Domestic half bridge or full brige ICs?

which current?

Wouter van Ooijen

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Joerg schrieb:

Hello Tilmann,

Thanks. I had checked these out but got a sticker shock. Typically in the several-Dollar class, too much for most designs. Maybe that's because most of theirs contain PWM circuits and other stuff but that is usually not needed if you drive it from a micro controller or other circuitry.

Regards, Joerg

Hello Wouter,

Around 1A and they don't have to stand more than 20V. Some used to contain protection against spikes from an inductive load but that can also be done outside the chip.

I am gradually finding myself migrating towards the good old ways of doing bridges. Some mainstream chips disappear, then you try FETs but as supply voltages are going ever lower that doesn't work or it becomes expensive. Last but not least there is that old standby, the plain vanilla bipolar transistor.

Regards, Joerg

I don't think you will find something cheap in that reagion. There are lots of cheap chips designed to handle small motors like in CDs, VCRs etc, typically

"Joerg" schreef in bericht news:smOOd.3837$ snipped-for-privacy@newssvr23.news.prodigy.net...

Did you look at BTL audio amplifiers? Philips has a lot of these.

Hello Frank,

I did look at audio amps but they are too expensive. Philips is a different story. Just take the TDA8512 as an example. Their web site is slow, tends to wait for their stock price quite often. I mean, who cares. Then I could not find a budget price (grayed out). Just great. If they don't straighten that stuff out, whatever is left from my design-in share for them is going to become even less. I wonder when they'll understand that.

What I am really looking for is a replacement for the LM18293 and its larger siblings. These were wonderful parts and cheap.

Regards, Joerg

"Joerg" schreef in bericht news:9h8Pd.4177$ snipped-for-privacy@newssvr23.news.prodigy.net...

That is true, without any indicative prices shown... yuk.

Still I wonder how well these audio amplifiers would suit for driving small motors. The wattage isn't really a good parameter to filter on. Assuming that these amplifiers outputs can go pretty much rail-to-rail, the dissipation would be low anyway, for a motor application. To know what the maximum current is, is more interesting.

Next week I plan to make a few small amplifiers for a gadget, trying a couple of these smaller BTL chips. I'm still waiting for some parts. I'll experiment a bit, what maximum current is that can be drawn from them before they pop.

And of cource, you can always make a discrete bridge. But I am sure you will find something excellent ;)

I read in sci.electronics.design that Frank Bemelman wrote (in ) about 'Domestic half bridge or full brige ICs?', on Sat, 12 Feb 2005:

The maximum current is usually quoted on the data sheet. Many such devices have internal current-limiting, of course, i.e. 'short-circuit protection'.

"John Woodgate" schreef in bericht news: snipped-for-privacy@jmwa.demon.co.uk...

Good point ;) I'm looking at the TDA7052A datasheet now, repetitive output current is 1.25A, non-repetitive 1.5A, 8 pin dip. Short-circuit proof and thermally protected. $1.40 at

I don't know how 'repetitive' translates into 'continious'. One would still like to know how well it goes 'rail-to-rail' and how much power is dissipated. A test on the bench would quickly reveal that, if I actually had the part.

The datasheet is more aimed at it's intended use, as an audio amplifier in linear mode.

Hello Frank,

That price isn't so bad. But if you plan to switch something big after peeking at the abs max ratings, don't hold your breath. The THD curves above 1W are not looking so encouraging. Often that indicates that the final stage might be kind of wimpy for switching heavy loads.

BTW, I am going with bipolar transistors. Ah, the good old days. Mainly because there aren't many reasonably priced FETs that can safely operate with Vgs < 3V. Best of all, bipolar transistors are cheap and ubiquitous.

Regards, Joerg