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***how to have contrast with my LCD display **

pea brain

Hello, i'm currently doing a project using LCD. Could someone help me on how to add contrast feature to my LCD display. I'm using C as my default programming language.

Thanks, greatly appreciated.

***Pea_brain***

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    Usually contrast is controlled by the bias voltage applied to the LCD. This voltage is different for different LCDs but is usually negative with respect to common. If there is a bias generator IC or it is built into the LCD and there is a control input, you can control contrast with that, using a digital pot, D/A output or PWM. If you are creating the bias voltage you can design the system to allow variable voltage, remembering that the contrast vs. bias voltage is usually temperature dependent. I've used a negative charge pump with output regulator run by the '167s PWM output to create a bias of -5 - -15Vdc @ 10ma. for an Optrex display.
    Best luck

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  • 0

    Usually contrast is controlled by the bias voltage applied to the LCD. This voltage is different for different LCDs but is usually negative with respect to common. If there is a bias generator IC or it is built into the LCD and there is a control input, you can control contrast with that, using a digital pot, D/A output or PWM. If you are creating the bias voltage you can design the system to allow variable voltage, remembering that the contrast vs. bias voltage is usually temperature dependent. I've used a negative charge pump with output regulator run by the '167s PWM output to create a bias of -5 - -15Vdc @ 10ma. for an Optrex display.
    Best luck

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