Abstract: Driver circuits to reduce or remove flicker of SSL devices are presented. A controller for a power converter which converts electrical power at an input voltage into electrical power at an output voltage is described. The controller is configured to determine whether the input voltage is greater or smaller than a pre-determined voltage threshold; to operate a first switcher stage to transfer electrical power from the input of the power converter to the output of the power converter, during a first time period when the input voltage is greater than the pre-determined voltage threshold; and to operate a second switcher stage to transfer electrical power from the reservoir capacitor to the output of the power converter, during a second time period when the input voltage is smaller than the pre-determined voltage threshold.

Abstract: A switching mode power supply (SMPS) includes a transformer having a primary winding for coupling to an input power source, a secondary winding for providing an output voltage of the SMPS, and an auxiliary winding. The SMPS also has a power transistor coupled to the primary winding and a primary side control circuit coupled to the auxiliary winding and the power transistor. The primary side control circuit is configured to regulate the output of the SMPS by controlling the power switch in response to a feedback voltage signal that is representative of an output of the SMPS. The SMPs also has a secondary-side control circuit coupled to the secondary winding and being configured to cause the output voltage of the SMPS to discharge when the output voltage of the SMPS is higher than a first reference voltage.

Abstract: A controller circuit for the control of a power converter is disclosed. An example controller circuit generates a waveform that drives a switch that controls the power converter. The controller circuit includes a divider module that generates a modification factor based on a ratio of the two input signals of the module. The circuit includes a module that generates a first waveform configured for a critical conducting mode of operation of a power converter and an on-time adjuster module that modifies the first waveform based on the modification factor and generates a second waveform. The second waveform is delivered to the switch. An example modification factor is the ratio of the output voltage to the rectified input voltage of the power converter.

Abstract: An example controller circuit includes a feedback sampling circuit, an oscillator, a drive logic, and a false sampling prevention circuit. The feedback sampling circuit generates a sample signal in response to a sampling of a feedback signal. The oscillator generates an on-time signal that transitions from a first logic state to a second logic state during each period of the on-time signal. The drive logic controls a switch to regulate the output of a power converter. The drive logic turns on the switch to end an off-time of the switch in response to the on-time signal transitioning from the first logic state to the second logic state. The false sampling prevention circuit prevents the on-time signal from transitioning from the first logic state to the second logic state to extend the off-time of the switch until a sampling complete signal indicates that sampling of the feedback signal is complete.

Abstract: A control circuit, a control method, and a power supply device are provided. The control circuit includes an obtaining module, adapted to obtain a voltage signal from a reverse surge current when the reverse surge current appears on a primary side of a switch power circuit of a synchronous rectification circuit; a maintaining module, adapted to continuously output a first control signal in a preset first time period when the voltage signal is greater than a preset first voltage threshold; and a control module, adapted to control and switch off switch tubes of the secondary side of the switch power circuit of the synchronous rectification circuit according to the first control signal. Thus, a reverse current surge of the switch power circuit of the synchronous rectification circuit can be effectively suppressed, and the safety of a switch power supply of the synchronous rectification circuit can be effectively protected.

Abstract: Common mode transient immunity for an isolation system is improved by using a common transient suppression circuit coupled to a receive circuit to suppress transients in signals received by the receive circuit that were transmitted from a transmit side of the isolation barrier using optical, magnetic, inductive, or other mechanisms.

Abstract: A LED driving circuit, a control circuit and associated current sensing circuit. The control circuit has a sensing circuit, an estimation circuit, an amplifying circuit, a comparing circuit, a zero-cross detection circuit and a logic circuit. The sensing circuit is configured to sense a switching current flowing through at least one switch of a switching circuit to provide a first sensing signal. The estimation circuit is configured to process the first sensing signal to provide a feedback signal, wherein the feedback signal is indicative of a average current signal flowing through a LED. An average current flowing through the LED is regulated by sensing a switching current flowing through at least one switch.

Abstract: A pulse modulator generates a pulse modulation signal SPM having a duty ratio which is adjusted according to a feedback voltage Vfb that corresponds to the output voltage VOUT of a DC/DC converter. A second oscillator generates a second cyclic signal which is asserted with each of a predetermined second period. A light load detection circuit generates a light load detection signal which is asserted when the feedback voltage Vfb becomes lower than a first threshold voltage. A driving circuit drives a switching transistor according to the pulse modulation signal SPM. Furthermore, the driving circuit suspends the driving of the switching transistor during a period until the second cyclic signal is next asserted after the light load detection signal is asserted.

Abstract: A switching power supply can reduce conduction noise when frequency spread control is conducted simultaneously with switching frequency reducing control. The switching power supply includes a frequency controller that controls the switching frequency of the switching element corresponding to a load condition and reduces the switching frequency in a light load period, a frequency spread modulator that modulates the switching frequency with a predetermined frequency spread width, and a frequency skipping controller that controls the frequency controller to skip a fundamental frequency of the switching frequency when the fundamental frequency becomes a predetermined threshold frequency.

Abstract: A circuit for controlling a latch mode of a pulse width modulation circuit includes a D flip-flop, a voltage generation unit, a comparator, and a logic unit. The D flip-flop generates a switch control signal according to a latch enable signal. The voltage generation unit generates a discharge current, and a voltage divider resistor group included in the voltage generation unit generates a first voltage when the voltage generation unit is turned on according to the switch control signal. A voltage of a predetermined pin of the pulse width modulation circuit is equal to a predetermined voltage when the discharge current is equal to the charge current. The comparator compares a reference voltage with the first voltage to generate a comparison signal. The logic unit generates a clear signal according to the comparison signal. The D flip-flop clears the switch control signal according to the clear signal.

Abstract: The embodiments herein describe a dynamic metal-oxide-semiconductor field-effect transistor (MOSFET) gate driver system architecture and control scheme. The MOSFET gate driver system dynamically adjusts both the gate driver turn-on-resistance and the gate driver turn-off resistance within a single (i.e., one) switching cycle to reduce electromagnetic interference (EMI) in the system and to minimize the conduction loss of a power MOSFET during operation.

Abstract: An integrated circuit controls a switch of a switching current regulator. The current regulator includes primary and secondary windings where a first and a second current flow, respectively. The switch is adapted to initiate or interrupt the circulation of the first current in the primary winding. The control integrated circuit includes a comparator configured to compare a first signal representative of the first current to a second signal and a divider circuit configured to generate the second signal as a ratio of a third signal, proportional to a voltage on the primary winding, with a voltage on a capacitor. The capacitor is charged by a further current controlled by the third signal when the second current is different from zero. The capacitor is discharged through a parallel-connected resistor when the value of said second current is substantially zero.

Abstract: A method can be used for controlling the switching operation of a switching power converter that includes a semiconductor switch coupled in series to an inductor. The switching power converter consumes an input current from a power supply and provides an output current to a load. In each switching cycle a switch-on time instant is detected for the semiconductor switch. The semiconductor switch is closed thus enabling, at the detected switch-on time instant, the input current passing through the semiconductor switch. The semiconductor switch is opened after a desired on-time, during which the input current rises from zero to a peak value, has passed. A time interval is detected, in which the instantaneous output current is not zero. A first value that represents the peak of the input current is obtained during the on-time.

Abstract: A converter and a driving method thereof are disclosed. The converter includes a transformer, a main switch, a clamp switch, and a switching controller. Here, the switching controller controls a turn-on time of the main switch and a turn-off time of the clamp switch corresponding to an output load.

Abstract: A controller of an isolated switching converter includes an error amplifying circuit, a modulation signal generator, a first comparison circuit, a primary off detection circuit, a secondary logic circuit, an isolation circuit and a primary logic circuit. The error amplifying circuit generates a compensation signal based on the difference between a reference signal and a feedback signal. The first comparison circuit compares the compensation signal with a modulation signal generated by the modulation signal generator and generates a first comparison signal. The primary off detection circuit detects whether the primary switch is off and generates a primary off detection signal. The secondary logic circuit generates a secondary control signal to control the secondary switch based on the first comparison signal and the primary off detection signal. The isolation circuit receives the first comparison signal and generates a synchronous signal electrically isolated from the first comparison signal.

Abstract: A control device for a DC-DC converter, which receives an input power and generates an output voltage, includes a first error amplifier for comparing a reference voltage signal and the output voltage to generate a feedback signal, a sampling and holding control circuit coupled to the first error amplifier for generating a reference current signal according to the feedback signal and an input current associated with the input power, a filter for receiving the input current associated with the input power and generating an average current value according to the input current, a second error amplifier coupled to the sampling and holding and the filter for comparing the reference current signal and the average current value before generating a control signal, and a switching control circuit coupled to the second error amplifier for generating a switching signal according to the control signal from the second error amplifier.

Abstract: The present invention relates to a switch control circuit, a power factor corrector including the same, and a driving method thereof. According to an exemplary embodiment of the present invention, a turn-on time of a power switch is controlled according to a zero crossing voltage to sense a voltage of both terminals of the power switch, and a turn-off time of the power switch is controlled according to a feedback voltage corresponding to the output voltage. At this time, the switching frequency of the power switch is sensed by the zero crossing voltage and the switching frequency is restricted by a predetermined threshold frequency.

Abstract: A PWM controller detecting temperature and AC line via a single pin and a power converter using the PWM controller, the PWM controller comprising: an output pin for providing a PWM signal; and a dual-function pin for receiving a temperature signal when the PWM signal is at a high level, and for receiving an AC line signal when the PWM signal is at a low level.

Abstract: A high-voltage power supply device includes: a piezoelectric transformer; a driving unit of the piezoelectric transformer; a detection unit configured to detect an output of the piezoelectric transformer; and a control unit configured to control the output of the piezoelectric transformer by giving a driving signal to the driving unit so that the output detected by the detection unit reaches a target value, wherein the control unit changes a frequency of the driving signal without changing a duty of the driving signal so as to set the frequency of the driving signal such that the output detected by the detection unit falls within a predetermined range including the target value, and after setting the frequency for the driving signal such that the output detected by the detection unit falls within the predetermined range, changes the duty of the driving signal so that the output detected by the detection unit reaches the target value.

Abstract: System and method for regulating a power conversion system. A system controller for regulating a power conversion system includes a first controller terminal and a second controller terminal. The system controller is configured to receive at least an input signal at the first controller terminal, and generate a gate drive signal at the second controller terminal based on at least information associated with the input signal to turn on or off a transistor in order to affect a current associated with a secondary winding of the power conversion system. The system controller is further configured to, if the input signal is larger than a first threshold, generate the gate drive signal at a first logic level to turn off the transistor.

Abstract: A controller for a switched mode power supply (SMPS) is provided. The SMPS is equipped with a transformer having a primary side winding, a secondary winding, and an auxiliary winding. The controller includes a detection circuit for detecting a transition from a first output load condition to a second output load condition of the SMPS and a control circuit coupled to the detection circuit and being configured to output one or more control signals in response to the detected output load transition. Depending on the embodiment, the one or more control signals include a first control signal for turning on a power switch to cause a current flow in a primary winding of the SMPS and/or one or more second control signals for turning off one or more functional circuit blocks in the controller.

Abstract: A controller of a switching power converter sets an actual turn-on time of a switch in the switching power converter in each switching cycle by selecting one of a plurality of valley points of the output voltage of the switching power converter occurring subsequent to the desired turn-on time of the switch. The desired turn-on time of the switch may be calculated according to the regulation scheme employed by the switching power converter. The controller selects one of the plurality of valley points randomly from switching cycle to switching cycle. The controller generates a control signal to turn on the switching power converter at the selected one of the plurality of valley points of the output voltage occurring subsequent to the desired turn-on time.

Abstract: A flyback-type switching power supply circuit provided with a transformer including a primary coil and a secondary coil, and a switching element connected to the primary coil, comprising: a multiplying circuit for multiplying a first value obtained by multiplying the on-duty ratio of a secondary current flowing to the secondary coil by a predetermined first constant, and a second value obtained by multiplying the peak value of a primary current flowing to the primary coil by a predetermined second constant; and a switching control circuit for controlling switching of the switching element so that the result of multiplication by the multiplying circuit and a third value obtained by multiplying a reference voltage by a predetermined third constant match; and the flyback-type switching power supply circuit is configured so that at least one of the first constant, the second constant, and the third constant is variable by an external signal.

Abstract: A primary side regulator according to an embodiment includes a power switch connected to a primary winding, a secondary winding configured to be insulated and coupled to the primary winding, a diode connected between the secondary winding and an output terminal, and an auxiliary winding coupled to the primary winding, and insulated and coupled to the secondary winding. The primary side regulator controls a switching operation of the power switch using a voltage obtained by filtering at least one of an estimation voltage signal corresponding to an output voltage of the output terminal and an estimation current signal corresponding to an output current flowing through the diode.

Abstract: Power conversion system and method. The system includes a first capacitor including a first capacitor terminal and a second capacitor terminal, a second capacitor including a third capacitor terminal and a fourth capacitor terminal, and a plurality of diodes including a first diode, a second diode, a third diode, and a fourth diode. The first diode is coupled to the second diode at a first node, the second diode is coupled to the fourth diode at a second node, the fourth diode is coupled to the third diode at a third node, and the third diode is coupled to the first diode at a fourth node. Additionally, the system includes a fifth diode including a first anode and a first cathode and a sixth diode including a second anode and a second cathode.

Abstract: A switching power supply apparatus includes a voltage step-up converter that increases input voltage in response to turning on and off of a switching element, a transformer including a primary winding and a secondary winding and the primary winding of which is connected to the output of the voltage step-up converter, a microcontroller that controls the turning on and off of the switching element, an input voltage detection circuit that detects input voltage of the microcontroller, and an intermediate bus voltage detection circuit that detects intermediate bus voltage from the microcontroller. The input voltage detection circuit and the intermediate bus voltage detection circuit are circuits including elements having the same specifications. The microcontroller controls the turning on and off of the switching element based on a result of calculation from voltage values detected by the input voltage detection circuit and the intermediate bus voltage detection circuit.

Abstract: A switching power converting apparatus includes a voltage conversion module, a detecting unit, and a switching signal generating unit. The voltage conversion module converts an input voltage into an output voltage associated with a secondary side current, which flows through a secondary winding of a transformer and is generated based on a switching signal. The detecting unit generates a detecting signal based on the output voltage and a predetermined reference voltage. The switching signal generating unit generates the switching signal based on the detecting signal and an adjusting signal so that the secondary side current is gradually increased during a start period of the switching power converting apparatus.

Abstract: A power converter having a current limit module and a method for controlling the power converter. The power converter converts an input voltage to an output voltage based at least on driving a main switch to switch on and off and regulates the output voltage through regulating a duty cycle of the main switch. The current limit module is configured to compensate a first current limit threshold indicative of a maximum allowable value of a peak value of a switching current of the main switch with a threshold compensation signal indicative of the duty cycle to provide a second current limit threshold. The second current limit threshold is used to limit the maximum value of the peak value, so that a maximum allowable output power of the power converter is substantially uninfluenced by the variation in the duty cycle.

Abstract: The present invention relates to a constant voltage constant current (CVCC) controller, and associated control methods. In one embodiment, a CVCC controller for a flyback converter can include: (i) a current controller configured to generate an error signal by comparing an output current feedback signal against a reference current; (ii) a voltage controller configured to receive an output voltage feedback signal and a reference voltage, and to generate a control signal; (iii) a selector configured to control the flyback converter to operate in a first or a second operation mode based on the control signal, and to further generate a constant voltage or a constant current control signal based on the error signal; and (iv) a pulse-width modulation (PWM) controller configured to generate a PWM control signal to control a main switch, and to maintain the output voltage and/or current of the flyback converter as substantially constant.

Abstract: The present invention discloses CVCC circuits and methods with improved load regulation for an SMPS. In one embodiment, the CVCC can include: a voltage feedback circuit to generate an output voltage feedback signal; a current feedback circuit to generate an output current feedback signal; a control signal generating circuit that receives the output voltage feedback signal and the output current feedback signal, and generates a constant voltage/constant current control signal; a first enable signal generating circuit that compares a first reference voltage and the constant voltage/constant current control signal to generate a first enable signal; and a PWM controller that generates a PWM control signal based on the constant voltage/constant current control signal to control a main switch of the flyback SMPS.

Abstract: Flyback converters are disclosed herein. An embodiment of a flyback converter includes a transformer having a primary side and a secondary side. A switch is connected to the primary side of the transformer, wherein the switch controls the current in the primary side of the transformer. A resistance is connected between the switch and a common node. The converter also includes a comparator having a first input and a second, the first input being connected between the switch and the resistor. Driver logic controls the state of the switch, wherein the output of the comparator is coupled to the driver logic. A voltage source is connected to the second input of the comparator. An error amplifier compares the voltage at the second input of the comparator to an adjustment voltage, the output of the error amplifier is coupled to the driver logic.

Abstract: Power conversion system and method. The system includes a first capacitor, a second capacitor, and a plurality of diodes including a first diode, a second diode, a third diode, and a fourth diode. Additionally, the system includes a fifth diode including a first anode and a first cathode and a sixth diode including a second anode and a second cathode. Moreover, the system includes a primary winding, and a secondary winding coupled to the primary winding. The first anode is connected to a first input terminal, and the second anode is connected to a second input terminal. The first input terminal and the second input terminal are configured to receive an input voltage. The secondary winding is configured to generate an output voltage based on at least information associated with the input voltage.

Abstract: System and method for regulating a power converter. The system includes a comparator configured to receive a first signal and a second signal and generate a comparison signal based on at least information associated with the first signal and the second signal. The first signal is associated with at least an output current of a power converter. Additionally, the system includes a pulse-width-modulation generator configured to receive at least the comparison signal and generate a modulation signal based on at least information associated with the comparison signal, and a driver component configured to receive the modulation signal and output a drive signal to a switch to adjust a primary current flowing through a primary winding of the power converter. The modulation signal is associated with a modulation frequency corresponding to a modulation period.

Abstract: An example controller circuit includes a feedback sampling circuit, an oscillator, a drive logic, and a false sampling prevention circuit. The feedback sampling circuit generates a sample signal in response to a sampling of a feedback signal. The oscillator generates an on-time signal that transitions from a first logic state to a second logic state during each period of the on-time signal. The drive logic controls a switch to regulate the output of a power converter. The drive logic turns on the switch to end an off-time of the switch in response to the on-time signal transitioning from the first logic state to the second logic state. The false sampling prevention circuit prevents the on-time signal from transitioning from the first logic state to the second logic state to extend the off-time of the switch until a sampling complete signal indicates that sampling of the feedback signal is complete.

Abstract: An embodiment provides a control method capable of controlling a switching-mode power supply to provide an output power source. The switching-mode power supply has a winding coupled to an input power source and controlled by a switch to be energized or de-energized. The maximum current peak through the winding is set to be a predetermined value. A discharge time of the winding in a switching cycle period is detected. The switching cycle period of the switch is controlled to keep the ratio of the discharge time to the switching cycle period as a constant.

Abstract: System and method for protecting a power converter. The system includes a first comparator configured to receive a first threshold signal and a first signal and to generate a first comparison signal. The first signal is associated with an input current for a power converter. Additionally, the system includes a second comparator configured to receive a second threshold signal and the first signal and to generate a second comparison signal. The second threshold signal is different from the first threshold signal in magnitude. Moreover, the system includes a first detection component configured to receive at least the second comparison signal, detect the second comparison signal only if one or more predetermined conditions are satisfied, and generate a first detection signal based on at least information associated with the detected second comparison signal.

Abstract: Provided are a power supply device and a method of controlling the same. The power supply device includes: a power factor corrector which corrects a power factor of an initial power; a standby power supply unit which is connected to the power factor corrector, the standby power supply unit including a transformer which converts an input power received from the power factor corrector; a sensor which detects a level of an induced power corresponding to the input power; and a power supply controller which determines whether the level of the induced power exceeds a critical value, activates the power factor corrector to correct the power factor of the initial power if the level of the induced power exceeds the critical value, and supplies a driving power to the system based on the level of the induced power.

Abstract: In one embodiment, a method of compensating for transmission voltage loss from a switching power supply, can include: (i) receiving a sampling signal that represents an output current of the switching power supply; (ii) delaying the sampling signal to generate a delayed sampling signal; (iii) converting the delayed sampling signal to generate a compensation signal; and (iv) regulating an output voltage of the switching power supply based on the compensation signal to compensate for the transmission voltage loss from the output voltage transmission to a load such that a voltage at the load is maintained as substantially consistent with an expected voltage at the load.

Abstract: A controller for use in a power converter includes an oscillator that generates a first signal that determines a duration of a switching cycle period of a switch included in the power converter. The controller also includes a logic circuit that generates a second signal to control switching of the switch in response to a feedback signal and in response to the first signal. The logic circuit generates the second signal to control a peak switch current of the switch during each switching cycle period according to either a first mode of operation or a second mode of operation. The peak switch current of the switch is varied in the first mode of operation in response to the feedback signal indicating that an output load is greater than a threshold and the peak switch current of the switch is kept at a constant value in the second mode of operation in response to the feedback signal indicating that the output load is less than the threshold.

Abstract: A switching power converter provides a communication link between a secondary side and a primary side of the switching power converter. During a messaging mode, the communication link enables information to be transmitted from an electronic device coupled to the secondary side to a controller on the primary side. The communication link may be used to transmit operating parameters related to powering the electronic device. The switching power converter may then adapt its switching operation to achieve different regulated output voltage and/or current to accommodate the detected electronic device.

Abstract: A method for controlling a synchronous rectifier for a power converter, a control circuit, and a power converter thereof are provided. The method comprises the following steps: turning on a transistor by a rectifier; generating a switching-period signal in accordance with a period of a voltage-sensing signal; generating a turn-on-period signal in accordance with a turned-on period of the rectifier; generating a first disabling signal responding to the switching-period signal; and generating a second disabling signal in response to the turn-on-period signal. The transistor is turned off in response to the first disabling signal and the second disabling signal, and the voltage-sensing signal is related to the switching waveform of a transformer.

Abstract: A switching power converter includes a controller configured to transition from a first operating mode to a second operating mode by determining the operating conditions at the transition point between the operation modes. The controller uses the value of the voltage-time product determined at the boundary between the first and second operating modes to predict the voltage to be applied to the primary-side of the transformer. Using the predicted voltage, the controller can adjust the peak-power control threshold on a cycle-by-cycle basis without the transformer reaching saturation.

Abstract: A secondary side synchronous rectification control circuit is disclosed. The control circuit includes an inverted amplifier, a first comparator, and a driving unit. The inverted amplifier has an input end for receiving a drain source voltage signal from a synchronous rectification transistor and outputting an inverted amplification signal. The first comparator receives the inverted amplification signal and a first reference voltage for outputting a first comparison signal. The driving unit receives the first comparison signal and generates a driving signal according to the first comparison signal, for controlling the conduction status of the synchronous rectification transistor. The drain source voltage of the synchronous rectification transistor in the present invention is inverted amplified by an inverted amplifier, and it is connected to a comparator for generating the driving signal. The errors and defects of the turn-off timing of the driving signal may be solved and eliminated.

Abstract: A power converter control circuit includes a ramp signal circuit, a blanking circuit, and a pulse driver circuit. The ramp signal circuit provides a ramp signal in response to a power converter feedback signal and an enable signal. The blanking circuit provides a blanking signal in response to the ramp signal and a clock signal. The blanking signal is provided when both the ramp signal is increasing in value and the enable signal indicates a light load operating condition. The pulse driver circuit provides a power switch control pulse in accordance with the clock signal and in the absence of the blanking signal.

Abstract: System and method for regulating a power conversion system. An example system controller for regulating a power conversion system includes a signal generator and a driving component. The signal generator is configured to receive a feedback signal associated with an output signal of a power conversion system and a current sensing signal associated with a primary current flowing through a primary winding of the power conversion system and generate a modulation signal based on at least information associated with the feedback signal and the current sensing signal. The driving component is configured to receive the modulation signal and output a drive signal to a switch based on at least information associated with the modulation signal.

Abstract: In one embodiment, an apparatus includes a sampling component. The sampling component receives a first voltage signal on a primary side of a transformer and monitors the first voltage signal to determine a voltage sampling time. The determined voltage sampling time is when the first voltage signal is used to estimate a second voltage level on a secondary side of the transformer. The first component further samples the first voltage signal at the voltage sampling time to determine a first voltage level. A second component outputs a control signal to control a switch to regulate the second voltage level based on the first voltage level.

Abstract: An example controller for a power converter includes a feedback sampling circuit, drive logic and a false sampling prevention circuit. The feedback sampling circuit is coupled to sample a feedback signal received from a terminal of the controller and to generate a sample signal representative of a value of the feedback signal. The drive logic is coupled to the feedback sampling circuit and coupled to control the power switch to regulate an output of the power converter in response to the sample signal. The false sampling prevention circuit is coupled to receive a sampling complete signal that indicates when the sampling of the feedback signal is complete. The false sampling prevention circuit is further coupled to the drive logic to extend the off time of the power switch until the sampling complete signal indicates that the sampling of the feedback signal by the feedback sampling circuit is complete.

Abstract: An example method of controlling a power supply to have a constant current output includes receiving an input current sense signal, an input voltage sense signal, and an output voltage sense signal. A control signal is then generated to control switching of a switch of the power supply to regulate an output current of the power supply. The generating of the control signal includes integrating the input current sense signal during a switching period of the control signal to generate an integrated signal representative of a charge taken from an input voltage source of the power supply. Generating the control signal also includes controlling the switching of the switch such that the integrated signal is proportional to a ratio of the output voltage sense signal to the input voltage sense signal.

Abstract: A controller for a switch and a method of operating the same. In one embodiment, the controller is configured to measure a voltage of a control terminal of the switch and select a first mode of operation if the voltage of the control terminal is greater than a threshold voltage, and a second mode of operation if the voltage of the control terminal is less than the threshold voltage.

Abstract: A secondary controller for use in a synchronous flyback converter includes a comparator, a drive circuit, and logic circuitry. The comparator is coupled to generate a compare signal in response to a comparison of a threshold to an input signal representative of a secondary winding voltage of the synchronous flyback converter. The drive circuit is coupled to generate a drive signal to control a first switch to be coupled to a primary side of the synchronous flyback converter. The drive signal is coupled to be generated by the drive circuit in response to a feedback signal representative of an output of the synchronous flyback converter. The logic circuitry is coupled to the drive circuit and coupled to the comparator. The logic circuitry is also coupled to generate a control signal to control a second switch in response to the drive signal and in response to the compare signal.