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US 12,232,230 B2Granted
LED driving circuit and driving method thereof
AssigneeLx Semicon Co., Ltd.
InventorsSang Suk Kim, Jang Su Kim, Ji Hwan Kim, Kyeong Rok Lee, Jong Min Lee
Life of this patent
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Abstract
The present embodiment relates to a technology for facilitating an increase of the number of LEDs to be driven by communication of a clock signal between chips forming a daisy chain when driving LEDs. The communication of a clock signal as well as data between chips allows improve the synchronization between the clock signal and data.
Claims20
A light emitting diode (LED) driving unit comprising:
- a first LED driving circuit configured to receive a serial clock signal from a microcontroller unit, output the serial clock signal to a second LED driving circuit, and adjust a driving current for a first light emitting diode;
- and
- the second LED driving circuit configured to receive the serial clock signal outputted from the first LED driving circuit, output the serial clock signal to a third LED driving circuit, and adjust a driving current for a second light emitting diode, wherein
- the microcontroller unit, the first LED driving circuit, and the second LED driving circuit are configured to sequentially transmit the serial clock signal, and
- the first LED driving circuit comprises:
- a first switch circuit configured to adjust a level of the driving current for the first light emitting diode according to a duty ratio of a pulse width modulation (PWM) signal;
- and
- a second switch circuit configured to adjust the level of the driving current for the first light emitting diode by receiving a pulse amplitude modulation (PAM) signal.
5 more elements
An LED driving unit comprising:
- a first LED driving circuit comprising a plurality of current channels configured to adjust driving currents for a first group of light emitting diodes;
- and
- a second LED driving circuit comprising a plurality of current channels configured to adjust driving currents for a second group of light emitting diodes, wherein
- the first LED driving circuit is configured to receive a serial clock signal from a microcontroller unit and output the serial clock signal to the second LED driving circuit,
- the second LED driving circuit is configured to receive the serial clock signal from the first LED driving circuit and output the serial clock signal to a third LED driving circuit,
- the first LED driving circuit and the second LED driving circuit are connected in series, and
- each of the first and the second LED driving circuits is configured to perform a buffering process for adjusting a rising edge timing or a falling edge timing of the serial clock signal.
4 more elements
A display device comprising:
- a panel comprising a color filter and liquid crystals;
- light emitting diodes configured to transmit light to the panel;
- a plurality of LED driving circuits configured to control driving currents for the light emitting diodes;
- and
- a microcontroller unit configured to transmit a serial clock signal and a local dimming signal to the plurality of LED driving circuits in order to control operations of the plurality of LED driving circuits, wherein
- the plurality of LED driving circuits is connected in series to form a daisy chain,
- the plurality of LED driving circuits comprises first through N-th LED driving circuits connected in series, and
- each of the serial clock signal and the local dimming signal outputted from the first LED driving circuit is provided to the N-th LED driving circuit via the second through (N-1)-th intermediate LED driving circuits.
5 more elements
Dependencies are inferred from the claim text.