Power Amplifier Circuit Design with IC LME49810
Power output level by the two pairs NJL3281D/1302D parallel to better drive 4 Ω impedance of the speakers or less, R19, R20, R22, R23 may be used to inhibit the high-frequency oscillations, from 10 Ω resistance can be. VD1 and VD2 for the protection of output power, to avoid being loaded on the induced voltage damage. VT7 and the surrounding circuit constitutes a bias voltage circuit, in our production, VT7 has been fixed in the power output of the heat sink, we can adjust potentiometer RP1 of resistance, to facilitate adjustment bias current So that the flow RP1 for the current 2.8 mA. The amplifier circuit is part of the feedback loop 2, the audio signal, the feedback loop from the main R11, R12, R30 and C12 components, the amplifier gain of [1 + (R11 + R30) / R12]. At a higher frequency, C11 and C12 can be regarded as short-circuit, the negative feedback to promote the routing level feedback to replace the power output level feedback, to gain power amplifier (1 + R29/R12). This feedback way to increase the stability of the circuit, especially the drive capacitive load of times. Therefore, the amplifier design more suitable for all types and purposes of the circuit experiment.
We generally understand the composition of the circuit, the output protection circuits and DC servo circuit does not draw the map, they will be placed on an independent board and will in the future in an article devoted to. Production process and the value of each component will also be presented in the following article. Readers could be in accordance with their friends in need of output power and circuit configuration calculated and the experimental.
Examples of welding see Figure 1, the transistor can be drive-TO-126 or TO-220 packages, the board reserved the heat sink position. Feedback circuit sampling point is very important, can refer to the original product manuals, in fact, PCB on the copper lines is not zero resistance, see Figure 11, A point and the existence of potential difference point B, B, is the correct Negative feedback sampling point, and point A is not.
We generally understand the composition of the circuit, the output protection circuits and DC servo circuit does not draw the map, they will be placed on an independent board and will in the future in an article devoted to. Production process and the value of each component will also be presented in the following article. Readers could be in accordance with their friends in need of output power and circuit configuration calculated and the experimental.
Examples of welding see Figure 1, the transistor can be drive-TO-126 or TO-220 packages, the board reserved the heat sink position. Feedback circuit sampling point is very important, can refer to the original product manuals, in fact, PCB on the copper lines is not zero resistance, see Figure 11, A point and the existence of potential difference point B, B, is the correct Negative feedback sampling point, and point A is not.
Figure 1 using the power amplifier circuit design LME49810
Figure 2 LME49810 amp components Location
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