TPA2028D1_17 Datasheet, PDF (25/43 Pages) Texas Instruments – 3-W Mono Class-D Audio Amplifier With Fast Gain Ramp SmartGain AGC/DRC

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TPA2028D1
SLOS660C – JANUARY 2010 – REVISED OCTOBER 2015
Device Functional Modes (continued)
gain during software shutdown, regardless the attack/ release time. For example:
– Audio is playing at fixed gain 6dB
– Devices goes to software shutdown (SWS = 1)
– Set fixed gain from 6 dB to 12 dB
– Remove software shutdown (SWS = 0)
– Amplifier starts up immediately at 12 dB
3. During audio playback with AGC on, gain changes according to attack/ release time. For example:
– Audio is playing at fixed gain 6 dB and 1:1 compression ratio
– Set fixed gain from 6 dB to 12 dB, at release time 500 ms / 6 dB
– Amplifier will take 500 ms to ramp from 6 dB to 12 dB
4. When EN = 0 and SWS = 0, the amplifier is set at fixed gain. The amplifier starts up at fixed gain when EN
transitions from 0 to 1.
The default conditions of TPA2028D1 allows audio playback without I2C control. Refer to Table 5 for entire
default conditions.
There are several options to disable the amplifier:
• Write EN = 0 to the register (0x01, 6). This write disables the amplifier, but leaves all other circuits operating.
• Write SWS = 1 to the register (0x01, 5). This action disables most of the amplifier functions.
• Apply V_IL to EN. This action shuts down all the circuits and has very low quiescent current consumption. This
action resets the register to its default values.
NOTE
Do not interrupt the shutdown sequence after changing EN from V_IH to V_IL.
Do not interrupt the shutdown sequence after changing SWS from 0 to 1.
9.4.3 Short Circuit Auto-Recovery
When a short circuit event happens, the TPA2028D1 goes to low duty cycle mode and tries to reactivate itself
every 110 µs. This auto-recovery will continue until the short circuit event stops. This feature can protect the
device without affecting the device's long term reliability. FAULT bit (register 1, bit 3) still requires a write to clear.
9.5 Programming
9.5.1 TPA2028D1 AGC Recommended Settings
Table 3. Recommended AGC Settings for Different Types of Audio Source (V_DD = 3.6 V)
AUDIO
SOURCE
COMPRESSION ATTACK TIME
RATIO
(ms/6 dB)
RELEASE TIME
(ms/6 dB)
HOLD TIME
(ms)
FIXED GAIN LIMITER LEVEL
(dB)
(dBV)
Pop Music
4:1
1.28 to 3.84
986 to 1640
137
6
7.5
Classical
2:1
2.56
1150
137
6
8
Jazz
2:1
5.12 to 10.2
3288
—
6
8
Rap / Hip Hop
4:1
1.28 to 3.84
1640
—
6
7.5
Rock
2:1
3.84
4110
—
6
8
Voice / News
4:1
2.56
1640
—
6
8.5
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