TCA2002 Datasheet, PDF (11/18 Pages) Tripath Technology Inc. – STEREO CLASS-T™ AUDIO CONTROLLER USING DIGITAL POWER PROCESSING (DPP™) TECHNOLOGY

Tripath Technology, Inc. - Technical Information
half-bridge output and load ground. The resistor divider networks at the TCA2002 scale the feedback
signals. The resistor values are determined based on the supply voltage, as explained below.
The modulator feedback resistors are:
RFBA = User specified, typically 1K Ω
R FBB = ^{RFBA * VPP}
(VPP - 4)
R FBC = ^{R FBA * VPP}
4
AV - MODULATOR ≈ ^{R FBC * (R FBA + R FBB )} + 1
R FBA * R FBB
The above equations assume that VPP=|VNN|.
For example, in a system with a SPLIT-SUPPLY, SINGLE ENDED amplifier of VPP_MAX=60V and
VNN_MAX=-60V,
R_FBA = 1kΩ, 1%
R_FBB = 1.071kΩ, use 1.07kΩ, 1%
R_FBC = 15.0kΩ, use 15.0kΩ, 1%
The resultant modulator gain is:
AV - MODULATOR ≈ ^{15.0k Ω * (1.0k Ω + 1.07k Ω )} + 1 = 30.02V/V
1.0k Ω * 1.07k Ω
For SPLIT-SUPPLY, BRIDGED OUTPUT operation:
VPP
TCA2002
Y1
Y1B
FET Driver
HIN1
LIN1
HS OUT1
LS OUT1
HIN2
LIN2
HS OUT2
LS OUT2
FBKP1 FBKN1
V5
R _{FBA RFBC}
MOSFETS
HS GATE1 ^{HB OUTP}
LS GATE1
HS GATE2
LS GATE2 ^{HB OUTN}
VNN
V5
R _FBB
R _{FBA RFBC}
R _FBB
Figure 4: Split Supply, Bridged Output (One Channel)
Figure 4 shows the basic split supply, bridged output amplifier using a TCA2002. The MOSFET
output stage operates from two power supplies, VPP and VNN, that are equal magnitude, but
opposite polarity (for instance +/-60VDC). Both terminals of the speaker are actively driven.
Differential feedback is taken from each half-bridge output. The resistor divider networks at the
TCA2002 scale the feedback signals. The resistor values are determined based on the supply
voltage, as explained below.
11
TCA2002 – KLi/0.95/04.06