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IC BLOCK DIAGRAM & DESCRIPTION
IC406,407 TA2022(Digital Audio Power Amp.)
VPP2 VNN2 VNN1 VPP1
VN10FBK
VN10SWK
VN10GND
VN10
FBKGND2 FBKOUT2
OUT2
VBOOT2
HMUTE
FBKGND1 FBKOUT1
OUT1
VBOOT1
4
8
9
12
14
5
3
2
28 29
7
1
32
30 31
10
23
27
NV2
REF
V5
AGND
V5
AGND
NC
NC
VPPSENSE
VNNSENSE
OAOUT2
MUTE
BIASCAP
INV1
OAOUT1
24
25
26
17
21
20
16
15
18
19
11
6
22
13
Processing & Modulation
Components
R
I
R
F
C
I
R
FBA
R
FBB
R
FBC
C
FB
R
OFA
R
OFB
R
REF
C
A
D
B
C
B
C
BAUX
R
B
C
SW
L
SW
D
SW
C
SWFB
R
SWFB
C
S
R
VNNSNESE
R
VPPSENSE
C
HBR
C
Z
R
Z
D
O
L
O
C
O
VN10
Generator
Processing & Modulation
V5
V5
2.5V
AGND
V5
AGND
VPP1
VPP2
VN10
VN10
VNN1
VNN2
Description
Inverting input resistance to provide AC gain in conjunction with RF. This input is biased at the BIASCAP voltage (approximately 2.5VDC).
Feedback resistor to set AC gain in conjunction with R1. Please refer to the Amplifier Gain paragraph, in the Application Information section.
Ac Input coupling capacitor which, in conjunction with RI, form a high pass filter aat f
C
= 1/(2 R
I
C
I
).
Feedback divider resistor connected to V5. This resistor is normally set at 1k .
Feedback divider resistor connectedto AGND. This value of this resistor depends on the supply voltage setting and helps set the TA2022 gain in conjunction with R
I
,R
F
,R
FBA
,
and R
FBC
. Please see the Modulator Feedback Design paragraphs in the Application Information Section.
Feedback resistor connected from either the OUT1(OUT2) to FBKOUT1(FBKOUT2) or speaker ground to FBKGND1(FBKGND2). The value of this resistor depends on the
supply voltage setting and helps set the TA2022 gain in conjunction with R
I
,R
F
,R
FBA
, and R
FBB
. It should be noted that the resistor from OUT1(OUT2) to FBKOUT1
(FBKOUT2) must have a power reting of greater than P
DISS
= VPP
2
/(2R
FBC
).
Please see the Modulator Feedbaack Design paragraphs in the Application Information Section.
Feedback delay capacitor that both lowers the idle switching frequency and filters very high frequency noise from the feedback signal, which improves amplifier performance.
The value of C
FB
should be offset between channel 1 and channel 2 so that the idle switching difference is greater than 40kHz. Please refer to the Application / Test Circuit.
Potentiometer used to manually trim the DC offset on the output of the TA2022.
Resistor that limits the manualDC offset trim range ang allows for mare precise adjustment.
Bias resistor Locate close to pin 17 and ground at pin 20.
BIASCAP decoupling capacitor. Should be located close to pin 27 and grounded at pin 20.
Bootstrap diode. This diode charges up the bootsyrap capacitors when the output is low(at VNN) to drive the high side gate circuitry. Sohottky or fast recovery diode rated at
least 200mA, 90V, 50nS is recommended for the bootstrap circuity. In addition, the bootstrap diode must be able to sustainthe entire VPP-VNN voltage.
Thus, for most applications, a 90V(or greater) diodeshould be used.
High frequency bootstrap capacitor, whih filters the high side gate drive supply. This capacitor must be located as close to pin 13(VBOOT1) or pin 1n (VBOOT2) for reliable
operation. The other side of C
B
should be connected directly to the OUT1(pin 10) or OUT2(pin 7). Please refer to the Application/Test Circuit.
Bulk bootsteap capacitor that supplements C
B
during "clipping" events, which result in a reduction in thee averagee switching frequency.
Bootstrap resistor that limits C
BAUX
charging current during TA2022 power up (bootstrap supply charging).
VN10 generator filter capacitors. The high frequency capacitor (0.1uF) must be located close to pin 2 (VN10) to maximize device performance. The value of the bulk capacitor
should be sized appropriately such that the VN10 voltage does not overshoot with respect to VNN during TA2022 turn on.
Tripath recommends using a value of 100 F for the bulk capacitor.
VN10 generator filter inductor. This inductor sized appropriately so that L
SW
does not saturate. If the recommended inductor value of 100 H is not used, the VN10 may
overshoot with respect to VNN during TA2022 turn on.
Flywheel diode for the internal VN10 buck converter. This diode also prevents VN10
SW
from going more than one diode drop negative with respect to VNN. This Diode can be
a Fast Recovery, Switching or Shottky, but must be rated at least 200mA, 30V, 50nS.
VN10 generator frrdback capacitor. This capacitor, in conjunction with R
SWFB
, filters the VN10 feedback signal such that the loop is unconditionally stable.
VN10 generator feedback resistor. This resistor sets the nominal VN10 voltage. With R
SWFB
equal to 1k , the internally VN10 voltage will typically be 11V above VNN.
Supply decoupling for the power supply pins. For optimum performance, these components should be located close to the TA2022 and returned to their respective ground as
shown in the Application/Test Circuit.
Overvoltage and undervoltage sense resistor for the negative supplly (VNN). Please refer to the Electrical Characteristics Section for the trip points as well as the hysteresis
band. Also, please refer to the Over / Under-voltage Protection section in theApplication Information hor a detailed discussion of the internal circuit operation and external
component selection.
Overvoltage and undervoltage sense resistor for the positive supply (VPP). Please refer to the Electrical Characteristics Section for the trip points as well as the hysteresis
band. Also, please refer to the Over / Under-voltage Protection section in the Application Information for a detailed discussion of the internal circuit operation and external
component selection.
Supply decoupling for the high current Half-bridge supply pins. These components must be located as close to the device as possible ro minimize supply overshoot and
maximize device reliability. These capacitors should have good high frequency performance including low ESR and low ESL. In addition, the capacitor voltage rating must be
twice the maximum VPP voltage.
Zobel capacitor, which in conjunction with R
Z
, terminates the output filter at high frequencies.
Use a high quality film capacitor capable of sustaining the ripple current caused by the switching outputs.
Zobel resistor, which in conjunction with C
Z
, terminates the output filter st high frequencies. The combination of R
Z
and C
Z
minimizes peaking of the output filter under both on
load conditions or with real world loads, including loudspeakers which usually exhibit a rising impedance with increasing frequency. The recommended power rating is 2 watts.
Fast Recovery diodes that minimize overshoots and undershoots of the outputs with respect to power ground during switching transitions as well as output shorts to ground.
For maximum effectiveness, these diodes must be located close to the output pins and returned to their respective VPP and VNN. Also, they shouid be rated with a mazimum
Forward Voltage of 1V at 10A. Please see Application/Test Circuit for VPP and VNN return pins.
Output inductor, which in conjunction with C
O
, demodulates (filters) the switching waveform into an audio signal. Formss a second order filter with a cutoff frequency of
f
C
= 1/(2 L
O
C
O
) and a quality factor of Q = R
L
C
O
/ L
O
C
O
.
These inductors must be rated at least 10A with high linearity. Olease see Output Filter Design section for details.
Outout capacitor, which, in conjunction with LO,demodulates (filters) the switching waveform into an audio signsl. Forms a second order low-pass filter with a cutoff frequency
of f
C
= 1/(2 L
O
C
O
) and a quqlity factor of Q = R
L
C
O
/ L
O
C
O
. Use a high quality film capacitor capable of sustaining the ripple current caused by the switching outputs.
Electrolytic capacitors should not be used.
