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MC34063 and PMP7006 Power Reference Design Min Input current

Hello,

I am looking at the PMP7006 power reference design and wanted to know what is the minimum input current at 15V input, 15V and 20 mA output for this design?

http://www.ti.com/tool/pmp7006

Thanks!

  • Hello Austin,

    I am looking into this, and should get back to you by the end of the day.

    One thing I did want to note is that if you look at the Test Report for this reference design, the output voltage at 20mA is more like 14.2V (From Table 4 in the test report: http://www.ti.com/lit/ug/sllu161/sllu161.pdf )

    Is this an acceptable variance for the end application?

    Best,
    Michael

  • Austin,

    From the PMP7006 test report I have the following information:

    Efficiency at 20mA = 54% from Figure 3

    Load Regulation at 20mA = 14.2V from Figure 4

    Based on this information we can say that that Pout = 14.2V * 0.02A = 284mW  (if we assume 15V output then Pout = 300 mW conservatively)

    From Efficiency calculation 0.54 = 300mW/Ptot

    Therefore Ptot = 556mW and given Vin = 15V then Ii(AVE) = 37mA 

    The MC34063 switching regulator has a duty cycle of approximately 86% when normally operating (not in overcurrent mode) 

    Based on this, the peak input current necessary would be 37mA/0.86 = 43mA 

    So overall the peak input current would need to be 43mA while the average would need to be 37mA.

    Hope this helps!
    Best,
    Michael