Using current feedback amplifier circuit of LM1875
Posted on Dec 11, 2010 6616
- Other Circuits
Current-sense amplifier to listen better t use amplifier IC LM1875 current-mode amplifier circuit shown in Figure 5-20. FIG resistor R3 and the speaker BL series resistance t i
s small, the speaker of the current flowing through the flow through R3. In its sampling generated across the feedback input through R2 forming a voltage on the output feedback voltage proportional to the current in R3 amplifier end, the composition of the current negative feedback, the amplifier output impedance rises t while reducing damping circuit © the network canceled the so-called Joubert, only C4 for lead compensation. R2 is provided, although then the output current is not fully feedback to the negative input of the feedback, but indeed preventing stop the harmful effects of the large amount of feedback inputs generated; t the same time also make the positive and negative input bias terminal balanced to eliminate output terminal DC offset. On the first, feet two small welding 0. 22 r -JI; F capacitance to their other end welded together as ground resistance grounding of about 6, are bent after welding at this point. 24V power supply line and the output line soldered directly related to the input terminals of the feet daily exchange of short circuit in a welding position the loudspeaker BL ion resistance, power testing ground output voltage 9 as described later, and less than half an hour almost no lOOrnV offset, you can disconnect the input shorting t connect speakers to.