TDA7594 Audio Amplifier 50W

TDA7594 general description:

The Type IC TDA7294 from SGS-Thomson is an integrated a.f. amplifier intended for use in all sorts of hi-f application. According to the manufacturer's data sheets, chip can deliver outputs of up to 100 watt. Considering other properties, such as low noise, low distortion and reliable short-circuit and thermal protection circuits as well, the chip is indeed an interesting one. Moreover, with peak supply voltages of ±40 V and a load impedance of 4 ohm, the maximum dissipation of the IC TDA7294 will easily be exceeded. For these reasons, the supply in the present amplifier has been kept down to a safe ±30 V. At these voltages, the chip delivers, without any difficulty, 50 W into an 8 ohm load and 80 W into a 4 ohm load. These are still very respectable figures, particularly in view of the reasonable IC price. The circuit diagram of the amplifier in shows that the IC TDA7294 needs only a small number of external components. The input signal is applied to pin 3 via capacitor C1 and low-pass filter R6-C10. The filter improves the pulse response and flattens the frequency response. For maximum output offset, the values of R1 and R3 should be equal, so that the input impedance is 10k. The roll-off frequencies of R1-C1 and R2-C2 determine the lower bandwidth limit of the amplifier: with values a specified, this is about 16 Hz. The upper -3 dB point is at about 100 kHz.The amplifier is muted by a relevant input to pin 10 and placed in the stand-by mode by a relevant signal at pin 9. Muting should always take place before the stand-by mode is selected. Connecting the mute and standby pins permanently to the supply line ensures that the amplifier comes on immediately the power is switched on. Any switch-on clicks may be eliminated by increasing time constants R3-C4 and R5-C5. If large-value electrolyte capacitors are used in the power supply, switching off will be rather slow. It is best to build the amplifier on the printed-circuit board shown below. Insulating material between the heat sink and the IS is. The amplifier will have good performance with toroidal mains transformer, a 25A bridge rectifier and two 10.000uf,50 V electrolytic capacitors.

TDA7594 Circuit diagram:

MUTE and ST-BY utilization:

TDA7594 pcb layout:

Datasheet for TDA7594: Download - No

Using the TLP250 Isolated MOSFET Driver Explanation and Example Circuits

I’ve already shown how to drive an N-channel MOSFET (or even an IGBT) in both high-side and low-side configurations in a multitude of ways. I’ve also explained the principles of driving the MOSFETs in these configurations. The dedicated drivers I’ve shown so far are the TC427 and IR2110. Some people have requested me to write up on MOSFET drive using the very popular TLP250. And I’ll explain that here. The TLP250, like any driver, has an input stage, an output stage and a power supply connection. What’s special about the TLP250 is that the TLP250 is an optically isolated driver, meaning that the input and output are “optically isolated”. The isolation is optical – the input stage is an LED and the receiving output stage is light sensitive (think “photodetector”). Before delving any further, let’s look at the pin configuration and the truth table. Fig. 1 - TLP250 Pin Configuration Fig. 2 - TLP250 Truth Table Fig. 1 clearly shows the input LED side and the receiving photodetector as well

Do More

Search This Blog