I know the 7052 can be configured to run single ended and the data sheet states it has an MLC protection circuit built in for this purpose however it isn't very clear on how to configure the chip for single ended operation. I'm assuming a coupling capacitor is in order on the output of pin 5 (Out+) to the speaker however what to do with the other (-) output on pin 6? Should this be left floating or would say a 50R resister and .1uF cap in series to ground be needed to prevent pops?
Anyone done this before? I'm running a 5V rail.
Anyone done this before? I'm running a 5V rail.
It is single ended.
Pin 5 to plus on speaker, pin 6 to minus on speaker.
It's a mono BTL ic and is meant to connect that way. It's not a stereo IC.
Pin 5 to plus on speaker, pin 6 to minus on speaker.
It's a mono BTL ic and is meant to connect that way. It's not a stereo IC.
You must be reading the TDA7052A datasheet as the part with no 'A' doesn't have the MCL feature. The MCL prevents TDA7052A being used single ended except with low power loads like headphones.
Ah, no I don't think I'm reading anything wrong regarding the MLC protection. The chip is designed to limit the output if one pin draws more current as it would with a single ended speaker and a Bridge Tied Load (BTL) is not a single ended configuration. I know this is done with these chips but I'm not sure wither the unused output should be left floating or not.
A single ended speaker system has the negative tied to ground not back to the - pin of the BTL. I lose output power because the rail is no longer split but thats ok in my application. I don't need the power.
A single ended speaker system has the negative tied to ground not back to the - pin of the BTL. I lose output power because the rail is no longer split but thats ok in my application. I don't need the power.
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Hi,
There is no chance of a chip amp being able to run
single ended except as a low power headphone amp.
rgds, sreten.
There is no chance of a chip amp being able to run
single ended except as a low power headphone amp.
rgds, sreten.
That's what I'm getting at. The output goes to a small speaker (a shoulder speaker/microphone actually) which is normally bypassed by plugging in a small ear bud. Very little output power is needed. Yes I lose fidelity on the speaker if the ear bud is unplugged but then it may be good enough too. What's needed is a common ground on the output jack which I don't have with the bridge tied load. Rather than replace the 7052 I'd like to try it single ended using only the positive output of the chip and grounding the speaker negative. This will require a coupling cap on the output to defeat the DC bias. Many BTL chips can be single ended but some require a resistance on the unused output. Does the 7052? I'll be giving it a try in any case but I just figured I'd toss it out there to see if anyone had some experience with it.
A capacitor and 4 ohm resistor on the negative out should keep the protection from kicking in. A 1/2 watt resistor should be fine. May only be able to find a 4.7 ohm but this should be ok. Get some with 20% tolerance and find one that's under a bit to get it close.
Hmm, never thought of actually defeating the MCL circuit but thats something to consider. I was thinking a higher resistance than that to keep the current down since its battery operated. I'll experiment with a few values. Why 4 ohms though? What are you basing that on?
nah, anything that resembles a load will do i think.
You can use even 1K if i'm not mistaking.
supposedly it should just not float, and should not be overloaded.
and i think You need a cap in series with the speaker or whatever You drive on the other output.
You can use even 1K if i'm not mistaking.
supposedly it should just not float, and should not be overloaded.
and i think You need a cap in series with the speaker or whatever You drive on the other output.
I agree a series cap is needed to the speaker to remove the DC bias and some sort of load is required on the unused output.
Some chips, like the TPA4861 are designed for it with an active high input that enables single end mode. If the 7052 doesn't work out I'll remake the board with that chip.
Some chips, like the TPA4861 are designed for it with an active high input that enables single end mode. If the 7052 doesn't work out I'll remake the board with that chip.
it should work.
block dc on puth outputs, and give the unused channel some load.
i think even 1k ohm ish anything you find will do just fine.
i do not see why it should not work.
block dc on puth outputs, and give the unused channel some load.
i think even 1k ohm ish anything you find will do just fine.
i do not see why it should not work.
I've been try using 7052 single ended for headphone. just add 470uF elco on +out (the -out is floating I guess), didn't remember wether its 7052A or no "A", it's covered heatsink.
the output noise is crazy.... 😀
the output noise is crazy.... 😀
Try it with a 50 ohm resistor and .1uF cap in series on the -output to ground. I haven't had a chance to try anything yet because I'm traveling but I'll be home tonight to give it a try myself. It sounds like you have some DC offset making it to ground.
I used a 4.7uF cap on the positive output of the 7052, a 270 ohm resistor with .1uF cap in series to ground on the negative output. It works fine as a mono headphone driver. The voltage controlled volume has very little effect beyond the mid-range setting. The sound is clean up to nearly max volume where it starts to distort just a bit. I didn't bother to scope it but I suspect this is clipping due to gains on the mixer and filter stages I have in front of the chip and of course in this configuration the 7052 is not operating mid supply. It will not be adequate in my application unfortunately since I need to be able to drive an 8 ohm speaker when the ear bud gets unplugged.
On the up side the chip works well single ended (if the output is enough for you) with no pops and it drew so little current it didn't even show on the bench supply.
I've been looking around and I think the TPA0211 is a better choice for this kind of thing. It's designed to run in BTL and SE modes with an active low pin to switch between the two modes.
On the up side the chip works well single ended (if the output is enough for you) with no pops and it drew so little current it didn't even show on the bench supply.
I've been looking around and I think the TPA0211 is a better choice for this kind of thing. It's designed to run in BTL and SE modes with an active low pin to switch between the two modes.
question, why you wanted it to be single ended ?
it was made for BTL application, if You need to drive a speaker that is 8 ohms, just use it as it was ment to be. BTL config.
it was made for BTL application, if You need to drive a speaker that is 8 ohms, just use it as it was ment to be. BTL config.
Ha ha, I was wondering if that question would come up. Its a little more complicated than that. The device is a transceiver mixer and interface that allows the use of a single speaker microphon. Transmitter selection is done using a logic circuit I came up with. I wanted the 7052 to get the voltage controlled volume aspect of the chip. Unfortunately the BTL design isn't compatible with the PTT system of the speaker mic. It needs a common ground. I was just trying to see if I could get enough performance out of it in SE mode to be usable. It will work with an ear bud plugged into the mic but it won't drive the larger speaker. I'm moving on.
I'm looking at simply changing the mic out for something that has a speaker positive and negative with separate mic and ground pinouts. That would allow the BTL mode and PTT functions to work independently.
mm You can still use it in BTL to drive a speaker,
and use SE for whatever You need it to do.
sure, one of the SE channels will see a slightly more demanding load,
but it will make no difference.
i would give it go 😀
and use SE for whatever You need it to do.
sure, one of the SE channels will see a slightly more demanding load,
but it will make no difference.
i would give it go 😀
Unfortunately the common speaker ground is a must in this current configuration, I just don't see any other way. It's the PTT function of the speaker/microphone that's the problem. The Push To Talk of the mic uses the same ground internally as the speaker and if the speaker isn't grounded (as is the case with a BTL) the PTT doesn't work.
This system works as is using an LM386 for the power amp but thats an old chip and I'm looking for better sound with a built in volume control if possible. I'm not satisfied with 386 is what it comes down to.
A speaker/mic with pins for SPK+, SPK-, Gnd and MIC would be ideal. Just have to find one.
This system works as is using an LM386 for the power amp but thats an old chip and I'm looking for better sound with a built in volume control if possible. I'm not satisfied with 386 is what it comes down to.
A speaker/mic with pins for SPK+, SPK-, Gnd and MIC would be ideal. Just have to find one.
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