Abstract: A phase-controlled power supply is disclosed. The power supply includes a power conditioner with an input configured to connect to an external source of electrical power, the power conditioner being configured to provide conditioned power on its output. The power supply also includes a transformer having a primary winding and a secondary winding, and a switching module coupled between the output of the power conditioner and to the primary winding of the transformer. The switching module has two modes of operation and a control signal input configured to accept a first control signal. The switching module includes a switching element configured to connect the power conditioner output to the primary winding of the transformer. The switching module operates in the first mode when the first control signal is in a first state, switching the first switching element at a first frequency and first duty cycle.

Abstract: An interleaved flyback converter device with leakage energy recycling includes: two flyback converters and an input power. Each flyback converter includes a capacitor, a switch, two diodes, and a transformer. The input power is connected to the capacitors of the two flyback converters respectively. By using the capacitors as input voltage, the two flyback converters are provided with lower voltage rating. The diodes are used to recycle leakage energy directly, and to clamp voltage on power components. Therefore, in addition to enhancing efficiency via recycling leakage energy, the two flyback converters have lower switching losses due to lower switching voltage.

Abstract: An example controller for a primary side control power converter includes a feedback circuit, a driver circuit, and an adjustable voltage reference circuit. The feedback circuit is coupled to compare a feedback signal representative of a bias winding voltage of the power converter with a voltage reference. The driver circuit is coupled to output a switching signal to control a switch of the power converter to regulate an output of the power converter in response the feedback circuit. The adjustable voltage reference circuit is coupled to adjust the voltage reference such that the bias winding voltage is adjusted nonlinearly in response to a load condition at the output of the power converter. The adjustable voltage reference circuit is further coupled to detect the load condition in response to the switching signal.

Abstract: A switching power conversion circuit receives an input voltage and generates an output voltage to a system circuit. The switching power conversion circuit includes a power circuit, a feedback circuit, a control circuit, and an initiation circuit. The power circuit includes a first switch circuit. The feedback circuit generates a feedback signal according to a power-status signal and the output voltage. The first switching circuit is conducted or shut off according to the feedback signal under control of the control circuit, so that the input voltage is converted into the output voltage and the first auxiliary voltage by the power circuit. If the power-status signal is in an off status, a ratio of the feedback signal to the output voltage is equal to a first feedback ratio and the magnitude of the first auxiliary voltage is lower than a normal operating voltage value, so that the control circuit is disabled.

Abstract: A secondary circuit of a flyback power converter has a resistor network to monitor the output current of the flyback power converter, so as to generate a voltage to apply to a base of a bipolar junction transistor to thereby provide a collector signal for output feedback. The resistor network has a temperature-dependent resistance to compensate the temperature dependence of the base-emitter voltage imparted to the output current and thereby stable the output current.

Abstract: System and method for regulating an output voltage of a power conversion system. The system includes an error amplifier coupled to a capacitor. The error amplifier is configured to receive a reference voltage, a first voltage, and an adjustment current and to generate a compensation voltage with the capacitor. The first voltage is associated with a feedback voltage. Additionally, the system includes a current generator configured to receive the compensation voltage and generate the adjustment current and a first current, and a signal generator configured to receive the first current and a second current. The signal generator is further configured to receive a sensing voltage and to generate a modulation signal. Moreover, the system includes the gate driver directly or indirectly coupled to the signal generator and configured to generate a drive signal based on at least information associated with the modulation signal.

Abstract: A driving circuit drives a switching element such that an ON-period of the switching element is shorter when a power receiving device is detected not to be placed than when the power receiving device is placed.

Abstract: A power conversion apparatus and an over current protection (OCP) method thereof are provided. The OCP method includes generating a pulse-width-modulation (PWM) signal according to a loading status of an electronic device, so as to switch a power switch in the power conversion apparatus and thus making the power conversion apparatus providing an output voltage to the electronic device; generating an OCP reference signal with variable slope according to a feedback signal related to the loading status of the electronic device and a system operation voltage of a PWM controller chip in the power conversion apparatus that is used for generating the PWM signal; and comparing a sensing voltage corresponding to a current following through the power switch on a resistor, and the OCP reference signal with variable slope to determine whether to activate an OCP mechanism to control the PWM controller chip whether to generate the PWM signal.

Abstract: The configurations of a compensation device configured in a circuit having a synchronous rectifier (SR), a controller and a load, and a compensation method thereof are provided in the present invention. In the proposed circuit, the SR includes a first terminal, a first inductor electrically connected to the first terminal in series, a second terminal and a second inductor electrically connected to the second terminal in series, the controller is coupled to the first and the second inductors, and the device includes a voltage source having a positive terminal coupled to the controller and a negative terminal coupled to the second inductor and providing a compensation voltage to reduce or eliminate the influence of the first and the second inductors towards a voltage value across the first and the second terminals.

Abstract: A power supply includes a first power converter, a second power converter, and a clamp reset circuit. The clamp reset circuit is electrically coupled to other components within the first power converter and the second power converter. A clamp standby connection can be provided to electrically couple the clamp reset circuit to components comprising the second power converter. The clamp reset circuit is coupled to reduce magnetizing energy of a transformer of the first power converter and limit voltage in a component of the second power converter. The clamp reset circuit may include a Zener diode and a resistor that are adapted to reduce magnetizing energy of the first power converter and voltage through the second power converter. The clamp reset circuit normally includes a capacitor that is adapted to store energy from the first power converter and the second power converter.

Abstract: A controller IC adjusts the on time and cycle time of current flowing through the primary inductor of a flyback converter to generate a constant output current and constant output voltage. A desired output current limit is achieved even with an inductor whose inductance varies from the stated magnitude. A transconductance current is generated from a voltage across an emitter resistor and is then integrated to generate an integrated-current voltage. An inductor switch is turned on by an oscillator signal and turned off at the earlier of when the integrated-current voltage reaches a charge limit voltage during constant current mode or when the emitter resistor voltage reaches an error voltage during constant voltage mode. Current is output independently of the primary inductance by varying the current limit voltage inversely proportionally to the input voltage and by adjusting the cycle time so that it varies inversely proportionally to the output voltage.

Abstract: Transformers and methods of constructing transformers are disclosed. In one embodiment, a method of constructing a transformer includes wrapping a first primary winding around a core, wrapping a secondary winding around the core, and wrapping a second primary winding around the core. The first primary winding traverses substantially an entire circumference of the core in a first circumferential direction. The secondary winding includes a first half and a second half. The first half traverses substantially the entire circumference of the core in the first circumferential direction, and the second half traverses substantially the entire circumference of the core in a second circumferential direction opposite the first circumferential direction. The second primary winding traverses substantially the entire circumference of the core in the second circumferential direction.

Abstract: A technique for controlling a power supply with power supply control element with a tap element. An example power supply control element includes a power transistor that has first and second main terminals, a control terminal and a tap terminal. A control circuit is coupled to the control terminal. The tap terminal and the second main terminal of the power transistor are to control switching of the power transistor. The tap terminal is coupled to provide a signal to the control circuit substantially proportional to a voltage between the first and second main terminals when the voltage is less than a pinch off voltage. The tap terminal is coupled to provide a substantially constant voltage that is less than the voltage between the first and second main terminals to the control circuit when the voltage between the first and second main terminals is greater than the pinch-off voltage.

Abstract: A circuit used to convert DC input to AC output comprises a transformer and three series sub-circuits. The first series sub-circuit is connected in parallel with the DC input and comprises first and second capacitors connected in series. The secondary series sub-circuit is connected in parallel with the DC input and comprises a first primary winding of the transformer, a clamping capacitor and a second primary winding of the transformer sequentially connected in series. The third series sub-circuit connected in parallel with said clamping capacitor and comprises first and second switches connected in series. The center nodes of the first and third series sub-circuits are connected together. Thus, while a secondary winding of the transformer provides AC voltage, the circuit is able to effectively reduce current ripple and decrease voltage stress on semiconductor switch with minimum component count. Similar topologies may be used for rectification instead of inversion.

Abstract: A device for diagnosing signal status of a driven object includes an insulation transformer, a signal generating device, a current measuring device, a feedback device, and a voltage measuring device. The insulation transformer has an intermediate tap at a midpoint of its primary winding. The signal generating device generates periodically vibrating voltage and includes a rectangular wave pulse voltage and alternating voltage. The current measuring device is connected to the intermediate tap of the primary winding to measure a current. The feedback device converts the current flowing from the intermediate tap of the primary side to a voltage corresponding to the drive voltage and feeds back the converted voltage to the input drive voltage signal. The voltage measuring device measures the voltage added with the feedback voltage. Diagnosis of the signal state is performed based on measurement results of the current measuring device and voltage measuring device.

Abstract: A power supply module includes an AC/DC converter, a voltage transforming circuit, a feedback circuit, and a detecting circuit. The AC/DC converter is used for converting the input AC voltage to a primary DC voltage. The voltage transforming circuit is used for transforming the primary DC voltage to the first DC voltage. The feedback circuit is used for sampling the first DC voltage to generate a feedback signal. The detecting circuit is used for detecting if the power supply module is powered on, and generating a first voltage when detecting that the power supply module is powered on. Wherein the voltage transforming circuit maintains the first DC voltage at a first predetermined value according to the feedback signal, the feedback circuit increases a magnitude of the feedback signal according to the first voltage.

Abstract: The present invention discloses an open loop LED driving circuit, having a turn-on period and a turn-off period, the circuit comprising: a power stage, used to store a magnetic energy supplied from a voltage source during the turn-on period and deliver the magnetic energy to a set of LEDs during the turn-off period; and a control unit, having a turn-off period control terminal coupled to the voltage source, and a channel of which a first terminal is coupled to the power stage and a second terminal is coupled to a reference ground, wherein the channel is switched on at a time according to the voltage of the voltage source to determine the turn-off period.

Abstract: A switching mode power supply and a method of operating the power supply in a power save mode. The switching mode power supply includes a first PWM controller and a second PWM controller that are driven by different driving voltages and control first and the second voltages to be output, respectively, a first transformer that is controlled by the first PWM controller to output the first voltage and having a primary coil, a secondary coil to induce the first voltage, and an auxiliary winding, and a rectifier that rectifies and smoothes a current flowing through the auxiliary winding of the first transformer, generates a power save mode voltage based on the respective driving voltages of the first and the second PWM controllers, and supplies the power save mode voltage to the first and the second PWM controllers. Accordingly, the power save mode is operated using a voltage difference without requiring an extra controller.

Abstract: An embodiment of a power-supply controller comprises a switching-control circuit, an error amplifier, and a signal generator. The switching-control circuit is operable to control a switch coupled to a primary winding of a transformer, and the error amplifier has a first input node operable to receive a feedback signal, a second input node operable to receive a comparison signal, and an output node operable to provide a control signal to the switching-control circuit. The signal generator is operable to generate either the feedback signal or the comparison signal in response to a compensation signal that is isolated from a secondary winding of the transformer and that is proportional to a load current through a conductor disposed between the secondary winding and a load.

Abstract: A switching circuit for use in a power converter in one aspect includes a first and second active switch and a first and second passive switch. The first active switch can be coupled to a first terminal of a primary winding of a transformer. The second active switch can be coupled to a second terminal of the primary winding of the transformer. The output capacitance of the first active switch is greater than the output capacitance of the second active switch. The first passive switch can be coupled to the second active switch and to the second terminal of the primary winding. The second passive switch can be coupled to the first active switch and to the first terminal of the primary winding. The reverse recovery time of the first passive switch is greater than the reverse recovery time of the second passive switch.

Abstract: An example apparatus to regulate an output voltage of a power converter at light/no load conditions includes a driver circuit, a feedback circuit, and an adjustable voltage reference circuit. The driver circuit is coupled to output a drive signal to switch a power switch between an ON state and an OFF state to regulate an output of the power converter. The feedback circuit is coupled to the driver circuit and is further coupled to output an enable signal to switch the power switch to an ON state in response to an output voltage signal. The adjustable voltage reference circuit is coupled to adjust a voltage reference such that a bias winding voltage of the power converter is adjusted nonlinearly in response to a load that is to be coupled to the output of the power converter.

Abstract: A switching power supply apparatus according to the present invention includes a switching device and a control circuit, and the control circuit includes: a control terminal through which an auxiliary power voltage is supplied; an error amplifier which generates a difference voltage depending on a difference between a control terminal voltage and a first reference voltage; a device current detection circuit which generates a device current detection signal indicating an amount of a current flowing in the switching device; a drive circuit which generates a drive pulse signal having a duty cycle based on a difference between the difference voltage and the device current detection signal and drives the switching device by using the generated drive pulse signal; and a dummy load circuit through which a dummy load current flows from the control terminal when the difference voltage becomes equal to or higher than a second reference voltage.

Abstract: A technique for controlling a power supply with power supply control element with a tap element. An example power supply control element includes a power transistor that has first and second main terminals, a control terminal and a tap terminal. A control circuit is coupled to the control terminal. The tap terminal and the second main terminal of the power transistor are to control switching of the power transistor. The tap terminal is coupled to provide a signal to the control circuit substantially proportional to a voltage between the first and second main terminals when the voltage is less than a pinch off voltage. The tap terminal is coupled to provide a substantially constant voltage that is less than the voltage between the first and second main terminals to the control circuit when the voltage between the first and second main terminals is greater than the pinch-off voltage.

Abstract: In a power converter, a primary coil receives an input voltage, and a switch includes a first electrode, a second electrode coupled to the primary coil, and a control electrode. An output unit includes a secondary coil, and outputs an output voltage. The primary coil and the secondary coil form a transformer, and the input voltage is converted to the output voltage by the transformer. A controller receives a sensing voltage corresponding to a switch current flowing between the first electrode and the second electrode of the switch, detects a valley point of a voltage between the first electrode and the second electrode of the switch based on the sensing voltage, and transmits a control signal to the control electrode of the switch in accordance with the valley point.

Abstract: A power converter including a main circuit and a sub-circuit. The main circuit serves as a step-up/down chopper circuit including a series-connected assembly of main switches, an inductor coupled to a joint of the main switches, and a capacitor connected in parallel to the series-connected assembly. The sub-circuit is designed to establish the soft-switching and includes a snubber capacitor, a first sub-switch coupled to the joint of the series-connected assembly and a negative terminal of the snubber capacitor, a second sub-switch coupled to the joint and a positive terminal of the snubber capacitor, a third sub-switch coupled to the positive terminal of the snubber capacitor and a high-potential terminal of the main circuit, and a fourth sub-switch coupled to the negative terminal of the snubber capacitor and a low-potential terminal of the main circuit.

Abstract: Systems and methods are provided for delivering energy using an energy conversion module that includes one or more switching elements. An exemplary electrical system comprises a DC interface, an AC interface, an isolation module, a first conversion module between the DC interface and the isolation module, and a second conversion module between the AC interface and the isolation module. A control module is configured to operate the first conversion module to provide an injection current to the second conversion module to reduce a magnitude of a current through a switching element of the second conversion module before opening the switching element.

Abstract: An AC-to-DC power converting device includes: a filter for filtering an external AC input voltage; a rectifier for rectifying the AC input voltage filtered by the filter to output a rectified voltage; a power factor corrector for receiving the rectified voltage from the rectifier to generate a boosted voltage; and a step-down converter for receiving the boosted voltage from the power factor corrector to output a DC output voltage. The power factor corrector includes first and second capacitors connected in series across an output side of the rectifier, a series connection of a first diode, a first inductor, a third capacitor, a second inductor and a second diode coupled to the output side of the rectifier, and first and second switches connected in series across the third capacitor. A common node between the first and second capacitors is coupled to a common node between the first and second switches.

Abstract: Primary and secondary coils are provided in the first through section and a coil group is also provided in the second through section. Hence, the surface area over which the coil group extends within a plane which is perpendicular to the through sections is greater than in the case where all of the coils are provided in a single through section. The surface area which is not covered by the magnetic body cores of the platelike members increases. In cases where the surface area of the members is large, the heat radiation characteristic is enhanced. Hence, the cooling efficiency of the transformer improves. In cases where there is a plurality of coil groups which are magnetically coupled to one another in particular, because it is difficult to move the heat produced in the plurality of coil groups through heat conduction, heat transfer, or heat radiation, a heat radiation structure of this kind is effective.

Abstract: A self-oscillating driver circuit comprises a driver stage, a feedforward path which is coupled to an input of the driver stage, and a feedback path which couples an output of the driver stage to an input of the feedforward path. The feedforward path comprises a feedforward filter which is designed as an active filter. In order to prevent an oscillatory state of the driver circuit at an unwanted frequency, it is proposed that an internal state variable of the feedforward filter be monitored and that the feedforward filter be reset if the value of the monitored internal state variable is outside a predefined range.

Abstract: A controller for a switching mode power supply includes two semiconductor chips. The first semiconductor chip has a high-voltage startup transistor coupled to a high voltage supply input terminal and configured to provide a charging current in a startup phase or protection mode of a switching mode power supply (SMPS) and to provide substantially no current in a normal operation phase of the SMPS. The second semiconductor chip has a control circuit for controlling the switching mode power supply. The second semiconductor chip also has first and second on-chip high-voltage resistors coupled to the high-voltage supply input terminal and the high-voltage startup transistor in the first semiconductor chip. The first and the second on-chip high-voltage resistors are configured to provide a voltage and a current related to a voltage at the high-voltage supply input terminal.

Abstract: Circuitry includes an acquiring circuit to acquire period and phase information of an oscillation. The acquiring circuit includes a first input electrically coupled to a first connection and a second input electrically coupled to a second connection. The first connection and the second connection are for electrically coupling to an oscillating circuit. A control circuit includes a first input electrically coupled to an output of the acquiring circuit. The control circuit includes a second input electrically coupled to a third connection for supply of a voltage that is based on the rectified voltage. A switch includes a controlled segment for electrically coupling a fourth connection to a reference potential connection, and a control connection that is electrically coupled to an output of the control circuit to excite an oscillation in the oscillating circuit via a DC voltage.

Abstract: Sensor for measuring electrical parameters in a high voltage environment comprising a high voltage side (4) for connection to high voltage conductors, a low voltage side (6) for connection to low voltage power supply and measurement signal control circuitry, a measurement signal circuit (16), and a power supply circuit (14), and at least one isolating transformer (18, 20) for transmission of electrical power supply and/or measurement signals between the low voltage side and the high voltage side. The isolating transformer comprises at least a first and a second transformer core (28), a transformer coil (33) on a circuit board around a branch (27) of the transformer core on the high voltage side and a transformer coil (32) on a circuit board around a branch (29) of the transformer core on the low voltage side, the isolating transformer further comprising an intermediate coil (36) encircling at least one branch of each said at least two transformer cores.

Abstract: The present invention discloses a charger control circuit and a charger control method for controlling a charger having a transformer, the transformer including a primary winding and a secondary winding. The charger control circuit comprises: a power switch coupled to the primary winding; a switch control circuit controlling the operation of the power switch; and a detection circuit which generates a signal according to a voltage at a node between the power switch and the primary winding, and supplies the signal to the switch control circuit.

Abstract: A current-sharing power supply apparatus is applied to regulate voltage level of an input DC voltage, and the regulated DC voltage is stabilized in a predetermined voltage to be used on rear-end circuits. The current-sharing power supply apparatus includes a square-wave generating circuit, a rectifier circuit, a conversion circuit, a rectifier circuit, a filter circuit, a first output terminal, and a second output terminal. The current-sharing power supply apparatus provides two output voltages with a multiple relation from the first output terminal and the second output terminal, respectively.

Abstract: The present invention discloses a full-range-duty PWM signal generation method for an AC-to-DC power conversion, comprising the steps of: generating a saw-tooth signal with a predetermined valley voltage; generating a reference signal according to at least one of a current feedback signal and a voltage feedback signal; and generating a PWM signal according to voltage comparison of the saw-tooth signal and the reference signal. Furthermore, the present invention also provides a full-range-duty PWM signal generation apparatus for an AC-to-DC power conversion, and a system using the full-range-duty PWM signal generation apparatus.

Abstract: A switching power conversion circuit includes a power circuit, a feedback circuit and a control circuit. The power circuit includes a switching circuit and a first magnetic element. The first magnetic element generates a magnetic flux change by alternately conducting or shutting off the switching circuit, so that an input voltage is converted into the output voltage by the power circuit. The feedback circuit generates a feedback signal according to the output voltage. The control circuit is used for controlling an on duration and an off duration of the switching circuit, thereby maintaining the output voltage at a rated voltage. The off duration of the switching circuit is maintained at a constant interval under control of the control circuit. The on duration of the switching circuit is adjusted to be a specified interval smaller than a maximum on duration according to the magnitude of the input voltage.

Abstract: Embodiments of the present invention relate to a low-output voltage converter, delivering voltage power less than 1 VDC, utilizing distributed secondary circuits. In one embodiment of the present invention, there is provided a voltage converter comprises a primary circuit for receiving an input voltage, comprising a plurality of primary windings arranged in series, a plurality of secondary circuits, each comprising a secondary winding for aligning with a primary winding to form a transformer, and each of the secondary circuits arranged in parallel, and an output for providing an output voltage down to, or less than 1 VDC.

Abstract: One embodiment of the invention relates to a switching control system for controlling an isolated power supply. The system includes a pulse-width modulation (PWM) switching controller configured to generate at least one primary switching signal having a first duty-cycle for activating at least one primary-side switch of the isolated power supply. A synchronous rectifier (SR) switching controller is configured to generate at least one SR switching signal having a second duty-cycle for activating at least one SR switch of the isolated power supply to conduct an output current through a secondary winding of a transformer and an output inductor to generate an output voltage, the second duty-cycle being independent of the first duty-cycle in a soft-start mode.

Abstract: A power supply includes a first power converter, a second power converter, and a clamp reset circuit. The clamp reset circuit is electrically coupled to other components within the first power converter and the second power converter. A clamp standby connection can be provided to electrically couple the clamp reset circuit to components comprising the second power converter. The clamp reset circuit is coupled to reduce magnetizing energy of a transformer of the first power converter and limit voltage in a component of the second power converter. The clamp reset circuit may include a Zener diode and a resistor that are adapted to reduce magnetizing energy of the first power converter and manage leakage inductance energy through the second power converter. The clamp reset circuit normally includes a capacitor that is adapted to store energy from the first power converter and the second power converter.

Abstract: This aims to provide a signal status diagnosing device for an external control means, which is enabled even by a simple constitution to prevent the rise of a production cost due to the increase in a parts count or the complexity of a circuit constitution, and which can perform a signal status diagnosis of an actuator (the external control means) such as an electromagnetic valve, a lamp, a relay or a small-sized DC motor precisely. The signal status diagnosing device comprises a switch circuit connected with an intermediate tap disposed on the primary side of a transformer, for sending a driving electric power to the external control means disposed on the secondary side, in response to an ON/OFF signal of the external control means, and a means connected with the switch circuit and driven by the external control means, for measuring the primary side electric current to flow in a manner to correspond to the electric current to flow to the transformer secondary side.

Abstract: A voltage across a capacitor provides a supply voltage for circuits in an integrated circuit used to control a switching voltage regulator. The capacitor is charged during an OFF portion of a pulse width modulated (PWM) control signal that controls a first transistor in the switching voltage regulator. The voltage across the capacitor is controlled to be between a high threshold and a low threshold. The voltage is controlled by comparing the voltage across the capacitor to a low threshold and charging the capacitor during the OFF portion of the PWM signal if the voltage across the capacitor is below the low threshold. The voltage across the capacitor is compared to a high threshold and the capacitor is not charged if the voltage across the capacitor is above the high threshold.

Abstract: A controller is capable of executing direct couple control that directly couples a first power device and a second power device without causing a DC/DC converter to convert voltage. During the direct couple control, a drive signal that causes no voltage conversion is intermittently output to at least one of a plurality of switching devices.

Abstract: A pulse width modulation (PWM) control circuit is applied to a power converter with a charging capacitor. The PWM control circuit includes a PWM signal generator, a first comparator, and a reference voltage modulator. A PWM signal generator generates a PWM signal to control a power switch in the power converter. Two input terminals of the first comparator respectively receive a first reference voltage and a sensing voltage, which is proportional to a primary-side current of a transformer. When the power switch is turned on and the sensing voltage rises to the level of the first reference voltage, the first comparator outputs a first control signal to the PWM signal generator. Then, the PWM signal generator outputs a signal to turn off the power switch. The reference voltage modulator outputs the first reference voltage according to a feedback voltage relative to the output voltage of the power converter.

Abstract: A common-mode choke level-shifter drives a power switch with sub-nanosecond timing integrity without requiring a high-side gate-drive power supply. The same level-shifter may also be used to drive a low-side switch to avoid ground bounce effects.

Abstract: A multi-tasking power processor (104) for a vehicle electric system (100) is provided. The multi-tasking power processor (104) includes a low voltage direct current bus interface (201), a high voltage direct current bus interface (202), and a motor interface (203). The multi-tasking power processor (104) also includes converter circuitry (200) selectively configurable as a direct current boost converter and a direct current buck converter between the low voltage direct current bus interface (201) and the high voltage direct current bus interface (202). The multi-tasking power processor (104) is further configurable as a motor drive between the motor interface (203) and the high voltage direct current bus interface (202).

Abstract: A switching mode power supply and a method of operating the power supply in a power save mode. The switching mode power supply includes a first PWM controller and a second PWM controller that are driven by different driving voltages and control first and the second voltages to be output, respectively, a first transformer that is controlled by the first PWM controller to output the first voltage and having a primary coil, a secondary coil to induce the first voltage, and an auxiliary winding, and a rectifier that rectifies and smoothes a current flowing through the auxiliary winding of the first transformer, generates a power save mode voltage based on the respective driving voltages of the first and the second PWM controllers, and supplies the power save mode voltage to the first and the second PWM controllers. Accordingly, the power save mode is operated using a voltage difference without requiring an extra controller.

Abstract: A flyback converter circuit in accordance with an embodiment of the present application includes a DC input operable to receive a DC voltage from a DC voltage source, a transformer including a primary coil and a secondary coil, a primary switch operable to selectively connect the primary coil to the DC input, a controller operable to provide a control signal to turn the primary switch ON and OFF, wherein the primary coil is connected to the DC input when the primary switch is ON, a delay device operable to delay an ON pulse of the control signal provided to the primary switch such that the primary switch is turned on after a delay of a predetermined period of time and a secondary switch connected in series with a capacitor and controlled by the control signal from the controller, wherein the secondary switch and the capacitor are connected in parallel with the primary switch.

Abstract: A power supply, which outputs a plurality of voltages in order to improve the cross regulation between output voltages and at the same time reduce the amount of electric power consumed, and an image forming device having the same are disclosed. The power supply includes a power converter, which generates a first output power source and a second output power source in response to an external power supply and a power control signal, respectively; a power output part, which includes output parts to rectify and smooth each of the first and second output power sources; a first output controller, which receives the first output power source feedback from the power output part to generate the power control signal; and a second output controller, which receives the second output power source feedback from the power output part to control to operate the power output part in stable mode.

Abstract: The Power Conversion Unit includes a single stage rectifier circuit that generates a DC voltage which is stored on a first capacitor. A circuit arrangement connected to the first capacitor monitors the DC voltage at the capacitor and other predefined signals to generate signals for smoothing ripples associated with the DC voltage and maintains the DC voltage at a predefined level for a predefined time interval. The holdup and smoothing voltages are generated by developing and storing a high voltage on a second capacitor. A switching device connected to the second capacitor causes energy to flow from the second capacitor into the primary winding of a transformer whose secondary winding are switched to deposit the energy stored in said transformer onto the first capacitor. A circuit for charging the second capacitor is also provided.

Abstract: A power control system includes a current transformer to step down a switch current of a switching power converter. In at least one embodiment, the stepped down current is received by a switching power converter controller. Since the current is received by the controller, the current is not converted into a voltage prior to receipt by the controller in order for the controller to monitor an inductor current of the switching power converter. In at least one embodiment, the controller compares the stepped down switch current with a reference current. In at least one embodiment, the controller includes a voltage converter to convert the switch current into a voltage within the controller. The controller compares the voltage representing the switch current with a reference voltage. The controller can use the current or voltage comparisons to control power factor correction and output voltage regulation of a switching power converter.