Abstract: We describe a switch mode power supply having a power input, a switch, a transformer, and a power output. The transformer has a primary winding coupled to said power input via said switch, and a secondary winding coupled to said power output. The transformer further comprises an auxiliary winding and a coupling structure capacitatively coupled to said secondary winding of said transformer; wherein said coupling structure does not comprise a shield or screen between said primary and secondary windings. The switch mode power supply further comprises a coupling capacitor connected between said coupling structure and said auxiliary winding to provide a noise suppression voltage from said auxiliary winding to said secondary winding to at least partially cancel a common mode noise voltage on said secondary winding from unshielded coupling from said primary winding.

Abstract: The present invention reduces switching noise generated in a switching control device having a switching element such as a switching power supply in linear linkage with the state of a load of the output and without increasing the control circuit scale which is a factor of cost increase. The present invention adopts a configuration of a control circuit having an ON/OFF circuit that controls the switching element such that one or both of two specified values (upper limit and lower limit) that specify triangular waves of a triangular wave generation circuit that specifies a drive oscillating frequency of the switching element is/are changed in linear linkage with the output load state.

Abstract: A power factor correction circuit (42/44) responsive to an input power supply signal at an input supply voltage (VAC) that varies largely sinusoidally with time at a fundamental supply frequency contains regulator/control circuitry (60, 62, and 64) for measuring and removing overtones (ILDm or IFWRm) in the input supply current (ILD) or in a rectified form (IFWR) of the input supply current. Each overtone is expressible as the product of an amplitude component (Im) and a sinusoidal function (Im sin [(m+1)?ACt]) that varies with time at an integer multiple of the fundamental supply frequency. The regulator/control circuitry measures an overtone by determining the overtone's amplitude component. After generating an adjustment factor (SADJ) largely as the product of that overtone's amplitude component and an associated sinusoidal function, the regulator/control circuitry adjusts the input supply current or its rectified form by an amount corresponding to the adjustment factor for each measured overtone.

Abstract: A resonant switching power converter having burst mode transitioning operates during low or zero load conditions with reduced audible noise and component stresses, while improving efficiency. Pulse bursts are generated with a beginning and/or ending pulse duration that differs from mid-burst pulse durations, in order to reduce an amplitude of transients otherwise generated at the beginning and/or end of the bursts. Alternatively, the spacing between the pulses at the beginning and/or end of the bursts may differ from the spacing between the pulses in the middle of the bursts to reduce the transient(s). A number of pulses at the beginning and/or end of the burst can also be set with gradually varying durations, to further reduce component stress and audible vibration in a transformer that couples the resonant tank to the output of the converter.

Abstract: The present invention provides a dynamic switch power conversion circuit to improve the efficiency of a solar cell array, and specifically to operate the solar cell array under various sunlight intensities, especially under low light conditions. In an embodiment of the invention, the dynamic switch power conversion circuit comprises: a processor to continuously monitor the power output of a solar panel under varying sunlight conditions, and a switching converter circuit comprising a plurality of circuit operations for different optimum power conversion. The processor gathers the output power from the solar panel and then uses predetermined power curves related to maximum generated power versus sunlight conditions of that particular solar panel to switch the switching converter circuit to a circuit operation particular suited to that sunlight condition to achieve the maximum power generated from the solar panel.

Abstract: A current supply circuit provides current that is substantially invariant with voltage supply and temperature changes. The current supply circuit has an input node connectable to a voltage supply and an output node operable to provide an output current. The current supply circuit includes a current source circuit coupled to a reference voltage node and configured to provide the output current at the output node, wherein a voltage at the reference voltage node controls current output of the current source circuit. The current supply circuit also includes a reference-setting circuit coupled to the reference voltage node and operable to establish a reference current level of the current source circuit, a common-emitter circuit coupled to the input node, and an emitter-follower circuit coupled to the input node, the emitter-follower circuit having an input coupled to an output of the common-emitter circuit and an output coupled to the reference voltage node.

Abstract: A power supply having an specified hold-up time to take a input voltage and convert it to an output voltage, comprising: a first power stage to receive the input voltage; a second power stage to generate the output voltage and an output current; an intermediate charge storage device coupled between the first and second power conversion stages providing an intermediate output voltage in response to the input voltage; and a controller that controls the intermediate output voltage according to a voltage function that is associated with the hold-up time.

Abstract: The present invention provides a system and method for operating a rechargeable battery, the system comprising: current maintaining device for maintaining a predetermined current to the rechargeable battery until the rechargeable battery reaches a predetermined maximum voltage; voltage maintaining device for maintaining a predetermined voltage to the rechargeable battery until a predetermined minimum current is delivered to the rechargeable battery; determining device for determining a cyclical charge value delivered to the rechargeable battery by the current maintaining device and the voltage maintaining device during a cycle; and a correction device for correcting the determining device when charge is not being delivered to the rechargeable battery, on the basis of the charge value.

Abstract: In one embodiment, an SMPS includes a rectifier for generating an input DC voltage from an input AC voltage. A switching transistor is coupled to a primary coil of a transformer for generating power which is transferred to a second side of the transformer according to an operation of the switching transistor. A switching controller receives a feedback voltage corresponding to an output voltage, a sensing signal corresponding to a current flowing through the switching transistor, and a first signal corresponding to a voltage difference between a first electrode and a second electrode of the switching transistor. The switching controller controls an on/off operation of the switching transistor. The switching controller sets a threshold period whenever the first signal has a value greater than a reference value, thereby setting a plurality of threshold periods during operation of the switching mode power supply.

Abstract: Multiple switching transistors are provided in parallel. An output circuit includes an inductor, an output capacitor, and a rectifying device. A pulse modulator generates a pulse signal with the duty ratio adjusted such that the output voltage of a switching regulator approaches a predetermined target value. A driver distributes a pulse signal to the multiple switching transistors, and switches the multiple switching transistors to the ON state in a time divisional manner.

Abstract: A power supply device comprises a driver circuit, a transistor switch, and a first transistor. The driver circuit is configured to provide a stable driving signal and a floating driving signal. The transistor switch has a first terminal, a second terminal connected to a first terminal of the driver circuit, and a third terminal connected to a second terminal of the driver circuit, and is configured to prevent a reverse current based on the floating driving signal. The first transistor has a first current electrode connected to the first terminal of the transistor switch, a second current electrode connected to the first voltage reference, and a control electrode connected to the third terminal of the driver circuit, and is configured to activate and deactivate based on the stable driving signal, and further configured to regulate an input voltage to a substantially constant direct current output voltage.

Abstract: Switching regulator circuits and methods are provided for regulating output voltage that include an adjustable minimum peak inductor current level and adjustable burst comparator hysteresis for Burst Mode operation in switching regulators. Control over minimum peak inductor current level and burst comparator hysteresis is achieved during Burst Mode operation by allowing external user control of the burst threshold level and the burst comparator hysteresis. A single user-accessible input pin, two user-accessible input pins, or three user-accessible input pins may be used to distinguish between forced continuous and Burst Mode operations, set a burst threshold level, and set a burst comparator hysteresis during Burst Mode operation. The present invention may be applied to buck, boost, buck-boost, or any other suitable regulator circuit configuration. The present invention also may be employed with synchronous and non-synchronous switching regulators.

Abstract: A controller for a multi-level converter regulates the DC midpoint voltage of the multi-level converter by accounting, for the effect non-redundant switch states have on the DC midpoint current. The controller includes a DC bus regulator that monitors the DC output voltage and generates in response a commanded voltage vector. The duty cycle calculator is operably connected to receive the commanded voltage vector generated by the DC-bus regulator and to generate in response to the commanded voltage vector duty cycles associated with non-redundant switch states. The DC midpoint regulator is operably connected to receive the non-redundant duty cycles calculated by the duty cycle calculator and to generate in response a first midpoint current command that accounts for the effect the non-redundant switch states have on the midpoint current.

Abstract: A piezoelectric transformer type high-voltage power source apparatus to control an output voltage from a piezoelectric transformer to a load, and an image forming apparatus including the same, the piezoelectric transformer type high-voltage power source apparatus including: an output voltage detection unit to compare the output voltage with an output control voltage, and to output a digital value according to the comparison; and a driving control unit to control a driving frequency and a duty rate of the piezoelectric transformer according to the digital value. Accordingly, the piezoelectric transformer type high-voltage power source apparatus can stably perform frequency and duty rate control without experiencing an abnormal oscillation or uncontrollable state due to a manufacturing irregularity of particular components and/or a change in temperature, and a high voltage can be output within a short rise time.

Abstract: Decrease in a voltage supplied to a load caused by load fluctuations is minimized. A pulse frequency modulated signal generating unit 13 outputs a signal PFMOUT having a pulse frequency modulated according to a voltage supplied to the load 20. A pulse width modulated signal generating unit 14 outputs a signal PWMOUT having a pulse width modulated according to a voltage supplied to the load 20. In a state where the signal PFMOUT is selected, a selection unit 17 refers to a determination result of a frequency determining unit 15 and selects the signal PWMOUT as on/off signal for a semiconductor switch 11 when a low-level period in one cycle of the signal PFMOUT is not more than a predetermined time period. In a state where the signal PWMOUT is selected, the selection unit 17 selects the signal PFMOUT as on/off signal for the semiconductor switch 11 when a voltage determining unit 16 detects that a DC voltage (VOUT) at the load 20 exceeds a predetermined voltage.

Abstract: An apparatus for detecting a switching current of the power converter, wherein the apparatus includes a signal generation circuit, a sample-and-hold circuit, and a calculating circuit. The signal generation circuit generates a sample signal in accordance with the pulse width of a switching signal. The sample-and-hold circuit is coupled to receive the sample signal and switching current signal for generating a first current signal and a second current signal. The calculating circuit is coupled to receive the first current signal and the second current signal for generating output signals. The switching signal is used for switching the magnetic device of the power converter, and the switching current signal is correlated to the switching current of the power converter; the output signals are correlated to the value of the switching current of the power converter.

Abstract: One aspect of the invention relates to a voltage regulation process as well as to a voltage regulation system. A first voltage, present at an input of the voltage regulating system, is changed into a second voltage, which can be tapped at an output of the voltage regulation system, with a first device for generating an essentially constant voltage from the first voltage, or a voltage derived from it. A further device is provided for generating a further voltage from the first voltage or a voltage derived from it, in particular a voltage which can be higher than the voltage generated by the first device.

Abstract: A power generation circuit generates and stores electric power utilizing electromagnetic wave energy. The power generation circuit has one of an antenna or a coil that receives an electromagnetic wave. A rectifying circuit is formed on a silicon substrate and rectifies a signal from the antenna or the coil. A storage circuit stores an output power obtained from the rectifying circuit for driving a load. A MOS transistor has a source and a drain connected to an output of the storage circuit and the load, respectively, so that the load is connected to the storage circuit in accordance with a threshold voltage of the MOS transistor.

Abstract: The invention relates to a power converter for converting a first electrical power signal into a second electrical power signal having an output voltage Vout with a DC component comprising a control circuit (320) arranged for measuring the output voltage Vout and controlling the operation of the power converter in dependence thereof. The control circuit (320) comprises voltage level shifting means (326) for generating a measurement voltage signal V2 by adjusting the DC component of the output voltage Vout.

Abstract: A power supply having a maximum power point tracking function that controls power switching so that a detected power value is within a reference range having a maximum power point in a predetermined current-voltage curve includes: a converter section switching input power and converting the switched input power into predetermined DC power; and a maximum power point tracking section detecting a power value determined according to a switching operation of the converter section among power values included in a predetermined power-voltage curve, and controlling the switching operation of the converter section so that the detected power value is located within a predetermined reference range having a maximum power value among the power values included in the power-voltage curve.