How to activate the professional speaker amplifier protection function?

Here are 6 working modes to enable the professional portable speaker amplifier protection function:

1. Overcurrent protection

When the load of the portable speaker amplifier is too low but does not reach the short-circuit state, the short-circuit protection will not act at this time, but the output current will be very large and exceed the safe use value of the portable speaker amplifier. At this time, the overcurrent protection circuit will intervene in the work. The usual practice est: Control the input voltage and output current so that the power amplifier always works within a safe range.

2. Overheating protection

The well-designed amplifier will not have overheating protection under normal use. It will only act when the external use environment is bad or the internal failure occurs. The hottest part of the whole portable speaker amplifier is the C pole (collector) of the output stage transistor, so the temperature sensor for overheating protection is generally installed in the place closest to the C pole of the transistor or the hottest place on the radiator. The threshold value of overheating protection is generally 95°C, but also 105°C, and the extreme temperature of the transistor is 105°C.

3. Soft start protection value

Audio equipment with a large current draw can flow 4-10 times the average current value at the moment when the power is turned on. This is a shock to the power grid and the equipment itself, and will damage the equipment in severe cases. The soft-start circuit can suppress the inrush of current at the moment when the equipment is switched on and off, so that it can reach normal smoothly to protect the equipment and not cause grid fluctuations. This function is usually achieved with the negative temperature characteristic of the thermistor (NTC).

4. DC protection

When the portable speaker amplifier output stage is damaged or the static bias is shifted, it is possible to deliver a DC signal. For the speaker, its working method only produces impedance to the AC signal, and it does not produce any impedance (equal to zero impedance) for the DC signal. At this time, the current is infinite, so the coil of the speaker is equivalent to a DC signal. A heating wire will burn quickly. So accurate and fast DC protection circuit is very important. The DC protection start value of the portable speaker amplifier is usually set at 2V. When it is greater than or equal to this value, the portable speaker amplifier will cut off the output to protect the speaker. There are also amplifiers that will cut off the output by blowing the built-in DC fuse.

If the DC protection circuit of a portable speaker amplifier is normal, but the coil of the speaker is burned out, there are only two reasons: the power input to the speaker is too large, or the signal output by the portable speaker amplifier is clipped into a square wave.

Short circuit protection

When the output of the portable speaker amplifier is short-circuited for some reason, the current output by the portable speaker amplifier will circulate in its own circuit and become infinite. Such a situation is very dangerous, so there must be accurate and fast short circuit protection circuits to protect the best portable speaker amplifier equipment. Under normal circumstances, when a short circuit occurs in the portable speaker amplifier, first it will control the input signal to reduce its amplitude even to zero. If the situation does not improve (the current flowing through the best portable speaker L'amplificateur dépasse toujours la valeur de sécurité), il supprimera le courant de sortie, permettant au courant qui coule à l'intérieur de l'amplificateur soit toujours inférieur à la valeur sûre de la sortie transistors de scène.

5. Compresseur de distorsion

La valeur de niveau d'entrée de l'équipement audio a une plage spécifiée. S'il dépasse cette plage, le signal sera coupé et dans les cas graves, il deviendra Une onde carrée. La fonction du limiteur de distorsion est de s'assurer que le niveau du signal d'entrée est toujours contrôlé dans la zone de travail linéaire autorisée par l'équipement audio. La norme générale doit démarrer lorsque 1%.