Automatic volume restrict in color TV and device of providing truly accompanying sound only

Abstract

In the invention, the switch regulated power supply runs at three modes: in normal operation, stand by, and as power source of truly accompanying sound only. The invention features energy saving, compact, reliable, avoiding distortion of accompanying sound and protecting loud speaker and power amplifier of accompanying sound.

Description

Technical field [0001] The invention mainly relates to the field of television technology. Background technique [0002] During the so-called "screen saver" or "listening alone" of the prior art, field scanning, decoding circuit and kinescope circuit are still working. Only turn down the contrast and brightness to the minimum. Power consumption has not slowed down significantly. What is even more harmful is: when the ultra-high voltage of the line output stage is in the screen saver or alone, it will rise to the maximum value, and it is easier to absorb moisture and cause high-voltage ignition failure. [Although "listening alone" for a long time can cut off the line output stage, the advantage of less power consumption. However, due to the excessive light load or no load of the power supply in most normal working states, the frequency rises and serious heating occurs. The power supply is easily damaged and unfavorable to the picture tube, unless a new "listening alone" p...

AI Technical Summary

Problems solved by technology

If the manufacturer sets the maximum distortion power at 70% of the original adjustment, then it is possible to encounter a channel with a low sound, even if the adjustment is increased to 100%, the sound is still extremely low, which cannot meet the needs.

If the manufacturer sets the original adjustment rate to 20% to achieve the maximum distortion-free, then it is possible to encounter a channel with a loud voice, which may cause sound distortion or even burn out the speaker or sound amplifier.

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