Tripath Technology, Inc. - Technical Information
The processor portion of the TA0102A is operated from a 5-volt supply (between V5 and AGND). In
the generation of the complementary modulation pattern for the output MOSFETs, the processor
inserts a “break-before-make” dead time between when it turns one transistor off and it turns the
other one on in order to minimize shoot-through currents in the MOSFETs. The dead time can be
programmed by setting the break-before-make control bits, BBM0 and BBM1. Feedback information
from the output of the half-bridge is supplied to the processor via FDBKN1. Additional feedback
information to account for ground bounce is supplied via GNDKELVIN1.
The MOSFET drivers in the TA0102A are operated from voltages obtained from VN12 and LO1COM
for the low-side driver, and VBOOT (generated internal to the TA0102A) and HO1COM for the high-
side. Only N-Channel MOSFETs are required for both the top and bottom of the half bridge. VN12
must be a stable 12V above VSNEG. The gate resistors, RG, are used to control MOSFET slew rate
and thereby minimize voltage overshoots.
Over- and Under-Voltage Protection
The TA0102A senses the power rails through VSPOS and VSNEG for over- and under-voltage
conditions. The over- and under-voltage limits are Vo and Vu respectively as specified in the
Electrical Characteristics table. If the supply voltage exceeds Vo or drops below Vu, the TA0102A
shuts off the output stages of the amplifiers and asserts a logic level high on HMUTE. The removal
of the over-voltage or under-voltage condition returns the TA0102A to normal operation and returns
HMUTE to a logic level low. Please note that the limits specified in the Electrical Characteristics
table are at 25°C and these limits may change over temperature.
Over-current Protection
The TA0102A has over-current protection circuitry to protect itself and the output transistors from
short-circuit conditions. The TA0102A uses the voltage across a resistor, RS (measured via
OCS1H+, OCS1H-, OCS1L+ and OCS1L-), that is in series with each output MOSFET to detect an
over-current condition. RS and ROCR are used to set the over-current threshold. The OCS pins must
be Kelvin connected for proper operation. See “Circuit Board Layout” in Applications Information for
details. An over-current condition will cause the TA0102A to shut off the output stages of the
amplifiers and supply a logic level high on HMUTE. The occurrence of an over-current condition is
latched in the TA0102A and can be cleared by toggling the MUTE input or cycling power.
Overload
When logic low, the OVERLOADB pin indicates that the level of the input signal has overloaded the
amplifier and that the audio output signal is starting to distort. The OVERLOADB signal is active
only when an overload is present. The OVERLOADB signal can be used to control a distortion
indicator light or LED through a simple buffer circuit.
Mute
When a logic high signal is supplied to MUTE, both amplifier channels are muted (both high- and
low-side transistors are turned off) and a logic level high is output on the HMUTE pin. When a logic
level low is supplied to MUTE, both amplifiers are fully operational and a logic level low is supplied
on HMUTE. There is a delay of approximately 200 milliseconds between the de-assertion of MUTE
and the un-muting of the TA0102A.
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TA0102A, Rev. 3.1/06.01
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
