Light emitting diode driver
View Patent ↗There is provided a light emitting diode (LED) driver removing signal interference by varying a switching frequency within a preset range. The LED driver includes a power supply section switching input power and supplying driving power to at least one LED; a switching control section controlling the switching of the power supply section according to a clock signal being supplied; and a clock signal generation section supplying the clock signal having a preset variable frequency range to the switching control section.
1. A light emitting diode (LED) driver, comprising:
a power supply section configured to switch input power and supply driving power to at least one LED;
a switching control section configured to control the switching of the power supply section according to a clock signal being supplied; and
a clock signal generation section configured to supply the clock signal having a preset variable frequency range to the switching control section, wherein the clock signal generation section comprises:
a triangular wave signal generating part configured to generate a triangular wave signal in a preset voltage range; and
an oscillating part configured to oscillate the clock signal having the preset variable frequency range, the preset variable frequency range being set according to the triangular wave signal generated by the triangular wave signal generating part.
2. The LED driver of claim 1 , wherein the triangular wave signal generating part comprises:
a first current mirror portion configured to mirror a current of a preset reference power to supply first and second current sources; and
a charge/discharge portion configured to charge and discharge the first and second current sources supplied by the first current mirror portion in the preset voltage range so that the triangular wave signal is supplied.
3. The LED driver of claim 1 , wherein the oscillating part comprises:
a second current mirror portion configured to mirror a current of a preset reference power according to the triangular wave signal; and
a clock signal generation portion configured to generate the clock signal by charging and discharging a voltage of the current mirrored by the second current mirror portion and a current mirrored according to a logical result of a preset reference voltage.
4. The LED driver of claim 1 , wherein the switching control section comprises:
a comparator configured to compare a feedback signal obtained by detecting the driving power supplied to the at least one LED by the power supply section with a reference signal and supply a Pulse Width Modulation (PWM) signal; and
a gate driver configured to control the switching of the power supply section according to the PWM signal supplied by the comparator.
5. The LED driver of claim 1 , wherein the power supply section supplies the driving power to a plurality of parallel-connected LEDs.
6. The LED driver of claim 1 , wherein the power supply section supplies the driving power to at least one LED array including a plurality of series-connected LEDs.
7. The LED driver of claim 6 , wherein the power supply section supplies the driving power to a plurality of parallel-connected LED arrays.