초록 ▼

A backlight for an LCD display comprised of an array of LEDs. The backlight may be driven and controlled by a fast pulse power converter, thus providing a response time for the backlight on the order of microseconds. The backlight may thus be used for image display, for example, in the depiction of

A backlight for an LCD display comprised of an array of LEDs. The backlight may be driven and controlled by a fast pulse power converter, thus providing a response time for the backlight on the order of microseconds. The backlight may thus be used for image display, for example, in the depiction of images in a video input to the LCD and removal of image artifacts.

대표청구항 ▼

1. A LED backlight for an LCD display, comprising:a primary circuit for generating a primary voltage; a first secondary circuit coupled to said primary circuit for receiving a first secondary voltage as a function of the primary voltage, said first secondary circuit including a first sub-array of LE

1. A LED backlight for an LCD display, comprising:a primary circuit for generating a primary voltage; a first secondary circuit coupled to said primary circuit for receiving a first secondary voltage as a function of the primary voltage, said first secondary circuit including a first sub-array of LEDs of a first color, a first sub-array switch operable in a first ON state for allowing a flow of a first LED current through said first sub-array of LEDs, the first LED current being a function of said first secondary voltage, and a first sub-array controller for controlling an operation of said first switch in the first ON state; and a second secondary circuit coupled to said primary circuit for receiving a second secondary voltage as a function of the primary voltage, said second secondary circuit including a second sub-array of LEDs of a second color, a second sub-array switch operable in a second ON state for allowing a flow of a second LED current through said second sub-array of LEDs, the second LED current being a function of said second secondary voltage, and a second sub-array controller for controlling an operation of said second switch in the second ON state, wherein said first sub-array controller controls the operation of said first sub-array switch in the first ON state and said second sub-array controller controls the operation of said second sub-array switch in the second ON state in a mutually exclusive manner. 2. The LED backlight of claim 1,wherein said first sub-array controller controls the operation of said first switch in the first ON state as a function of a first feedback voltage indicative of a first LED voltage across said first sub-may of LEDs. 3. The LED backlight of claim 2,wherein said second sub-array controller controls the operation of said second switch in the second ON state as a function of a second feedback voltage indicative of a second LED voltage across said second sub-array of LEDs. 4. The LED backlight of claim 1,wherein said first sub-array controller controls the operation of said first switch in the first ON state as a function of a first reference current indicative of a first commanded light output of said first sub-array of LEDs. 5. The LED backlight of claim 4,wherein said second sub-array controller controls the operation of said second switch in the second ON state as a function of a second reference current indicative of a second commanded light output of said second sub-array of LEDs. 6. The LED backlight of claim 1,wherein said first sub-array controller modulates the first LED current when said first sub-array switch is operating in the first ON state. 7. The LED backlight of claim 6,wherein said second sub-array controller modulates the second LED current when said second sub-array switch is operating in the second ON state. 8. The LED backlight of claim 1,wherein said first sub-array controller controls at least one of a first pulse-amplitude modulation, a first pulse-width modulation, and a first pulse-frequency modulation of the first LED current when said first sub-array switch is operating in the first ON state. 9. The LED backlight of claim 8,wherein said second sub-array controller controls at least one of a second pulse-amplitude modulation, a second pulse-width modulation, and a second pulse-frequency modulation of the second LED current when said second sub-array switch is operating in the second ON state. 10. The LED backlight of claim 1,wherein said first secondary voltage is applied between a first point and a second point; wherein said first sub-array switch includes a first current path for connecting said first point to said first sub-array of LEDs when said first sub-array switch is operating in the first ON state; wherein said first sub-array switch further includes a first control input for controlling the operation of said first sub-array switch in the first ON state; and wherein said first sub-array controller is connected to said first control input to thereby control the operation of said first sub-array switch in the first ON state. 11. The LED backlight of claim 10,wherein said second secondary voltage is applied between a third point and a fourth point; wherein said second sub-array switch includes a second current path connecting said third point to said second sub-array of LEDs when said second sub-array switch is operating in the second ON state; wherein said second sub-array switch further includes a second control input for controlling the operation of said second sub-array switch in the second ON slate; and wherein said second sub-array controller is connected to said second control input to thereby control the operation of said second sub-array switch in the second ON state. 12. The LED backlight of claim 2,wherein said first secondary voltage is applied between a first point and a second point; wherein said first sub-array switch includes a first current path for connecting said first point to said first sub-array of LEDs when said first sub-array switch is operating in the first ON state; wherein said first sub-array switch further includes a first control input for controlling the operation of said first sub-array switch in the first ON state; and wherein said first sub-array controller is connected to said first control input to thereby control the operation of said first sub-array switch in the first ON state. 13. The LED backlight of claim 12,wherein said first secondary circuit further includes a resistor connected to said first sub-array of LEDs and said first sub-array controller to facilitate a determination of the first feedback voltage by said first sub-array controller. 14. The LED backlight of claim 3,wherein said first secondary voltage is applied between a first point and a second point; wherein said first sub-array switch includes a first current path for connecting said first point to said first sub-array of LEDs when said first sub-array switch is operating in the first ON state; wherein said first sub-array switch further includes a first control input for controlling the operation of said first sub-array switch in the first ON stale; wherein said first sub-array controller is connected to said first control input to thereby control the operation of said first sub-array switch in the first ON state. 15. The LED backlight of claim 14,wherein said first secondary circuit further includes a resistor connected to said first sub-array of LEDs and said first sub-array controller to facilitate a determination of the first feedback voltage by said first sub-array controller. 16. The LED backlight of claim 14,wherein said second secondary voltage is applied between a third point and a fourth point; wherein said second sub-array switch includes a second current path for connecting said third point to said second sub-array of LEDs when said second sub-array switch is operating in the second ON state; wherein said second sub-array switch further includes a second control input for controlling the operation of said second sub-array switch in the second ON state; and wherein said second sub-array controller is connected to said second control input to thereby control the operation of said second sub-array switch in the second ON state. 17. The LED backlight of claim 16,wherein said first secondary circuit further includes a first resistor connected to said first sub-array of LEDs and said first sub-array controller to facilitate a determination of the first feedback voltage by said first sub-array controller; and wherein said second secondary circuit further includes a second resistor connected to said second sub-array of LEDs and said second sub-array controller to facilitate a determination of the second feedback voltage by said second sub-array controller. 18. The LED backlight of claim 1, further comprising:a transformer including a first magnetic coupling of a primary winding and a first secondary winding, wherein said primary circuit is connected to said primary winding to thereby apply the primary voltage across said primary winding whereby the first secondary voltage is applied across said first secondary winding, and wherein said first secondary circuit is connected to said first secondary winding. 19. The LED backlight of claim 1,wherein said transformer further includes a first magnetic coupling of a primary winding and a first secondary winding, and a second magnetic coupling of said primary winding and a second secondary winding; wherein said primary circuit is connected to said primary winding to thereby apply the primary voltage across said primary winding whereby the first secondary voltage is applied across said first secondary winding and the second secondary voltage is applied across said second secondary winding; and wherein said first secondary circuit is connected to said first secondary winding and the second secondary circuit is connected to said second secondary winding. 20. The LED backlight of claim 1, further comprising:a third secondary circuit coupled to said primary circuit for receiving a third secondary voltage as a function of the primary voltage, said third secondary circuit including a third sub-array of LEDs of a third color, a third sub-array switch operable in a third ON state for allowing a flow of a third LED current through said third sub-array of LEDs, the third LED current being a function of said third secondary voltage, and a third sub-array controller for controlling an operation of said third switch in the third ON state, wherein said first sub-array controller controls the operation of said first sub-array switch in the first ON state, said second sub-array controller controls the operation of said second sub-array switch in the second ON state, and said third sub-array controller controls the operation of said third sub-array switch in the thud ON state in a mutually exclusive manner.