System and method for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer. For example, the system for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer includes: a first current controller configured to receive a rectified voltage generated by a rectifier that directly receives an AC input voltage without through any TRIAC dimmer; and a second current controller configured to: control a light emitting diode current flowing through one or more light emitting diodes that receive the rectified voltage not clipped by any TRIAC dimmer; and generate a sensing voltage based at least in part upon the light emitting diode current, the sensing voltage representing the light emitting diode current in magnitude.