LED lighting systems and methods for constant current control in various operation modes

摘要

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.

主权项

1. A system for providing at least an output current to one or more light emitting diodes, the system comprising:
a first signal processing component configured to receive at least a sensed signal and generate a first signal, the sensed signal being associated with an inductor current flowing through an inductor coupled to a switch; 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; 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; a signal generator configured to receive at least the comparison signal and generate a modulation signal; and a gate driver configured to receive the modulation signal and output a drive signal to the switch; wherein the drive signal is associated with at least one or more switching periods, each switching period of the one or more switching periods including at least an on-time period for the switch and a demagnetization period for a demagnetization process; wherein for the each switching period of the one or more switching periods,
the first signal represents a multiplication result of a first sum of the on-time period and the demagnetization period and a second sum of a first current magnitude and a second current magnitude, the first current magnitude representing the inductor current at the beginning of the on-time period, the second current magnitude representing the inductor current at the end of the on-time period; andthe second signal represents the switching period multiplied by a predetermined current magnitude; wherein:
the integrator component is further configured to integrate period-by-period differences between the first signal and the second signal for a plurality of switching periods; andthe third signal represents the integrated period-by-period differences, the integrated period-by-period differences being smaller than a predetermined threshold in magnitude.