The LD is a series of low dropout positive voltage regulators The LD series includes a current limiting circuit and a trimmed band-gap reference. LDV 5a Low Drop Positive Voltage Regulator Adjustable And Fixed 5A LOW DROP POSITIVE Details, datasheet, quote on part number: LDV. The LD is a LOW DROP Voltage Regulator able to provide up to 5A of Output Current. Dropout is guaranteed at a maximum of V at the maximum output.
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Panici Full Member Posts: Working with adjustable voltage regulators.
Working with adjustable voltage regulators
I was looking at the LD Datasheet: I’ve never worked with adjustable voltage regulators before, what supporting circuitry will I need to make this work? Test equipment, replica and original sci fi props and costume pieces, and whatever else I feel like at the time. I have an Ultimaker and a 3D engraver. That regulator requires 1.
The minimum output is 1. Do you -really- need 0V output? I’m in the process of modifying a PC power supply so that it puts out about 18V from the 12V output. My plan is to rewire it so that the 3. Then the power supply should boost the PWM so that the 3.
So the 12V output should put out 18V. Newer power supplies regulate 3. So I’ll need to spoof the other outputs back to the chip.
I’m not sure yet if it is really checking each one, or just feeding them pd1084v into a voltage divider so if datasjeet one output goes dead, it shuts down. I am going to use the same linear regulator, and use 10 turn potentiometers to adjust voltage and maximum current. I really, really hate having a “coarse” and “fine” control, that is the mark of a cheap POS power supply. Oh, and a huge heat sink. Worst case, 5A 1. Quite a lot of heat. See page 6 of the datasheet.
Vo is the maximum, R2 will be the potentiometer. Keep in mind, an unmodified PC power supply regulates the 3. So put a load of about mA to mA on the 3.
ST Microelectronics – datasheet pdf
And it gets worse if you mod the PC supply to put out, for instance in my case 18V in order to get at least 15V at the highest point: For mine, I’m going to do some tests with a few heat sinks, with a small fan for forced air cooling. Back inI built a “very linear” based bench power supply using a junkbox 30V transformer from my stash and a handful of parts. The only expensive item was a 5K ohm 10 turn potentiometer for voltage adjustment.
The design was straight from the manufacturers datasheet. I use a small finned sink and the metal case for cooling. So what does all this mean. Build the reference design from the datasheet or sadly, since the LDadj does not really have a nice reference design like the LM, use the datasheet as a guideline. This prevents a situation happening where the output pin has a greater voltage on it than the input pin. Not sure about this series of chip, but the LM and LM78xx regulators can be damaged by this.
Possible if you have an outside extra capacitance connected to the power supply, via some external circuit or you are experimenting with supercaps, and you turn the power supply off.
Thanks for the advice guys. How would I go about boosting the available voltage? It would be cool to be able to get v out of it.
You will need to determine which control IC is on the board l1084v let us know. If it is a TL, it is quite a bit simpler as that chip has been around for a very long time and is well documented.
If it is labeled “”, it gets more complex. I have a half-dozen PC power supplies with dattasheet chip I’m figuring out how to mod, but haven’t had time to dig any deeper.
Try googling for “FSP ” without the quotes. This is giving me the impetus to work on this project again.
Also, move the higher current shottky rectifiers to the 12V output. Modding the psu is a good idea. But if you can’t, leave the 12v rail as it is power directly from it for 12v applications.
For any voltage lower, use an lm or a switching reg, you could use a pass transistor and pass control of the regulated output to a transistor unless it’s a switching reg. Making a switching regulator to cover that wide an output range could be interesting.