Tripath Technology, Inc. - Technical Information
Application Information
Figure 1 is a simplified diagram of one channel (Channel 1) of a TK2150 amplifier to assist in
understanding its operation.
TC2001
TP2150
BBM0 26
BBM1
51 OCS1HP
VPP
25
OVER
DB
CB
CS
CURRENT
DETECTION
RS
OAOUT1 22
VN10
RB
OCS1HN
50
57 VBOOT1
RI
RF
CI
V5
QO
RG
RG
INV1 23
ROFB
+
+
-
Y1
9
17
16
48 HO1
47 HO1COM
CBAUX
0.1uF
+
CHBR
AGND
V5
VN10
OUTPUT
FILTER
QO
Processing
&
Modulation
10
Y1B
44 LO1
RL
ROFA
45
LO1COM
COF
2.5V
V5
54 OCS1LP
Offset Trim
Circuit
OVER
CURRENT
DETECTION
RS
CA
5V
53 OCS1LN
BIASCAP
1
VNN
41,43
VN10
VN10
CS
CSW
VNN
VNN
42
6
MUTE 24
REF 15
OCR1
7
VNN
V5
5V
CS
5
AGND
RREF
RVNN1
16
OCR1
COCR
VNNSENSE 17
VPPSENSE 19
V5
VNN
VPP
OVER/
OVER
CURRENT
DETECTION
UNDER
VOLTAGE
DETECTION
ROCR
RVPP1
RFBA
RFBA
RFBC
RVNN2
RVPP1
6
7
FBKOUT1
FBKGND1
V5
V5
RFBC
CFB
V5
21
RFBB
RFBB
5V
CS
8
HMUTE
AGND 20
Analog
Ground
F. BEAD
Power Ground
Figure 1: Simplified TK2150 Amplifier
TK2150 Basic Amplifier Operation
The audio input signal is fed to the processor internal to the TC2001, where a switching pattern is
generated. The average idle (no input) switching frequency is approximately 700kHz. With an
input signal, the pattern is spread spectrum and varies between approximately 200kHz and
1.5MHz depending on input signal level and frequency. Complementary copies of the switching
pattern is output through the Y1 and Y1B pins on the TC2001. These switching patterns are input
to the TP2150 where they are level-shifted by the MOSFET drivers and then output to 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 VPP
and VNN. This signal is then low-pass filtered to obtain an amplified reproduction of the audio
input signal.
The TC2001 processor is operated from a 5-volt supply. In the generation of the switching
patterns for the output MOSFETs, the processor inserts a “break-before-make” dead time
between the turn-off of one transistor and the turn-on of the other in order to minimize shoot-
through currents in the external MOSFETs. The dead time can be programmed by setting the
break-before-make control bits, BBM1 and BBM0. Feedback information from the output of the
half-bridge is supplied to the processor via FBKOUT1. Additional feedback information to
account for ground bounce is supplied via FBKGND1.
15
TK2150 – Rev. 1.0/12.02
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
