Versatile DC-DC Converter.pdf - Versatile DC-DC Converter 1...

This preview shows page 1 - 2 out of 4 pages.

Circuits Careers Videos Features Technical Articles Electronics of Things Special Subscription TI Design Aerospace Automation Automotive Communication Consumer LEDs Medical Power Management Solar Test & Measurement Related Circuits CELL-PHONE-CONTROLLED AUDIO/ VIDEO MUTE SWITCH Light-Operated Internal Door Latch 8-Digit Code Lock for Appliance Switching Simple Key-Operated Gate Locking System Mains Box Heat Monitor Subscribe to Login | Register | Advertise | About Us | Contact Us C I R C U I T L A B Versatile DC-DC Converter Raju Baddi Here is a versatile power coupler that connects a device to 5V-19V DC generated from AC mains by a power adaptor. Power adaptors come in different voltage outputs like 5V (for mobile phones), 12V (for external hard drives) and 19V (for laptops). Sometimes the power adaptor may have a voltage rating higher than the required voltage. With the converter circuit given here, the adaptor can be used to power any device at a lower voltage. For instance, by using a 19V laptop adaptor, you can power a TTL circuit at 5V. There can also be other instances when one needs a 3V or 6V supply. All these and many other intermediate voltages are easily possible with this versatile converter circuit when used together with any off-hand power adaptor. Fig. 1 shows the circuit of the DC-DC converter. Smooth reduction in the voltage is achieved using the LM317 regulator IC. The complete unit can fit inside a piece of a glue stick tube. Adjusting variable resistor VR1 gives the desired output voltage. The output voltage is read using a 0-100μA ammeter, whose series resistance R* is chosen such that the maximum desired voltage could be covered. For instance, if full-scale deflection (FSD) current of the meter is 100 μA and you need an output voltage of up to 15V, then R* = 15/0.0001 = 150 kΩ. The desire d value of R* is obtained by using 150-kilo-ohm preset VR2.
Image of page 1

Subscribe to view the full document.

Image of page 2

{[ snackBarMessage ]}

Get FREE access by uploading your study materials

Upload your study materials now and get free access to over 25 million documents.

Upload now for FREE access Or pay now for instant access
Christopher Reinemann
"Before using Course Hero my grade was at 78%. By the end of the semester my grade was at 90%. I could not have done it without all the class material I found."
— Christopher R., University of Rhode Island '15, Course Hero Intern

Ask a question for free

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern