TDA7571 STMicroelectronics, TDA7571 Datasheet - Page 14

• Manufacturer Part Number: TDA7571
• Description: STPDACsw - Fully digital high efficiency power audio amplifier
• Manufacturer: STMicroelectronics

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Functions, pins and components description
4
4.1
Figure 5.
4.2
14/21
Typ. Values = 10 – 30 mOhm
(not inductive resistor)
to -Vs
Functions, pins and components description
Short circuit protection current calculation
Short circuit protection current diagram
External thermal protection network
The purpose of this function is to sense critical points of the amplifier system, as example
the heatsink of the power transistors, avoiding too high temperature.
Through the external thermal warning pin (THWEXT, pin 37), a signal useful to reduce the
power dissipation reducing (as example) the output power and/or, in a system provided of
regulated power supply, reducing the voltage supply of the amplifier (±V
Example of external thermal protection circuitry
●
●
Components:
–
–
Results (simulations):
–
–
–
Rsens
type: B57621 C621/100k/+
Text = 10K
External thermal warning temperature intervention: 90 °C
External thermal shut down temperature intervention: 100 °C
External thermal shut down hysteresis: 6°C
Imos
Vrfil = Ispx1 x Rfil = 20mV Typ
Rp1 (typ=4.7kOhm)
Rfil (typ. 100 Ohm)
I
lim
Cfil (typ 2.2nF)
I
lim
=
----------------- - Vpx
Rsens
=
1
----------------- - Vpx
Rsens
1
(
⎛
⎝
------------------------------------------------- -
+
Vfil
⋅
(
)
Rp1
Rp2
Rp2
← if Rp2 is not used
+
SPx2 pin
SPx1 pin
Rp2
Vp=100mV Typ
)
comparator
+
Vfil
⎞
⎠
TDA7571
S
) is present.
TDA7571