Texas Instruments TLV320AIC3105 Evaluation Module (EVM) and USB motherboard TLV320AIC3105EVM-K TLV320AIC3105EVM-K Datenbogen
Produktcode
TLV320AIC3105EVM-K
SHORT-CIRCUIT OUTPUT PROTECTION
JACK/HEADSET DETECTION
www.ti.com
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SLAS513B – FEBRUARY 2007 – REVISED DECEMBER 2008
The high-power output drivers include additional circuitry to avoid artifacts on the audio output during power-on
and power-off transient conditions. The user should first program the type of output configuration being used in
page 0, register 14 to allow the device to select the optimal power-up scheme to avoid output artifacts. The
power-up delay time for the high-power output drivers is also programmable over a wide range of time delays,
from instantaneous up to 4 s, using page 0, register 42.
and power-off transient conditions. The user should first program the type of output configuration being used in
page 0, register 14 to allow the device to select the optimal power-up scheme to avoid output artifacts. The
power-up delay time for the high-power output drivers is also programmable over a wide range of time delays,
from instantaneous up to 4 s, using page 0, register 42.
When these output drivers are powered down, they can be placed into a variety of output conditions based on
register programming. If lowest-power operation is desired, then the outputs can be placed into a
high-impedance state, and all power to the output stage is removed. However, this generally results in the output
nodes drifting to rest near the upper or lower analog supply, due to small leakage currents at the pins. This then
results in a longer delay requirement to avoid output artifacts during driver power on. In order to reduce this
required power-on delay, the TLV320AIC3105 includes an option for the output pins of the drivers to be weakly
driven to the VCM level they would normally rest at when powered with no signal applied. This output VCM level
is determined by an internal bandgap voltage reference, and thus results in extra power dissipation when the
drivers are in power down. However, this option provides the fastest method for transitioning the drivers from
power down to full-power operation without any output artifact introduced.
register programming. If lowest-power operation is desired, then the outputs can be placed into a
high-impedance state, and all power to the output stage is removed. However, this generally results in the output
nodes drifting to rest near the upper or lower analog supply, due to small leakage currents at the pins. This then
results in a longer delay requirement to avoid output artifacts during driver power on. In order to reduce this
required power-on delay, the TLV320AIC3105 includes an option for the output pins of the drivers to be weakly
driven to the VCM level they would normally rest at when powered with no signal applied. This output VCM level
is determined by an internal bandgap voltage reference, and thus results in extra power dissipation when the
drivers are in power down. However, this option provides the fastest method for transitioning the drivers from
power down to full-power operation without any output artifact introduced.
The device includes a further option that falls between the other two—although it requires less power drawn
while the output drivers are in power down, it also takes a slightly longer delay to power up without artifact than if
the bandgap reference is kept alive. In this alternate mode, the powered-down output driver pin is weakly driven
to a voltage of approximately half the DRVDD1/2 supply level using an internal voltage divider. This voltage does
not match the actual VCM of a fully powered driver, but due to the output voltage being close to its final value, a
much shorter power-up delay time setting can be used and still avoid any audible output artifacts. These output
voltage options are controlled in page 0, register 42.
while the output drivers are in power down, it also takes a slightly longer delay to power up without artifact than if
the bandgap reference is kept alive. In this alternate mode, the powered-down output driver pin is weakly driven
to a voltage of approximately half the DRVDD1/2 supply level using an internal voltage divider. This voltage does
not match the actual VCM of a fully powered driver, but due to the output voltage being close to its final value, a
much shorter power-up delay time setting can be used and still avoid any audible output artifacts. These output
voltage options are controlled in page 0, register 42.
The high-power output drivers can also be programmed to power up first with the output level (gain) control in a
highly attenuated state; then the output driver automatically reduces the output attenuation slowly to reach the
programmed output gain. This capability is enabled by default but can be disabled in page 0, register 40.
highly attenuated state; then the output driver automatically reduces the output attenuation slowly to reach the
programmed output gain. This capability is enabled by default but can be disabled in page 0, register 40.
The TLV320AIC3105 includes programmable short-circuit protection for the high-power output drivers, for
maximum flexibility in a given application. By default, if these output drivers are shorted, they automatically limit
the maximum amount of current that can be sourced to or sunk from a load, thereby protecting the device from
an overcurrent condition. In this mode, the user can read page 0, register 95 to determine whether the part is in
short-circuit protection or not, and then decide whether to program the device to power down the output drivers.
However, the device includes further capability to power down an output driver automatically whenever it goes
into short-circuit protection, without requiring intervention from the user. In this case, the output driver stays in a
power-down condition until the user specifically programs it to power down and then power back up again, to
clear the short-circuit flag.
maximum flexibility in a given application. By default, if these output drivers are shorted, they automatically limit
the maximum amount of current that can be sourced to or sunk from a load, thereby protecting the device from
an overcurrent condition. In this mode, the user can read page 0, register 95 to determine whether the part is in
short-circuit protection or not, and then decide whether to program the device to power down the output drivers.
However, the device includes further capability to power down an output driver automatically whenever it goes
into short-circuit protection, without requiring intervention from the user. In this case, the output driver stays in a
power-down condition until the user specifically programs it to power down and then power back up again, to
clear the short-circuit flag.
The TLV320AIC3105 includes extensive capability to monitor a headphone, microphone, or headset jack,
determine if a plug has been inserted into the jack, and then determine what type of headset/headphone is wired
to the plug.
determine if a plug has been inserted into the jack, and then determine what type of headset/headphone is wired
to the plug.
shows one configuration of the device that enables detection and determination of headset
type when a pseudo-differential (capless) stereo headphone output configuration is used. The registers used for
this function are page 0, registers 14, 96, 97, and 13. The type of headset detected can be read back from page
0, register 13. Note that for best results, it is recommended to select a MICBIAS value as high as possible, and
to program the output driver common-mode level at a 1.35-V or 1.5-V level.
this function are page 0, registers 14, 96, 97, and 13. The type of headset detected can be read back from page
0, register 13. Note that for best results, it is recommended to select a MICBIAS value as high as possible, and
to program the output driver common-mode level at a 1.35-V or 1.5-V level.
Copyright © 2007–2008, Texas Instruments Incorporated
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