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Preliminary data sheet

Rev. 01 — 14 January 2004

6 of 31

Philips Semiconductors

TDA8931

Power comparator 1

× 20 W

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

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.

[1]

Pin DIAG = LOW for minimal 1.5

µs.

8.6.1 Overtemperature protection (OTP)

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.

Table 5:

Overview protections

Protection

Output

pin DIAG

Remark

Symbol

Condition

OTP

self recovering when fault is removed

OCP

OVP

UVP

ODP

LOW

recovering by switching pin POWERUP: first to Sleep

mode and then to Standby mode

recovering by removing supply voltage