Abstract: The present invention discloses a synchronous rectification control circuit, comprising at least one switch unit, a pulse width control unit, a transformer, a first rectification unit, a second rectification unit, a plurality of driving units, a logic operation unit and a signal transmission unit. The logic operation unit is used for receiving a working cycle signal generated by the pulse width control unit. When the working cycle signal is changed, the signal transmission unit transmits a switching signal for changing the working conditions of the first and second rectification units at a secondary side of the transformer, so as to switch the first and second rectification units before the switch unit operates and prevent possible short circuits or overlaps.

Abstract: A controller for a driving circuit of power source comprises a frequency generator, a pulse width modulator, and a driving device. The frequency generator comprises a latch circuit. The frequency generator provides a pulse signal at a first frequency after the controller is started. After the frequency generator receives an indicating signal, the frequency generator changes the frequency of pulse signal from the first frequency to a second frequency and locks the frequency of pulse signal at the second frequency. The pulse width modulator provides a PWM signal according to the pulse signal and a feedback signal which indicates a status of electric power supply of the driving circuit. The driving device controls semiconductor switches according to the PWM signal.

Abstract: A comparing circuit and a control loop are used to maintain the peak level of current flowing through an inductor of a flyback converter. An inductor switch control signal controls an inductor switch through which the inductor current flows. The inductor current increases at a ramp-up rate during a ramp time and stops increasing at the end of the ramp time. The comparing circuit generates a timing signal that indicates a target time at which the inductor current would reach a predetermined current limit if the inductor current continued to increase at the ramp-up rate. The control loop then receives the timing signal and compares the target time to the end of the ramp time. The pulse width of the inductor switch control signal is increased when the target time occurs after the end of the ramp time. Adjusting the pulse width controls the peak of the inductor current.

Abstract: A digital high voltage generating apparatus and a method thereof are provided where a switching block controls voltage generated in a second side coil of a power transformer, a digital interface block provides a communication interface, and a digital controlling block controls intermittence of the switching block. The digital controlling block includes a switching section width computing unit for computing a switching section width of the switching block, a frequency counting unit for computing a count value corresponding to a half period of an output voltage of the digital controlling block, and a switching time point determining unit for determining a switching time point of the switching block based on the computed switching section width and the count value. Improved protection of a switch from damage, by a reduction in heat-generation quantity in the switch, is one of the achieved advantages.

Abstract: There is provided a power supply for AC/DC and DC/DC conversion which receives the DC power supplied from airplanes, vehicles and vessels as well as normal AC power, and converts the power to DC power and supplies it to portable electronic products. The power supply for AC/DC and DC/DC conversion includes an AC input 10, a DC input 20, a switch 30 for selecting AC input power or DC input power, a DC output 40, and a circuit used for AC/DC and DC/DC conversion 100 which converts the power input from the AC input or the DC input to DC power having predetermined values of current and voltage, and a secondary side of a transformer (TL) for AC/DC conversion inside the circuit for conversion serves as an inductor for performing DC/DC conversion.

Abstract: A system and method for a bridgeless power supply is disclosed. The bridgeless power supply includes a digital control module that controls a first switch, a second switch, and a transistor, thereby the bridgeless power supply rectifies an alternating current (AC) variable input voltage and regulates a direct current (DC) output voltage. The digital control module applies a first and second control signal to the first and second switches thereby rectifying and regulating the AC variable input voltage. Additionally, the digital control module provides a high frequency and constant duty cycle third control signal to the transistor in series with an output transformer of the bridgeless power supply device, to assure primary-to-secondary isolation.

Abstract: A control arrangement (1) for a voltage converter for converting a first DC voltage (UBAT) into a second DC voltage (U-G) comprises a first input (3) that is provided for coupling to a means of sensing a first current (I1) on the primary side of the transformer (11). The output of the control arrangement (1) is coupled to a control terminal (17) of a transistor (16) that can be connected in series with the primary side of the transformer (11). The control arrangement (1) furthermore comprises a computing unit (2), provided for giving the transistor (16) a low value of resistance during a switched-on phase (T-ON), and a high value of resistance during a switched-off phase (T-OFF). The control arrangement (1) furthermore incorporates a first comparator (42) for comparing a value of the first current (I1), or a value derived from the value of the first current (I1), with an adjustable setpoint value (SO1).

Abstract: A method is disclosed for generating pulse width modulated pulse control signals for controlling switches in a switching power supply. First, a count value is determined of a master clock within a switching cycle of the power supply from beginning to end thereof. A separate state machine providing for each edge in each of pulse control signals and each is operated to generate the associated edge as a function of the sum of a fixed reference count value from the beginning of the switching cycle and a determined count value when the sum is determined to equal the actual count value.

Abstract: In one embodiment, a power factor correction circuit is configured to use a stored value of a feedback signal to assist in regulating the value of an output voltage and to bypass the sample and hold circuit if the output voltage increase to an upper limit or decreases to a lower limit.

Abstract: A charging circuit has a battery 12, switching element 14, and resistor 16 for current detection arranged on the primary side of transformer 10. Diode 18 and capacitor 20 for storing electric power are arranged on the secondary side of transformer 10. In a normal state, the ON/OFF states of switching element 14 are repeated corresponding to output signals U1, U2 of two comparators 28, 30. However, if switching element 14 stays on or off longer than a prescribed period of time for some reason, the status of switching 14 will be switched forcibly by an auxiliary sequence of the logic parts in control logic 42.

Abstract: A DC/DC converter includes: a boost converter that boosts an input voltage in accordance with a first control signal; an insulated converter that converts an output of the boost converter in accordance with a second control signal; a current sensor that detects an output current of the insulated converter; a first controller that generates the first control signal based on an error between the output current detected by the current sensor and a first threshold value; and a second controller that generates the second control signal based on an error between the output current detected by the current sensor and a second threshold value that is larger than the first threshold value.

Abstract: A closed loop power converter circuit of a UPS or other power supply includes a pulse width modulator circuit in a forward path of the closed loop power circuit. A compensation circuit provides pulse width commands to the pulse width modulator at a first rate. A feedback circuit digitally filters samples of an output of the closed loop power converter at a second rate greater the first rate and that provides the filtered samples to the compensation circuit. In some embodiments, the compensation circuit may be operative to compensate for the phase lag associated with a low pass output filter.

Abstract: A control method for controlling a switching power supply circuit has a control circuit including a setting device that limits the exciting current of a transformer at the time of changeover from a switching delay to a switching period. The setting value set by the setting device is changed slowly to prevent the exciting current of transformer from changing rapidly and to reduce the excitation noise of transformer, and the setting value is changed gradually to prevent the output voltage from lowering even when the load becomes heavier than a certain value during the light load operation. The control method facilitates reducing the electric power consumption of the switching power supply circuit under a light load, reducing the transformer excitation noise and preventing the output voltage from lowering when the load is light.

Abstract: The present invention discloses a power supply device for outputting a stable programmable power supply, which comprises a transformer disposed at a DC output end of the power supply device, and a clamp circuit connected to a secondary current of the transformer. Since the clamp circuit is disposed on the secondary current of the transformer, therefore it does not require a high DC voltage to drive the clamp circuit. The clamp circuit can release the high voltage produced when the metal oxide semiconductor field effect transistor (MOSFET) is off, and thus reducing the high voltage borne by the MOSFET to enhance the reliability of the MOSFET. Additionally, the present invention can prevent the transformer from being saturated due to magnetic leakage, inductance, and stored energies released or eliminated from the transformer.

Abstract: A power converter using a microcontroller is disclosed herein. In one embodiment, the power converter can be a digital flyback or forward converter. The microcontroller may have a digital pulse-width-modulation (PWM) controller, arithmetic logic unit (ALU) core, internal random access memory (RAM), read-only memory (ROM), and one or more analog-to-digital (A/D) and digital-to-analog (D/A) converters. For a fast dynamic response in an inner current control loop, an analog comparator is used to provide analog-based current control. The analog comparator may compare a signal representative of the current flowing in the power converter against a voltage reference, which can be programmable. The analog comparator may be integrated with the digital microcontroller into single integrated circuit (IC) chip. Furthermore, the power converter can send signals for the status of various conditions (e.g., output voltage levels, current levels, errors, etc.) or can receive signals for system control commands (e.g.

Abstract: A method of regulating voltage at an output of a switching power converter includes sensing an output voltage feedback signal; comparing the sensed feedback signal to a reference at a determined time during a cycling of the switch; and regulating the output voltage by either enabling or inhibiting cycling of a switch by a cycle of a drive signal produced by pulse generation circuitry in response to an output of the comparison.

Abstract: A method of regulating voltage at an output of a switching power converter, the converter comprising a switch and pulse generation circuitry, the pulse generation circuitry producing one or more drive signals for cycling the switch ON and OFF, wherein if the switch is cycled ON and OFF according to a cycle of a drive signal, power is transferred from a source to a load. The method includes sensing an output voltage feedback signal, comparing the sensed feedback signal to a reference at a determined time during a cycling of the switch, and regulating an output voltage at the load by controlling whether a cycle of one of the drive signals cycles the switch in response to the comparison.

Abstract: A power converter for delivering power from a source to a load includes a switch, pulse generation circuitry producing one or more drive signals for cycling the switch ON and OFF, wherein if the switch is cycled ON and OFF according to a cycle of a drive signal, power is transferred from the source to the load, a comparator for comparing a feedback signal approximating an output voltage at the load to a reference, and a controller coupled to the pulse generation circuitry for controlling which, if any, cycle of a drive signal cycles the switch in response to an output of the comparator.

Abstract: A converter for converting an input voltage (Ui) between a first supply terminal (1) and a second supply terminal (2) to an output voltage (U0), which converter includes switching means (S0) which, in the operating state of the converter, are alternately switched on and off under the control of a control signal (Vcntrl), an inductive element (T) which, in conjunction with the switching means (S0), forms a series circuit which is coupled between the first supply terminal (1) and the second supply terminal (2), a control circuit (CNTRL) for supplying the control signal (Vcntrl), and evaluation means (EVMNS) for evaluating a voltage (US) across the switching means (S0), which voltage (US) exhibits ringing, and for supplying the control circuit (CNTRL) with information causing the switching on of the switching means (S0) during a given valley of the voltage (US) across the switching means (S0).

Abstract: The present invention provides an apparatus and method for reducing the voltage stress in a single-stage single-switch (SSSS) converter by modulating the predetermined operating frequency of the converter lower responsive to increasing voltage stress. A control circuit (116) and associated cooperable frequency setting capacitance (CT) and resistance (RT) are coupled to the primary circuit (112) and the secondary circuit (114) of the SSSS converter via a switch (120). A frequency foldback device (180) is coupled to CT or RT and cooperable therewith to lower bus voltage stress by modulating the switch frequency. The operating frequency is modulated (i.e. reduced) from the predetermined operating frequency upon detection of a voltage threshold transition.

Abstract: Presented is a circuit and method capable to digitally control and, in particular, to control the switching of one or two MOSFETs used as rectifiers in switched mode power supply isolated topologies. Basic circuit implementation of the presented technique is also introduced. A controller has a fixed frequency square wave signal main clock input, generically switching from a low to a high value in two different time intervals. The controller has one or two square wave outputs, swinging from low to high in phase or in opposite with respect to the clock signal. The digital control method is able to generate output signals timed to anticipate output transitions from high to low level with respect to the clock signal transitions. In the control scheme, one or two other secondary inputs set the amount of anticipation time of the respective transitions of the outputs.

Abstract: A power supply control circuit connectable with an input power monitor that monitors an input power value to the power supply, an output power monitor that monitors an output power value from the power supply, and an output power controller that varies the output power value from the power supply, the power supply control circuit having an output power determiner that determines a determined output power value depending on the input power value and a power adjuster that adjusts the output power value to the determined output power value by controlling the output power controller.

Abstract: A converter for the conversion of an input voltage between a first supply terminal and a second supply terminal into an output voltage, including a switching means which in operation are turned on and off alternatively under control of a control signal, an inductive element which together with the switching means forms a series arrangement coupled between the firs supply terminal and the second supply terminal, a control circuit for supplying the control signal, and evaluation means for evaluating a voltage across the switching means, which voltage exhibits ringing, and for supplying an evaluation signal to the control circuit. The frequency of the control signal is approximately constant and is determined by an oscillator.