Tripath Technology, Inc. - Technical Information
saturate. If the recommended inductor value of 100 H is not used, the VN10 may
overshoot with respect to VNN during TA2022 turn on.
DSW
Flywheel diode for the internal VN10 buck converter. This diode also prevents VN10SW
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 feedback capacitor. This capacitor, in conjunction with RSWFB, filters the
VN10 feedback signal such that the loop is unconditionally stable.
CSWFB
RSWFB
CS
VN10 generator feedback resistor. This resistor sets the nominal VN10 voltage. With
RSWFB equal to 1kΩ, 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.
RVNNSNESE
RVPPSENSE
CHBR
Overvoltage and undervoltage sense resistor for the negative supply (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 the Application
Information for 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 to 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.
CZ
RZ
Zobel capacitor, which in conjunction with RZ, 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 CZ, terminates the output filter at high
frequencies. The combination of RZ and CZ minimizes peaking of the output filter under
both no 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 should be rated with a maximum Forward
DO
Voltage of 1V at 10A. Please see Application/Test Circuit for VPP and VNN return pins.
Output inductor, which in conjunction with CO, demodulates (filters) the switching
waveform into an audio signal. Forms a second order filter with a cutoff frequency
LO
of
and a quality factor of
. These
LO CO
fC = 1 (2π LO C O
)
Q = RL CO
inductors must be rated at least 10A with high linearity. Please see Output Filter
Design section for details.
Output capacitor, which, in conjunction with LO, demodulates (filters) the switching
waveform into an audio signal. Forms a second order low-pass filter with a cutoff
CO
frequency of
and a quality factor of
)
. Use a
LO CO
fC = 1 (2π LO C O
Q = RL CO
high quality film capacitor capable of sustaining the ripple current caused by the
switching outputs. Electrolytic capacitors should not be used.
9
TA2022 – KLI/1.2/07-04
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
