TDA8932T/N1112 View Datasheet(PDF) - NXP Semiconductors.

Part Name

Description

Manufacturer

TDA8932T/N1112

Class-D audio amplifier

NXP Semiconductors. 

NXP Semiconductors

TDA8932

Class-D audio amplifier

Example 2

In case of music output power at 25 % of the rated power, the Tj(max) is much lower.

• At VP = 30 V and Po = 2 × (0.25 × 15) = 2 × 3.75 W into 8 Ω, the power dissipation

P = 1.6 W at Po = 3.75 W (see Figure 20)

• Rth(j-a) = 43 K/W

The maximum junction temperature Tj(max) = 25 + 1.6 × 43 = 93.8 °C.

14.8 Pumping effects

When the amplifier is used in a SE configuration, a so-called 'pumping effect' can occur.

During one switching interval, energy is taken from one supply (e.g. VDDP1), while a part of

that energy is delivered back to the other supply line (e.g. VSSP1) and visa versa. When

the power supply cannot sink energy, the voltage across the output capacitors of that

power supply will increase.

The voltage increase caused by the pumping effect depends on:

• Speaker impedance

• Supply voltage

• Audio signal frequency

• Value of decoupling capacitors on supply lines

• Source and sink currents of other channels

The pumping effect should not cause a malfunction of either the audio amplifier and/or the

power supply. For instance, this malfunction can be caused by triggering of the

undervoltage or overvoltage protection of the amplifier.

Pumping effects in a SE configuration can be minimized by connecting audio inputs in

anti-phase and change the polarity of one speaker. This is illustrated in Figure 12.

audio

in1

audio

in2

IN1P

IN1N

IN2N

IN2P

OUT1

OUT2

Fig 12. SE application for reducing pumping effects

001aad763

TDA8932_2

Preliminary data sheet

Rev. 02 — 12 December 2006

© NXP B.V. 2006. All rights reserved.

29 of 45

Share Link: