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UCC28810: Design led driver circuit output 90V, 1.2A

Mohitha Venkit
Prodigy 230 points
Part Number: UCC28810
Other Parts Discussed in Thread: PMP

I was trying to design 90v,1.2A driver circuit however i cant increase the voltage from 80V and decrease the current from 2A. Which part of the design i should change to get the required values.

http://www.ti.com/lit/pdf/slur337

This is the document I considered. It have output 80V, 2A. So in order to reduce the current and to increase voltage is it enough to reduce transformer winding to 60uH?

  • 0
    TI__Mastermind 26830 points
    Hello Mohitha,

    Thank you for your interest in the UCC28810 LED Lighting controller.

    The schematic diagram that you mention(SLUR337) belongs to the PMP5430 reference design for constant output voltage of 80V.
    To adapt to your applications, there is more design change required than simply changing inductance. Your power level is lower and output voltage is higher than that of the PMP4530 design. Also, the PMP4530 operates over the low-line range (85Vac~132Vac) only. If you need to operate over the "universal" range of 85Vac to 264Vac, then that will impact many design decisions.
    In any case, many parameters need to be considered, such as turns ratios, feedback dividers and component voltage and current ratings.

    Unfortunately, there is no design guide for the PMP4530 or for other designs similar to it. However, there are design guides in the application section of the UCC288810 datasheet, and in this reference document: www.ti.com/.../slua752.pdf

    In the datasheet and in the SLUA752 application guide, the single-stage-PFC LED drivers are designed for constant current control, not constant voltage (like the PMP4530). Therefore, there are additional circuits (like a buck converter and current sensing) that help accomplish constant current and also accommodate triac dimming that you may not need.
    If you only need constant output voltage as shown in PMP4530, then you can redesign the portions of the circuit that match the PMP4530 schematic and ignore those sub-circuits that do not apply to your design.

    Regards,
    Ulrich
  • 0 in reply to Ulrich Goerke
    Prodigy 230 points

    Hi sir,

    Thank you for replying. I need to design a constant current LED driver. I came across this pdF. It says PMP4862.1 gives100v,1.2 A. But this pdf is not clear. Can you please help me with finding 100v,1.2A using thispdf. This page has a tale explaining this output 1.

    But not in pdf . In this pdf J7,second page is given to where?

  • 0 in reply to Mohitha Venkit
    TI__Mastermind 26830 points
    Hello Mohitha,

    The PMP4862 reference design is the entire circuit including the PFC stage and three current regulation stages. The TI website refers to the outputs of each of these stages as PMP4862.1, .2, .3, and .4, but they are all on the same board.
    J7 (and J8 and J9) is a pin header for connecting to external control signals to be provide by the user.

    I have requested information on how to use these signals and how to design the PFC stage from the PMP designer.
    When this information is made available, I will include a link to it in another reply to this E2E posting.

    For your single-string design, I expect that the PFC stage will be very similar, but the LED current regulator design will need to be increased for about 3X the power level of the PMP4862.2 section. Of course, the specific voltages and currents will need to be adjusted to your requirements.

    Regards,
    Ulrich
  • 0 in reply to Ulrich Goerke
    Prodigy 230 points

    Thank you for your support and concern. I would be grateful if you could help me with relevant information and guidelines in a short span of time.

    Regards

    Mohitha

  • 0 in reply to Mohitha Venkit
    TI__Mastermind 26830 points

    Hello Mohitha,

    Sorry for the delay.  I only got his information today, and have limited access to email this week. 

    Here is a listing of the signals on the control connector:

    Enable : Active high enable signal.  Turns LED driver ON/OFF by driving the gate of a 2N7002 small signal FET.

    Dim : PWM dimming signal.  Accepts a 1kHz PWM signal to control dimming of the LED by varying the duty cycle.  Signal drives the gate of a 2N7002 small signal FET.

    Trim : Analog dimming signal.  Controls the amplitude of LED current.  The relationship between the voltage on the Trim signal and the LED current is provided in section 3.6 of the PMP4862 test report.

    Isns :  Current sense output signal.  This is an output for external monitoring of the LED current.  The relationship between the voltage on the Isns signal and the LED current is provided in section 3.6 of the PMP4862 test report.

     

    Unfortunately, the designer of the PMP4862 does not have a design guide, and recommends this app-note  as the closest reference to designing the LED driver:    http://www.ti.com/lit/an/slua752/slua752.pdf

     

    I hope with this information, you can make progress on your design.

     

    Regards,
    Ulrich

     



  • 0 in reply to Ulrich Goerke
    Prodigy 230 points
    THANK YOU sir for getting the info, I need one more favor. That is in http://www.ti.com/tool/PMP4862 schematic the transformer inductance and winding ratio is not mentioned. Would you mind sharing the info?
  • 0 in reply to Mohitha Venkit
    TI__Mastermind 26830 points
    Hi Mohitha,

    Fortunately it was easier to get this information quickly today.

    Primary Inductance = 150uH +/-10% at 100kHz, 0.1Vac
    Leakage Inductance = 5uH max at 100kHz, 0.1Vac, short (5+6+7+8+10+12)
    Turns-ratios:
    Pri to Sec1 (1-3):(10-12) = 1 : 0.500
    Pri to Sec2 (1-3):(7-8) = 1 : 0.055
    Pri to Aux (1-3):(5-6) = 1 : 0.083

    Regards,
    Ulrich