TDA8922C NXP Semiconductors, TDA8922C Datasheet - Page 8

• Manufacturer Part Number: TDA8922C
• Description: The TDA8922C is a high-efficiency Class D audio power amplifier
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TDA8922C_1
Product data sheet
8.3.1.1 Thermal FoldBack (TFB)
8.3.1 Thermal protection
8.2 Pulse-width modulation frequency
8.3 Protection
The amplifier output signal is a PWM signal with a typical carrier frequency of between
250 kHz and 450 kHz. A second order LC demodulation filter on the output converts the
PWM signal into an analog audio signal. The carrier frequency is determined by an
external resistor, R
frequency setting is between 250 kHz and 450 kHz.
The carrier frequency is set to 345 kHz by connecting an external 30 k resistor between
pins OSC and VSSA. See
If two or more Class D amplifiers are used in the same audio application, it is
recommended that an external clock circuit be used with all devices (see
This will ensure that they operate at the same switching frequency, thus avoiding beat
tones (if the switching frequencies are different, audible interference known as ‘beat tones’
can be generated).
The following protection circuits are incorporated into the TDA8922C:
How the device reacts to a fault conditions depends on which protection circuit has been
activated.
The TDA8922C employes an advanced thermal protection strategy. A TFB function
gradually reduces the output power within a defined temperature range. If the temperature
continues to rise, OTP is activated to shut down the device completely.
If the junction temperature (T
is gradually reduced. This reduces the output signal amplitude and the power dissipation,
eventually stabilizing the temperature.
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Thermal protection:
– Thermal FoldBack (TFB)
– OverTemperature Protection (OTP)
OverCurrent Protection (OCP)
Window Protection (WP)
Supply voltage protection:
– UnderVoltage Protection (UVP)
– OverVoltage Protection (OVP)
– UnBalance Protection (UBP)
OSC
Rev. 01 — 7 September 2009
, connected between pins OSC and VSSA. The optimal carrier
Table 9
j
) exceeds the thermal foldback activation threshold, the gain
for more details.
2
75 W class-D power amplifier
TDA8922C
© NXP B.V. 2009. All rights reserved.
Section
13.4).
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