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| 10 Amps power supply with LM723 |
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| mike_mike:
Hello, I am planning to build a new power supply using LM723 and NPN power transistors. I saw that there are a lot of schematics on the internet, but I am wondering which of them is a good one ? So my questions are: 1. Can you recommend a good 10 Amps power supply with LM723 ? 2. Is there the possibility to appear oscillation in this power supply that you recommended ? How can I prevent the oscillations ? 3. What are the layout guidelines for such a power supply ? 4. What other problems can appear in the circuit ? |
| Wolfgang:
The ARRL (American Radio Relay League) has some 30V/10A supply suggestions. Important things are: - adequate cooling (fan) - bridge rectifier with sufficient current loading capability (20A min) - 4 x 2N3055 - frequency compensation (see ARRL schematics) - overtemp protection - output crowbar to protect your load if something goes wrong. http://www.dd1us.de/Downloads/an%20rf%20proof%2030%20amps%20power%20supply%201_0.pdf |
| mike_mike:
Thanks for the document. It is very interesting. I built the power supply from the link: http://www.electronics-lab.com/project/3-30-v2-5-a-stabilized-power-supply/ The single difference was that I used 0.33 R in parallel with 0.18 R for R5. I tested the power supply using a 24V ac / 100VA transformer. The output voltage was 19.97Vdc without load and with load it was 19.94Vdc. The load was a resistive load of 2.90A. It is normal the difference of 0.03V between the output voltage with and without load ? The output voltage was measured on the divider formed by R4 and R3. |
| iMo:
I would add a small resistor, like 100ohm, into TR1's base. 30mV change with 2.90A load? -> the 723 NS datasheet says the load regulation with an external NPN pass transistor is 15mV per 1A change. With thin wires and larger currents it could be even more.. PS: --- Quote ---10 Amps power supply with LM723 --- End quote --- with your 0.18ohm || 0.33ohm the over-current protection trips at something like 5.5Amperes.. |
| mike_mike:
Can you be more explicit ? I saw in the datasheet that load regulation is maximum 0.6% of Vout, so in my case it is about 0.11V (0.6% * 19.97V). Is that correct ? |
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