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how PWM IC UC2843 works?

Discussion in 'General Electronics Discussion' started by Zippora, Aug 26, 2016.

  1. Zippora

    Zippora

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    Aug 26, 2016
    how PWM IC UC2843 works?
     
  2. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
  3. Zippora

    Zippora

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    Aug 26, 2016
    Thanks.
    Can you explain about comp pin no.1. It is given in datasheet as Input voltage in error amplification section 2.5V. On 2nd page functional block diagram it is connected to output of error amplifier and Vfb.
     
  4. Zippora

    Zippora

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    Aug 26, 2016
    Can you explain me how the circuit works? It is DC driver circuit of LED Light?
     

    Attached Files:

  5. Alec_t

    Alec_t

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    Jul 7, 2015
    Have a look at Fig 32 (page 13) of this version of the datasheet.
    Also, read the Design Considerations on page 11.
     
  6. Zippora

    Zippora

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    Aug 26, 2016
    Thanks.
     
  7. Zippora

    Zippora

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    Aug 26, 2016
    In attached DC driver circuit, I_Sense is applied to inverting terminal of OPAMP LM324 and then it is applied to pin no. 3 current sense of UC 2843. Is I_Sense input is integrated by opamp LM324 and then applied to UC2843?
     
  8. Alec_t

    Alec_t

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    Jul 7, 2015
    Hard to say, since component values aren't specified.
    Looks as though the Isense signal is being low-pass filtered.
     
  9. Zippora

    Zippora

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    Aug 26, 2016
    Thanks.
     
  10. Zippora

    Zippora

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    Aug 26, 2016
    Please find attached file. R49 and R30 are used to change the driver configuration say 18W to 15W,etc. Will it help?
     

    Attached Files:

  11. Alec_t

    Alec_t

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    Jul 7, 2015
    Changing R30/49 will change the opamp gain and hence the current feedback value that the regulator receives. This will change the regulator's output.
     
  12. Zippora

    Zippora

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    Aug 26, 2016
    Thanks.
     
  13. Manoj kundu

    Manoj kundu

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    Mar 23, 2018
    How pulse control logic and v ref good logic works in IC UC2843AQ with internal logic cct
     
  14. Alec_t

    Alec_t

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    Jul 7, 2015
    Read the datasheet and any Application Notes you can find.
     
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