Tripath Technology, Inc. - Preliminary Information
For SINGLE-SUPPLY operation:
The modulator feedback resistors are:
R
R
FBB = User specified, typically 1KΩ
FBC = 350 *VPP − 1000
2333.33 * RFBC
FBB =
R
A
(1000 + RFBC
)
R
FBC * (RFBA + RFBB )
V - MODULATOR
≈
+ 1
R
FBA * RFBB
For example, in a system with a SINGLE-SUPPLY of VPPMAX = 60V,
RFBA = 2.22kΩ, use 2.21kΩ, 1%
RFBB = 1kΩ, 1%
R
FBC = 20kΩ, 1%
The resultant modulator gain is:
20.0k Ω * (1.0k Ω + 2.21k Ω)
1.0k Ω * 2.21k Ω
A
V - MODULATOR
≈
+ 1 = 30.05V/V
For SPLIT-SUPPLY operation:
The modulator feedback resistors are:
R
R
FBA = User specified, typically 1KΩ
R
FBA * VPP
FBB
=
(VPP - 4)
R
FBA * VPP
R
FBC
=
4
R
FBC * (RFBA + RFBB )
A
V - MODULATOR
≈
+ 1
R
FBA * RFBB
The above equations assume that VPP=|VNN|.
For example, in a system with a SPLIT-SUPPLY of VPPMAX=60V and VNNMAX=-60V,
RFBA = 1kΩ, 1%
R
FBB = 1.071kΩ, use 1.07kΩ, 1%
RFBC = 15.0kΩ, use 15.0kΩ, 1%
The resultant modulator gain is:
15.0k Ω * (1.0k Ω + 1.07k Ω)
AV - MODULATOR
≈
+ 1 = 30.02V/V
1.0k Ω * 1.07k Ω
18
TDA1400 – Rev. 0.65/KLi/02.06
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
