參數(shù)資料
型號(hào)： MAX4295
廠商： Maxim Integrated Products, Inc.
英文描述： Mono/Stereo 2W Switch-Mode (Class-D) Audio Power Amplifiers
中文描述： 單聲道/立體聲、2W、開(kāi)關(guān)模式(D類)音頻功率放大器
文件頁(yè)數(shù)： 14/18頁(yè)
文件大?。?/td> 719K
代理商： MAX4295
M
Mono/Stereo 2W Switch-Mode (Class-D)
Audio Power Amplifiers
14
______________________________________________________________________________________
Output Filter
An output filter is required to attenuate the PWM switch-
ing frequency. Without the filter, the ripple in the load
can substantially degrade efficiency and may cause
interference problems with other electronic equipment.
A Butterworth lowpass filter is chosen for its flat pass
band and nice phase response, though other filter
implementations may also be used. Three examples
are presented below. The filter parameters for bal-
anced 2-pole (Figure 4b) and 4-pole (Figure 4d)
Butterworth filters are taken from
Electronic Filter
Design Handbook
by Arthur B. Williams, McGraw Hill,
Inc. These filter designs assume that the load is purely
resistive and load impedance is constant over frequen-
cy. Calculation of filter component values should
include the DC resistance of the inductors and take into
account the worst-case load scenario:
Single Ended 2-Pole Filter (Figure 4a)
C = 1 / (
√
2
R
L
ω
o
), L =
√
2
R
L
/
ω
o
where
ω
o
= 2
π
f
o
(f
o
= filter cutoff frequency);
choosing f
o
= 30kHz and R
L
= 4
, C = 0.937μF, L =
30μH.
A single-ended 2-pole filter uses the minimum number
of external components, but the load (speaker) sees
the large common-mode switching voltage, which can
increase power dissipation and cause EMI problems.
Balanced 2-Pole (Figure 4b):
A balanced 2-Pole filter does not have the common-
mode swing problem of the single-ended filter.
C = 2 / (
√
2
R
L
ω
o
), L = (
√
2
R
L
)/(2
ω
o
); choosing
f
o
= 30kHz and R
L
= 4
, C1a = C1b = 2.0μF, L1a =
L1b = 15μH.
A single capacitor connected across R
L
, with a value of
CL = 1/(
√
2
R
L
ω
o
), can be used in place of C1a and
C1b. However, the configuration as shown gives an
improved rejection to common-mode signal compo-
nents of OUT+_ and OUT-_. If the single capacitor
scheme is used, additional capacitors (Ca and Cb) can
be added from each side of R
L
, providing a high-fre-
quency short to ground (Figure 4c). These capacitors
should be approximately 0.2
CL.
Balanced 4-Pole Filter (Figure 4d)
A balanced 4-pole filter is more effective in suppress-
ing the switching frequency and its harmonics.
For the 4-pole Butterworth filter, the normalized values
are: L1
N
= 1.5307, L2
N
= 1.0824, C1
N
= 1.5772, C2
N
=
0.3827.
The actual inductance and capacitance values for f
o
=
30kHz and a bridge-tied load of R
L
= 4
are given by:
L1 = (L1
N
R
L
) / (2
ω
o
) = 16.24μH, L2 = (L2
N
R
L
) /
(2
ω
o
) = 11.5μH, C1 = C1
N
/ (R
L
ω
o
) = 2.1μF, C2a =
C2b = (2
C2
N
) / (R
L
ω
o
) = 1.0μF.
OUT+
OUT-
L
C
R
L
Figure 4a. Single-Ended 2-Pole Filter
OUT+
OUT-
L1
C1a
R
L
L2
C1b
Figure 4b. Balanced 2-Pole Filter
OUT+
OUT-
L1
Ca
R
L
L2
Cb
CL
Figure 4c. Alternate Balanced 2-Pole Filter
OUT+
OUT-
L2a
C2a
R
L
L2b
C2b
L1b
L1a
C1
Figure 4d. Balanced 4-Pole Filter
相關(guān)PDF資料
PDF描述
MAX4295EEE Mono/Stereo 2W Switch-Mode (Class-D) Audio Power Amplifiers
MAX4295ESE Mono/Stereo 2W Switch-Mode (Class-D) Audio Power Amplifiers
MAX4297 Mono/Stereo 2W Switch-Mode (Class-D) Audio Power Amplifiers
MAX4297EAG Mono/Stereo 2W Switch-Mode (Class-D) Audio Power Amplifiers
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX4295EEE 功能描述:音頻放大器 Integrated Circuits (ICs) RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
MAX4295EEE+ 功能描述:音頻放大器 Mono 2W Switch Mode (Class D) RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
MAX4295EEE+T 功能描述:音頻放大器 Mono 2W Switch Mode (Class D) RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
MAX4295EEE-T 功能描述:音頻放大器 RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
MAX4295ESE 功能描述:音頻放大器 RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
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