BACKGROUND

This disclosure relates generally to a display device, and more specifically to a display device with selectable driving currents for light emitting diode (LED) channels.

LEDs are used in many electronic display devices, such as televisions, computer monitors, laptop computers, tablets, smartphones, projection systems, and head-mounted devices. With improvements in LED technology that reduce the physical size of the LEDs, display devices with significantly larger numbers of LEDs have become possible. However, as the density of LEDs in a display device increases, it becomes increasingly challenging to manage heat dissipation and power consumption.

SUMMARY

A display device includes a control circuit and a plurality of LED channels coupled to a shared supply voltage. For a given image frame, the control circuit obtains brightness data comprising respective brightness levels for each of the LED channels. The control circuit determines, based on the brightness levels, a group current level sufficient to drive all of the LED channels. For example, the control circuit selects the group current level from a set of predefined current levels. The control circuit also determines for each of the LED channels based on the respective brightness levels and the group current level, respective duty cycles for each of the LED channels to achieve the respective brightness levels when each of the LED channels are driven with the group current level. The control circuit configures driver circuits to drive the LED channels in accordance with the group current level and the respective duty cycles. The group current level and respective duty cycles may be updated each frame based on the brightness levels.

In an embodiment, the control circuit maps the respective brightness levels for each of the LED channels to respective average channel currents for each of the LED channels. The control circuit then selects the group current level as a lowest one of the set of predefined current levels that exceeds all of the respective average channel currents. The control circuit furthermore configures the respective duty cycles by determining the respective ratios of the respective average channel currents for each of the LED channels to the group current level.

In an embodiment, the control circuit furthermore sets the shared supply voltage to a voltage level sufficient to drive all of the LED channels when operating with the group current level. Here, the control circuit may determine a preset supply voltage level for the shared supply voltage selected from a set of predefined supply voltage levels each corresponding to one of the predefined current levels. The control circuit may furthermore obtain respective channel voltages associated with the each of the LED channels, determine a minimum channel voltage of the respective channel voltages associated with each of the LED channels, and adjust the shared voltage supply based on the minimum channel voltage across the LED channels.

In a further embodiment, the control circuit determines that the group current level for a current frame is unchanged from an immediately prior frame and sets the shared supply voltage to a same voltage level as the immediately prior frame.

In an embodiment of the display device, the LEDs may comprise mini-LEDs having a size range between 100 to 300 micrometers, or micro-LEDs having a size of less than 100 micrometers.

