Has anyone used any of the consumer-grade audio power amps such as the LM1825, TDA2030, or TDS7297 as a basic DC power opamp? Any reason they shouldn't be used as power supply regulators, TEC controllers, etc?
Dave M
Only the TDA2030 comes up in a search (as obsolete) check your part numbers.
I'm guessing the DC performance is not as good as it could be. Lots of DC offset perhaps.
George H.
On a sunny day (Mon, 15 May 2017 09:49:45 -0500) it happened "Dave M" wrote in :
I have an audio amp with tda7294. 100V - 100W DMOS AUDIO AMPLIFIER WITH MUTE/ST-BY
All works, but not used or DC, these amps have a bootstrap cap from the output.
It has no problem with reactive loads, been using it to drive a 24 to 230 V transformer in reverse to drive my cryocooler at 60 Hz (we have 50 Hz here).
The fact that it is still in one piece proves it is a great chip... And it does not even need a Boucherot network:
I have been told other version of TDA.. whatever are NOT stable without that network, so this seems to be unique to this DMOS chip.
I like TCA0372, which is a real opamp. With the right caps, it's c-load stable, so you can use it in programmable power supplies and such.
And it's cheap!
-- John Larkin Highland Technology, Inc lunatic fringe electronics
A number of those audio power amplifiers aren't designed for direct coupling, so some fudge will be necessary to get them working... so that, in conjunction with an OpAmp, they can oscillate >:-} ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
Thinking outside the box... producing elegant solutions.
"It is not in doing what you like, but in liking what you do that is the secret of happiness." -James Barrie
On a sunny day (Mon, 15 May 2017 09:03:06 -0700) it happened Jim Thompson wrote in :
You do not even need an opamp, I had an old tube amp driving a car ignition coil as my first HV generator, and simple feedback to the phone input. Being able to oscillate is a plus, we are, in some way also oscillators. No ocillations = death.
I used an old classic coil, and discharged an oil cap into it with a thyratron tube. The spark climbed over the insulator back to the primary terminals, so I had to add an oil-filled extension tube.
Messy.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
On a sunny day (Mon, 15 May 2017 09:17:13 -0700) it happened John Larkin wrote in :
These days it is so easy:
I have one, but do not think it really is 400 kV. More like 40 kV perhaps. Had no time / urge to play with it... Too many ESD sensitive parts around,,,,
There are a lot of those Tesla coil projects around too:
Nice pictures!
400K Chinese volts. You have to factor in the exchange rate.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
If the super-est best-est performance isn't an issue, a plain old op-amp driving an emitter follower stage often works well, particularly in a 1- quadrant amplifier such as a regulator or TEC controller.
-- Tim Wescott Wescott Design Services http://www.wescottdesign.com I'm looking for work -- see my website!
Sno-o-o-o-ort >:-} ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
Thinking outside the box... producing elegant solutions.
"It is not in doing what you like, but in liking what you do that
is the secret of happiness." -James Barrie
Or an opamp driving the adjust pin of a 3T regulator. That has some nice points.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
----------------
** Generally they are not unity gain stable.Audio power amps have a voltage gain of 10 to 50 times in most cases.
..... Phil
Hah! It also says "1-2cm arc" which translates to 10-20kV in dry air. That sounds possible.
-------------------------
** Dave's list is full of typos.It should read: LM1875, TDA2030 and TDA7294
.... Phil
Sorry, but these days "consumer-grade audio power amps" are all class-D. In general most of these can perform as well as a linear amps. I have my favorites. Especially high-performance ICs that are well represented in complete PCBs from China, available at rock-bottom prices on eBay.
An example, IRS2092. This Intersil PWM IC has +/-100V range, can be pushed to 1MHz, and provides 1A gate drive to a pair of n-channel HV MOSFETs. A popular combo: a 250W amplifier using an IRFI4019: two 150V, 6A FETs in a TO-220F-5 package.
E.g., eBay item 122463174432 for $20 + $3 shipping. These can be DC coupled by bypassing the AC coupling capacitor. This item, an L15DSMD 250W amp, is based on IR's IRAUDAMP7S.
Another combo, IRS2092 + two IRFB4227: 200V, 45A TO-220 FETs, for a 1000-Watt amplifier, eBay item 222177230692, $63+$10.
--
Thanks,
- Win
Define "consumer grade". Class-AB amplifiers are the norm in automotive applications.
I am having a hard time figuring out why anyone would want to do that. Just a simple circuit would be cheaper. Single ended, transistor or whatever fed by an OP AMP or even a comparator of discrete components.
On a sunny day (Tue, 16 May 2017 10:14:38 +1000) it happened Clifford Heath wrote in :
Indeed.
Yes, that is a consideration. The "noise gain" needs to be high but not necessarily the gain from the input of the circuit as a whole. You can of course lower the gain back to unity by attenuating the input, or a number of other tricks.
The TDA2030 and similar ones also need a series R-C from the output to ground, I think it is called a "Zobel network". Usually the capacitor is
100nF or so, and the resistor 1 Ohm or so. Without this it can oscillate.The DC offset voltage is also pretty terrible and unstable with temperature.
The quiescent supply current of the TDA2030 is also quite high and could be a problem in some applications.
I have used TDA2030 chips in electroplating power supplies, configured as Howland current sources. I also used similar ones in voice coil drivers using an old hard driver voice coil as an actuator, and for driving power LEDs with a controlled current waveform. The reason why I used these audio amplifier chips is because they were very cheap and quite powerful.
The TDA2030 is discontinued now. It was one of my favourite parts, not because it was easy to use but I guess because I got a lot of use out of them (e.g. as a kid I connected one to my crystal radio for driving a speaker) and they were very cheap so they seemed like a good deal.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.