TDA2030A amplifier with split and single power supply - Page 1
Forum section: electronics / beginners

author: Adhith
author_rank: Frequent Contributor
timestamp: June 27, 2017, 07:15:28 am
content: hello everyone..I just saw these two circuits from TDA2030 datasheet and I can't understand between single & split power supply circuit means. I was under the assumption that in a split power supply circuit the negative power terminal is isolated from the ground audio terminal and don't know its true or not. I'm providing the supply with a 12v wall adapter.I believe that the 2000uf cap and the speaker impedance in the single power supply circuit deals with the cutoff frequency for the audio output, then what about the cutoff frequency of the audio in the split power supply circuit (I can't see a larger cap there). I'm trying to use the circuit to drive a sub woofer so I'm looking for a lower cutoff frequency.So could anyone help me out??Also I would like to know that is it not necessary to maintain two separate channels for audio ground and the negative power supply terminal for the amplifier but most of the circuits shows a single ground for both.

author: capt bullshot
author_rank: Super Contributor
timestamp: June 27, 2017, 07:46:03 am
content: Using these circuits, the ouput of the amplifier typically rests at half of the supply voltage (DC) and is superimposed with the audio (AC) signal.In case of a split supply this equals GND level, in case of a single supply this is half of the supply voltage.The speaker doesn't like DC applied to it. Using a split supply you have the amplifiers DC output level at GND, so you can connect the speaker directly from amp output to GND.In case of single supply the large capacitor takes care of the DC offset (half supply to GND) that may not applied to the speaker. The capacitor gets charged to half suppy voltage (DC wise) and passes the audio band AC to the speaker. Capacity and speaker impedance set a lower pass band limit. In case of the split supply, there is no lower pass band limit at the output side of the amplifier.

author: Adhith
author_rank: Frequent Contributor
timestamp: June 28, 2017, 05:20:22 pm
content: Thank you very much for your reply,so if I have a normal 12 ac adapter what would be the best thing to do??

author: Audioguru
author_rank: Super Contributor
timestamp: June 28, 2017, 09:31:50 pm
content: A normal 12V AC adapter has an AC output. The amplifier must be powered with DC, not AC. If your adapter has a 12VDC output then it can power the TDA2030A with its single supply but the datasheet shows that its maximum output power will be almost nothing since the datasheet does not show the output power when its single supply is less than 24V. All its spec's are shown with a +/- 16V or 32V single supply.

author: Audioguru
author_rank: Super Contributor
timestamp: June 28, 2017, 09:41:44 pm
content: The circuit with the split supply has a 1uF input capacitor feeding 22k which is a highpass filter with -3dB at 7.3Hz, and its negative feedback is another highpass filter of 22uF to 680 ohms at 10.7Hz.

author: Audioguru
author_rank: Super Contributor
timestamp: June 28, 2017, 11:30:01 pm
content: The datasheet of the TDA2030A has a graph of output power vs supply voltage. The graph does not show anything below a supply of 24V so I expended it and it shows with a supply less than 14V the output power is zero. I think the output will be 1.2W with a 12V supply and an 8 ohm speaker.

author: mariush
author_rank: Super Contributor
timestamp: June 29, 2017, 12:25:02 am
content: You can use a bridge rectifier and a big capacitor to get maybe 15-16v DC from a 12v AC adapter or transformer.If you wish to use a 12v power supply then my advice would be to switch to tda2050 which will produce some output with as little as 9v (or +/- 4.5v)note that these chips are maybe 50-70% efficient, so if your 12v ac adapter is rated for 1a (12w), don't expect to get more than around 4-5w out of whatever circuit you makehere's some project pages to learn some morehttp://diyaudioprojects.com/Chip/DIY-TDA2050-Hi-Fi-Chip-Amplifier/DIY TDA2050 IC Hi-Fi Chip Amplifierhttp://www.eleccircuit.com/tda2050-amplifier-stereo-35w-75w/TDA2050 amplifier stereo 35W-75W

author: Audioguru
author_rank: Super Contributor
timestamp: June 29, 2017, 01:54:59 am
content: The TDA amplifiers are very old. Why not use a modern bridged class-D stereo amplifier that has plenty of output power when fed from a 12VDC or a little more wall-wart and wastes a very low amount of power making heat. Texas Instruments makes many of them.

author: capt bullshot
author_rank: Super Contributor
timestamp: June 29, 2017, 05:22:05 am
content: It's not clear what kind of AC adapter you have. My guess would be a wall wart or power brick outputting 12V DC (regulated or unregulated). In this case you'd have to use the single supply circuit. As the others pointed out, this amplifier won't give a reasonable output power in this configuration. If you have only this type of IC, you should go for a higher supply voltage (e. g. 24V DC with the single supply circuit or +/- 12V with the split supply circuit. If you have a 12V DC single supply only, you may try to build a BTL (bridge tied load) configuration using two of the amplifiers.

author: Adhith
author_rank: Frequent Contributor
timestamp: June 29, 2017, 12:48:23 pm
content: sorry my friends I meant 12v dc adapter

author: Audioguru
author_rank: Super Contributor
timestamp: June 29, 2017, 01:37:12 pm
content: Quote from: capt bullshot on June 29, 2017, 05:22:05 amThe datasheet shows the schematic of a bridged amplifier. With a 32VDC supply its output is 34W into 8 ohms. With a 12VDC supply its output is close to zero.

author: Adhith
author_rank: Frequent Contributor
timestamp: June 29, 2017, 05:55:17 pm
content: Thank you everyone for your detailed explanations and suggestions It was very helpful for me since I'm not good in electronics. Since I can only provide 12v, which is insufficient for the IC I think of moving forward with another IC. Once again thank you guys

author: Zero999
author_rank: Super Contributor
timestamp: June 30, 2017, 03:17:20 pm
content: I'd recommend the TDA7297.Alternatively buy a pre-assembled class D amplifier board. The MAX9744 and PAM8403 are cheap class D amplifier ICs but it's cheaper and easier to buy the whole board with all of the components, pre-assembled than making it yourself.

author: Audioguru
author_rank: Super Contributor
timestamp: June 30, 2017, 05:48:59 pm
content: A sub-woofer is usually in mono (with both stereo channels mixed together) and at a fairly high power.How much power do you want and what is the impedance of the speaker? A 12V supply is low for high power, is it for a car?

author: Zero999
author_rank: Super Contributor
timestamp: June 30, 2017, 08:46:49 pm
content: The ICs I listed are for stereo but you don't have to use both channels if you don't need to. I have looked for mono class D ICs but they're no cheaper and are often more expensive.I've done another search and found this:http://www.ebay.co.uk/itm/DC-12V-8V-20W-Mono-Class-D-Audio-digital-Power-Amplifier-Board-AMP-Module-/171970881985Searching for OEP20W, brings up the datasheet for the TPA3001D1, which is most likely the IC used on the board.http://www.ti.com/lit/ds/symlink/tpa3001d1.pdf