Platform Signal Routing And Outputs - Texas Instruments TPA0152 User Manual

Using The TPA0152 EVM With the Plug-N-Play Evaluation Platform
3.3.3 Signal Routing
Signal flow on the platform is controlled by two signal routing switches, as
shown in Figure 3 – 6.
Figure 3–6. Platform Signal Routing and Outputs
R
U1
Audio
Signal
Input
Conditioning
L
3.3.3.1 Signal Conditioning
The audio signal from the input jacks can be applied to the signal conditioning
socket (U1) if an EVM is installed there, or socket U1 can be bypassed and the
audio input signal applied directly to the inputs of the TPA0152.
3.3.3.2 Headphone Output Jack
Switch S3 is the source select for the stereo headphone output jack, J10. The
headphone jack is capacitively coupled (via 470 µF electrolytics) and can
output either the signal from the headphone amplifier in socket U5, or the
signal from the TPA0152 power amplifier installed in socket U2, as determined
by the setting of headphone source select switch S3.
When S3 is set to the power amplifier position (U2 – U4), the headphone jack
is connected to the TPA0152 power amplifier OUT+ output lines. When a plug
is inserted into the jack, signals output through J10 are returned to platform
ground, requiring single-ended power amplifier operation. A switch inside the
headphone jack produces a control signal that can be routed to the power
amplifier socket to shut down the TPA0152 EVM or switch it to single-ended
output mode when a plug is inserted.
Source select switch S3 connects the headphone jack to the output lines of
either the headphone amplifier socket U5, or the power amplifier sockets
(U2 – U4).
3-12
Off
U2
TPA0152
S2
Amplifier EVM
On
U5
Stereo
Headphone
Amplifier
Switch S2 selects signal conditioning or bypasses it
J
To keep the TPA0152 amplifier outputs separated, set switch S3 to the
headphone amplifier position ( U5 ) and use the speaker outputs (J7,
J8, and J9)
J
To route the TPA0152 amplifier outputs to the headphone output jack
(J10), set switch S3 to the power amplifier position ( U2 – U4 ) — use
this setting only if the TPA0152 EVM is to drive single-ended loads
connected to J10
+
R
R
–
–
L L
+
U2 – U4
R
+
R
–
GND
S3
L
–
+
L
U5
J7, J8, J9
Speaker
Outputs
J10
Headphone
Output
Details