Voice IC is generally divided into four audio output modes. But there are only two common ones. What are the four? They are: current DAC audio output mode, dual PWM Direct Push audio output mode, voltage DAC audio output mode and class a/b output mode. Let’s talk about their advantages and disadvantages.
Current mode DAC audio output mode
Compared with the external circuit, it is simple and can be directly connected to the triode amplifier. Because the triode is a current type device, if the triode amplifier is connected, only one shunt resistor and one triode can output audio. If it is connected to a power amplifier, it only needs a shunt resistor and a coupling capacitor.
The disadvantage is that if the external triode is used for output, the DC component in the horn is easy to cause excessive power of the horn. The no-load current is also large, burning the horn. And the audio output efficiency is low. If the shunt resistance value is not appropriate, it is easy to cause the output sound quality to deteriorate.
PWM Direct Push audio output mode
The main advantage of this audio output mode is that it can directly connect the horn to output audio without external components, and will not produce distortion. However, the disadvantages are also obvious. The output power is limited. If you want greater output power, the power amplifier circuit is relatively complicated, and the sound quality is also lost. The second disadvantage is that it is easy to generate high-frequency current in the horn when playing sound, resulting in the increase of martial arts power.
Voltage type DAC audio output mode
This kind of voice IC is generally used for external power amplifier. You can also use a triode to amplify audio, but the circuit is relatively complex. And the class a amplification efficiency of triode is less than 50%, so it is generally used for external power amplifier. The external power amplifier circuit is similar to the voice chip of current mode DAC audio output mode. Of course, this kind of audio output voice IC is not without advantages. The advantage is that the output sound quality is good.
Class a/b audio output mode
This kind of voice IC has the advantage of good sound quality and high relative efficiency, generally more than 75%. If the external audio power amplifier is relatively simple, it is similar to the voice chip of DAC audio output mode.
The disadvantage is that the circuit is relatively complex and the cost is relatively high. In fact, this kind of audio output mode can be said to be an audio output mode. This kind of audio output mode is mainly a voltage type DAC plus an a/b class audio amplifier. Because this kind of audio output is processed by full analog circuit, there is relatively no high-frequency harmonic current.