Led driver - current switch

Thread Starter

Vovkta1

Joined Oct 22, 2019
2
Hello,
I have 30V 700mA LED power supply and two LED modules are connected to this supply.
After 1h the current on the power supply change from 700mA to 350mA and then I want that one LED modul turn off and the secound one stay on.

How can I make this with low cost ?
Thank you for answers and have a nice day. :)
 

DickCappels

Joined Aug 21, 2008
5,877
What you need is a 350 ma current limit circuit and a timer. How accurate does the 1 hour timeout need to be?
 

ronsimpson

Joined Oct 7, 2019
110
Are the two LEDs in parallel or serial?
More information on the LED power supply. I think it is fixed at 700mA. Part number please.
 
Last edited:

crutschow

Joined Mar 14, 2008
23,310
Why is the power supply current change from 700ma to 350mA?
It is being overloaded?
 

Thread Starter

Vovkta1

Joined Oct 22, 2019
2
@DickCappels - do you have maybe any scheme (circuit) how to make this because input voltage is still 30V ? About timer, the time 1 hour is not fixed, so I need focus just on the current.

@ronsimpson - for now I just looking for solution and how to make this. For me is crucial just that when the current is 350mA or less that one LED modul turn off.
 

DickCappels

Joined Aug 21, 2008
5,877
The CD4060 (and that version in other families) comes to mind. I just Googled "LED timing circuit" without the quotes and got this 24 hour timer that you can modify:
1571823537457.png


You would run the timer at a lower voltage, depending upon the logic family using a 7805 or similar regulator, then use a switching device such as a MOSFET, transistor, or relay to turn your LEDs on and off (not the LEDs shown in the schematic above).

See the related web page for information about how it works and how to get 1 hour instead of 24. Of course, there is the duty cycle to consider...

https://www.gadgetronicx.com/how-to-build-24-hours-timer-circuit-cd4060/

Edit:
CD4060B datasheet link
The author of the schematic above omitted the power supply connections for the CD4060. Pin 8 should be ground and pin 16 should be connected to the logic power supply, in the case of this schematic it is 6V.
 
Last edited:

ronsimpson

Joined Oct 7, 2019
110
I have 30V 700mA LED power supply and two LED modules are connected to this supply.
More information on the LED power supply. I think it is fixed at 700mA. Part number please.
crucial just that when the current is 350mA or less that one LED modul turn off.
There is not enough information to help you. Can you send pictures. Or an advertisement on the power supply and LEDs. Maybe the paperwork showing how it is connected up.
Do you want us to say how to get the 700mA down to 350mA? or do you know how?
 
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