Abstract: System and method for regulating a power conversion system. A system controller for regulating a power conversion system includes a first controller terminal, a second controller terminal and a third controller terminal. The system controller is configured to receive an input signal at the first controller terminal and turn on or off a switch based on at least information associated with the input signal to adjust a primary current flowing through a primary winding of the power conversion system, receive a first signal at the second controller terminal from the switch, and charge a capacitor through the third controller terminal in response to the first signal.

Abstract: System and method for adjusting brightness of one or more cold-cathode fluorescent lamps. The system includes a voltage selector configured to receive a dimming voltage and a first threshold voltage and generate an output voltage. The output voltage is selected from a group consisting of the dimming voltage and the first threshold voltage. Additionally, the system includes an oscillator coupled to a first capacitor and configured to generate a ramp signal with the first capacitor, and a signal generator configured to receive the ramp signal and the output voltage and generate a first signal. The first signal corresponds to a lamp brightness level. Moreover, the system includes a brightness detector configured to receive the first signal and output a second signal. The second signal indicates whether the lamp brightness level is higher than a threshold brightness level.

Abstract: System and method for controlling one or more switches. The system includes a first converting circuit, a second converting circuit, and a signal processing component. The first converting circuit is configured to convert a first current and generate a first converted voltage signal based on at least information associated with the first current. The second converting circuit is configured to convert a second current and generate a second converted voltage signal based on at least information associated with the second current. The signal processing component is configured to receive the first converted voltage signal and the second converted voltage signal and generate an output signal based on at least information associated with the first converted voltage signal and the second converted voltage signal.

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: 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 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 are provided for driving a transistor. The system includes a floating-voltage generator, a first driving circuit, and a second driving circuit. The floating-voltage generator is configured to receive a first bias voltage and generate a floating voltage, the floating-voltage generator being further configured to change the floating voltage if the first bias voltage changes and to maintain the floating voltage to be lower than the first bias voltage by a first predetermined value in magnitude. The first driving circuit is configured to receive an input signal, the first bias voltage and the floating voltage. The second driving circuit is configured to receive the input signal, a second bias voltage and a third bias voltage, the first driving circuit and the second driving circuit being configured to generate an output signal to drive a transistor.

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 are provided for driving a transistor. The system includes a floating-voltage generator, a first driving circuit, and a second driving circuit. The floating-voltage generator is configured to receive a first bias voltage and generate a floating voltage, the floating-voltage generator being further configured to change the floating voltage if the first bias voltage changes and to maintain the floating voltage to be lower than the first bias voltage by a first predetermined value in magnitude. The first driving circuit is configured to receive an input signal, the first bias voltage and the floating voltage. The second driving circuit is configured to receive the input signal, a second bias voltage and a third bias voltage, the first driving circuit and the second driving circuit being configured to generate an output signal to drive a transistor.

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: System and method for regulating a power conversion system. For example, a system controller includes a signal generator and one or more power-consumption components. The signal generator is configured to receive a feedback signal related to an output signal of the power conversion system, a current sensing signal and an input voltage, and to generate a control signal based on at least information associated with the feedback signal, the current sensing signal and the input voltage. The power-consumption components are configured to receive the control signal. The signal generator is further configured to determine whether the feedback signal is smaller than a feedback threshold for a first predetermined period of time, the current sensing signal is smaller than a current sensing threshold for a second predetermined period of time, and the input voltage is smaller than a first threshold for a third predetermined period of time in magnitude.

Abstract: System and method for regulating an output voltage of a power conversion system. The system includes an error amplifier coupled to a capacitor. The error amplifier is configured to receive a reference voltage, a first voltage, and an adjustment current and to generate a compensation voltage with the capacitor. The first voltage is associated with a feedback voltage. Additionally, the system includes a current generator configured to receive the compensation voltage and generate the adjustment current and a first current, and a signal generator configured to receive the first current and a second current. The signal generator is further configured to receive a sensing voltage and to generate a modulation signal. Moreover, the system includes the gate driver directly or indirectly coupled to the signal generator and configured to generate a drive signal based on at least information associated with the modulation signal.

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: System and method for amplifying an input signal to generate an output signal. The system includes a current generator, an oscillator, and a comparator. The current generator is configured to receive a first voltage signal, and generate a first current signal based on at least information associated with the first voltage signal and the first reference signal. The oscillator is configured to receive at least the first current signal and a second reference signal, and to generate a second voltage signal based on at least information associated with the first current signal and the second reference signal, the second voltage signal being associated with a modulation frequency. Additionally, the comparator is configured to receive the second voltage signal and a third voltage signal, and to generate a modulation signal related to the modulation frequency based on at least information associated with the second voltage signal and the third voltage signal.

Abstract: Oscillator system and method thereof. The oscillator system includes a first voltage-to-current converter configured to receive a first voltage and generate a first current based on at least information associated with the first voltage, and a second voltage-to-current converter configured to receive a second voltage and generate a second current based on at least information associated with the second voltage. Additionally, the oscillator system further includes a current-mode N-bit digital-to-analog converter configured to receive at least the second current and a first clock signal and to generate a third current based on at least information associated with the second current and the first clock signal. N is a first integer. The first clock signal is associated with a first clock frequency corresponding to a first clock period. Moreover, the oscillator system further includes a current comparator coupled to the first voltage-to-current converter and the current-mode N-bit digital-to-analog converter.

Abstract: System and method for protecting a power converter. The system includes a duty-cycle detection component configured to receive a modulation signal, determine a first duty cycle corresponding to a first period of the modulation signal, compare the first duty cycle with a threshold duty cycle, and generate a duty-cycle comparison signal. Additionally, the system includes a threshold generator configured to receive the duty-cycle comparison signal and generate a threshold signal corresponding to a second period of the modulation signal, the second period being after the first period, and a comparator configured to receive the 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. Moreover, the system includes a pulse-width-modulation component configured to receive the first comparison signal and generate the modulation signal for adjusting the input current for the power converter.

Abstract: System and method for regulating a power conversion system. For example, a system controller includes a signal generator and one or more power-consumption components. The signal generator is configured to receive a feedback signal related to an output signal of the power conversion system, a current sensing signal and an input voltage, and to generate a control signal based on at least information associated with the feedback signal, the current sensing signal and the input voltage. The power-consumption components are configured to receive the control signal. The signal generator is further configured to determine whether the feedback signal is smaller than a feedback threshold for a first predetermined period of time, the current sensing signal is smaller than a current sensing threshold for a second predetermined period of time, and the input voltage is smaller than a first threshold for a third predetermined period of time in magnitude.

Abstract: System and method for driving one or more cold-cathode fluorescent lamps. For example, the method includes generating at least one drive signal associated with a signal frequency, the signal frequency being equal to a first predetermined frequency, receiving a current-sensing signal, the current-sensing signal being associated with a lamp current for the one or more cold-cathode fluorescent lamps in response to at least the first predetermined frequency, and determining whether the current-sensing signal is larger than a first threshold in magnitude, the current-sensing signal being related to the first predetermined frequency.

Abstract: System and method for regulating a power converter. The system includes a first signal generator configured to receive at least an input signal and generate at least a first output signal associated with demagnetization and a second output signal associated with sampling. Additionally, the system includes a sampling component configured to receive at least the input signal and the second output signal, sample the input signal based on at least information associated with the second output signal, and generate at least a third output signal associated with one or more sampled magnitudes. Moreover, the system includes an error amplifier configured to receive at least the third output signal and a first threshold voltage and generate at least a fourth output signal with a capacitor, the capacitor being coupled to the error amplifier.

Abstract: System and method for dimming control. The system includes a system controller, a transistor, and a resistor. The system controller includes a first controller terminal and a second controller terminal. The transistor includes a first transistor terminal, a second transistor terminal and a third transistor terminal. The resistor including a first resistor terminal and a second resistor terminal. The first transistor terminal is coupled, directly or indirectly, to the second controller terminal. The first resistor terminal is coupled to the second transistor terminal. The second resistor terminal is coupled to the third transistor terminal. The system controller is configured to receive an input signal at the first controller terminal and to generate an output signal at the second controller terminal. The transistor is configured to receive the output signal at the first transistor terminal and to change between a first condition and a second condition.