Hi All,
I am finally working on a my first amp with TPA3116D2. Could someone please explain the purpose of BSNL pin on the chip?
The datasheet says the following:
Boot strap for negative left channel output, connect to 220 nF X5R, or better ceramic cap to OUTNL.
Similarly, BSPL defined as the Boot strap for positive left channel output, connect to 220 nF X5R, or better ceramic cap to OUTPL.
but I have no idea what is the meaning of "boot strap" in this context.
For the reference, the datasheet is available here: https://www.ti.com/lit/ds/symlink/tpa3116d2.pdf
Thank you!
I am finally working on a my first amp with TPA3116D2. Could someone please explain the purpose of BSNL pin on the chip?
The datasheet says the following:
Boot strap for negative left channel output, connect to 220 nF X5R, or better ceramic cap to OUTNL.
Similarly, BSPL defined as the Boot strap for positive left channel output, connect to 220 nF X5R, or better ceramic cap to OUTPL.
but I have no idea what is the meaning of "boot strap" in this context.
For the reference, the datasheet is available here: https://www.ti.com/lit/ds/symlink/tpa3116d2.pdf
Thank you!
Here 'bootstrap' refers to the way that enough gate enhancement voltage is generated for the N-channel output transistors. Seeing they're configured as source followers and the output pin (the source terminal of these FETs) switches between the rails, on the positive side a higher voltage than the main rail is required for turning the high-side MOSFET fully on. That's generated by a charge pump fed from the output, hence 'bootstrap'.
That RC network is connected to the output pin (as is the bootstrap cap), its a snubber to soak up any ringing from the output inductor. TDA8932 - another class D amp chip - has a similar snubber on its outputs.
