Hello,
I'm trying to design a circuit that will detect a voltage above 60V or 25Arms and then illuminate an LED array. The power source I have available is a 300V DC bus battery. I have looked into step down converters and have already purchased one from Vicor; namely, the DCM3414V75H13C2T01, which steps voltages between 180V to 480V down to 12V which meets my design criteria. My problem right now is figuring out how to detect voltages between 60V and the lower limit of the converter at 180V and then stepping those down to 12V to power my LED array. Converters with such wide ranges don't exist and frankly I'm at a loss. Is there any relay or transducer solution I could look into?

(I should note that I'm limited by the constraint that the circuit must utilize strictly hardware elements and cannot involve any software at all)
(Also my LED circuit is already designed)

Thanks for any suggestions!

 

You have a DC to DC converter that makes 300V into 12V to power the LED's right?

1) Post the LED circuit schematic.

2) Sounds like you need a voltage and current detector, are these AC voltages/Currents? You mention RMS?

More detail gets you better answers

 

Sure thing!

^ The LED circuit (simple enough, yes I'm aware that it will draw more current because the LEDs are in parallel but the power I have is sufficient)

And yes I have the converter that has 300V -> 12V It's specifications are found in the datasheet here:
http://www.vicorpower.com/documents/datasheets/DCM3714xD2J13D0yzz_ds.pdf

With regards to (2) yes I need to detect those voltages and have an analog output complete the circuit that provides 12V to the LEDs. Problem is that even if I manage to detect the 60V in the battery, I won't have 12V live because it isn't in the operating range of the converter.

(All voltages are DC)

 

Hello,

What kind of leds are you using?
The LD1117 can deliver a max current of 800 mA.
It is not a good idea to have the leds in parallel.
You could run a lot os leds in series using a LM3404HV.

Bertus

 

These are the LEDs that I have:

http://www.mouser.com/ds/2/244/SSI-LXH1090BID-102242.pdf

They're flashing LEDs because I'm also constrained that they have to flash at a frequency between 2Hz and 5Hz. They require a voltage of 3V across the lot of them in order for them to flash at that frequency which is why I have connected them in parallel because I'm constrained by the voltage. Each LED at 3V pulls 6mA and since I'm using 12 of them the total current drawn should be 6mA*12=72mA. Have I made a mistake in my reasoning?

 

Hello,

Looking at the led properties, they could be run at 12 Volts directly.



You could also trim down the vicor to say 9 Volts:



Bertus

 

Thanks for the prompt replies!
If I run them at 12V they won't satisfy my constraint of blinking between 2Hz and 5hz, because the higher the forward voltage the lower the blinking frequency. This is why I have implemented the 3V regulator.

Perhaps my approach is wrong? Is there some method of creating a square wave voltage at a frequency of 2Hz to 5Hz from a regulated DC supply? Because if so I can simply connect non-blinking LEDs in series and let the square wave handle the blinking.

 

Hello,

The led will blink with about 2.5 Hz @ 3.0 Volts and with 1.5 Hz @ 9.0 Volts.
You can use the LD1117, even when you trim down the Vicor to 9 Volts (or even lower), to reduce the heat produced by the LD1117.
Be aware that the leds likely will not blink at the exact the same speed and on the same time.

Bertus

 

What is the 300 VDC source for the converter, and how much amperage can it supply?

"My problem right now is figuring out how to detect voltages between 60V and the lower limit of the converter at 180V and then stepping those down to 12V to power my LED array."

What does that mean?

 

Thank you for the feedback regarding the LEDs, do you have any recommendation of what I should do about my voltage detection problem?

 

What is the 300 VDC source for the converter, and how much amperage can it supply?

"My problem right now is figuring out how to detect voltages between 60V and the lower limit of the converter at 180V and then stepping those down to 12V to power my LED array."

What does that mean?

The 300V source is a battery that can provide 260Amps .

I have a method of stepping down any voltage between 180V and 420V to 12V in the Vicor converter. I now need to figure out how to drive my LEDs between the required 60V and the lower limit of my DC/DC buck converter (180V).

 

Please draw a picture of the whole system......I do not understand you.

 

 

What kind of battery are you using? I never saw a battery like that.

 

It's a large battery meant to power a motor controller

 

What is the battery voltage at full charge?

At what voltage do you recharge battery?