NXP Semiconductors TDA8932B Product Data Sheet

NXP Semiconductors TDA8932B Product Data Sheet Manual pdf 10 page image

TDA8932B_3 © NXP B.V. 21 June 2007. All rights reserved.Product data sheet Rev. 03— 21 June 2007 10 of 48NXP Semiconductors TDA8932BClass-D audio amplifier• When the amplifier is completely shut down due to activation of the OCP because ashort-circuit to one of the supply lines is made, then during restart (after 100 ms) thewindow protection will be activated. As a result the amplifier will not start until theshort-circuit to the supply lines is removed.8.4.5 Supply voltage protectionIf the supply voltage drops below 10 V, the UnderVoltage Protection (UVP) circuit isactivated and the system will shut down directly. This switch-off will be silent and withoutpop noise. When the supply voltage rises above the threshold level, the system isrestarted again after 100 ms.If the supply voltage exceeds 36 V the OverVoltage Protection (OVP) circuit is activatedand the power stages will shut down. It is re-enabled as soon as the supply voltage dropsbelow the threshold level. The system is restarted again after 100 ms.It should be noted that supply voltages > 40 V may damage the TDA8932B. Twoconditions should be distinguished:1. If the supply voltage is pumped to higher values by the TDA8932B application itself(see also Section 14.3), the OVP is triggered and the TDA8932B is shut down. Thesupply voltage will decrease and the TDA8932B is protected against any overstress.2. If a supply voltage > 40 V is caused by other or external causes, then the TDA8932Bwill shut down, but the device can still be damaged since the supply voltage willremain > 40 V in this case. The OVP protection is not a supply voltage clamp.An additional UnBalance Protection (UBP) circuit compares the positive analog supplyvoltage (VDDA) and the negative analog supply voltage (VSSA ) and is triggered if thevoltage difference between them exceeds a certain level. This level depends on the sumof both supply voltages. The unbalance threshold levels can be defined as follows:• LOW-level threshold: V P(th)(ubp)l < 8⁄5 × VHVPREF• HIGH-level threshold: V P(th)(ubp)h > 8⁄3 × VHVPREFIn a symmetrical supply the UBP is released when the unbalance of the supply voltage iswithin 6 % of its starting value.Table 6 shows an overview of all protection and the effect on the output signal.Table 6. Protection overviewProtection RestartWhen fault is removed Every 100 msOTP no yesOCP yes noWP yes noUVP no yesOVP no yesUBP no yes