Gavin 在 2004-2-7 18:17:44 发表的内容
小弟认为, 大电流功放设计是指末级功率管工作点采用大静态电流设计,而不是功放的输出电流. 好处不用多说, A类(甲类)机优势.
NELSON PASS设计理念中一个重要的特点是,晶体管的静态电流要远远大于信号电流.他为DIY土炮党提供过一个叫SON OF ZEN的电路,A类两声道2X10W左右的输出功率,竟然要1000W的电源变压器.是一个很典型很疯狂的大电流功放设计.我和一些DIY好友却非常喜欢. |
Large current design topology is not what you mean. When you said, idleing current is much larger than the signal current is incorrect. Signal current
is so small that idleing current of the power transistor is much larger then signal current. Idling current is designed fromthe designer according to his
design. Sometimes related to the power transistors used. Furthermore,
signal is on the issue of signal voltage but not count on how large is the
current unless the signal source is of very low impedance such as the ouput signal from the power amplifier. Then again this is low impedance drive,
it take lots of current but it also need certain high voltage to drive the
current into the loading. In this case, loading is the loudspeaker.
Class A is another matter. The theory is based on the idling current is
biased at half of the full power output current. This is class A.
When one claims that large current design, means the power amp is able
to drive theoritically almost any impedance loading,say from 1 to 8 Ohm
load and when one claims at 8 Ohm load would produce 100 Watt,
then at 4 Ohm, it gives 200 Watt, and so on. Some amp even can drive
down to 1 Ohm. In this case the power output should produce 800 Watts.
Of course, any amplifier cannot drive zero Ohm loading, at this point, the
output become infinity and also the required current is infinity.
Your comment might mislead the juniors. Please be careful.
