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First, the chip description
TDA7294 is a leading European SGS-THOMSON Microelectronics STMicroelectronics to the Chinese mainland in the 90’s introduced a quite innovative integration of DMOS power amplifier circuit. It swept away the past, integrated amplifiers and linear integrated Health thick, cold, hard sound, widely used in HI-FI areas: such as home theater, active speakers.
The chip was designed to focus sound, both the signal processing circuit and power bipolar MOS advantages. With high voltage, low noise, low distortion, reproducing sound great affinity and other characteristics; and has a quiet standby, short-circuit current and thermal protection to better performance, the electrical parameters are as follows.
Operating voltage range: (VCC + VEE) = 80V
Output power: up to 100W
Voltage Range: | VCC | + | VEE | = 20V-80V
Static current: 30MA
Output Power: | VCC | = | VEE | = 35V, RL = 8 70W when in Europe
Total harmonic distortion (THD): 0.01% (typical)
Slew rate (SR): 10V/us
Open-loop gain: 80dB
I located purchase price is 13 yuan; the conditions of restrictions, I test the circuit with a universal plate welding, as long as the speaker is not too hard to sound pretty good; the author is not yet mature technology, to better play this audio chip also invited experts pointing improvement.
Second, the pin information
Each end of the pin functions as follows:
1 foot to stand side; 2 feet to the inverting input;
3-phase input pin is positive; 4 feet grounded;
5,11,12 empty legs feet; 6 feet for the bootstrap side;
7 feet for the + Vs (signal processing); 8 feet to-Vs (signal processing);
9 feet for the stand-feet; 10 feet to silent feet;
13 feet to + Vs (last stage); 14 pin output;
15 feet to-Vs (last stage).
Third, the circuit description
1. R1, R2 and R5 R5/R1 magnification composed of about 32 times the typical power amplifier;
2. C1, C2, C8, C9 for the power supply filter capacitor;
10 feet to 3.9 feet and an additional standby switch control and mute, C6, C7 as a filter and to shake.
Fourth, test conditions
1, no load, with the WD-5 +12.1 -12.1 +5.0 voltage source to provide power and allow the bit.
2, with SG1732SB5A DC stabilized power supply as input.
3, measured with a multimeter SYG DT9205G.
Fifth, test summary
Mistake to start testing the linear range of low, after the analysis is just too much magnification, but the maximum voltage of 3.86V or too small for some of the high voltage output is not required; as a universal audio chip is good (excluding fever class).