6 ms·
I had to learn the hard way about circuits like the superbuffer here, and even more so the H-bridge: real components are not ideal, switching times are not ze
by quercusa 4y ago
I had to learn the hard way about circuits like the superbuffer here, and even more so the H-bridge: real components are not ideal, switching times are not zero, and until you learn that lesson you'll be releasing a lot of smoke.
Great write-up as always, Ken.
- kens 4y agoThis is why microprocessors usually have non-overlapping clock phases, so everything has time to switch and you don't end up with unexpected shorts. Also, the nice thing about reverse-engineering is that I can assume the circuit works; someone else dealt with all the obscure timing issues.
- FpUser 4y ago>"...switching times are not zero, and until you learn that lesson you'll be releasing a lot of smoke." This is particularly spectacular when those babies control motors ;)
- femto 4y agoIt's particularly satisfying when a design doesn't just account for parasitic elements but uses them to advantage.
- adql 4y agoYou mean "fragile". That kind of design likes to break on smallest component type change. It's akin to relying on compiler quirks to make your code work. Sure, sometimes you don't have a choice due to various constraints but in general it is to be avoided.
- femto 4y agoNot so much if they are on chip. It's reliable with discrete components if the parasitic is just backing an external component. For example, a capacitor across a junction contributes most of the capacitance so the capacitance of the junction is just a small parallel capacitance. I agree that it's not good to use a "bare" parasitic in a discrete circuit, unless the circuit is very insensitive to its value.