Principle of current negative feedback power amplifier circuit
In this paper, a WDB228 Class B power amplifier is "Motor", which makes it a current negative feedback power amplifier. The sound quality is very satisfactory.
Circuit principle: Figure 4-13 shows the WDB228 power amplifier circuit. The circuit is a quasi-DC structure, the input stage (VT1, VT2) is differentially amplified; the main voltage amplification stage (VT3, VT4) also uses differential amplification; VT5 and VT6 form a mirror circuit, and the VT5 collector is connected to the base to make the collector of VT3 The signal is directly applied to the base of VT6. As a result, VT4 and VT6 form a push-pull amplifier stage, which not only has low distortion, but also high gain. In addition, the input stage is equipped with a low-pass filter, and the output has a "Jubel" RC network to improve the resistance. Interference and anti-vibration performance; VD3~VD5 is to enhance the temperature compensation capability. However, because the final stage is designed as a pure B-type output, the playback effect of the "stone machine" is very strong, the sound quality of the small and medium volume is good, the sound is hard at high volume, and accompanied by severe crossover distortion. In view of this deficiency, one is to increase the class A dynamic bias circuit, to increase the final stage quiescent current to reduce the effect of the distortion, and the other is to change the feedback form of the circuit, so that the voltage negative feedback is the current negative feedback. To improve the distortion caused by the mechanical vibration of the speaker.
Fiber Optic Splice Closure,Fiber Optic Splice Case,Fiber Splice Closures,Outdoor Fiber Optic Splice Closure
Cixi Dani Plastic Products Co.,Ltd , https://www.danifiberoptic.com