汽车音响内置音效IC TA8276HQ 歌乐机头OEM芯片电路图技术资料
TA8276HQLarge current capacity switch BATTERY RELAY BATTERYVCCVCC – Conventional Method –FROM MICROCOMPUTERSmall current capacity switch BATTERYDIRECTLY FROM MICROCOMPUTER BATTERYStand-By VCCStand-By VCC – Stand-by Switch Method –Figure 33. Muting Function (pin 22)By means of controlling pin 22 less than 0.5 V, it can make the audio muting condition. The muting time constant is decided by R1 and C4 and these parts is related the pop noise at power ON/OFF. The series resistance; R1 must be set up less than 10 k to get enough muting attenuation. The muting function have to be controlled by a transistor, FET and µ-COM port which has IMUTE > 250 µA ability. Pin 22 terminal voltage has the temperature characteristics of 4.6 V (low temperature) to 3.2 V (high temperature). Therefore, it is need to design with attention as using the microcontroller of which operating voltage is less than 5 V. Terminal 22 may not be pulled up and shall be controlled by OPEN/LOW. When it is obliged to do, it must be pulled up via diode, because it has to defend flowing reverse current to internal circuit of pin 22.<Recommended Application> ATT – VMUTE20I (100 µA) IMUTE (OFF) 22 C4 R1 IMUTEA(dB)10 k 0 20 40 605 k VMUTE<Application for pulled up>Mute attenuation ATTVCC = 13.2 V 80 100 0 0.4 0.8 1 1.2 1.6 Po = 10 W PL = 4 f = 1 kHz BW = 400~30 kHz 2 2.4 2.8 3I (100 µA) IMUTE (OFF) 22 C4 R1 IMUTE VMUTEPoint A voltage: VMUTE(V)Figure 4Muting FunctionFigure 5 4Mute Attenuation VMUTE (V) 2004-05-10
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