A pulser .. again

A project log for A HSDK for ultrasound imaging

Using a Raspberry-based hardware and software development kit to understand ultrasound imaging

kelu124kelu124 03/08/2018 at 22:420 Comments

I was wondering why I couldn't get pulses on all negative... when the following design (from un0rick) works.

The reason is stupid.

1. When OE is high, Pon needs to go L->H during the pulse, but the second control is _inversed_: Poff needs to gow H->L during the damping period.

2. When OE is low, OutA is high (as if InA was high) and OutB is low (as if InB was low).

Hence, when two TC6320 were used, as in alt.tbo first of the name:

- Pulser side: InA is right, but InB needs to be high by default.

- Damper side: OE activates or desactivates the damper... but it doesn't do anything! With OE high or low, the output is the same...

Well well well.. alt.tbo can still be used with HVPos at 25 to 75V, but then HVNeg has to be set to GND. And then, PPoson has to be on L->H, whereas the damper is activated by PNeg going H->L. Unipolar, but working!