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    Reduce 9V to 5V without 7805

    I want to know how to reduce 9V to 5V without 7805 or voltage divider?

    •   Alt5th March 2011, 17:39

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    Re: Reduce 9V to 5V without 7805

    A voltage divider will be anything that divides the voltage , not just two resistors but also a zener , a transistor or anything
    that can be used in a linear voltage "regulator", all the designs are based an a pass element that introduces a voltage drop and keeps the output level to a constant level,
    this is based on a voltage divider.

    The only solution that doesn't use a voltage divider is a pulse psu because it is either on (full voltage) or off,
    the duration of the on time adjusts the output voltage level.

    Alex



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    Re: Reduce 9V to 5V without 7805

    you can use diodes
    http://pdfdata.datasheetsite.com/web/11164/1N4689.pdf

    ---------- Post added at 23:20 ---------- Previous post was at 23:19 ----------

    But they are all low current capacitiy or use a 5V zener diode...
    " It is so simple to be happy,
    but it is so difficult to be simple"



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    Re: Reduce 9V to 5V without 7805

    What do you think about switching mode power supply? I want to do this with low power dissipation.



    •   Alt5th March 2011, 17:54

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    Re: Reduce 9V to 5V without 7805

    You can use MC34063 switching regulator http://www.onsemi.com/pub_link/Colla...MC34063A-D.PDF , can provide up to 1.5A

    Use this tool MC34063A design tool to calculate the needed component values.

    Alex



    •   Alt5th March 2011, 18:38

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    Re: Reduce 9V to 5V without 7805

    It can be implemented with charge pump too. Its efficiency is better than linear regulator and it is cheaper than inductor-based DC/DC.
    Last edited by leo_o2; 6th March 2011 at 09:47.



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    Re: Reduce 9V to 5V without 7805

    The 33063 / 3063 / NCP3064 is a good choice for this application, has current limit, and a shutdown pin (3064)

    Regards, Orson Cart
    Last edited by Orson Cart; 7th March 2011 at 00:11.



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    Re: Reduce 9V to 5V without 7805

    I suggest you to use IC 34063 for these application...

    The IT34063 is a monolithic switching regulator control circuit containing the primary functions required for DC-DC converters. This device consists of internal temperature compensated reference, voltage comparator, controlled duty cycle oscillator with active current limit circuit, driver and high current output switch. This device was specifically designed to be used in Step-Down, Step-Up and Voltage-Inverting applications with a minimum number of external components.
    if you have any queries please do not hesitate to ask



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    Re: Reduce 9V to 5V without 7805

    Charge pump dosn't give high output current (>50mA). But Inductor based converter does.

    My job is run PIC & another IC which has 9V supply voltage using same battery without regulator.(without high power dissipation).



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    Re: Reduce 9V to 5V without 7805

    No. Dolphins provide up to 1A chargepump IP. It depends on operating frequency and capacitor value.



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    Re: Reduce 9V to 5V without 7805

    something in detail?try lm2576 or lm2596?



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