TDA8931
Philips Semiconductors
Power comparator 1 × 20 W
Pin HVPI will be on its final level of 0.5VP before the device starts switching. This results
into a plop-noise free start-up behavior.
8.5 Half supply voltage capacitor charger (pin HVP)
When the device is in Standby mode, the SE capacitor C15 (see Figure 5) will be charged
until it reaches the half of the supply voltage. This current charges capacitor C15 within
0.5 seconds when a capacitor of 1000 µF is used. When the voltage on pin HVP has
reached the level of 0.5VP it releases pin ENABLE for external use.
When the device is in Operating mode, pin HVP is switched to floating to minimize
dissipation.
When the supply voltage drops, capacitor C15 is discharged and the device is switched off
to avoid plop noise.
8.6 Protections
Overtemperature, overcurrent, overvoltage and undervoltage sensors are included in the
TDA8931. When one of these sensors exceeds its threshold level the output power stage
is switched off and the output stage becomes floating. After 1.5 µs the device will try to
restart. When the fault condition is removed the output stage is switched on.
Table 5:
Protection
Symbol
OTP
Overview protections
Output
Remark
pin DIAG
Condition
Tj > 150 °C
IO > IOCP
LOW[1]
self recovering when fault is removed
OCP
OVP
VP > VP(OVP)fix
VP < VP(UVP)
UVP
ODP
IO > IOCP and
Tj > 140 °C
LOW
recovering by switching pin POWERUP: first to Sleep
mode and then to Standby mode
recovering by removing supply voltage
[1] Pin DIAG = LOW for minimal 1.5 µs.
8.6.1 Overtemperature protection (OTP)
If the junction temperature Tj exceeds the threshold level of approximately 150 °C then the
device will shut down immediately. The device will start switching again when the
temperature drops.
8.6.2 Overcurrent protection (OCP)
If the output current exceeds the maximum output current threshold level (e.g. when the
loudspeaker terminals are short-circuited it will be detected by the current protection) the
device will shut-down.
8.6.3 Overvoltage protection (OVP)
When the supply voltage applied to the TDA8931 exceeds the maximum supply voltage
threshold level the device will shut down. The supply voltage on which the device stops
operating is determined by two external resistors R1 and R2.
9397 750 13847
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Preliminary data sheet
Rev. 01 — 14 January 2004
6 of 31
NXP [ NXP ]
