Systems and methods for regulating output currents of power conversion systems
Systems and methods are provided for regulating a power conversion system. An example system controller includes a first controller terminal and a second controller terminal. The first controller terminal is configured to receive a first signal associated with an input signal for a primary winding of a power conversation system. The second controller terminal is configured to output a drive signal to a switch to affect a first current flowing through the primary winding of the power conversion system, the drive signal being associated with an on-time period, the switch being closed during the on-time period. The system controller is configured to adjust a duration of the on-time period based on at least information associated with the first signal.
1. A system controller for regulating a power conversion system, the system controller comprising:
a first controller terminal configured to receive a first signal associated with 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 first current flowing through the primary winding of the power conversion system, the drive signal being associated with an on-time period, the switch being closed during the on-time period;
wherein the system controller is configured to adjust a duration of the on-time period based on at least information associated with the first signal.
2. The system controller of claim 1 wherein the input signal corresponds to an input voltage.
3. The system controller of claim 1 , further comprising a first conversion component configured to generate a second current based on at least information associated with the first signal.
4. The system controller of claim 1 , further comprising:
a demagnetization detector configured to receive a feedback signal associated with an output signal of the power conversion system and generates a trigger signal based on at least information associated with the feedback signal; and
a logic controller configured to receive the trigger signal and output a second signal based on at least information associated with the trigger signal to affect the drive signal.
5. The system controller of claim 1 wherein:
the first controller terminal is coupled to a first resistor terminal of a first resistor;
a second resistor terminal of the first resistor is configured to receive the input signal; and
the first resistor terminal of the first resistor is configured to provide the first signal.
6. The system controller of claim 1 wherein the first signal corresponds to a feedback current related to a first voltage associated with an auxiliary winding of the power conversion system.
7. The system controller of claim 1 wherein:
the first controller terminal is a first pin; and
the second controller terminal is a second pin.
8. The system controller of claim 1 wherein the system controller operates in a voltage mode.
9. The system controller of claim 1 wherein the power conversion system operates in a quasi-resonant mode.
10. A method for regulating a power conversion system, the method comprising:
receiving a first signal from a first controller terminal, the first signal being associated with an input signal for a primary winding of a power conversation system;
adjusting a duration of an on-time period related to a drive signal based on at least information associated with the first signal; and
outputting the drive signal from a second controller terminal to a switch to affect a first current flowing through the primary winding of the power conversion system, the switch being closed during the on-time period.