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 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 one or more currents. An example system controller includes: a thermal detector configured to detect a temperature associated with the system controller and generate a thermal detection signal based at least in part on the detected temperature; and a modulation-and-driver component configured to receive the thermal detection signal and generate a drive signal based at least in part on the thermal detection signal to close or open a switch to affect a drive current associated with one or more light emitting diodes. The modulation-and-driver component is further configured to, in response to the detected temperature increasing from a first temperature threshold but remaining smaller than a second temperature threshold, generate the drive signal to keep the drive current at a first current magnitude, the second temperature threshold being higher than the first temperature threshold.

Abstract: System and method for regulating a power conversion system. An example system controller for regulating a power conversion system includes a first controller terminal associated with a first controller voltage and coupled to a first transistor terminal of a first transistor, the first transistor further including a second transistor terminal and a third transistor terminal, the second transistor terminal being coupled to a primary winding of a power conversion system, a second controller terminal associated with a second controller voltage and coupled to the third transistor terminal, and a third controller terminal associated with a third controller voltage. The first controller voltage is equal to a sum of the third controller voltage and a first voltage difference. The second controller voltage is equal to a sum of the third controller voltage and a second voltage difference.

Abstract: System controller and method for a power converter. For example, a system controller for a power converter includes a logic controller configured to generate a modulation signal, and a driver configured to receive the modulation signal, generate a drive signal based at least in part on the modulation signal, and output the drive signal to a switch to affect a current flowing through an inductive winding for a power converter. Additionally, the system controller includes a voltage-to-voltage converter configured to receive a first voltage signal, the modulation signal, and a demagnetization signal, and to generate a second voltage signal based at least in part on the first voltage signal, the modulation signal, and the demagnetization signal.

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: 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 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 are provided for protecting a power converter. The system includes a first comparator, and an off-time component. The first comparator is configured to receive a sensing signal and a first threshold signal and generate a first comparison signal based on at least information associated with the sensing signal and the first threshold signal, the power converter being associated with a switching frequency and further including a switch configured to affect the primary current. The off-time component is configured to receive the first comparison signal and generate an off-time signal based on at least information associated with the first comparison signal. The off-time component is further configured to, if the first comparison signal indicates the sensing signal to be larger than the first threshold signal in magnitude, generate the off-time signal to keep the switch to be turned off for at least a predetermined period of time.

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: A two-terminal IC chip and method thereof. For example, a two-terminal IC chip includes a first chip terminal, a second chip terminal, a first switch configured to receive a control signal, a first capacitor coupled to the first switch, a second switch configured to receive the control signal, a second capacitor coupled to the second switch, a third switch configured to receive the control signal, and a third capacitor coupled to the third switch. 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.

Abstract: System and method for adjusting a threshold of a power conversion system. The system includes a threshold generator configured to receive a first signal and generate a threshold signal based on at least information associated with the first signal, a comparator configured to receive the threshold signal and a second signal and generate a comparison signal, and a gate driver configured to generate a drive signal based on at least information associated with the comparison signal. The gate driver is coupled to at least a switch configured to receive the drive signal and affect a current flowing through a primary winding coupled to a secondary winding. If the second signal is larger than the threshold signal in magnitude, the drive signal causes the switch to open. The drive signal is associated with a switching frequency.

Abstract: System controller and method for protecting a power converter. The system controller includes a first controller terminal configured to output a drive signal to a switch to affect a first current flowing through a primary winding of a power converter. The power converter further includes a secondary winding coupled to the primary winding, and the drive signal is associated with one or more switching periods. Additionally, the system controller includes a second controller terminal configured to receive a sensing voltage from a sensing resistor. The sensing voltage represents a magnitude of the first current flowing through the primary winding of the power converter. The system controller is configured to process information associated with the sensing voltage and a reference voltage, and determine whether an average output current of the power converter is larger than a current threshold.

Abstract: Systems and methods are provided for signal processing. An example error amplifier for processing a reference signal and an input signal associated with a current of a power conversion system includes a first operational amplifier, a second operational amplifier, a first transistor, a second transistor, a current mirror component, a switch, a first resistor and a second resistor. The first operational amplifier includes a first input terminal, a second input terminal and a first output terminal, the first input terminal being configured to receive a reference signal. The first transistor includes a first transistor terminal, a second transistor terminal and a third transistor terminal, the first transistor terminal being configured to receive a first amplified signal from the first output terminal, the third transistor terminal being coupled to the second input terminal.

Abstract: System controller and method for a power converter. For example, a system controller for a power converter includes a logic controller configured to generate a modulation signal, and a driver configured to receive the modulation signal, generate a drive signal based at least in part on the modulation signal, and output the drive signal to a switch to affect a current flowing through an inductive winding for a power converter. Additionally, the system controller includes a voltage-to-voltage converter configured to receive a first voltage signal, the modulation signal, and a demagnetization signal, and to generate a second voltage signal based at least in part on the first voltage signal, the modulation signal, and the demagnetization signal.

Abstract: Systems and methods are provided for voltage regulation of power conversion systems. An example system controller includes: a first sampling component configured to sample a sensing signal and determine a compensation signal based on at least in part on the sensing signal, the sensing signal being associated with a first current flowing through a primary winding of a power conversion system; a signal processing component configured to receive a feedback signal and the compensation signal and generate a first signal based at least in part on the feedback signal and the compensation signal, the feedback signal being associated with an auxiliary winding coupled with a secondary winding of the power conversion system; an error amplifier configured to receive the first signal and a reference signal and generate an amplified signal based at least in part on the first signal and the reference signal.

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 an output current of a power conversion system. An example system controller for regulating an output current of a power conversion system includes a driving component, a demagnetization detector, a current-regulation component, and a signal processing component. The driving component is configured to output a drive signal to a switch in order to affect a primary current flowing through a primary winding of the power conversion system. The demagnetization detector is configured to receive a feedback signal associated with an output voltage of the power conversion system and generate a detection signal based on at least information associated with the feedback signal. The current-regulation component is configured to receive the drive signal, the detection signal and a current-sensing signal and output a current-regulation signal based on at least information associated with the drive signal, the detection signal, and the current sensing signal.

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: 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.