You don't get more power from a bridged amp anyway, you merely get the same power but feeding a different impedance.Hello,
I am wondering if it is possible to make a bridged amplifier with op-amps?
I want to have a bridged op-amp to get more output power.
That's not true.You don't get more power from a bridged amp anyway, you merely get the same power but feeding a different impedance.
I did not get your mean NigelYou don't get more power from a bridged amp anyway, you merely get the same power but feeding a different impedance.
You can certainly bridge opamps, it's probably simpler than poweramps - and will give you the same double the output VOLTAGE - the current doesn't alter though (obviously).
audioguru,Yes you can bridge two opamps. But the ouput power from one opamp is very low and the output power from two bridged opamps is also very low.
An opamp is spec'd to have a minimum load of 2k ohms because its output current is limited to a max of only 30mA.
An LM386 is a little power amplifier, not an opamp. It can drive an 8 ohm speaker because its output current is limited to 375mA. Its output power is 0.25W into 8 ohms at clipping with a 6V supply. It is not bridged.
A TDA2822M is a little power amplifier that is bridged. Its output power is 0.8W into 8 ohms at clipping with a 6V supply.
Please tell me how bridge does work?That's not true.
You get double the power.
The output voltage swing is doubled but the output current remains the same so the minimum impedance you can drive is also doubled.
So it does not have the bridge problems you mentioned at the other post about other opamps working on bridge mode??I would use an MC34072 dual opamp to drive your piezo transducer in a bridge. It has an ouput swing of about 27V p-p driving 10k ohms with a 14V supply and can directly drive a high load capacitance. It performs perfectly up to 100kHz.
Only if the amplifier can supply enough power - as I said before a bridged amplifier can only provide exactly the same power as the two individual ones, only the load impedance changes.Please tell me how bridge does work?
I think after bridging the impedance of the load remains constant. I think what will happen is that the voltage across the load will be 2 times when bridging and finally causes the current into load to be doubled too, right?
No, the power quadruples, but only because it was running at half power from the single ended amp, as my example above - due to using the wrong impedance speaker.Bridging in that aspect is pointless, it's smarter to run two amps to the two loads separately. But it's a TOTALLY different picture when you're talking about one speaker being driven from a single ended amp vs bridged, the power does double, it however does require an amplifier made for bridging or for the two separate amplifiers to be isolated.
Only if the amplifier can supply enough power - as I said before a bridged amplifier can only provide exactly the same power as the two individual ones, only the load impedance changes.
I'll give you a common example:
You have two 100W 4 ohm amplifiers, and two 4 ohm speakers.
You connect one speaker to each amplifier, and get 100W in each speaker, total 200W.
You now bridge the same two amplifiers, and connect the same two speakers in series across the output (giving 8 ohms), you get the exact same 100W in each speaker, and the exact same total 200W.
Where bridging gives an advantage is if you don't have the correct impedance speakers - say you only have one speaker, 8 ohm 200W. You connect the speaker to one of the amplifiers, but you now only get 50W from it - by using the two amplifiers bridged, you get the full 200W as before.
If you connect a 4 ohm speaker to the bridged amp, it will try and provide 400W to the speaker (200W from each amp) and both amplifiers will be destroyed.