To a range of voltage of 3 V to 12 V to a fixed 5 V

[messlia]

Hi,

I am designing a solar application for charging up the batteries, the variable output to be 3V to 12V to be to used to charge up the 5V battery... I though of using the LM7508 to bring the voltage to a fixed voltage of 5v but the 5V at the output requires at least the input to be 1 to 2 V then the output... i though of increasing the input voltage to a higher voltage level but if the voltage level is too high then this will heat up the LM7508.
Need suggestion as how to go about on the input of this LM7508


suggestions and guidance is be welcomed....

Thank you

 

[tpetar]

Hi,

I am designing a solar application for charging up the batteries, the variable output to be 3V to 12V to be to used to charge up the 5V battery... I though of using the LM7508 to bring the voltage to a fixed voltage of 5v but the 5V at the output requires at least the input to be 1 to 2 V then the output... i though of increasing the input voltage to a higher voltage level but if the voltage level is too high then this will heat up the LM7508.
Need suggestion as how to go about on the input of this LM7508


suggestions and guidance is be welcomed....

Thank you

7805 require minimum 2,5V-3V voltage difference between input and output voltages. Plus, its linear voltage regulator which means that you will have good heat and power loss if you have higher needs for current, but if current is low 10-50-100-150mA its not problem to use 7805 regulator.

In situation where you want to save power and avoid heat in device or on PCB, the use switching voltager regulator design.

Additional to switchers you can try LDO regulators which also can do the great job. LDO needs small Vi-Vo difference to operate which means lower heat and power loss, but only if you keep small voltage difference Vi-Vo.


Best regards,
Peter

 

[crutschow]

For best efficiency you can use a CUK or SEPIC type converter.

 

[messlia]

I am doing on a school project... and the input range that is given to me is 3 V to 12V to charge up li-ion batteries... I am really confused and struck as how to go on here... suggestion are welcome...

 

[tpetar]

Use 12V to make 5V needed for Li-Ion charger.

Read this thread:

https://www.edaboard.com/threads/298045/


Best regards,
Peter