Method for VCOM level adjustment with integrated programmable resistive arrays
AssigneeSTMicroelectronics R&D (Shanghai) Co. Ltd.
InventorsYuxing Zhang, Xiaoru Gao
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Abstract
A calibrator circuit and method for VCOM voltage adjustment for an LCD includes using integrated programmable resistive arrays. The method uses two DACs and three integrated circuit arrays to provide all of the advantages of VCOM calibrator circuits using external resistive voltage-dividers. The integrated circuit resistor arrays reduce the number of external components and PCB space. The method used is suitable for higher resolution adjustment of the VCOM voltage and no calculation is required in the whole adjustment procedure, which saves labor cost, time and enables automation of the calibrator fabrication.
Claims20
A calibrator comprising:
- a first Digital-to-Analog converter;
- a second Digital-to-Analog converter;
- a first resistor coupled between a power supply voltage and a calibrator output having an adjustable value controlled by the first Digital-to-Analog converter;
- a second resistor coupled between the calibrator output and ground having an adjustable value controlled by the first Digital-to-Analog converter;
- and
- a set resistor coupled between an output of the second Digital-to-Analog converter and ground, wherein the current flowing through the set resistor is sourced from the calibrator output.
A calibration method comprising:
- providing a first Digital-to-Analog converter;
- providing a second Digital-to-Analog converter;
- coupling a first resistor between a power supply voltage and a calibrator output having an adjustable value controlled by the first Digital-to-Analog converter;
- coupling a second resistor coupled between the calibrator output and ground having an adjustable value controlled by the first Digital-to-Analog converter;
- coupling a set resistor between an output of the second Digital-to-Analog converter and ground;
- and
- sourcing the current flowing through the set resistor is from the calibrator output.
A calibrator comprising:
- a first resistor, a second resistor, and set resistor in an integrated circuit having an adjustable value controlled by a first Digital-to-Analog converter;
- a resistor divider formed by the first and second resistors having a calibrator output;
- and
- a second Digital-to-Analog converter for controlling the voltage across the set resistor, wherein the current through the set resistor is sourced from the calibrator output.
Dependencies are inferred from the claim text.