Abstract: A LED driving circuit and a backlight module using the same are disclosed. The LED driving circuit comprises a LED module and a current controlling unit. The LED module has a plurality of the LED strings, each having a driving terminal. The current controlling unit has a plurality of current balancing terminal coupled to the driving terminal, for balancing the currents flowing through the LED strings. The current controlling unit receives a mode switch signal, controls the amount of the currents of the LED strings about a first current value when the mode switch signal represent a first mode, and controls the amount of the currents of the LED strings about a second current value when the mode switch signal represent a second mode.

Abstract: A frequency jitter generator and a frequency jitter PWM controller are provided for overcoming the shortcoming that a conventional PWM controller reduces the electromagnetic interference issue by means of varying the operating frequency of the PWM controller based on an input voltage, while resulting in the uncertainty of the range of frequency jitter and the difficulty circuit design due to the effect of the input voltage and the load. The frequency jitter generator and PWM controller adjust the range of frequency jitter by using a signal within a fixed voltage range. The invention not only gets rid of the effect of the input voltage and the loading, but also simplifies the circuit design by fixing the range of frequency jitter no greater than a predetermined percentage regardless of the operating frequency of the PWM controller.

Abstract: A LED driving circuit and a backlight module using the same are disclosed. The LED driving circuit comprises a LED module and a current controlling unit. The LED module has a plurality of the LED strings, each having a driving terminal. The current controlling unit has a plurality of current balancing terminal coupled to the driving terminal, for balancing the currents flowing through the LED strings. The current controlling unit receives a mode switch signal, controls the amount of the currents of the LED strings about a first current value when the mode switch signal represent a first mode, and controls the amount of the currents of the LED strings about a second current value when the mode switch signal represent a second mode.

Abstract: A frequency jitter generator and a frequency jitter PWM controller are provided for overcoming the shortcoming that a conventional PWM controller reduces the electromagnetic interference issue by means of varying the operating frequency of the PWM controller based on an input voltage, while resulting in the uncertainty of the range of frequency jitter and the difficulty circuit design due to the effect of the input voltage and the load. The frequency jitter generator and PWM controller adjust the range of frequency jitter by using a signal within a fixed voltage range. The invention not only gets rid of the effect of the input voltage and the loading, but also simplifies the circuit design by fixing the range of frequency jitter no greater than a predetermined percentage regardless of the operating frequency of the PWM controller.