Using The TPA0242 EVM With the
3.3.4Mute (Shutdown)/Mode
The TPA0242 EVM is equipped with a shutdown control input pin. When this input is pulled to ground, the TPA0242 amplifier IC on the module enters the shutdown mode and dissipates very little power. While in the shutdown mode, the PC BEEP input is still active. When the EVM control input is tied to GND or allowed to float, normal amplifier operation resumes.
In typical applications, as often found in notebook computers, portable audio products, and such, the internal speakers mute when headphones are plugged into the headphone jack, or internal speakers mute when external speakers are connected. In applications using separate speaker and headphone amplifiers, the one not being used can be shut down to conserve power.
A mode control input pin on the EVM switches the TPA0242 amplifier IC between the
In the typical application, output mode switching allows the TPA0242 to operate in the BTL output mode for increased power to internal speakers and then switch to
3.3.4.1Headphone Jack Control Signals
The platform headphone output jack (J10) contains an internal switch that changes the state of a pair of control lines when a plug is inserted (Figure 3±7). Each control line is pulled down by a
Figure 3±7. Mute/Mode and Polarity Control
| VDD |
|
| R3 | Polarity |
| 240 Ω | |
| JP8 | |
|
| |
J10 |
| Lo |
|
|
Headphone
Jack |
| Hi | |
R4 | R5 | ||
SPK | |||
1 kΩ | 1 kΩ | (U2±U4) |
JP6
Mode | U2 |
| |
| Power |
Mute | Amplifier |
|
Details |