Abstract: A switching power supply circuit with synchronous rectification has an energy storage component, a SR switch coupled to a secondary side of the energy storage component, and a secondary control circuit. The secondary control circuit has a turning-ON control circuit for providing a turning-ON control signal based on a comparison of a drain to source sensing voltage of the SR switch and a turn ON threshold, a mode determination circuit for providing a mode signal to determine a turn ON delay based on a detection to a transient event or the drain to source sensing voltage ringing of the SR switch, and a gate driver circuit for driving the SR switch. When the turning-ON control signal is asserted, the gate driver circuit charges a gate voltage of the SR switch after the turn ON delay based on the mode signal, to turn ON the SR switch.

Abstract: A multi-converter switching power supply includes a first switching converter with a first output capacitor, a second switching converter with a second output capacitor, a bypass switch coupled across the second output capacitor, and a bypass control circuit for controlling the bypass switch. Input terminals of the first and switching converters are coupled in parallel, while output terminals of the first and switching converters are coupled in series to provide a total output voltage to a load. When detecting that the second output voltage approaches a negative voltage, the bypass control circuit turns on the bypass switch, so as to protect the second output capacitor from being damaged by a reverse DC voltage.

Abstract: An isolated switching converter has a primary switch and a control circuit. The control circuit has a first sampling circuit, a second sampling circuit, a compensation circuit and a feedback control circuit. The first sampling circuit is coupled to an auxiliary winding of a transformer to receive a voltage on the auxiliary winding and is configured to generate a first feedback signal having an alternating current signal indicative of an output voltage. The second sampling circuit is coupled to the auxiliary winding through a first rectifier and is configured to generate a second feedback signal having a direct current signal indicative of the output voltage. The compensation circuit is configured to generate a compensation signal based on the first feedback signal, the second feedback signal and a reference threshold. The feedback control circuit is configured to generate a primary control signal of the primary switch based on the compensation signal.

Abstract: A control circuit and control method for an interleaved switching converter having a first and second interleaved voltage regulating circuit. The control method is: controlling a first switch of the first voltage regulating circuit operating in quasi-resonant mode, turning ON a second switch of the second voltage regulating circuit after the first switch is turned ON for a half switching period, generating a current sensing signal by detecting a current flowing through the second switch, generating a peak signal, wherein the peak signal is adjusted when a voltage across the second switch is higher than a voltage reference at the time the second switch is turned ON, and turning OFF the second switch when the current sensing signal increases to the peak signal.

Abstract: A control circuit used in a resonant converter with a switching circuit and a resonant circuit is provided, the switching circuit has a high side transistor and a low side transistor, the resonant circuit has a resonant capacitor and a resonant inductor. The control circuit includes: a calculating module used to generate an output current calculating value based on a voltage across the resonant capacitor and a correction signal at an off moment of the high side transistor; a comparing module used to compare the output current calculating value with a burst mode threshold value and generate a burst mode control signal by comparing the output current calculating value with the burst mode threshold value; and a switching control module used to control the resonant converter to work in a burst mode or a normal mode based on the burst mode control signal.

Abstract: A test method of a voltage regulator having a plurality of parameters that need to be set, the test method includes: receiving a user requirement on a computer; generating a plurality of setting combinations of the plurality of parameters, the plurality of parameters has different combination of values in different setting combinations; downloading the plurality of setting combinations to the voltage regulator via a first I/O bus and configuring the voltage regulator with each setting combination; configuring communication between a controller provided by the computer and measurement devices; executing the communication between the controller and the measurement devices via a second I/O bus; and displaying test result of each configured voltage regulator on the computer.

Abstract: A control circuit of a zero current controlled dimming circuit having a high side power switch, a low side power switch and an inductor, having: an error circuit, providing a compensation signal based on a reference signal and a current sense signal indicative of an output current; a compensation circuit, providing a compensation off time signal based on the compensation signal and a peak value sample and hold signal indicative of a peak value of an inductor current; and a control signal generating circuit, providing a low side switch control signal to control the low side power switch based on the compensation off time signal, wherein after the inductor current decreases to zero, the low side power switch maintains on for a compensation off time period determined by the compensation off time signal.

Abstract: A switching power supply circuit with synchronous rectifier has an energy storage component, a rectifier switch coupled to a secondary side of the energy storage component, and a secondary side control circuit. The secondary side control circuit provides a driving signal to control the rectifier switch. When the drain-source voltage across the rectifier switch is less than a first threshold value, the secondary side control circuit controls the driving signal to be a maximum voltage to control the rectifier switch being fully on for a predetermined duration. After a predetermined duration, the secondary side control circuit adjusts the voltage of the driving signal based on the drain-source voltage across the rectifier switch and a second threshold value.

Abstract: A power converter includes a first and a second transformers having different auxiliary winding voltage levels. A bias voltage supply circuit generates a bias supply voltage of an integrated circuit used to control the power converter, and includes a first and a second bias supply branches jointly coupled to a supply capacitor to provide the bias supply voltage. When the bias supply voltage is higher than a threshold voltage, the first bias supply branch to receive the one with lower level of the two auxiliary winding voltages is switched from a deactivation state to an activation state to provide the bias supply voltage, when the bias supply voltage is less than the threshold voltage, the second bias supply branch to receive the one with larger level of the two auxiliary winding voltages is switched from the deactivation state to the activation state to provide the bias supply voltage.

Abstract: A switching power supply circuit with synchronous rectification has an energy storage component, a SR switch coupled to a secondary side of the energy storage component, and a secondary control circuit. The secondary control circuit has a turning-ON control circuit for providing a turning-ON control signal based on a comparison of a drain to source sensing voltage of the SR switch and a turn ON threshold, a mode determination circuit for providing a mode signal to determine a turn ON delay based on a detection to a transient event or the drain to source sensing voltage ringing of the SR switch, and a gate driver circuit for driving the SR switch. When the turning-ON control signal is asserted, the gate driver circuit charges a gate voltage of the SR switch after the turn ON delay based on the mode signal, to turn ON the SR switch.

Abstract: A control circuit used in a resonant converter with a switching circuit and a resonant circuit is provided, the switching circuit has a high side transistor and a low side transistor, the resonant circuit has a resonant capacitor and a resonant inductor. The control circuit includes: a calculating module used to generate an output current calculating value based on a voltage across the resonant capacitor and a correction signal at an off moment of the high side transistor; a comparing module used to compare the output current calculating value with a burst mode threshold value and generate a burst mode control signal by comparing the output current calculating value with the burst mode threshold value; and a switching control module used to control the resonant converter to work in a burst mode or a normal mode based on the burst mode control signal.

Abstract: A switching power supply circuit has an energy storage component, a synchronous rectifier switch and a synchronous rectifier control circuit. The synchronous rectifier switch is coupled to a secondary side of the energy storage component, and the synchronous rectifier control circuit turns ON the synchronous rectifier switch based on a drain-source voltage across the synchronous rectifier switch when a primary switch is judged as turned ON. When the switching power supply circuit is not operating in a preset mode, the primary switch is judged as turned ON when the drain-source voltage remains larger than a dynamic reference voltage during a preset window time period, and when the switching power supply circuit is operating in the preset mode, the primary switch is judged as turned ON once the drain-source voltage is larger than the dynamic reference voltage.

Abstract: In some embodiments, the present invention provides tissue compositions including a first silk scaffold comprising a plurality of epithelial cells, a second silk scaffold comprising a plurality of stromal cells, and a plurality of neurons. In some embodiments, provided compositions can function as physiologically relevant corneal model systems for, inter alia, testing of therapeutics for corneal disease and/or injury and production of functional corneal tissue (e.g., for transplant, etc). The present invention also provides methods for making and using provided compositions.

Abstract: Input AC voltage sensing for a flyback circuit. The flyback circuit is configured as “primary-high”, namely a primary switch of the flyback circuit is positioned “high” to receive an input AC voltage through a first rectifying circuit. A primary winding of the flyback circuit is coupled to a primary ground reference. A voltage sensing circuit has a processing circuit and a first sensing resistor. The processing circuit has a first terminal coupled to the input AC source through a second rectifying circuit, a second terminal coupled to the primary ground reference and an output terminal. The processing circuit subtracts a voltage at the second terminal from a voltage at the first terminal to obtain a differential voltage, which is then sampled and held as an input AC voltage sensing signal.

Abstract: An example method for cutting a plurality of lenticules from a donor cornea includes receiving a donor cornea, cutting a first layer of a first set of lenticules from the donor cornea, and cutting a second layer of a second set of lenticules from the donor cornea. The lenticules are cut according to a pattern that to maximizes the number of lenticules, thereby maximizing the number of implants from the single donor cornea. An example implant handling device includes a body. The body includes a flattened end configured to receive a corneal implant and keep the corneal implant from rolling or folding. The flattened end has a width and a height, the width being greater than the height. The body includes a slit opening to the flattened end, the slit opening configured to allow the corneal implant to pass into the flattened end.

Abstract: A test method of a voltage regulator having a plurality of parameters that need to be set, the test method includes: receiving a user requirement on a computer; generating a plurality of setting combinations of the plurality of parameters, the plurality of parameters has different combination of values in different setting combinations; downloading the plurality of setting combinations to the voltage regulator via a first I/O bus and configuring the voltage regulator with each setting combination; configuring communication between a controller provided by the computer and measurement devices; executing the communication between the controller and the measurement devices via a second I/O bus; and displaying test result of each configured voltage regulator on the computer.

Abstract: A switching power supply circuit with synchronous rectifier has an energy storage component, a rectifier switch coupled to a secondary side of the energy storage component, and a secondary side control circuit. The secondary side control circuit provides a driving signal to control the rectifier switch. When the drain-source voltage across the rectifier switch is less than a first threshold value, the secondary side control circuit controls the driving signal to be a maximum voltage to control the rectifier switch being fully on for a predetermined duration. After a predetermined duration, the secondary side control circuit adjusts the voltage of the driving signal based on the drain-source voltage across the rectifier switch and a second threshold value.

Abstract: A switching power supply circuit has an energy storage component, a synchronous rectifier switch and a synchronous rectifier control circuit. The synchronous rectifier switch is coupled to a secondary side of the energy storage component, and the synchronous rectifier control circuit turns ON the synchronous rectifier switch based on a drain-source voltage across the synchronous rectifier switch when a primary switch is judged as turned ON. When the switching power supply circuit is not operating in a preset mode, the primary switch is judged as turned ON when the drain-source voltage remains larger than a dynamic reference voltage during a preset window time period, and when the switching power supply circuit is operating in the preset mode, the primary switch is judged as turned ON once the drain-source voltage is larger than the dynamic reference voltage.

Abstract: A switching power supply circuit with synchronous rectifier has an energy storage component, a rectifier switch coupled to a secondary side of the energy storage component, and a secondary side control circuit. The secondary side control circuit provides a driving signal to control the rectifier switch. When the drain-source voltage across the rectifier switch is less than a first threshold value, the secondary side control circuit controls the driving signal to be a maximum voltage to control the rectifier switch being fully on for a predetermined duration. After a predetermined duration, the secondary side control circuit adjusts the voltage of the driving signal based on the drain-source voltage across the rectifier switch and a second threshold value.

Abstract: A synchronous switching converter with an energy storage component and a synchronous rectifier coupled to the energy storage component, having: a secondary control circuit configured to receive a slew rate threshold adjusting signal and a voltage across the synchronous rectifier, and to provide a secondary control signal; wherein the secondary control circuit detects a slew rate of the voltage across the synchronous rectifier, and maintains the synchronous rectifier being off when the slew rate of the voltage across the synchronous rectifier is lower than a slew rate threshold.