TDA8932T-T View Datasheet(PDF) - NXP Semiconductors.

Part Name

Description

Manufacturer

TDA8932T-T

Class-D audio amplifier

NXP Semiconductors. 

NXP Semiconductors

TDA8932

Class-D audio amplifier

8.4 Protection

The following protection is included in the TDA8932:

• Thermal Foldback (TF)

• OverTemperature Protection (OTP)

• OverCurrent Protection (OCP)

• Window Protection (WP)

• Supply voltage protection:

– UnderVoltage Protection (UVP)

– OverVoltage Protection (OVP)

– UnBalance Protection (UBP)

• ESD

The reaction of the device to the different fault conditions differs per protection.

8.4.1 Thermal Foldback (TF)

If the junction temperature of the TDA8932 exceeds the threshold level (Tj > 140 °C) the

gain of the amplifier is decreased gradually to a level where the combination of dissipation

(P) and the thermal resistance from junction to ambient [Rth(j-a)] results in a junction

temperature around the threshold level.

This means that the device will not completely switch off, but remains operational at lower

output power levels. Especially with music output signals this feature enables high peak

output power while still operating without any external heat sink other than the

printed-circuit board area.

If the junction temperature still increases due to external causes, the OTP shuts down the

amplifier completely.

8.4.2 OverTemperature Protection (OTP)

If the junction temperature Tj > 155 °C, then the power stage will shut down immediately.

8.4.3 OverCurrent Protection (OCP)

When the loudspeaker terminals are short-circuited or if one of the demodulated outputs

of the amplifier is short-circuited to one of the supply lines, this will be detected by the

OCP.

If the output current exceeds the maximum output current (IO(ocp) > 4 A), this current will

be limited by the amplifier to 4 A while the amplifier outputs remain switching (the amplifier

is not shut down completely). This is called current limiting.

The amplifier can distinguish between an impedance drop of the loudspeaker and a

low-ohmic short-circuit across the load or to one of the supply lines. This impedance

threshold depends on the supply voltage used:

• In case of a short-circuit across the load, the audio amplifier is switched off completely

and after approximately 100 ms it will try to restart again. If the short-circuit condition

is still present after this time, this cycle will be repeated. The average dissipation will

be low because of this low duty cycle.

TDA8932_2

Preliminary data sheet

Rev. 02 — 12 December 2006

© NXP B.V. 2006. All rights reserved.

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