Light-emitting diode driving apparatus and operating method thereof

A light-emitting diode (LED) driving apparatus, for driving at least one LED, comprising:

• a power converter, coupled to the at least one LED, for converting an input voltage into an output voltage and outputting the output voltage to the at least one LED;
• a judging module, coupled to the at least one LED, for judging whether a LED current of the at least one LED is changed from a first LED current value to a second LED current value, if a judging result of the judging module is yes, the judging module generating a judging signal;
• and
• a control module, coupled to the judging module, comprising a transconductance amplifier and a current source coupled to an output terminal of the transconductance amplifier, when the control module receives the judging signal, the control module changing a current value of the current source and a transconductance of the transconductance amplifier according to the judging signal;
• wherein the second LED current value is larger than the first LED current value and a difference between the first LED current value and the second LED current value is larger than a default current difference, if the judging module judges that the LED current of the at least one LED is changed from the first LED current value to a third LED current value, and a difference between the first LED current value and the third LED current value is smaller than default current difference, then the judging module does not generate the judging signal to the control module.

A light-emitting diode (LED) driving apparatus operating method used for operating a LED driving apparatus to drive at least one LED, the LED driving apparatus comprising a power converter, a judging module and a control module, the power converter being coupled to the at least one LED, the judging module being coupled to the at least one LED, the control module being coupled to the judging module, the control module comprising a transconductance amplifier and a current source coupled to an output terminal of the transconductance amplifier, the LED driving apparatus operating method comprising steps of:

• the power converter converting an input voltage into an output voltage and outputting the output voltage to the at least one LED;
• the judging module judging whether a LED current of the at least one LED is changed from a first LED current value to a second LED current value;
• if a judging result of the judging module is yes, the judging module generating a judging signal;
• and
• when the control module receives the judging signal, the control module changing a current value of the current source and a transconductance of the transconductance amplifier according to the judging signal;
• wherein the control module further comprises a compensation unit coupled between the current source and the transconductance amplifier.