Abstract: A power conversion apparatus includes a converter circuit converting AC voltage output from an AC power supply into DC voltage. The converter circuit includes unit converters. The power conversion apparatus includes a low current-oriented controller the unit converters to cause current corresponding to a single phase to flow through a current detector, and a high current-oriented controller controlling operation of the unit converters based on a result of comparison between a duty command and a carrier signal, where the duty command is generated based on detection values detected by the current detector and a voltage detector. When the detection value detected by the current detector is less than or equal to a first threshold, the low current-oriented controller is activated, and when the detection value detected by the current detector is greater than the first threshold, the high current-oriented controller is activated.

Abstract: A system for rectifying power is disclosed. The system includes a switch network that includes a plurality of switches configured to receive wireless power input and generate a rectified voltage. The system further includes a first conductor coupled to the first receiver and the switch network configured to transmit a first alternating current to the switch network. The system further includes a second conductor electrically coupled to the first receiver and the switch network, configured to transmit a second alternating current having a second voltage to the first receiver. The system further includes a controller configured to determine a rectified voltage signal and to transmit an input to at least one switch of the plurality of switches based on the rectified voltage signal to change an ON/OFF state of the at least one switch of the plurality of switches, modifying the voltage.

Abstract: A DC to DC boost converter for boosting low voltage power to levels for MVDC and HVDC transmission. The DC to DC boost converter comprises a bridge converter configured to receive a direct current (DC) input and to generate a resultant alternating current (AC) output, the bridge converter comprising a high-speed semiconductor switch bridge; a transformer configured to receive and step up the AC output of the bridge converter; and a rectifier configured to convert the stepped up AC output to pulsating DC output.

Abstract: This disclosure describes systems, methods, and apparatus for controlling a voltage provided to a plurality of configurable output modules using a resonant converter, the resonant converter comprising: an inverter circuit; a resonant capacitor bridge coupled across the inverter circuit; N groups of output modules, each of the N groups comprising terminals configured for coupling to up to M output modules, the output modules each comprising: a transformer having a primary and a secondary; and a rectified output coupled to the secondary and configured for coupling to a load; and a resonant inductor network configured to be coupled between the resonant capacitor bridge and the primaries of the transformers, the resonant inductor network comprising: at least one parallel inductor; and N parallel branches arranged in parallel and each branch comprising a series inductor, each of the series inductors configured for transformer-coupling to up to M output modules.

Abstract: An alternating current (AC)-to-direct current (DC) (AC-DC) converter circuit system, and a method of designing the AC-DC converter circuit system. The AC-DC converter circuit system includes an AC-DC converter configured to receive an AC grid input from an electric power source and convert the AC grid input into DC battery power. The AC-DC converter may include a primary transformer including a plurality of field-effect transistors (FETs), and a secondary transformer configured to allow the DC battery power to be output from a grid that is allowed to have a positive value by the primary transformer.

Abstract: A two-stage power converter can incorporate a buck pre-regulator and a resonant bus converter. Such a converter may be operated to achieve unconditional soft switching operation (zero voltage switching a/k/a ZVS) over a wide input and output range, while delivering excellent power conversion efficiency at lower power levels and in a no load condition.

Abstract: A space efficient planar transformer can include a coupled inductor circuit that can include a metallic core, a first planar winding comprising a conductive coil having an electrical path encircling a first post of the metallic core, and a second planar winding configured to magnetically couple with the first winding via the metallic core. The second planar winding can have multiple portions. A portion of the second winding can include a first sub-portion comprising a single U-shaped planar conductive trace wrapped about the first post and a second sub-portion comprising a single U-shaped planar conductive trace wrapped about the first post. A layout of the first sub-portion can be oriented opposite a layout of the second sub-portion.

Abstract: An electronic apparatus includes: an operator; and a power circuit configured to supply power to the operator, wherein the power circuit includes a first voltage converter configured to output a first voltage based on input power, and a power factor corrector (PFC) configured to output a second voltage by performing power factor correction for the first voltage, and supplies power based on the first voltage or the second voltage to the operator, wherein the power circuit stops an operation of the PFC, lowers the first voltage to have a level corresponding to the second voltage, and supplies power based on the lowered first voltage to the operator, based on power consumption of the operator lower than or equal to a predetermined value.

Abstract: Embodiments include systems for regulating windings in a power supply. Aspects include a transformer comprising a first primary winding and a first secondary winding, a DC to DC converter, a saturable reactor coupled to an output of the first secondary winding and an input to the DC to DC converter, and a controlled current source coupled to a node between the saturable reactor and the input of the DC to DC converter, wherein the controlled current source is configured to provide a current rate based on an output voltage of the DC to DC converter, wherein a first filter inductor of the DC to DC converter is magnetically coupled to a second filter inductor of a second DC to DC converter.

Abstract: An adjustable power supply suitable for a power switch driver circuit takes an input voltage and generates output voltages at three output terminals. Two of the output terminals provide gate voltage signals to a power switch control device while the third is connected to a reference voltage. The output voltages may be adjusted using a first and second external resistor enabling power requirements for a wide variety of power switch devices to be satisfied.

Abstract: A wireless power transmission apparatus includes a power transmission coil that transmits electric power; a power transmission-side resonant capacitor that is connected to the power transmission coil and that, with the power transmission coil, forms a power transmission-side resonance circuit; and a self-oscillation circuit that converts a DC voltage to an AC voltage, and that supplies the AC voltage to the power transmission coil. The wireless power transmission apparatus has a state, during power transmission, in which multiple resonance points exist in a combined resonance circuit formed by magnetic coupling of the power transmission-side resonance circuit with a power reception-side resonance circuit formed from a power reception coil and a power reception-side resonant capacitor. In the state, the self-oscillation circuit operates at the highest frequency among the multiple resonance points.

Abstract: A driver circuit for a resonant converter includes a comparator that generates a first control signal indicating when a resonant current changes sign. A first ramp generator circuit outputs a first ramp signal, and a comparison circuit determines whether the first ramp signal reaches a reference threshold. The driver circuit drives a half-bridge via drive signals during consecutive first second switching semi-periods, each of which ends when the comparison circuit indicates the first ramp signal has reached a reference threshold. A control circuit generates in each of the first and the second switching semi-periods control signals indicating a first interval and a second interval. A correction circuit modifies the first ramp signal to have a first gradient value during the first interval and a second gradient value during the second interval. Alternatively, the correction circuit modifies a reference threshold by adding a second ramp signal to an initial threshold value.

Abstract: A magnetically coupled reactor and a DC/DC converter are provided between a DC power supply and an inverter. A first smoothing capacitor is provided between the DC power supply and the coupled reactor. A second smoothing capacitor is provided between the DC/DC converter and the inverter. A controller is provided in order to control switching operations of the inverter and the DC/DC converter. The controller causes semiconductor switching elements composing upper and lower arms of the DC/DC converter to perform complementary operations so as to be alternately turned on/off, and causes left and right legs to operate with their switching phases shifted from each other, thereby electric charges stored in both smoothing capacitors are discharged by energy loss in the coupled reactor and the DC/DC converter.

Abstract: The present disclosure relates to a high voltage generator including multiple high voltage generating modules configured to provide a total voltage. Each of the multiple high voltage generating modules may be configured to receive a driving pulse and generate a voltage component of the total voltage according to the driving pulse. The multiple high voltage generating modules may be in a series connection. Time points when the multiple high voltage generating modules receive driving pulses may be different, and waveforms of the driving pulses may be the same.

Abstract: A clock stretcher includes a DLL that derives delayed versions of an input clock signal, and a combiner that cyclically selects the delayed versions to generate a modified clock signal. The combiner uses a hop code, dependent on a sensed condition, to determine the step size for the cyclical selection. The DLL may have a phase error that would cause a glitch in the modified clock during phase selection wraparound. The clock stretcher proactively increases the step size during wraparound by adding an offset skip parameter value to the hop code. The clock stretcher may operate from a sensed power supply without intervening voltage regulation.

Abstract: A solid-state transformer (SST) comprises a transformer core, a primary winding, a secondary winding, a primary-side switch bank, and a secondary-side switch bank. Each of the switch banks includes six 4-quadrant switches. The twelve 4-quadrant switches are toggled on and off over six clock cycles in a repetitive sequence with a period that is a function of a desired operating frequency of the transformer. The sequence is configured such that at any given time, 2 of 3 input and output phases are connected to the primary and secondary windings. The SST further includes L-C filter circuits that are configured to filter high-frequency components of current and voltage waveforms such that these components are not back-fed to the electrical mains or delivered to a load. The SST includes a primary-side filter circuit and a secondary-side filter circuit that can each include respective L-C filters for three input or output phases.

Abstract: A synchronous generator may comprise a rotor and a stator. The stator may comprise a first armature winding configured to output a first three-phase voltage and a second armature winding configured to output a second three-phase voltage. The synchronous generator may further comprise a first rectifier configured to rectify the first three-phase voltage received from the first armature winding, and a second rectifier configured to rectify the second three-phase voltage received from the second armature winding.

Abstract: A three-level modulation for an isolated multilevel DC/DC resonant converter offers output voltage regulation capability with fixed switching frequency and achieves high efficiency along with soft-switching of the power switches. The three-level modulation enables current balance in all power devices, therefore, realizes better thermal performance and longer circuit life. An efficient control method that combines the three-level modulation with conventional frequency modulation achieves a wide output voltage range with a narrow switching frequency range. At any given time, a control circuit selects one of two different modulation schemes to operate the primary-side switches of the resonant converter based on an output voltage, or to one or more external control signals. Together with a selected device switching frequency and duty cycles, the two modulation schemes generate different voltage waveforms to a primary-side transformer, which are coupled to the secondary-side to provide different output voltages.

Abstract: Systems and methods for transferring power across an isolation barrier using an active self-synchronized rectifier are described. A rectifier as described herein may provide DC to DC power conversion with high efficiency. Furthermore, by using a microfabricated transformer or microfabricated capacitor as an isolation component, an isolation component and rectifier may be microfabricated and implemented on chip.

Abstract: Systems and methods for transferring power across an isolation barrier using an active self-synchronized resonator are described. A resonator may use the isolation barrier to resonate with active devices arranged on both sides of the barrier, to provide DC to DC power conversion with high efficiency. Furthermore, by using a microfabricated transformer or microfabricated capacitor as an isolator, the entire resonator may be microfabricated and implemented on chip. The resonator is also bidirectional, allowing power transfer in either direction across the isolation barrier.

Abstract: A switching circuit includes a first half-bridge circuit, a second half-bridge circuit and a voltage divider circuit connected in parallel with each other and a DC input power (VDC). The first half-bridge circuit includes a first pair of series connected switches and the second half-bridge circuit includes a second pair of series connected switches.

Abstract: A method for controlling a converter system includes: determining, with a first controller stage, an output voltage reference for the converter system; generating, with the first controller stage, switching commands for a main converter based on the output voltage reference, such that the main converter converts an input voltage into an intermediate voltage provided at an output of the main converter and following the output voltage reference; and generating, with a second controller stage, switching commands for a floating converter cell connected to the output of the main converter, such that the floating converter cell converts the intermediate voltage into an output voltage provided at an output of the floating converter cell, wherein the floating converter cell comprises a cell capacitor and a semiconductor switch arrangement for connecting and disconnecting the cell capacitor between the output of the main converter and the output of the floating converter cell.

Abstract: A switched mode power supply (SMPS) to output a smoothly rising voltage (VOUT) during startup and still operate efficiently during steady state. A smoothly rising VOUT that avoids a negative voltage slope and voltage overshoot may be desirable in some applications. The techniques of this disclosure include an adaptive loading time controlled oscillator (TCO) compensation circuit that adjusts the TCO frequency to linearly regulate the feedback voltage from the half-bridge (VHBFB). The TCO compensation circuit adapts to the startup loading and self-adjusts the regulation speed for the handover point between the TCO and the voltage controlled oscillator (VCO).

Abstract: A power conversion apparatus (10) includes a plurality of power conversion units (12) each having a function of converting an input direct current voltage to a different direct current voltage, and a control unit (15) that controls the plurality of power conversion units (12) in accordance with a target value Vaim for the sum of voltages output from the plurality of power conversion units (12). When making one or more of the power conversion units (12) output a first voltage which is fixed and making a different one of the power conversion units (12) output a second voltage which is adjusted in accordance with the target value Vaim, the control unit (15) repeatedly switches a power conversion unit (12) to output the second voltage at least between two of the power conversion units (12).

Abstract: A DC/AC power converter (“DPC”) capable of generating multi-phase power supply is disclosed. DPC, in one embodiment, includes a first switching bridge, second switching bridge, patch component, first phase generator, and second phase generator. The first switching bridge is coupled to a DC bus and configured to extract a first portion of the DC bus in accordance with a first phase of DC waveform. The second switching bridge, in one aspect, extracts a second portion of the DC bus in accordance with a second phase of DC waveform. The patch component is capable of generating a first patch waveform in response to a third portion of the DC bus. The first phase generator is configured to generate a first phase AC waveform based on the first portion of the DC bus and a first patch waveform.

Abstract: A rectifier IC seals, in a single package, a first transistor chip which integrates a first transistor, a second transistor chip which integrates a second transistor and a controller chip which detects a first node voltage and a second node voltage of each of the transistors so as to perform on/off control on the transistors, and the rectifier IC functions as a secondary-side rectification means of an isolated switching power supply.

Abstract: A main unit 2 and a subsidiary unit 4 include two inverters 6m, 8m and 6s, 8s, and PWM control circuits 26m, 26s, respectively. A changeover switch 20 operates to simultaneously connect the inputs of the two inverters of the main unit 2 and the inputs of the two inverters of the subsidiary unit 4 in series or in parallel. An imbalance detecting circuit 28 detects imbalance in the input voltages to the two inverters of the main unit 2, and provides the detection result to the PWM control circuits 26m and 26s. The PWM control circuit 26m controls the inverters 6m and 8m of the main unit 2 in accordance with the detection result supplied from the imbalance detecting circuit 26m, and the PWM control circuit 26s controls the subsidiary unit 4 in accordance with the detection result supplied from the imbalance detecting circuit 26m. The input current to the main unit 2 is larger than the input current to the subsidiary unit 4.

Abstract: A wireless power transmission system using multiple coils comprises a transmitter; and a receiver, wherein the transmitter includes a module for receiving a predetermined voltage, and a primary coil for generating a primary resonance frequency in accordance with the received voltage. The receiver spaced apart from the transmitter includes a load for emitting light, capacitors connected in series or in parallel in accordance with an equivalent resistance of the load, and a secondary coil for generating a secondary resonance frequency greater than the primary resonance frequency.

Abstract: According to the present invention there is provided methods and devices for detecting open and/or short circuits in MEMS micro-mirror devices, which use relative comparisons of voltage levels within the MEMS micro-mirror devices for detecting the occurrence of open and/or short circuits.

Abstract: A method of driving a network device for outputting signals to a physical network transmission medium. The network device includes a DAC circuit that comprises a plurality of digital-to-analog conversion units. Each digital-to-analog conversion unit includes a first auxiliary current source and a second auxiliary current source. The method includes the steps of: detecting a length of the physical network transmission medium; generating a control signal according to the length; generating a bias signal according to the control signal; applying the bias signal to the first auxiliary current source and the second auxiliary current source to control the currents of the first auxiliary current source and the second auxiliary current source.

Abstract: A reactive power compensator includes a plurality of phase clusters each including plurality of cells and a controller configured to control the plurality of phase clusters. The controller performs control to generate an offset signal through phasor transformation based on respective voltage values and current values of the plurality of phase clusters and to compensate for energy errors between the plurality of phase clusters based on the generated offset signal.

Abstract: A power transmitter transfers power to a power receiver using a wireless power signal. The power transmitter comprises an inductor driven by a power signal generator to provide the power signal. A calibration controller determines whether a power loss calibration has been performed for the power transmitter and power receiver pairing. The calibration adapts an expected relationship between a received power indication provided by the power receiver and a transmitted power indication for the power transmitter. A power limiter restricts the power provided to the inductor to not exceed a threshold unless a power loss calibration has been performed for the pairing. The expected relationship may be used to detect unaccounted for power losses, e.g. due to foreign objects being present. The calibrated expected relationship may provide improved accuracy allowing accurate detection at higher power levels. At lower power levels such accuracy is not needed, and no calibration needs to be performed.

Abstract: A device for controlling a plurality of electrical consumers to which a constant control current is applied at control nodes. A transformer to which a regulated and/or constant predetermined frequency current is applied at the input end has at least one first and a second winding at the output end which have a common tap, first and second circuit branches forming first and second control nodes for first and second electrical consumers are associated with the first and second windings respectively. The first and second circuit branches each have a magnetically interacting pair of reactors which are wound in opposite relative directions. The first and second reactors of the pair are connected to the first and second control nodes, respectively, via a rectifier. The reactors that are connected to one of the control nodes are oppositely wound. Reactors pairs are magnetically coupled, in particular having a common reactor core.

Abstract: When the preferred voltage source for a static transfer switch is a UPS, there can be a brief interruption in the voltage received from the UPS while the UPS is switching from economy mode to normal mode. Operation of the static transfer switch can be improved during such voltage disturbances. Specifically, the static transfer switch may be in data communication with the UPS and thereby made aware that the voltage disturbance is temporary. As a result, the static transfer switch can avoid an unnecessary transfer to an alternate voltage source.

Abstract: An image forming apparatus includes an image processing unit and a switching unit. The image processing unit includes: a charging unit that is provided to face an image carrier and applies a direct current voltage on which an alternating voltage of a first frequency is superimposed to charge the image carrier; an electrostatic latent image forming unit that forms an electrostatic latent image on the charged image carrier with light scanning based on image information; a developing unit that develops the electrostatic latent image; and a transfer unit that transfers the developed image to a recording medium. When an image density based on the image information is greater than or equal to a specific image density, the switching unit switches a frequency of the alternating voltage at least during charging performed by the charging unit to a second frequency different from the first frequency.

Abstract: A control section for a current resonant converter section controls a DC output voltage of a current resonant converter section to settle to a target voltage by varying a resonant period between predetermined two resonant periods based on an error signal between the DC output voltage and the target voltage. A gain converter is provided in a preceding stage of a frequency generator for generating a square waveform signal with a duty ratio of 50% and the gain converter has a setting of a nonlinear gain characteristic that cancels nonlinearity in the input-output characteristics of the current resonant converter section. The nonlinear gain characteristic can be a characteristic of continuous gain conversion or discrete gain conversion.

Abstract: Provided are a parallel inverter system, and a shutdown control method and a shutdown control device for the parallel inverter system. A shutdown instruction is determined and responded according to a level of the shutdown instruction. The shutdown instruction is determined to be an emergency shutdown instruction under certain emergency shutdown conditions, and a driving signal for the power switch devices of the inverter apparatus is needed to be instantly locked out. The shutdown instruction is determined to be a normal shutdown instruction under non-emergency shutdown conditions, a switch-off signal is transmitted to alternating-current switches connected to the inverter apparatus to be shut down, states of the alternating-current switches connected to the inverter apparatus to be shut down are detected, the driving signal for the power switch devices of the inverter apparatus to be shut down is instantly locked out in a case that the alternating-current switches are switched off.

Abstract: A method for controlling a converter including a resonant circuit, where the converter is controlled such that control switches are switched into a first state at the occurrence of an event that is related to a dependent variable of the converter and are switched into a second state at the occurrence of an event that is not related to a dependent variable of the converter. The method may be employed in a converter or an inductive power transfer transmitter.

Abstract: An inverter apparatus includes a direct current to direct current converter (DC/DC converter), a direct current to alternating current converter (DC/AC converter), a primary-side control circuit and a secondary-side control circuit. The DC/DC converter is arranged for outputting a first DC power and a second DC power. The DC/AC converter is coupled to the DC/DC converter, and is arranged for receiving the first DC power. The primary-side control circuit is coupled to the DC/DC converter, and is arranged for controlling an operation of the DC/DC converter. The secondary-side control circuit is coupled to the DC/DC converter and the DC/AC converter, and is arranged for receiving the second DC power, and controlling an operation of the DC/AC converter according to the second DC power.

Abstract: There is provided a single stage forward-flyback converter including a power converting unit switching input power to perform a forward power conversion operation while being switched on and perform a flyback power conversion operation while being switched off, a path providing unit clamping power formed by the forward power conversion operation of the power converting unit and power formed by the flyback power conversion operation thereof to provide power transfer paths, and a controlling unit controlling the power conversion operation of the power converting unit according to a voltage level of the input power.

Abstract: A SEPIC-type voltage converter for converting an input voltage supplied by a power supply into an output voltage comprises an inductive component comprising primary and secondary windings, an output capacitor for delivering power to a load by way of an output node, an AC coupling capacitor, a first rectifier for rectifying the output voltage, and a switch for periodically switching between an ON state in which the primary winding is energized by the power supply and in which the secondary winding is energized by the coupling capacitor, and an OFF state in which the output capacitor is charged by both the primary winding and the secondary winding. A second rectifier is connected in series with the secondary winding and the secondary winding is inductively coupled to the primary winding such that the secondary winding is influenced by changes in the voltage applied across the primary winding by the power supply.

Abstract: In accordance with an embodiment, a power converter includes an H-bridge switching arrangement, a transformer having a primary winding coupled to an output of the H-bridge switching arrangement, a first switch coupled between a power input of the H-bridge switching arrangement and a first power supply node, and a second switch coupled between a center-tap of the primary winding of the transformer and a low impedance node.

Abstract: A converter with at least one or more transformers having at least one primary side magnetically coupled to at least one secondary side, the primary side being electrically isolated from the secondary side, wherein a first transformer has first and second sets of coils and a second transformer has third and fourth sets of coils. The first set of coils is connected in series to the third set of coils, wherein one of the secondary sides is connectable to an external output unit, wherein another secondary side is connectable to an external input source, wherein the two secondary sides are electrically isolated from each other, wherein the primary side is adapted to drive the transformers that are connectable to an external power source. The converter uses a shared current path and an isolated current-to-current transfer between the input and output sides to replicate the input current to an output current.

Abstract: A switched mode power converter includes a closed loop feedback control mechanism for regulating an output characteristic and a resonant type circuit for inclusion of resonant energy delivery. The characteristic impedance of the resonant type circuit is modified from an optimal energy transfer configuration to one that dampens fluctuations in a feedback signal used by the closed loop feedback mechanism. The modified characteristic impedance functions to dampen those fluctuations in the feedback signal resulting from leakage inductance energy provided by the resonant type circuit.

Abstract: A controller for estimating a power of a power converter and method of estimating the same has been introduced herein. In one embodiment, the controller includes an analog/digital converter configured to provide samples of a rectified voltage waveform corresponding to a rectified sensed voltage of the power converter. The controller also includes a processor configured to estimate a minimum value of the rectified voltage waveform in accordance with the samples and remove an offset from the rectified voltage waveform to obtain an unbiased rectified voltage waveform in accordance with the estimate of the minimum value. The controller is also configured to obtain an unbiased rectified current waveform corresponding to sensed current of the power converter and provide an average power of the power converter.

Abstract: A solid state circuit-breaker switch has a first solid state switch coupled to a positive terminal of a high voltage source, a second solid state switch coupled to a return terminal of the high voltage source, and a diode connected between the switches. A load is coupled between the switches and in parallel with the diode such that voltage transients across the load are limited during turn of conditions. Related methods of operating the switch during turn-on and turn-off events within rated current operation are described, as are turn-on and turn-off events in overload conditions.

Abstract: A power converter apparatus includes a primary bridge having a plurality of diagonally opposed primary power elements, and a secondary bridge having a plurality of diagonally opposed secondary power elements. The primary and secondary bridges are electrically coupled by a transformer. At least one control unit is configured to phase-shift switch the primary and secondary power elements, such that one or more of the primary and secondary power elements are switched off under near-zero current conditions to reduce voltage and current stresses and commutation losses within the power converter.

Abstract: An improved arrangement for detecting DC current leakage in implanted devices is disclosed. Currents are monitored, so that any unexpected imbalance indicates that a fault condition has occurred. The principle of the system is that if everything working correctly, the same current should be flowing into the tissue from VDDH-ELEC as is passing out of the tissue into VSS_ELEC. Any difference is indicative of current flowing into or out of the tissue from unknown paths, which is indicative of some fault. This replaces routine monitoring for specific faults.

Abstract: A light emitting diode (LED) backlight driving circuit includes an LED lightbar, and a driver integrated circuit (IC) coupled to the LED lightbar. The driver IC is configured with a protection pin that controls the driver IC to enter a protection mode when a voltage of the protection pin exceeds a preset voltage range, an undervoltage module is coupled between a power input end of the LED lightbar and the protection pin, and an overvoltage protection module is coupled between a power output end of the LED lightbar and the protection pin. An output overvoltage protection module is coupled between the power output end of the LED lightbar and the protection pin. The input undervoltage protection module outputs a first control voltage that exceeds the preset voltage range to the protection pin when the power input end of the LED lightbar is in an undervoltage state.

Abstract: Some implementations are directed to a A DC-to-DC converter that includes a power transformer having a primary side and a secondary side and a plurality of power transistors coupled to the primary side of the transformer. The converter also includes a secondary bias supply coupled to the secondary side of the transformer and a secondary side controller coupled to the secondary side of the transformer and configured to generate a feedback control signal based on a voltage level associated with the secondary side of the transformer. The secondary side controller receives operating power only from the secondary bias supply.