Super power amplifier circuit

The super power amplifier module circuit is actually a quasi-Class B synchronous dynamic bias power amplifier circuit. It not only has
the high efficiency of Class B power amplifiers, but also has the excellent sound quality of Class A power amplifiers, and completely eliminates the switching distortion of Class A and B amplifiers
. The actual circuit is different from the Class A synchronous dynamic bias circuit. It has a simple structure and
integrates multiple protection functions such as overvoltage, overcurrent, overheating, anti-speaker impact, and anti-polarity reverse connection.
It has reached a high level in many aspects such as static micro-power consumption, dynamic response speed, low distortion , frequency response, etc. The circuit structure is shown in Figure 2-17. The differential input stage consists of VT6 to VT8
. The middle main gain stage is composed of VTg.VTi2 and so on. The power output stage is composed of VTii - VT13.VT14, VT16,
VT17.VTis, VT19VT20, VT2i, etc. The dynamic bias circuit is composed of VT4, VTs, VTi2, etc. The protection
circuit is composed of VTi.VT2, VT3, VD4, VTio, Vrl5, etc. The total bias voltage regulator is composed of, 1) l, c1, VI,
Rt, etc. The anti-polarity reverse connection consists of VI wind, v] domain, C3.Rio, C6, and Rl2. The switch anti-shock circuit
is composed of VTl, Ci.VT4, VT6, etc. The entire circuit uses direct coupling.
    Main gain stage dynamic bias circuit: This circuit uses a unique synchronous dynamic bias circuit, cleverly setting VT4
in the constant current source link of the differential stage, making full use of the dynamic exchange of the AC impedance (potential) of the constant current source. During the change process,
the shield-level VT12 is controlled with bias current synchronized with the signal through VT4, so as to achieve the purpose of dynamic bias amplification in synchronization with the subsequent stage power amplifier.
Usually, VTLZ in a traditional power amplifier is the constant current source load of the intermediate voltage amplifier stage Vb. Here, VTiz and
VTg are used as collector synchronization dynamic current loads with each other. VT12 is also
the main control tube for the final stage of overcurrent, overheating, overvoltage and dynamic bias current .
    When static, the stable bias voltage of 6, SV (to V one) provided by VD2 passes through the eb junction of R7, VDb, VT6, and R14
to form the static bias of the differential input stage and the static bias of VTs, which can be calculated VrU4≈0,5V, VT5 is in the cut-off state
and VT4 is also in the cut-off state, so it cannot provide a bias voltage for VTiz, so that the final power amplifier tube is in a non-biased
cut-off state. At this time, the quiescent current of the entire power amplifier circuit is only The operating current of the integrated control circuit and differential input stage in the dotted box
,