Application and replacement of car power amplifier IC TA8205AH

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Application and replacement of car power amplifier IC TA8205AH [Copy link]

A Mitsubishi Pajero car audio system had a fault phenomenon of no sound, but other functions were working normally. After checking, it
was found that the power amplifier integrated circuit TA8205AH was damaged. TA8205AH is a 22W×2 dual-channel audio power amplifier integrated circuit produced by Toshiba, using a 17-pin package. Each channel consists of a preamplifier stage and a power amplifier stage. The power amplifier stage is internally connected in a BTL form, so the output power is large. It is widely used in high-end car audio systems of many brands such as Mitsubishi Pajero, CLARION, and SONY. TA8205AH has a low thermal resistance coefficient, low noise, adjustable voltage gain, and low distortion. In addition to overload protection, overheating protection, short circuit protection, and mute functions, it also has a standby function. Its operating voltage range is 9~18V. When Vcc=13.2V, f=1kHz, RL=4Ω, PO=15W×2 (THD=10%); when Vcc=14.4V, f=1kHz, RL=4Ω, PO=18W×2 (THD=10%). The application circuit of TA8205AH is shown in the figure. Pin ① and pin ④ of TA8205AH are the mute control and standby control pins respectively. When the voltage of pin ① is in the range of 1.0~2.0V, the mute function is turned off. When the voltage of pin ① is lower than the threshold level of 1V, the mute circuit works. When the voltage of pin ④ is greater than the threshold voltage of 2.5V, the electronic switch inside the circuit is turned on, and the circuit outputs normal power. As long as the voltage of pin ④ is lower than 2.5V, the circuit is in standby state without power output. If the standby function is not used, the ④ pin can be connected to the power supply VCC. At this time, the operating current of the amplifier is only about 1mA. In the figure, C1 is the input coupling capacitor, and C2 is the negative feedback capacitor of the preamplifier. The capacity of C1 and C2 should be selected according to the specific usage to obtain the best anti-impact sound effect. C3 is a filter capacitor to reduce power supply fluctuations. It determines the time constant to reach a steady state when turning on/off. C4 is an anti-vibration capacitor, which forms an anti-vibration circuit with a series resistor. Generally, a polyester film capacitor with good temperature characteristics and high-frequency characteristics is used. C5 is a power filter capacitor, and C6 is an input end vibration elimination capacitor.