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Five kinds of sound system amplifier protection mechanism

A good amplifier is very important to the sound system. Sometimes, the sound system at work suddenly suddenly no sound, and may be the protection function of the amplifier at work. So, what are the power amplifier protection it, when the amplifier fails how to investigate? Today, we come to reveal the five kinds of amplifier protection function. High-current absorption beats earphones of audio equipment, when the instantaneous power supply connected to the current value reaches its average current value of 4-10 times, the power grid Beats By Dre Cheap and the device itself will have an impact, or even damage the device. At this point, the soft-start circuit in the equipment switch instantaneous suppression of the influx of current, so that it smoothly to normal, in order to protect the equipment and does not cause grid fluctuations. Soft-start protection is usually achieved with the negative temperature characteristic of a thermistor (NTC). When the power amplifier output stage is damaged or the static bias is offset, the DC signal may be transmitted. For a loudspeaker, it only produces impedance for the ac signal, but it does not produce any impedance (equal to zero impedance) for the dc signal, and the current is infinite. The coil of the loudspeaker is in this case equivalent to a heat Silk, will be quickly burned. Therefore, fast and accurate DC protection circuit is very important. Normally, the amplifier DC protection start value is set at 2V, when greater than or equal to this value the amplifier will cut off the output to protect the speaker. In addition, there is also a power amplifier with a built-in DC blow fuse to cut off the output.

This may happen. Amplifier DC protection circuit is normal, the speaker coil is burned, the reason - the input power to the speaker is too large or amplifier output signal into a square wave. When the output of the amplifier is shorted for some reason, the output current will cycle through its own line and become infinite. Once this situation is very dangerous, there must be an accurate and fast short circuit protection circuit to protect the equipment. Under normal circumstances, the amplifier in the event of a short circuit, first of all it will control the input signal, so that its amplitude decreases even zero. If the situation does not improve (the current flowing through the amplifier still exceeds the safe level), it suppresses the output current, leaving the current flowing inside the amplifier always below the safe level of the output stage transistor.

When the power amplifier load is too low and did not reach the short circuit state, no short circuit protection action, but the output beats by dre current will be very large power amplifier safety value, the overcurrent protection circuit will intervene: control input voltage and output current , Let the power amplifier always work in the safe range. Under normal use, the amplifier will not overheat protection, only when the external use of harsh environment or internal failure will be action. The hottest part of the entire amplifier is the C-pole (collector) of the output stage transistor, so the overheat-protected temperature sensor is typically mounted in the hottest place on the C pole of the transistor or on the heatsink. Overheating protection threshold is generally 95 , there are 105 , the extreme temperature of the transistor is 105 .