SN761677DAR

Due to market price fluctuations, if you need to purchase or consult the price. You can contact us or emial to us:   sales@allicdata.com

SN761677DAR Application Field and Working Principle

The SN761677DAR is a linear integrated circuit that is widely used in applications needing an adaptive control scheme to maintain an output signal level that is feedback-compensated against changing conditions. It can be used in video processing, such as video scalers and video signalling, as its digital output is slaved to an input digitized video signal that can itself change level with a fast variation.

Because the circuit combines control feedback with a zener diode, it is useful in providing signal correction even with long-term input variations that might otherwise require manual adjustment. It is also useful in applications where the peak level should remain constant with changing input signal conditions such as signal level adaptation, absolute video level indicators and display drivers.

Working Principle

When used in video processing, the SN761677DAR circuit maintains a constant output voltage for a given input voltage, irrespective of varying conditions such as the age of components over time, temperature, humidity and supply voltage. Once the circuit is powered up, the output level is adjusted by applying a reference voltage to the circuit\'s linear input, which will then automatically regulate the output to a predetermined level.

The circuit functions by combining a standard voltage regulator with a zener diode. The reference voltage is based on the zener voltage and a current is passed through the zener diode which is monitored and then used to determine the output voltage. The zener voltage will remain constant no matter what the output voltage is which allows the circuit to adjust itself to maintain the pre-determined output level.

The output voltage is slightly pre-regulated by the circuit\'s Voltage Reference Stage and then further adjusted to the exact preset level. The output voltage is then combined with the zener voltage in the Error Amp stage, which is directly connected to the feedback loop. If the output voltage does not match the preset reference level, the Error Amp will generate an error signal that is used to adjust the voltage regulator, which in turn will adjust the output voltage until the preset voltage is reached.

Applications

The SN761677DAR is a versatile, linear circuit that is used in many video processing applications. It can be used in video scalers, video signalling, absolute video level indicators, display drivers, signal level adaptation and any other application that requires a feedback-compensated output.

In video scalers, the SN761677DAR is used to create smooth transitions of the video signal, allowing it to better match the input and output device, while also maintaining a constant image brightness level. Video signalling applications, such as television broadcast or cable, can use this circuit to maintain a constant signal level despite varying input voltage and temperature. Signal level adaptation applications also make use of this circuit, allowing a device to detect the input and output signals with minimal discrepancies.

The SN761677DAR is also used in display drivers, providing them with the ability to display a consistent image with no visible variation in brightness level, despite changes of the driving current. Additionally, absolute video level indicators make use of the SN761677DAR to ensure that an output voltage is reached and maintained irrespective of varying conditions, such as temperature, load, age and supply voltage.

The specific data is subject to PDF, and the above content is for reference