东芝 TA8276HQ 功放音效芯片技术资料(3)

汽车音响内置音效IC TA8276HQ 歌乐机头OEM芯片电路图技术资料

TA8276HQCaution and Application Method(Description is made only on the single channel.) 1. Voltage Gain AdjustmentThis IC has no NF (negative feedback) terminals. Therefore, the voltage gain can’t adjusted, but it makes the device a space and total costs saver.Amp. 2A Amp. 1 InputAmp. 2BFigure 1Block DiagramThe voltage gain of Amp.1: GV1 = 0 dB The voltage gain of Amp.2A, B: GV2 = 20 dB The voltage gain of BLT Connection: GV (BTL) = 6 dB Therefore, the total voltage gain is decided by expression below. GV = GV1 + GV2 + GV (BTL) = 0 + 20 + 6 = 26 dB2. Stand-by SW Function (pin 4)By means of controlling pin 4 (stand-by terminal) to high and low, the power supply can be set to ON and OFF. The threshold voltage of pin 4 is set at about 3VBE (typ.), and the power supply current is about 2 µA (typ.) at the stand-by state.VCC ON Power OFF 4 10 k ≈ 2VBE to BIAS CUTTING CIRCUITControl Voltage of pin 4: VSBStand-by ON OFF Power OFF ON VSB (V) 0~1.5 3~VCCFigure 2 With pin 4 set to High, Power is turned ONAdjustage of Stand-by SW(1) (2) Since VCC can directly be controlled to ON or OFF by the microcomputer, the switching relay can be omitted. Since the control current is microscopic, the switching relay of small current capacity is satisfactory for switching32004-05-10

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