TA0104A 查看數據表（PDF） - Tripath Technology Inc.

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TA0104A

STEREO 500W (4Ω) CLASS-T DIGITAL AUDIO AMPLIFIER DRIVER USING DIGITAL POWER PROCESSING (DPPTM) TECHNOLOGY

Tripath Technology Inc. 

Tripath Technology, Inc. - Technical Information

TA0104A Amplifier Operation

Figure 1 is a simplified diagram of one channel (Channel 1) of a TA0104A amplifier to assist in

understanding its operation.

The audio input signal (IN1) is fed to the processor internal to the TA0104A, where a modulation

pattern is generated. This pattern is spread spectrum and varies between approximately 200kHz and

1.5MHz. Complementary copies of the switching pattern are level-shifted by the MOSFET drivers and

output from the TA0104A where they drive the gates (HO1 and LO1) of external power MOSFETs that

are connected as a half bridge. The output of the half bridge is a power-amplified version of the

switching pattern that switches between VSPOS and VSNEG. This signal is then low-pass filtered to

obtain amplified audio.

The processor portion of the TA0104A 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 TA0104A are operated from voltages obtained from VN12 and LO1COM

for the low-side driver, and VBOOT (generated internal to the TA0104A) 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 TA0104A 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 TA0104A 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 TA0104A 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 TA0104A has over-current protection circuitry to protect itself and the output transistors from

short-circuit conditions. The TA0104A 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 Application Information for

details. An over-current condition will cause the TA0104A 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 TA0104A and can be cleared by toggling the MUTE input or cycling power.

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TA104A – Rev. 3.1/06.00

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