Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations MintJulep on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  • Users: treez
  • Content: Threads
  • Order by date
  1. treez

    PNP current limiter accuracy

    Hello sorry if this is too many on the same topic-please delete me if you have seen enough of this I am doing a LED lamp powered by SEPIC SMPS. It is 10W and the LEDs will be end up being switched in one by one by FETs, so that the lamp comes on “chaser” style. Here is the schematic...
  2. treez

    8 parallel mini switchers casue bad EMC?

    hello, I am making a LED lamp using eight 300mA LEDs. (It is a re-design of my previous post's circuit) It will run off a battery with voltage 13.5V. I dont want all the LEDs to simply come on all at once, -i want them to come on in succession, LED "chaser" style. Therefore, i have...
  3. treez

    LEDs turning off causes EMC problem?

    hello, i am doing a lamp with 8 300mA LEDs powered by SMPS. Source is 13.5V The LEDs must come on one-by-one in a line then stay ON. The simple way is to put the 8 in series then switch out FETs which short out each of the LEDs. However, this means that just as the next LED is switched ON...
  4. treez

    10 SMPS fails EMC

    Hello, I work in a company that makes LED lighting products that run off car batteries at about 13.5V and we are in Washington. There are 5 members of staff in the Electronics Dept. Eighteen months ago, the Electronics Dept was asked to design and build a 10W SMPS which would power a series...
  5. treez

    Stop supply current going to zero

    Hello, i am trying to stop the current into a 3W SMPS ever going below 40mA. (i posted before but now have a new design) It goes to zero when the smps fails or when there is a transient input voltage step (momentarily). -or during start-up Here is the circuit (smps represented by resistor)...
  6. treez

    How to stop supply current going to zero?

    hello, the input supply current into the following circuit from the ~13V source (V1) must never go to zero. if it goes to zero then a fault detector at the source thinks that the circuitry has failed. -we don't want this to happen. Thing is, when there is a transient in the supply from 14V...
  7. treez

    Boost SMPS compensation problem

    Hi, I'm working for a company in Chicago and doing continuous mode boost smps 17V in and 27V out to drive LEDs at 350mA for signage. Anyway: The following circuit uses components C1, C2 and R5 to give a Type 2 compensaton to the boost:- ..... Here is the LED current at start up for the...
  8. treez

    Software package to plot SMPS Bode plots

    Hello I am working on stability of SMPS’s. I am currently getting the Bode plots of the SMPS transfer function in a very time consuming way by manipulating the complex numbers “by hand” in Excel. This is prone to typing errors. I would like to find a cheap mathematical software package...
  9. treez

    No gain/phase analyser for SMPS design is OK?

    Hello, I am working for an SMPS company in Chicago. I am testing the SMPS’s. Lately I tested a 200W Buck converter with:- Vin = 120 – 360VDC V(out) = 50V I(out) = 0 to 4A Switching Frequency = 100KHz Think its current mode but do not have much access to schematic. The Engineering Manager...
  10. treez

    LED vs Fluorescent Lamps

    Hello, I have been working on Domestic Mains White LED Lighting (for sale to the cheap-end, mass market) for a while. I have been working at the 15W level as this is equivalent luminous output to a 60W incandescent. However, there are multiple problems with LED lights here, and in fact...
  11. treez

    SMPS transfer functions

    Hello, I have just searched through the contents pages of various well known SMPS Design books on Amazon.com in order to see if any book provides a comprehensive list of transfer functions for SMPS modulators for the various topologies....and also transfer functions for error amplifiers...
  12. treez

    Electric Cars with wheel motors

    Hello, Is it true that electric cars with wheel-motors (ie motor in each wheel) are destined to failure because they will break when the car goes over bumps?
  13. treez

    Battery charger reverse polarity protection.

    Hello, I am doing a switch mode lead acid battery (12v) charger with UC3909 IC Datasheet:- http://focus.ti.com/lit/ds/symlink/uc3909.pdf The circuit i am using is like page 7 on the datasheet. I am trying to incorporate reverse polarity protection for when the battery is connected the wrong...
  14. treez

    Battery charger current sense

    hello, I am doing a switch mode, lead acid battery charger with UC3909 Charger IC..... Datasheet..... http://focus.ti.com/lit/ds/symlink/uc3909.pdf ..on pg 7 of the datasheet for UC3909, it shows the charge current sense resistor being placed at the non load side of the buck converter.....can...
  15. treez

    Sufficiently Isolated scope

    Hello, We have increased staffing levels and now wish to buy more scopes. We are currently making 4KW H-bridge inverter drives for brushless DC motors and also all the associated control, auxiliary and also CAN comms circuitry. We currently use Tektronix TDS 210, TDS 2012 and TDS 2014...
  16. treez

    32 digital channels on scope

    Hello, We are expanding our engineering operations and need new kit. We are currently using an Agilent MSO6034A scope which we need for the 16 digital channels..... http://www.home.agilent.com/agilent/product.jspx?cc=US&lc=eng&ckey=564674&nid=-35165.536905500.00&id=564674 However, we would...
  17. treez

    Cannot get started in Visio 2007

    Hello, I have just downloaded the free trial of Visio 2007. However, I cannot use it as when i click on "new" to create a new document, all the options are greyed out. When i installed visio, i was asked for an 8 character referral key (the dialog box said that this could be found on the...
  18. treez

    Detecting cracks in metal

    Hello, (This is a double post and i apologise though the other post is in the electric motors section and i considered that the audiences would be likely different for these two places.) We are having problems with cracks sometimes occurring in the welds in our stators. We would be most...
  19. treez

    How detect a Leaky stator ?

    Hello, We are designing and manufacturing electric motors. They have a stator of diameter about 40cm. This stator houses many power electronic inverter (H-Bridge) boards which help to drive the rotor. These stators have like a water jacket in them which is for cooling. Unfortunately, the...
  20. treez

    PCB Gerbers not understood

    Hello, I have recently layed out a PCB for mounting a current transducer on and sent the corresponding gerber file (RS274X) and drill file to a PCB manufacturer. However, the PCB manufacturer has said that the gerber and drill file that i sent him is not understandable. Here is a view of the...

Part and Inventory Search

Back
Top