TDA8932T/N1112 View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
Manufacturer
TDA8932T/N1112 Datasheet PDF : 45 Pages
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NXP Semiconductors
TDA8932
Class-D audio amplifier
14.2 Output current limiting
The peak output current IO(max) is internally limited above a level of 4 A (minimum). During
normal operation the output current should not exceed this threshold level of 4 A
otherwise the output signal is distorted. The peak output current in SE or BTL
configurations can be estimated using Equation 5 and Equation 6.
SE configuration:
IO(max) ≤ -R----L----+-----R---D---0-S--.-o5--n---×-+---V--R---P-s---+-----R----E---S---R- ≤ 4 A
(5)
BTL configuration:
IO(max) ≤ -R----L----+----2-----×-----(-V-R----PD----S--o---n----+-----R----s--) ≤ 4 A
(6)
Where:
VP = supply voltage VDDP1 − VSSP1 [V] or VDDP2 − VSSP2 [V]
RL = load impedance [Ω]
RDSon = on-resistance power switch [Ω]
Rs = series resistance output inductor [Ω]
RESR = equivalent series resistance SE capacitor [Ω]
Example:
A 4 Ω speaker in the BTL configuration can be used up to a supply voltage of 18 V without
running into current limiting. Current limiting (clipping) will avoid audio holes but it causes
a comparable distortion like voltage clipping.
14.3 Speaker configuration and impedance
For a flat frequency response (second-order Butterworth filter) it is necessary to change
the low-pass filter components Llc and Clc according to the speaker configuration and
impedance. Table 14 shows the practical required values.
Table 14. Filter component values
Configuration
SE
RL (Ω)
4
6
8
BTL
4
6
8
Llc (µH)
22
33
47
10
15
22
Clc (nF)
680
470
330
1500
1000
680
14.4 Single-ended capacitor
The SE capacitor forms a high-pass filter with the speaker impedance. So the frequency
response will roll-off with 20 dB per decade below f-3dB (3 dB cut-off frequency).
TDA8932_2
Preliminary data sheet
Rev. 02 — 12 December 2006
© NXP B.V. 2006. All rights reserved.
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