| Electronics > Beginners |
| How do I implement ESD protection for a voltage reference? |
| << < (4/5) > >> |
| Brak:
I'm not real sure about this. Especially not sure about the component values. Does this look like something that might work with the right components? Brak |
| David Hess:
That looks about right. That configuration is commonly used to drive capacitive loads and if you want the math, this application note from Analog Devices covers it under "In-loop compensation". http://www.analog.com/en/analog-dialogue/articles/ask-the-applications-engineer-25.html One such application involves the buffering or inverting of a reference voltage, driving a large decoupling capacitor. Here, CL is a fixed value, allowing accurate cancellation of pole/zero combinations. The low dc output impedance and low noise of this method (compared to the previous two) can be very beneficial. Furthermore, the large amount of capacitance likely to decouple a reference voltage (often many microfarads) is impractical to compensate by any other method. With some care, you can also place a relatively large output capacitance (10 to 100 microfarad aluminum electrolytic or solid tantalum capacitor can work) directly from the operational amplifiers output to ground forcing "dominant pole" frequency compensation but I do not really recommend this unless you want to delve into the details of frequency compensation. Some newer operational amplifiers can operate this way without restrictions; there is a list at the link. |
| T3sl4co1l:
Yeah, like that. Don't need D1-D3, since D4 is fine in a single-supply situation. (Otherwise, clamp diodes to the supplies, or a bidirectional TVS or back-to-back zeners, would do.) May want more supply, since 13 - 10 = 3V (if it were a RRO amp) isn't much current through the 100 ohm resistor. Well, maybe not that bad, but YMMV. Something to keep in mind. Tim |
| Brak:
Excellent, thank you both. That gives me something concrete to study on. I had the analog link bookmarked. Does the "Seven Transistor Labs" have anything to do with "Six Transistor Radios"? I still remember my first one. It was red and so small it'd fit in my Dad's shirt pocket. IIRC one of the transistors was used as a diode, but they could advertise six transistors. Brak |
| T3sl4co1l:
Nah, more that I like to make circuits like this from time to time, which, if you ignore the complementary emitter follower, and count the TL431 as a single transistor, almost works... :P (This circuit has functionality similar to UC3842, but with far fewer transistors, hence the challenge. Doing it in less than ~4 is iffy, and you're giving up things like input voltage range, or output overload handling, when you do that.) Tim |
| Navigation |
| Message Index |
| Next page |
| Previous page |