TA2021-100 ETC1 [List of Unclassifed Manufacturers], TA2021-100 Datasheet - Page 7

• Manufacturer Part Number: TA2021-100
• Description: STEREO 100W (4-ohm) CLASS-T DIGITAL AUDIO AMPLIFIER DRIVER USING DPP-TM TECHNOLOGY
• Manufacturer: ETC1 [List of Unclassifed Manufacturers]

T E C H N I C A L I N F O R M A T I O N
Modes of Operation
The TA2021-100 has two modes of operation: Mode 1, where control/status of the amplifier is
by signals on analog pins of the TA2021-100, and Mode 2, where control/status of the amplifier
is by registers accessed through a digital serial control bus. When OVRLD/SCL is tied to V5
through a 5 K
resistor and the TA2021-100 senses this during power-up it will go into Mode 2
operation. Otherwise the TA2021-100 will use Mode 1 operation. The operating description in
this section explains operation of the TA2021-100 in Mode 1. Mode 2 operation is described in
the next section.
TA2021-100 Basic Amplifier Operation
The audio input signal is fed to the processor internal to the TA2021-100, 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
MOSFET drivers which drive the gates of internal 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 VP and VN. This signal is then low-pass filtered to obtain amplified
audio.
The processor portion of the TA2021-100 is operated from a 5-volt supply (between V5 and
GND). 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.
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 TA2021-100 are operated from voltages obtained from VGG for the
low-side driver, and VB1 for the high-side driver. VGG must be a stable 12V above VN. The
TA2021-100 provides switching regulator circuitry to supply VGG and VB1.
Over- and Under-Voltage Protection
The TA2021-100 senses the power rails 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 TA2021-100 shuts off the
output stages of the amplifiers and asserts a logic level high on HMUTE/SDA. The removal of
the over-voltage or under-voltage condition returns the TA2021-100 to normal operation and
returns HMUTE/SDA 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 TA2021-100 has over-current protection circuitry to protect itself and the output transistors
from short-circuit conditions. The TA2021-100 uses the voltage across a resistor that is in series
with each output MOSFET to detect an over-current condition.
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