Texas Instruments SLOU121 manual 5.Block Diagram of SE Volume Control, Details

The TPA6011A4 Audio Power Amplifier Evaluation Module

SEDIFF and SEMAX pins control the singe-ended gain proportional to the gain set by the voltage on the VOLUME pin. When SEDIFF = 0 V, the difference between the BTL gain and the SE gain is 6 dB. The voltage on the SEDIFF terminal is subtracted from the voltage on the VOLUME terminal and the value is used to determine the SE gain. Turning the potentiometer R6 in the clock- wise direction decreases the voltage on the SEDIFF terminal, resulting in a higher volume in the single-ended mode of operation. The voltage on the SE- DIFF terminal is subtracted from the voltage on the VOLUME terminal and the value is used to determine the SE gain.

The SEMAX terminal controls the maximum gain for single ended mode. Turn- ing potentiometer R7 in the clockwise direction increases the voltage on the SEMAX terminal, resulting in a higher volume limit for single-ended operation. The functionality of the SEDIFF and SEMAX pin are combined to set the SE gain. A block diagram of the combined functionality is shown in Figure 3–5. The value obtained from the block diagram for SE_VOLUME is a dc voltage that can be used to determine the SE gain using Table 3–2. Again, the voltages listed in the table are for VDD = 5 V. The values must be scaled for other VDD voltages.

Figure 3–5. Block Diagram of SE Volume Control

	SEDIFF (V)			SEMAX (V)
VOLUME (V)	+	–	VOLUME–SEDIFF	Is SEMAX>
					NO
				(VOLUME–SEDIFF)?
				YES
			SE_VOLUME (V) = SEMAX (V)

SE_VOLUME (V) = VOLUME (V) – SEDIFF (V)

3-6 Details