High speed image refresh system
A LED controller for an LED pixel array includes a serial interface to an external data bus, along with an address generator connected to the serial interface and the LED pixel array. An image frame buffer is connected to the interface to receive image data and further connected to the address generator to receive an image frame buffer address. A command and control module is connected to the serial interface and configured to modify image frame buffer output signals. A calibration data storage module is connected to the command and control module to store calibration data related to pixel voltage response in the LED pixel array.
1. A light emitting diode (LED) controller comprising:
a serial interface configured to connect the LED controller to an external data bus;
an address generator connected to the serial interface and configured to be connected to an LED pixel array;
an image frame buffer connected to the serial interface to receive image data and further connected to the address generator to receive an image frame buffer address;
a command and control module connected to the serial interface, the command and control module configured to modify output signals from the image frame buffer; and
a calibration data storage module connected to the command and control module, the calibration data storage module configured to store calibration data related to pixel voltage responses of pixels in the LED pixel array.
2. The LED controller of claim 1 , further comprising a standby image buffer connected to the image frame buffer to hold a default image.
3. The LED controller of claim 1 , further comprising a pulse width modulator connected between the image frame buffer and the LED pixel array.
4. The LED controller of claim 1 , wherein the image frame buffer can refresh held images at 60 Hz or greater speed.
5. The LED controller of claim 1 , wherein the command and control module is connected to an analog to digital converter that receives temperature data.
6. The LED controller of claim 1 , wherein the command and control module is connected to an analog to digital converter that receives forward voltage (V f ) data.
7. The LED controller of claim 1 , wherein the command and control module is connected to a digital to analog converter that receives a set voltage bias (V bias ) data.
8. The LED controller of claim 1 , wherein the command and control module is connected to a second interface providing external control signals.
9. The LED controller of claim 1 , wherein the command and control module includes a bypass line connected to the LED pixel array to allow individual pixel addressing.
10. The LED controller of claim 1 , wherein images in the image buffer can be partially refreshed.
11. The LED controller of claim 1 , wherein images in the image buffer can be differentially refreshed.
12. The LED controller of claim 1 , wherein images in the image buffer can be modified by the command and control module.
13. The LED controller of claim 1 , wherein the LED controller is configured to perform a calibration procedure on the LED pixel array, the calibration procedure comprising measuring a forward voltage (V f ) of each pixel in the LED pixel array.
14. The LED controller of claim 13 , wherein the calibration procedure comprises measuring a minimum V f , a maximum V f , and an average V f of each pixel in an active area of the LED pixel array.
15. The LED controller of claim 13 , wherein the calibration procedure further comprises measuring a relationship between V f and temperature.
16. A light emitting diode (LED) assembly comprising:
an LED pixel array; and
an LED controller comprising:
a serial interface configured to connect the LED controller to an external data bus;
an address generator connected to the serial interface and connected to the LED pixel array;
an image frame buffer connected to the serial interface to receive image data and further connected to the address generator to receive an image frame buffer address;
a command and control module connected to the serial interface, the command and control module configured to modify output signals from the image frame buffer; and
a calibration data storage module connected to the command and control module, the calibration data storage module storing calibration data related to pixel voltage responses of pixels in the LED pixel array.
17. The LED assembly of claim 16 , wherein the calibration data comprises a measured forward voltage (V f ) of each pixel in the LED pixel array.
18. The LED assembly of claim 16 , wherein the calibration data comprises a minimum V f , a maximum V f , and an average V f measured for each pixel in an active area of the LED pixel array.
19. The LED assembly of claim 16 , wherein the calibration data further comprises data describing a relationship between V f and temperature.
20. The LED assembly of claim 16 , further comprising a standby image buffer connected to the image frame buffer to hold a default image.