The IC has been shown in the same format that's shown in the data sheet, but has been cleaned up for publication here. A LED is included to indicate that power is available, and because of the low current this will typically be a high brightness type.įigure 1 - Schematic of Power Amplifier (One Channel Shown) While the board is designed to take two TDA7293 ICs, it can naturally be operated with only one, and the PCB is small enough so that this is not an inconvenience. All unnecessary functions have been disabled, so it functions as a perfectly normal power amplifier. The schematic is shown in Figure 1, and is based on the PCB version. It also features muting and standby functions, although I've elected not to use these. This improves power into low impedance loads, but is a rather expensive way to get a relatively small power increase. The TDA7293 has a bewildering number of options, even allowing you to add a second power stage (in another IC) in parallel with the main one.
provided adequate heatsinking is available of course. The board is very small - only 77 x 31mm, so getting it into tight spaces is easy.
This is now rectified, and it's ready to "rock and roll". This particular project has been planned for a long time, but for some reason I never got around to completing the board or the project description. This is not a limitation, since both are tied to the positive supply rail and are therefore disabled. There are no apparent downsides to the TDA7293, although it was found that one batch required a much higher voltage on the Standby and Mute pins than specified, or the amps would not work. The main benefit of the MOSFET stage is that it doesn't need such radical protection circuitry as a bipolar stage, so unpleasant protection circuit artefacts are eliminated. The TDA7293 IC uses a MOSFET power stage, where the others featured use bipolar transistors.
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