1. A system for providing at least an output current to one or more light emitting diodes, the system comprising:a transconductance amplifier configured to receive a sensed signal and generate a current signal;
a capacitor coupled to the transconductance amplifier and configured to generate a voltage signal;
a comparator configured to process information associated with the voltage signal and the sensed signal and generate a comparison signal based on at least information associated with the voltage signal and the sensed signal;
a modulation-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 a switch;
the drive signal is associated with at least one or more switching periods, each of the one or more switching periods including at least an on-time period for the switch;
the transconductance amplifier is further configured to, for each of the one or more switching periods, receive at least a predetermined voltage signal only during the on-time period; and
the current signal is configured to charge or discharge the capacitor.