Abstract: A DC-DC converter for generating an output voltage from input voltage, includes: an output stage for outputting the output voltage; an error amplifier having an input and a reference input for receiving a feedback voltage at the input in accordance with the output voltage and for receiving a reference voltage at the reference input, the error amplifier generating an amplified voltage for driving the output stage, the amplifier voltage corresponding to the difference between the feedback voltage and the reference voltage; a phase compensation unit for generating a phase compensation component to the feedback voltage; and a phase compensation controller for controlling the phase of the phase compensation unit; wherein the feedback voltage determined by the output voltage plus said phase compensation component.

Abstract: A drive circuit includes a first transistor coupled in series with a second transistor at a first intermediate node coupled to a load. An amplifier has an output driving a control terminal of the second transistor. The amplifier includes a first input coupled to a second intermediate node and a second input coupled to a reference voltage. A feedback circuit is coupled between the first intermediate node and the second intermediate node. A slope control circuit is coupled the second intermediate node. The slope control circuit injects a selected value of current into the second intermediate node, that current operating to control the output of the amplifier in setting a slope for change in voltage at the first intermediate node.

Abstract: A power converter includes a power module, a feedback module, and a control module. The power module is used for converting an input voltage into an output voltage. The feedback module is electrically connected with the power module for generating a feedback voltage according to the output voltage. The control module is electrically connected with the feedback module and the power module for comparing a reference duty cycle value with a duty cycle, generating a variable reference voltage according to the comparison between the reference duty cycle value and the duty cycle, comparing the variable reference voltage with the feedback voltage, and adjusting the duty cycle according to the comparison between the variable reference voltage and the feedback voltage.

Abstract: A DC/DC converter includes a switch mode converter for providing an output voltage based on an input voltage and a drive signal generator configured to provide a drive signal for the switch mode converter. The drive signal generator is configured to switch between a non-pulse-skipping mode and a pulse-skipping mode. Moreover, the drive signal generator is configured to adapt a setting of a pulse generation such that a length of a first pulse following a pulse skipping is larger than a minimum length of a pulse in the non-pulse-skipping mode.

Abstract: A regulator device includes: a power input terminal; a power output terminal; a plurality of regulators each including an operating FET and a monitoring FET to be driven together with the operating FET, the plurality of regulators being arranged in parallel between the power input terminal and the power output terminal; and a controller configured to drive the operating FET and the monitoring FET included in one of the regulators, when the controller determines whether the monitoring FET included in the one of the regulators have degraded, the controller configured to stop driving the operating FET and the monitoring FET included in the one of the regulators and configured to drive the operating FET and the monitoring FET included in another of the regulators.

Abstract: A current detection circuit for detecting a current in a SMPS which has a first switch and a second switch; a current sensing circuit sensing a second switch current flowing through the second switch and providing a current sensing signal; and a current emulation circuit which generates a first current according to the current sensing signal and generate a second current according to the first current source, and the current emulation circuit further providing a current emulation signal based on the first current source and the second current source; wherein a current detection signal during a first period is proportional to the current emulation signal, and the current detection signal during a second period is proportional to the current sensing signal.

Abstract: A current mode controlled power converter controllable in a digitally processing current mode even during an on time. In the power converter, each control period based on a reference signal includes a slope calculation period in which a slope compensation signal for the control period is calculated by a slope compensation unit. During each slope calculation period, the slope compensation unit negates the slope compensation signal calculated previous to the control period including the slope calculation period, and a reset signal generation unit compares a current detection signal detected by a current detection unit with a current instruction set to an error signal generated by an error signal generation unit to generate a reset signal.

Abstract: Aspects of the invention provide a switching power supply that exhibits an improved conversion efficiency. In aspects of the invention, a load condition detecting circuit sets a threshold voltage for determining the magnitude of the load on the DC-DC converter based on the maximum value of the output voltage of the power factor correction converter in a suspended period of the power factor correction converter. An operation permission signal is delivered when a feedback voltage that indicates the magnitude of the load of the DC-DC converter exceeds the threshold voltage. When the feedback voltage exceeds a threshold voltage that is set at a value higher than the threshold voltage, the operation permission signal is delivered.

Abstract: A voltage regulator circuit includes a soft start module, a pulse width modulation (PWM) module, and a voltage regulator module. The soft start module is used to receive a current feedback voltage corresponding to an input current, and compare the current feedback voltage with a comparison voltage, so as to output a switching signal. The PWM module is used to receive a clock signal and the switching signal, and determine a first PWM signal and a second PWM signal outputted by the PWM module is a high voltage level or a low voltage level according to the clock signal and the switching signal. The voltage regulator module is used to receive and adjust an output voltage corresponding to the first PWM signal and the second PWM signal.

Abstract: A control circuit of a power converter includes: a zero current detection circuit for detecting a current flowing between an inductor and a voltage output terminal of the power converter to generate a zero current detection signal; an adjusting circuit for generating an adjustment signal according to the zero current detection signal; a clock signal generating circuit for adjusting a frequency of a clock signal according to the adjustment signal; a periodical signal generating circuit for generating a periodical signal according to the clock signal; an error detection circuit for generating an error signal; and a control signal generating circuit for generating a control signal to control operations of a power switch. If the and amount of pulses generated by the zero current detection circuit satisfy a predetermined condition, the adjusting circuit switches the power converter's operation mode from DCM to CCM.

Abstract: In a control circuit that controls an interleaved power supply, a clock generator generates a clock pulse having a predetermined frequency. A signal doubler generates a master switch on-interval pulse signal indicating information concerning an on-interval of the master switch based on the clock pulse and a master drive pulse signal that drives the master switch, and generates a doubled duty pulse signal having a duty that is double that of the master switch on-interval pulse signal. An edge pulse generator generates a first edge pulse signal based on the master drive pulse signal, and generates a second edge pulse signal based on the doubled duty pulse signal. A slave drive pulse signal generator generates, based on the first and second edge pulse signals, a slave drive pulse signal that drives the slave switch so that an on-interval of the slave switch is identical to that of the master switch.

Abstract: A control device controls a switching converter. The converter has an input alternating supply voltage, a regulated direct voltage on the output terminal, and a switch connected to an inductor. The control device controls the closing and opening time period of said switch for each cycle and receives a first input signal representative of the current flowing through one element of the converter. The control device comprises a counter configured to count a time period, a comparator configured to compare said first input signal with a second signal, digital control block configured to control the closing and opening of said switch and to activate said counter to start the counting of said time period when the said first input signal crosses said second signal, with said switch being closed. The digital control block is configured to open the switch when the counter finishes the counting of said time period.

Abstract: A light-emitting diode driving apparatus including a rectifying circuit, a switching element, a choke coil, an output current sensing circuit, an LED light source, a rectifier diode, a control circuit, and a feedback sensing circuit which is connected to the output current sensing circuit for receiving an output feedback signal output from the output current sensing circuit, wherein the feedback sensing circuit outputs a feedback dummy signal, and outputs to the control circuit a control signal that controls switching of the switching element in response to a signal based on an error between the output feedback signal and the feedback dummy signal.

Abstract: The transient response of an output voltage to a load fluctuation is improved, in a switching power source that carries out a PWM control. In a DC-DC converter wherein a switching element of an output stage is controlled by a drive signal, whose pulse width is set at a minimum value, output from a PWM signal generating circuit based on an output voltage output from an error amplifier in accordance with the difference between a feedback voltage in accordance with an output voltage of the output stage and a reference voltage, there is provided a minimum pulse width detector circuit that supplies a current to a phase compensation capacitor when the pulse width of the drive signal is at the minimum value, thus preventing the output voltage from dropping below a value corresponding to the minimum value when the load fluctuates, and improving transient response characteristics of the output voltage.

Abstract: A voltage generating unit generates a standard output voltage and sends to a voltage output side. A voltage detection unit detects a voltage of the voltage output side and informs a voltage gain control unit. When the voltage of the voltage output side is decreasing due to a dynamic load, the voltage gain control unit is configured to control the voltage generating unit to increase a gain of a voltage generated by the voltage generating unit, and the voltage generated by the voltage generating unit is lower than the standard output voltage. Then, the voltage gain control unit is configured to control the voltage generating unit to decrease the gain of the voltage generated by the voltage generating unit, and the voltage generated by the voltage generating unit is equal to the standard output voltage.

Abstract: A fuel cell system includes: a converter disposed between a fuel cell and a load to increase an output voltage of the fuel cell; and a control unit that controls the converter at a predetermined duty ratio, wherein the control unit determines a duty command value for the converter from a feed-forward duty and a feed-back duty which are calculated using a command value of a reactor current that flows through a reactor in the converter and/or using a measurement value of the reactor current. In a low-load operation, the control unit sets, as a measurement value of the reactor current, a value obtained by multiplying a midpoint measurement value measured at an intermediate time of an on-duty period by a predetermined coefficient.

Abstract: A DC-DC controller is provided. The DC-DC controller is connected to an output stage and a load, and the output stage is connected to the load through an output inductor. The DC-DC controller includes an error amplifier, a pulse width modulation (PWM) generation circuit and a compensation circuit. A first input terminal of the error amplifier is connected to one terminal of the output inductor. A second terminal of the error amplifier receives a reference voltage. The PWM generation circuit is connected to the error amplifier and provides a PWM signal to the output stage. The compensation circuit is at least connected to an output terminal of the error amplifier. The compensation circuit includes an adjustable capacitor circuit. The adjustable capacitor circuit adjusts an equivalent capacitance value according to a change of the load dynamically, so as to speed up a reaction rate in the transient response.

Abstract: A power conversion apparatus is disclosed. The power conversion apparatus includes a power transistor, a thermal resistor and a temperature detection circuit. A control terminal of the power transistor receives a control signal. The power transistor converts an input voltage into an output voltage according to the control signal. The thermal resistor has a negative temperature coefficient. The temperature detection circuit generates the control signal and provides a driving current to the control terminal of the power transistor according to the control signal. The temperature detection circuit further generates an over temperature protection signal according to the driving current.

Abstract: A light fixture includes a converter operable to drive a light source of the light fixture. The buck converter is operable to provide a predetermined average current to the light source or load. A switch of the buck converter is located in the low side of the buck converters such that a controller of the buck converter may drive the switch directly without the use of an isolation transformer. The buck converter controls operation of the switch based on current through the switch and current through the primary inductor of the buck converter.

Abstract: An embodiment of a method includes generating a regulated output signal from a regulated intermediate signal in response to a reference signal and the regulated output signal, and generating the regulated intermediate signal from an input signal in response to the regulated output signal and the regulated intermediate signal. By generating one regulated signal (e.g., a regulated output voltage) from another regulated signal (e.g., a regulated intermediate voltage), the magnitude of the ripple component of the one regulated signal may be reduced. Furthermore, by generating the regulated intermediate signal in response to the regulated output signal, the efficiency of the regulation may be increased.

Abstract: A control circuit for controlling one or more power switches of a power converter includes a voltage control loop and a current control loop. The control circuit is configured to generate a current reference for the current control loop using the voltage control loop and an AC reference signal. The control circuit is configured to operate in at least a first mode in which a parameter of the voltage control loop is sampled only at every other zero crossing of the AC reference signal and the sampled parameter is used to generate the current reference for the current control loop. The power converter may be an AC-DC converter or a DC-AC converter (i.e., inverter). Alternatively, the voltage control loop may be sampled at every zero crossing of the AC reference signal, and/or more frequently during transient load conditions.

Abstract: In a clock-based soft-start circuit configured to generate a soft-start reference voltage that restrains an inrush current at an initialization of power supplied to a DC-DC converter, the clock-based soft-start circuit comprises a time setting unit configured to set a soft-start time period in response to a clock signal. A ramp circuit is configured to generate a soft-start reference voltage which is ramped upward or downward between a base level and a reference voltage level during the soft start time period set by the time setting unit. In this manner, the clock-based soft-start circuit is applicable for all DC-DC converters and the soft-start in a linear slope is possible.

Abstract: Two hysteresis levels, a high level and a low level, may be used to set a period (and the switching frequency) of the output voltage of a DC-DC converter, as well as the output ripple of the converter. These two thresholds may be changed using pairs of switches. By controlling the sequence and the duration of the on-time of the switches, spectral spurs in the output can be controlled and the amplitude and the frequency band of interest can be reduced. Additional spur reduction may be possible by randomizing the control of the switches.

Abstract: Power control circuits and methods are disclosed, suitable for a power supplier. A power control circuit has a clock generator, a phase controller and a power limiter. The clock generator provides a clock signal, substantially determining switching cycles of a power supply. The phase controller outputs a burst signal based on a group reference signal and a burst initiation signal, and makes a burst period corresponding to a burst signal not less than a group reference period corresponding to the group reference signal. The burst signal is capable of switching the power supplier between a switching state and a non-switching state. The power limiter limits the power transferred by the power supply in every switching cycle, during a burst-up duration after the power supply is switched from the non-switching state to the switching state. The burst initiation signal correlates to an output voltage of the power supplier.

Abstract: A step-down regulator comprising a pseudo constant on time control circuit is disclosed, comprising an on-time generator configured to receive a switching signal provided by the step-down regulator and a control signal provided by the pseudo constant on time control circuit, and generates an on-time signal; a feedback control circuit configured to receive a feedback signal representative of the output voltage of the step-down regulator and generate an output signal; and a logic control circuit coupled to the on-time generator and the feedback control circuit to receive the on-time signal and the output signal and generating the control signal, and a power stage configured to receive an input voltage and the control signal and generate the switching signal.

Abstract: Systems and methods that provide control circuits having multiple sub-control inputs that control operation of a power electronics device (e.g., a power converter). Each of the multiple sub-control inputs are output from a separate sub-control circuit that includes a feedback circuit having an input tied to a common control node. The common control node is coupled to an input of a controller (e.g., a PWM controller). Outputs of each of the sub-control circuits are coupled to the common control node by a respective switch (e.g., diode, transistor, etc.) so that each of the sub-control circuits may be selectively coupled to the common control node to provide a control signal to a controller. Since components of each of the feedback compensations circuits are biased at a regulation voltage instead of a higher power supply voltage, the control circuit may switch between control modes with minimal delay.

Abstract: A synchronous DC-DC converter having a soft-stop function includes an output stage for supplying an output voltage, wherein the output stage includes a high-side transistor for charging the output voltage and a low-side transistor for discharging the output voltage; an output control circuit, coupled to the output stage, for controlling the high-side transistor and the low-side transistor of the output stage; at least one protection device, for controlling the high-side transistor to be turned off when a specific situation occurs, in order to stop supplying the output voltage; and a soft-stop control circuit, coupled to the output control circuit, for controlling the low-side transistor of the output stage to be turned on when the protection device controls the high-side transistor to be turned off or the synchronous DC-DC converter is disabled, in order to discharge the output voltage.

Abstract: The multi-channel power supply comprises a first channel, a second channel, a current sensing module, a current average control circuit, and a modulator. The first channel and the second channel respectively transform an input voltage into an output voltage according to a first pulse width modulation (PWM) signal and a second PWM signal. The current sensing module respectively sense a first channel current and a second channel current to output a first sensing current and a second sensing current. The current average control circuit generates a first error current and a second error current according to the first sensing current and the second sensing current and an average current thereof. The modulator generates the first PWM signal and the second PWM signal according to the first error current, the second error current and the output voltage.

Abstract: A controller used in a buck-boost converter includes a clock generator, an error amplifying circuit, a comparing circuit, a proportional sampling circuit, a logic circuit, a pulse width increasing circuit, first and second driving circuits. Based on a clock signal generated by the clock generator, the proportional sampling circuit samples the difference between a current sensing signal and a compensation signal generated by the error amplifying circuit, and generates a proportional sampling signal. The pulse width increasing circuit generates a sum control signal based on the proportional sampling signal and a logic control signal generated by the logic circuit, wherein a modulation value adjusted by the proportional sampling signal is added to the pulse width of the logic control signal to generate the pulse width of the sum control signal. The first and second driving circuits generate driving signals based on the sum control signal and the logic control signal.

Abstract: Methods and systems are described for providing power factor correction for high-power loads using two interleaved power factor correction stages. Each power factor correction stage includes a controllable switch that is operated to control the phasing of each power factor correction stage. The phasing of output current from the second power factor correction stage is shifted 180 degree relative to the output current from the first power factor correction stage.

Abstract: The present disclosure is directed to a voltage-to-current sensing circuit having a bias terminal configured to receive a reference voltage, an offset terminal configured to receive an offset current, and an operational amplifier configured to output a low voltage signal. The device includes a first amplifier having first and second high voltage inputs configured to receive a first voltage difference across a sense component on a high voltage line and to generate a first current, a second amplifier having first and second low voltage inputs configured to receive a second voltage difference between the bias terminal and the offset terminal and to generate a second current, a summing circuit configured to provide an intermediate voltage corresponding to a sum of the first and the second currents, and a low-voltage transistor coupled to an output of the amplifier and controlled by the intermediate voltage to generate the output current.

Abstract: Circuits and processes for detecting a peak value of an input signal are disclosed. In one example, a peak detector circuit may sample a line sense signal, determine the peak value of the line sense signal during a search window, and output a peak detection signal representative of the determined peak value. In a first mode, the peak detector circuit may cause the peak detection signal to be representative of the determined peak value from an immediately preceding search window. In a second mode, the peak detector circuit may cause the peak detection signal to follow the sampled line sense signal. The peak detector circuit may operate in the second mode in response to the sample of the line sense signal being greater than a peak value of the line sense signal from an immediately preceding search window by more than a threshold amount.

Abstract: A DC/DC converter arrangement includes an input terminal to receive a supply voltage, an output terminal to provide an output voltage and a switching arrangement, including a coil and at least two switches to provide a Buck-Boost conversion. The arrangement further includes a current detection circuit which is coupled to the switching arrangement for sensing a coil current and a comparator, including a first input which is coupled to the output terminal and a second input which is coupled to an output of the current detection circuit. An output of the comparator is coupled to the switching arrangement. Furthermore, the arrangement includes a ramp generator which is coupled to the first or the second input of the comparator.

Abstract: A power supply system including switched-mode power supply circuitry configured to generate a DC output voltage from a DC input voltage and soft-start feedback circuitry configured to control the switched-mode power supply circuitry to generate a predefined output voltage during a soft-start period of operation. The soft-start feedback circuitry includes a controllable current source configured to generate a reference current and a reference voltage, wherein the reference current is based on a difference between the reference voltage and a feedback voltage proportional to the output voltage, and amplifier circuitry configured to compare the feedback voltage with the reference voltage and generate a control signal to control the operation of the switched-mode power supply during a soft-start period of operation.

Abstract: A power converter used in the current control circuit and control method, consisting of a converter, a voltage divider circuit, a current sampling circuit, a first gain circuit, a differential amplifier, a second gain circuit, a multiplier, a saw tooth wave generator, a modulation comparator, and a driver. The invention samples inductor current through the current sampling circuit and generates the current sense signal, then processes again. With the differential amplifier, it compares the feedback voltage from the voltage divider circuit with the reference voltage, and the results along a modulation comparator output a drive signal to control the duty cycle in order to avoid the generation of inrush current. The present invention avoids inrush current caused by the large drive signal and achieves a good response rate and better system stability.

Abstract: In a switching power supply device which intermittently executes a switching operation, a power loss which occurs in resumption of the switching operation is reduced. A semiconductor device works as a control circuit for the switching power supply device, and includes: an intermittent oscillation control circuit which alternately gives an instruction for execution and suspension of the switching operation of a switching element; a bottom detecting circuit which detects a bottom of a ringing voltage that develops when the switching element is OFF; a bottom-monitoring time period timing circuit which times a bottom-monitoring time period starting as soon as the instruction for the execution of the switching operation is given; and a turn-on control circuit which turns ON, before the timing of the bottom-monitoring time period ends, the switching element only when the bottom of the ringing voltage is detected.

Abstract: A ripple-control switched-mode power supply includes a control circuit to switch on/off a drive switching element. The control circuit includes a simulated voltage generation circuit that smoothes a voltage at a node connecting the drive switching element and an inductor and that generates a simulated voltage corresponding to an output voltage; a timer that measures a time corresponding to an input voltage and the simulated voltage; a voltage comparison circuit that compares a feedback voltage and a predetermined voltage; and a control pulse generation circuit that generates a control pulse having a pulse width corresponding to the time based on outputs from the timer and the voltage comparison circuit. The control circuit varies the pulse width of the control pulse in accordance with a variation in the input voltage to maintain a constant switching cycle.

Abstract: A power factor correction circuit includes a first series circuit, a second series circuit, a smoothing capacitor, and a reactor. The power factor correction circuit further includes an input voltage detector that detects an input voltage of at least one end of an AC power source based on one end on a ground side of the smoothing capacitor, and a current detector that detects a reactor current from the AC power source, the current detector having a transformer in which the reactor is a primary side, and first and second switching elements are controlled based at least partially on a reactor current detection signal that is output in accordance with the reactor current from a secondary side of the transformer to supply a desired DC voltage to a load circuit.

Abstract: A DC-DC converter and a voltage conversion method thereof are provided. The DC-DC converter includes an output unit, a control unit and a trigger unit. The output unit converts an input voltage into an output voltage. The control unit generates a control signal according to the input voltage, an output feedback voltage related to the output voltage and a reference voltage, so as to make the output unit generate the output voltage. The trigger unit generates a first trigger signal according to the control signal, the output feedback voltage and the reference voltage. When the output feedback voltage is less than the reference voltage by a preset voltage, the control unit controls the output unit to perform a voltage-regulating process to the output voltage in advance.

Abstract: A buck converter comprises a switching unit configured to control a connection between a power terminal and a load terminal, a PWM controller configured to provide a PWM signal to the switching unit, and a control signal generator configured to generate a first control signal and a second control signal based on a current flowing to the load terminal, wherein the first control signal controls generation of the PWM signal and the second control signal controls a pulse width of the PWM signal.

Abstract: A modulator with balanced slope compensation including a control network, a slope compensation network, an offset network and an adjust network. The control network receives a feedback signal indicative of an output voltage and provides a loop control signal. The slope compensation network develops a slope compensation signal. The offset network determines a DC offset of the slope compensation signal. The adjust network combines the DC offset, the slope compensation signal and the loop control signal to provide a balanced slope compensated control signal. The DC offset may be determined as a peak of the slope compensation signal. The slope compensation signal may be developed based on the output voltage and a pulse control signal, in which the pulse control signal is developed using the balanced slope compensated control signal.

Abstract: A multi-phase DC-DC power converter is provided, which includes a pulse width modulation (PWM) controller and a plurality of output stage circuits. The plurality of output stage circuits converts an input voltage into an output voltage. The PWM controller includes a feedback circuit and a PWM generation module. The feedback circuit outputs a trigger signal according to the output voltage and a ramp signal. The PWM generation module at least generates a first PWM signal and a second PWM signal. In addition, a waveform of the first PWM signal partially overlaps a waveform of the second PWM signal at a logic high level.

Abstract: A voltage converting apparatus is disclosed. The voltage converting apparatus includes a pulse width modulation (PWM) signal generating circuit, a power transistor, a first inductor, a second inductor and a feedback rectifier. The PWM signal generating circuit receives a feedback power to be an operating power and generates a PWM signal. A first terminal of the power transistor receives an input voltage, and a control terminal of the power transistor receives the PWM signal. The second inductor couples with a voltage on the first inductor and generates a coupling voltage. The feedback rectifier rectifies the coupling voltage to generate a feedback power.

Abstract: A controller with a multi-function pin, adapted to control a converting circuit according to a control signal for converting an input voltage into an output voltage, is disclosed. The controller has the multi-function pin, an enable unit, an over-current detecting unit and a logic control unit. The enable unit is coupled to the multi-function pin for receiving an enable signal and activates the controller in response to the enable signal. The over-current detecting is coupled to the multi-function pin and determines an over-current value according to an over-current set resistance coupled between the multi-function pin and a voltage source. The over-current detecting unit generates an over-current protection signal according to the over-current value and a current flowing through the converting circuit. The logic control unit determines whether executing an over-current protection according to the over-current protection signal.

Abstract: The present invention includes a load-adaptive power generator including a feedback detecting module, a load determining module, a load driving module, and a control module. The feedback detecting module detects a load voltage of a load device, and converts the load voltage into a feedback voltage. The load determining module determines whether the feedback voltage is within a preset range for generating a periodical load driving signal. The load driving module has a plurality of driving units and at least one switch. The driving units drive the load device according to the load driving signal, and at least one driving unit receives the load driving signal through the switch. The control module turns on the switch when the frequency of the load driving signal is less than a frequency threshold. Accordingly, the load-adaptive power generator of the present invention can save energy.

Abstract: A switching power supply apparatus includes: an input terminal; an output terminal; a switching element; an input and output converting unit which converts input voltage applied through the switching element into output voltage to supply output power to a load; an output voltage feedback unit which outputs a feedback signal, based on the output voltage; a switch current detecting unit which detects current flowing through the switching element; an oscillating frequency setting unit which sets the switching frequency of the switching element, based on the feedback signal; a peak current setting unit which controls turn-off of the switching element by setting a current threshold such that a switch current peak (i) is constant regardless of a change in the output power and (ii) increases as the input voltage increases; and a switching control unit which controls switching operation of the switching element.

Abstract: A power conversion system and method includes a DC-DC converter and an auxiliary circuit configured to ensure that a minimum input voltage is provided to the DC-DC converter during power interruption and for at least a predetermined hold-up time period. The auxiliary circuit includes an energy storage device, an auxiliary energy source for charging the energy storage device, and a clamping circuit to limit the energy stored by the energy storage device to a threshold voltage. A discharge time of the energy storage device from the threshold voltage to the minimum voltage thereby exceeds the predetermined hold-up time, but is only incrementally greater such that the size of the energy storage device is substantially reduced. The auxiliary energy source may typically be a current source, with the clamping circuit being control logic effective to disable the current source as a voltage across the storage device approaches the threshold.

Abstract: A pulse width modulation (PWM) power conversion system has improved efficiency over a wide operating input voltage and load range. Being able to measure relative efficiency of an analog PWM system allows enhanced control while maintaining the benefits of analog control. An analog low pass filter produces an average value of the PWM pulse train, then this analog average value is converted into digital values with an analog-to-digital converter and stored so that relative efficiencies of the PWM power conversion system may be compared for various combinations of operating parameters.

Abstract: A constant on-time controller, comprising a ripple generator, a comparing circuit and a logic control circuit, is provided. The ripple generator generates a ripple signal, which is injected into one of a voltage reference signal and a voltage detection signal to form a ripple modulated signal with ripple information. The comparing circuit compares the ripple modulated signal with the other of the voltage reference signal and the voltage detection signal and accordingly generates a comparison result signal. The logic control circuit generates a control signal with a fixed pulse width according to the comparison result signal. The ripple generator has a level modulation circuit for modulating an amplitude of the ripple modulated signal to make the amplitude within an preset range under different applications.

Abstract: Circuits and methods to detect a threshold for entering and leaving a discontinuous current mode of a buck converter have been disclosed. A buck converter is switched to continuous mode if the filtered battery current has reached a defined threshold current Ithccm. In order to expedite the transition from DCM mode to CCM mode the time delay between two or more pulses of a current through an inductor is monitored and the buck converter is switched to CCM mode if this time delay is smaller than a defined threshold.