter is discharged through a pull-down unit until the output voltage substantially equals the internal reference voltage and then restarting the Buck converter.

Abstract: An apparatus and method for detecting a disconnection of lamps are provided. The apparatus includes a power supply that is configured to supply power to a vehicle and a controller. The controller receives operation power for at least one lamp mounted within the vehicle and supplies the operation power to the at least one lamp. In addition, the controller measures an inrush current value generated from the at least one lamp for a plurality of time intervals and detects the disconnection of the at least one lamp based on the inrush current value.

Abstract: There is provided an output circuit for supplying an output current to a load coupled to an output terminal in response to an input signal. The output circuit includes an output transistor for supplying the output current to the output terminal, an output-drive circuit for driving the output transistor, a constant-current limiting circuit for generating a current control signal for limiting the output current to a predetermined current value, and a control circuit for implementing a control such that the output current is controlled on the basis of the current control signal if a voltage at the output terminal is at a predetermined voltage, or less after the input signal is supplied while the output transistor is driven by the output-drive circuit if the voltage at the output terminal is in excess of the predetermined voltage.

Abstract: An energy efficient apparatus includes a switching device, a frequency dependent reactive device, and a control element is provided. The switching device is coupled to a source of electrical power and includes a pair of transistors and is adapted to receive a control signal and to produce an alternating current power signal. The frequency of the alternating current power signal is responsive to the control signal. The frequency dependent reactive device is electrically coupled to the pair of transistors for receiving the alternating current power signal and producing an output power signal. The frequency dependent reactive device is chosen to achieve a desired voltage of the output power signal relative to the frequency of the alternating current power signal. The control element senses an actual voltage of the direct current power signal and modifies the control signal delivered to achieve the desired voltage of the direct current power signal.

Abstract: An electric power conversion system includes: a primary circuit including a first port, a second port and a primary electric power conversion unit; and a secondary circuit magnetically coupled to the primary circuit by a transformer and including a third port, a fourth port and a secondary electric power conversion unit. The electric power conversion system is configured to convert electric power between any two of the four ports with the use of the primary and secondary electric power conversion units, and convert electric power between the first and second ports and between the third and fourth ports with the use of electric power conversion circuit portions other than a faulty electric power conversion circuit portion among a plurality of electric power conversion circuit portions configured in the primary and secondary electric power conversion units.

Abstract: An energy efficient apparatus includes a switching device, a frequency dependent reactive device, and a control element is provided. The switching device is coupled to a source of electrical power and includes a pair of transistors and is adapted to receive a control signal and to produce an alternating current power signal. The frequency of the alternating current power signal is responsive to the control signal. The frequency dependent reactive device is electrically coupled to the pair of transistors for receiving the alternating current power signal and producing an output power signal. The frequency dependent reactive device is chosen to achieve a desired voltage of the output power signal relative to the frequency of the alternating current power signal. The control element senses an actual voltage of the direct current power signal and modifies the control signal delivered to achieve the desired voltage of the direct current power signal.

Abstract: An ultra high voltage regulator for converting includes a rectifying circuit, a first transistor, a second transistor, an output capacitor, a first resistor, a second resistor, and a third resistor. The ultra high voltage regulator converts a received alternative current into a direct voltage to an electrical component. The ultra high voltage regulator capable of providing a larger current becomes more compact and thinner in size without cooperating with a mass transformer/high voltage capacitor, which satisfies the request for miniaturization of the electrical components.

Abstract: An AC-DC power converter includes a rectifying unit, an output stage, a controller and a soft-start circuit. The rectifying unit is configured to rectify an AC voltage to a rectified voltage. The output stage is coupled to the rectifying unit and configured to convert the rectified voltage into a DC voltage for a load. The controller is coupled to the output stage and configured to control the output stage. The soft-start circuit is coupled to the rectifying unit to receive the rectified voltage. The soft-start circuit is configured to detect whether the rectified voltage is at or below a predetermined level, and to enable the controller if the rectified voltage is detected to be at or below the predetermined level.

Abstract: A power converter startup circuit establishes an operating voltage for control circuitry during startup and is then disabled to reduce no-load power dissipation. The startup circuit has a normally on characteristic to automatically provide startup charging current for a startup capacitor. The control circuitry begins operating as the startup capacitor voltage reaches an operating value, and it generates an inhibitory signal that disables the startup circuit to stop the startup charging current and reduce power dissipation. The normally on characteristic is achieved by an emitter switched current source employing a normally on device such as a depletion-mode J-FET. A resistor divider network provides both biasing for the startup current source and a point of monitoring the power supply input voltage during steady state operation.