Analog driver for led or similar display element
OwnerCharles J Hollomaninventor
Life of this patent
Estimating the term…
Abstract
The analog driver for a display device which is controlled by current, such as an LED, includes a strobed analog input which charges a storage capacitor. The voltage across the storage capacitor is fed to the positive input of a comparator. The negative input of the comparator receives the voltage from a feedback resistor which is in series with the drive voltage, the drive FET (with a gate connected to the output of the comparator) and the light emitting device. Additionally, a reset FET is provided in parallel with the storage capacitor. Displays can be manufactured by a series of panels, each of the panels including an array of these drivers and light emitting devices, along with appropriate control circuitry.
Claims22
A device for controlling current through a light emitting device in accordance with an analog informational signal, comprising:
- means for receiving the analog informational signal,
- means for charging a capacitor in accordance with the analog informational signal, and
- feedback means for controlling current through the light emitting device through a substantially continuous range thereby varying a brightness of the light emitting device through a substantially continuous range in response to changes in a voltage across said capacitor responsive to said analog informational signal.
A device for controlling current through a three color light emitting device in accordance with three respective analog informational signals, wherein said three color light emitting device includes three respective color circuits, the device comprising for each respective analog informational signal:
- means for receiving the respective analog informational signal,
- means for charging a capacitor in accordance with the respective analog informational signal, and
- feedback means for controlling current through the respective color circuit of light emitting device through a substantially continuous range thereby varying a brightness of the light emitting device through a substantially continuous range in response to changes in a voltage across said capacitor responsive to said respective analog informational signal.
A panel including rows and columns of three color light emitting devices, each of said three color light emitting device responding in accordance with three respective analog informational signals, wherein each said three color light emitting device includes three respective color circuits, and comprising for each respective analog informational signal:
- means for receiving the respective analog informational signal,
- means for charging a capacitor in accordance with the respective analog informational signal, and
- feedback means for controlling current through the respective color circuit of light emitting device through a substantially continuous range thereby varying a brightness of the light emitting device through a substantially continuous range in response to changes in a voltage across said capacitor responsive to said respective analog informational signal.
Dependencies are inferred from the claim text.