How to draw regulated 5 V or 3.3 V from LED driver

[Rohan Vardekar]

Hi there,
I have Street light LED driver which gives 48V with no load condition.I have to attach microcontroller along with it, for that I need either 5V or 3.3V from this driver itself so I am thinking whether I should connect my regulator or Dc-to-Dc convertors(I found some on internet) at LED driver output in parallel along with LED panel or is there any better way.If yes do suggest.It is to be noted that Light intensity should be maintained even after connecting microcontroller+regulator in circuit.

Thanks....

 

[BobK]

Hi Rohan, and welcome to the forum!

I assume the LED driver is a constant current source.

If you connect the regulator in parallel to the LEDs, it would take some of the current from the LEDs. This might or might not be a problem, depending on how much current you need for your microcontroller circuit.

Bob

 

[Rohan Vardekar]

Can you please suggest any 5V regulator,7805 won't work as it's input range is only 7 to 25 V .My input voltage is 48V.
Thanks for Replying,

Rohan

 

[BobK]

How much current do you need for the micro and associated circuitry?

Is the driver a current source? If so, what is the current setting?

Bob

 

[Gryd3]

Can we please determine if the LED driver is a constant current or constant voltage driver?

Can we please also determine the reason for the 5V or 3.3V ... you could simply get a mains powered USB charger and wire it in parallel to the 120/240V side of the LED driver and be done with it.

If the LED driver is constant current, and you pull 500mA, then it will directly remove 500mA from the LEDs resulting in lower brightness.
If the LED driver is constant voltage, you will need to ensure that the driver has enough current to spare to support the additional circuitry.

 

[Rohan Vardekar]

LED driver:
No load condition voltage:48V
Full LED load voltage:44.1V
Full LED load current :around 800mA(measured using DMM)

I want to digitally control this LED lamp through relay or dimmer.

Relay I am looking for:

Coil voltage around 5 to 6V
Output DC Voltage :Around 60V(To be on safe side)
Output DC Current :5 to 6A(Considering switching or fluctuations)

Please suggest me cost effective product perfect for this scenario.(It would be helpful if product is being already used by you).
On searching online I found these
1)SSR3A48D05 - SPST 0-48Vdc 3A DC/DC Solid State Relay (5Vdc Control)

2)SSR2A50D - SPST 3-100Vdc 2A DC/DC Solid State Relay (5Vdc Control)

Please suggest me the relay I should buy?

Thanks..

 

[Gryd3]

LED driver:
No load condition voltage:48V
Full LED load voltage:44.1V
Full LED load current :around 800mA(measured using DMM)

I want to digitally control this LED lamp through relay or dimmer.

Relay I am looking for:

Coil voltage around 5 to 6V
Output DC Voltage :Around 60V(To be on safe side)
Output DC Current :5 to 6A(Considering switching or fluctuations)

Please suggest me cost effective product perfect for this scenario.(It would be helpful if product is being already used by you).
On searching online I found these
1)SSR3A48D05 - SPST 0-48Vdc 3A DC/DC Solid State Relay (5Vdc Control)

2)SSR2A50D - SPST 3-100Vdc 2A DC/DC Solid State Relay (5Vdc Control)

Please suggest me the relay I should buy?

Thanks..

This should have been the first post...
It appears as though the driver is constant current... in which case connecting a 5V regulator in parallel with your LEDs will reduce their brightness depending on the current draw of the additional circuit.
Due to the voltage the driver is operating at, it would be highly discouraged to use an analogue 3-pin regulator like a 7805.
... I don't know what you plan to control the light with ... I understand you want a relay to switch the lights on and off, but with what? Will you be using a microcontroller, or some other signal or device?

 

[Rohan Vardekar]

yes i am going to use microcontroller for that but I need to know the relay with capability of 60V dc load and around 5 to 6V Coil voltage.

Thanks

 

[Gryd3]

yes i am going to use microcontroller for that but I need to know the relay with capability of 60V dc load and around 5 to 6V Coil voltage.

Thanks

So a relay will be pretty easy. You made great progress already with the parts you linked. You should of course make sure the relay has a low switching current, or use a transistor to turn it on.

 

[Rohan Vardekar]

Well I am using ULN2803 for current boosting but I want the name of relay product which I can use for my application.I am not getting relay with required specifications in local shops so I have to order it online.

Thanks