voltage regulator for cctv cameras (5VDC/2A)

Discussion in 'The Projects Forum' started by ericma, Jun 26, 2013.

  1. ericma

    Thread Starter New Member

    Jun 26, 2013
    4
    0
    I'm looking for alternative design ideas with low BOM counts and lower cost DC voltage regulator ( output 5VDC/2A). Currently under consideration is NTE1934

    http://www.nteinc.com/specs/1900to1999/pdf/nte1934.pdf

    Project details:
    * 8 CCTV cameras that require 5VDC /2A each and will be connected to a central source supplying 12VDC. The wires (18AWG) running from cctv to central sources range from 50 feet to 120 feet.
    * additional 16 cctv cameras are also connected to central source without modification, since each requires only 12VDC/300mA.

    NOTE: the cctv that are located 120 feet from the central voltage source supplying 12VDC/2A will have voltage drop of 3.82VDC (8.18VDC at the load). This should meet the minimum operating voltage input of NTE1934 of 8VDC.

    Trying to figure out if NT1934 would require heatsink.(power dissipation = (voltage drop)x(load current) = 7.64watts??)

    Thanks for your advanced inputs/suggestions.
     
  2. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
    5,003
    745
    Why dont you use an ATX psu , readily giving out 12Volts at 20Amps easy!
     
  3. Papabravo

    Expert

    Feb 24, 2006
    10,179
    1,800
    Stop using NTE components. They are easily 10 times the cost of normal components and intended for the repair market.

    You should design your system with a higher voltage supply that delivers 12 V to the load. You can also have a regulator at the load as long as you provide sufficient headroom.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    NTE Inc. has IC manufacturers make NTE-labeled parts for them, and the list price is usually at least three times higher than the original part was. I looked up the NTE1934 on findchips.com, and they're selling for around $14/ea - not a bargain by any stretch of the imagination. A ST Microelectronics L78S05CV 5V 2A regulator can be purchased for $0.39, so that's nearly 1/36th the price.

    If your cameras require 2A @ 5v, then your supply should be rated for at least 20% more current, or 2.4A, otherwise they will have a rather short life. You never want to operate electronic devices at 100% of their rating if you can avoid it.
     
  5. ericma

    Thread Starter New Member

    Jun 26, 2013
    4
    0
    yes, that's into consideration, but 8 cameras require 5volts / 2amps supply.
     
  6. ericma

    Thread Starter New Member

    Jun 26, 2013
    4
    0

    Actually the power supply that came with the camera require spec to 5vdc/2.5amps each. So From your recommendation, I should be looking at a voltage regulator spec output of 5vdc/3amps?

    With the remote main supply of 12vdc, at the end of 120feet near the camera, the voltage will drop down to 6.25vdc using 18awg wire. Then I would need a voltage regulator that will operate with an input voltage of 6.25vdc. If I were to use a thicker wires (16awg) then the voltage drop from 120 feet will come down to 8.37vdc in case the voltage regulator require a higher input voltage.

    Ok, Thanks. I will look for 5vdc/3amps voltage regulator at ST Micro.
     
  7. ericma

    Thread Starter New Member

    Jun 26, 2013
    4
    0
    I think the other 16 cameras (rated @ 12vdc/300mA) were intended to run from a 12vdc power supply located remotely from as far as 100+ feet.

    On the other hand, the other 8 cameras require 5vdc/2.5amps at the load. So I just needed a 5v regulator near these 8 cameras while using the 12v power supply from the remote site about 20-120 feet away.

    My response to SgtWookie need correction. He is right I would need a voltage regulator rated at 5vdc/2.5amps instead of what I wrote down 5vdc/3amps.
     
  8. Evil Lurker

    Member

    Aug 25, 2011
    117
    23
    Get an LM2596 switching regulator module off ebay, they are like $2-5 each. Some are pretty plain, but a few have low pass filters on them to greatly reduce the ripple current. Board size is tiny.
     
  9. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
    5,003
    745
    So you can use an ATX then, that will give 12V & 5V supplies both at high currents, ifyou choose a 700W type.
     
  10. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
  11. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    If cheap is the goal, TI has a real cheap 3A reg called the LP3963.

    FYI: the best way to do this would be to use a reg with a "remote sense" capability and that would let it regulate the 5V out at the camera itself. This type of reg has a sense pin. The LP396X family has versions with a sense pin.
     
  12. michelleandrada

    New Member

    Jul 15, 2014
    1
    0
    These thread is so helpful. Good job guys :)
     
Loading...