Abstract: System and method for protecting a power converter. An example system controller for protecting a power converter includes a signal generator, a comparator, and a modulation and drive component. The signal generator is configured to generate a threshold signal. The comparator is configured to receive the threshold signal and a current sensing signal and generate a comparison signal based on at least information associated with the threshold signal and the current sensing signal, the current sensing signal indicating a magnitude of a primary current flowing through a primary winding of a power converter. The modulation and drive component is coupled to the signal generator.

Abstract: System and method for providing at least an output current to one or more light emitting diodes. The system includes a control component configured to receive at least a demagnetization signal, a sensed signal and a reference signal and to generate a control signal based on at least information associated with the demagnetization signal, the sensed signal and the reference signal, and a logic and driving component configured to receive at least the control signal and output a drive signal to a switch based on at least information associated with the control signal. The switch is connected to a first diode terminal of a diode and a first inductor terminal of an inductor. The diode further includes a second diode terminal, and the inductor further includes a second inductor terminal.

Abstract: Systems and methods are provided herein for current regulation. An example system controller includes: a first controller terminal configured to receive an input voltage, the first controller terminal being further configured to allow a first current flowing into the system controller based at least in part on the input voltage in response to one or more switches being closed; a second controller terminal configured to allow the first current to flow out of the system controller through the second controller terminal in response to the one or more switches being closed; a fourth controller terminal coupled to the third controller terminal through a first capacitor, the first capacitor not being any part of the system controller; and an error amplifier configured to generate a compensation signal based at least in part on the current sensing signal, the error amplifier including a second capacitor.

Abstract: Systems and methods are provided for regulating a power converter. An example system controller includes: a driver configured to output a drive signal to a switch to affect a current flowing through an inductive winding of a power converter, the drive signal being associated with a switching period including an on-time period and an off-time period. The switch is closed in response to the drive signal during the on-time period. The switch is opened in response to the drive signal during the off-time period. A duty cycle is equal to a duration of the on-time period divided by a duration of the switching period. One minus the duty cycle is equal to a parameter. The system controller is configured to keep a multiplication product of the duty cycle, the parameter and the duration of the on-time period approximately constant.

Abstract: Systems and methods are provided for regulating power conversion systems. A system controller includes: a first controller terminal configured to receive a first signal related to an input signal for a primary winding of a power conversation system; and a second controller terminal configured to output a drive signal to a switch to affect a current flowing through the primary winding, the drive signal being associated with a switching period including an on-time period and an off-time period. The switch is closed (e.g., being turned on) in response to the drive signal during the on-time period. The switch is opened (e.g., being turned off) in response to the drive signal during the off-time period. A duty cycle is equal to a duration of the on-time period divided by a duration of the switching period. The system controller is configured to keep a multiplication product of the duty cycle and the duration of the on-time period approximately constant.

Abstract: System and method for dimming control of one or more light emitting diodes. An example system includes one or more signal processing components configured to receive a first signal associated with a TRIAC dimmer, process information associated with the first signal, determine whether the TRIAC dimmer is in a first condition or a second condition, generate a second signal based on at least information associated with the first signal, and send the second signal to a switch. The one or more signal processing components are further configured to, if the TRIAC dimmer is determined to be in the first condition, generate the second signal to cause the switch to be opened and closed corresponding to a modulation frequency.

Abstract: Systems and methods are provided for regulating a power converter. An example system controller includes: a driver configured to output a drive signal to a switch to affect a current flowing through an inductive winding of a power converter, the drive signal being associated with a switching period including an on-time period and an off-time period. The switch is closed in response to the drive signal during the on-time period. The switch is opened in response to the drive signal during the off-time period. A duty cycle is equal to a duration of the on-time period divided by a duration of the switching period. One minus the duty cycle is equal to a parameter. The system controller is configured to keep a multiplication product of the duty cycle, the parameter and the duration of the on-time period approximately constant.

Abstract: System and method for driving a bipolar junction transistor for a power converter. The system includes a current generator configured to output a drive current signal to a bipolar junction transistor to adjust a primary current flowing through a primary winding of a power converter. The current generator is further configured to output the drive current signal to turn on the bipolar junction transistor during a first time period, a second time period, and a third time period, the second time period separating the first time period from the third time period, drive the bipolar junction transistor to operate in a hard-saturation region during the first time period and the second time period, and drive the bipolar junction transistor to operate in a quasi-saturation region during the third time period.

Abstract: System and method for regulating a power converter. The system includes a first signal processing component configured to receive at least a sensed signal and generate a first signal. The sensed signal is associated with a primary current flowing through a primary winding coupled to a secondary winding for a power converter. Additionally, the system includes a second signal processing component configured to generate a second signal, an integrator component configured to receive the first signal and the second signal and generate a third signal, and a comparator configured to process information associated with the third signal and the sensed signal and generate a comparison signal based on at least information associated with the third signal and the sensed signal.

Abstract: System and method for regulating a power conversion system. A system controller for regulating a power conversion system includes an operation-mode-selection component and a driving component. The operation-mode-selection component is configured to receive a first signal related to an output load of the power conversion system and a second signal related to an input signal received by the power conversion system and output a mode-selection signal based on at least information associated with the first signal and the second signal. The driving component is configured to receive the mode-selection signal and generate a drive signal based on at least information associated with the mode-selection signal, the driving signal corresponding to a switching frequency.

Abstract: System and method for regulating a power conversion system. A system controller for regulating a power conversion system includes an operation-mode-selection component and a driving component. The operation-mode-selection component is configured to receive a first signal related to an output load of the power conversion system and a second signal related to an input signal received by the power conversion system and output a mode-selection signal based on at least information associated with the first signal and the second signal. The driving component is configured to receive the mode-selection signal and generate a drive signal based on at least information associated with the mode-selection signal, the driving signal corresponding to a switching frequency.

Abstract: Systems and methods are provided for power conversion system regulation. A system controller includes: a first signal processing component configured to receive a first signal associated with an auxiliary winding of a power conversion system and generate a second signal based at least in part on the first signal, the power conversion system further including a primary winding and a secondary winding; and a drive component configured to receive the second signal and output a drive signal to open or close a switch to affect a current flowing through the primary winding. The first signal processing component is further configured to: detect a plurality of valleys of the first signal, the plurality of valleys corresponding to a same demagnetization process of the power conversion system; select a valley from the plurality of valleys; and change the second signal at the selected valley.

Abstract: Systems and methods for dimming control using TRIAC dimmers are provided. An example apparatus for a power conversion system includes: a process-and-drive component configured to receive an input signal and output a drive signal to a switch to affect a current that flows through a primary winding of a power conversion system. The input signal includes a first pulse associated with a first input period and a second pulse associated with a second input period. The drive signal is associated with a first modulation period for the first input period and a second modulation period for the second input period. The process-and-drive component is further configured to: determine the first modulation period for the first input period; change the drive signal between a first logic level and a second logic level at a modulation frequency during the first modulation period; determine the second modulation period for the second input period.

Abstract: A two-terminal IC chip and method thereof. For example, a two-terminal IC chip includes a first chip terminal and a second chip terminal. A first terminal voltage is a voltage of the first chip terminal, a second terminal voltage is a voltage of the second chip terminal, and a chip voltage is equal to a difference between the first terminal voltage and the second terminal voltage. The chip is configured to allow a chip current to flow into the chip at the first chip terminal and out of the chip at the second chip terminal, or to flow into the chip at the second chip terminal and out of the chip at the first chip terminal. The chip current is larger than or equal to zero in magnitude. The chip is further configured to change a relationship between the chip voltage and the chip current with respect to time. The chip is an integrated circuit, and the chip does not include any additional chip terminal other than the first chip terminal and the second chip terminal.

Abstract: System and method for discharging a capacitor. An example system includes a signal detector and a discharge control component. The signal detector is configured to receive an input signal and generate a detection signal based on at least information associated with the input signal, the input signal being associated with an alternate current signal received by a capacitor including a first capacitor terminal and a second capacitor terminal. The discharge control component configured to receive at least the detection signal and generate an output signal to discharge the capacitor if the detection signal satisfies one or more conditions.

Abstract: Systems and methods are provided herein for current regulation. An example system controller includes: a first controller terminal configured to receive an input voltage, the first controller terminal being further configured to allow a first current flowing into the system controller based at least in part on the input voltage in response to one or more switches being closed; a second controller terminal configured to allow the first current to flow out of the system controller through the second controller terminal in response to the one or more switches being closed; a fourth controller terminal coupled to the third controller terminal through a first capacitor, the first capacitor not being any part of the system controller; and an error amplifier configured to generate a compensation signal based at least in part on the current sensing signal, the error amplifier including a second capacitor.

Abstract: System and method for regulating a power conversion system. For example, a system controller for regulating a power conversion system includes an amplifier, a variable-resistance component, a capacitor, and a modulation and drive component. The amplifier is configured to receive a reference signal and a feedback signal associated with an output signal of the power conversion system, the amplifier including an amplifier terminal. The variable-resistance component is associated with a first variable resistance value, the variable-resistance component including a first component terminal and a second component terminal, the first component terminal being coupled with the amplifier terminal. The capacitor includes a first capacitor terminal and a second capacitor terminal, the first capacitor terminal being coupled with the second component terminal. The modulation and drive component includes a first terminal and a second terminal, the first terminal being coupled with the amplifier terminal.

Abstract: Systems and methods are provided for regulating a power converter. An example system controller includes: a first controller terminal configured to output a drive signal to a switch to affect a current flowing through a primary winding of a power converter, the drive signal being associated with a switching period corresponding to a switching frequency; and a second controller terminal configured to receive a feedback signal associated with an output voltage related to a secondary winding of the power converter. The first controller terminal is further configured to: output the drive signal to close the switch during the on-time period; and output the drive signal to open the switch during the off-time period. The system controller is configured to set the switching frequency to one or more frequency magnitudes, each of the one or more frequency magnitudes being smaller than or equal to an upper frequency limit.

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: 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.