# 2.4V to 5V Step Up DC-DC Converter

Rajkumar Sharma      http://www.rajkumarsharma.com
26210
Project tested

This project is a step up DC to DC power converter able to convert 2.4V – 5V to 5Vdc.

### Description

This project has been designed around Texas Instruments LM2623 IC, The LM2623 is a high efficiency, general purpose step-up DC-DC switching regulator for battery powered and low input voltage systems. It accepts an input voltage between 2.4V to 12V volts and converts it into 5V DC. Efficiencies up to 90% are achievable with the LM2623.

### Features:

• Good Efficiency over a very wide load range
• Very low output voltage ripple
• 2.4V to 5V (Possible Input Supply up to 14V operating voltage)
• 5V output voltage (Other output voltages possible by changing R3 and R4)
• 600mA output current

### Application:

• Hand held instruments
• Cameras, PDA, Cellphones
• White LED driver

## PCB

### 40 Response on “2.4V to 5V Step Up DC-DC Converter”

1. Nizam uddin says:

I like electronics lab.com

1. Electronics Lab says:

Thanks for visiting!

2. hakanak says:

Does it provide 5V continously even when the input is 2.5V ?

1. Electronics Lab says:

Sure, input can be in the range of 2.4 – 12V

1. AlexRogers says:

will the output be stable if the Vin fluctuates?

That’s the purpose of this voltage converter. Keep in mind that the voltage should be inside the input limits.

3. Sorry, i am really zero knowledge of this, and i dont know where to start learning. can i ask how much R3 and R4 should be for output around 3.3v-3.5v. thanx if you want share how to calculate it. 🙂

1. Electronics Lab says:

I can’t enter the equation here. Please check on datasheet page 11 – chapter 8.2.2.3 Setting the Output Voltage. http://www.ti.com.cn/cn/lit/ds/symlink/lm2623.pdf A value of 50k to 100k is suggested for R4. Then, R3 can be selected using Equation 1.

1. yes, i see.. thanx for the link and reference page number..:) so if R4 is 100k, i just need R3 150-160K.. really thanks…

4. kim says:

What kind of inductor you used here and what is R2 0E?

R2 it’s a zero Ohm resistor

No, you will need a high power inductor like the one on the mouser.com link above. As for C5 you can use a through hole capacitor that will be fitted on the PCB.

5. kim says:

Can you recommend an alternative inductor that is not surface mounted because i need it for my project and we need to put it on breadboard. Thank you so much 🙂

It should work.

6. kim says:

can i use electrolytic capacitor on C5?

7. kim says:

How about using a 1.5V or 6V battery for the input?

8. kim says:

can i use a polarize capacitor for C5?

It’s better to use a ceramic capacitor there.

9. kim says:

Can i use solar panel that’s 3V for the input instead of a battery?

You may use a solar panel on the input that is able to provide 2.4 to 12V output.

10. kim says:

Hi! When i finished breadboarding the circuit and put an input voltage of 6 volts the output was 6 volts too. Why does it happened? 🙁

Please try a lower input voltage at the range of 2.4-4.5V to check if the regulator converts it to 5V

1. kim says:

Hi 🙂 I changed the input into 3V but the output is 3V too.

11. mixos says:

Please check for damaged diode or IC.

max output current is 600mA

12. Eddy says:

What are the exact dimensions of the pcb drawn in this page. Thanks.

PCB dimensions are 24.13 x 26.99mm

13. Eddy says:

Can i use through hole components (on a new pcb) for all the parts (except the lm2623 of course) ?

Sure, it will work just fine.

1. Eddy says:

Another issue : is there a way to improve the maximum output current to let’s say 1.5A or 2A. What are the modifications needed for this purpose? Thanks in advance.

For that output current, you probably need a completely new design with different IC.

1. Eddy says:

Thanks

14. Eddy says:

Why the output is oscillating continuously between 4.8 and 5.3 V (not stable) ?