This post explains for the audio amplifier.
The Part Number is TB2931HQ.
The function of this semiconductor is 49W BTL x 4ch.
The package is SIP 25 Pin type
Manufacturers : Toshiba
Preview images :
Maximum output 49 W BTL x 4CH TB2931HQ for low frequency power amplification is a power IC with a built-in 4-channel BTL amplifier developed for car audio. The output stage adopts DMOS and is composed of pure complementary of upper P-ch and lower N-ch, and achieves maximum output power POUT = 49 W. In addition, the standby switch and mute required for car audio
It has a built-in function and various protection circuits
1. Low distortion. : THD = 0.01% (standard) (VCC = 13.2 V, f = 1 kHz, POUT = 5 W, RL = 4 Ω)
2. Low noise. : VNO = 50 µVrms (standard)
(VCC = 13.2 V, Rg = 0 Ω, BW = 20 Hz ~ 20 kHz, RL = 4 Ω)
3. Built-in standby switch (4 pin)
4. Built-in muting function (22 pins)