Recommend High Efficiency Power Converter 10mA - 1A Step-Down?

[asrock70]

I need recommend IC for power supply
input voltage 24V
output voltage 3.3V or 5V
current 10mA - 1A
efficiency about 80%
I would use lm2675, but in Europe this circuit is really expensive.
Is something similar and cheaper?

 

[onmyphd]

I would use lm2675, but in Europe this circuit is really expensive.

How much do mean by really expensive? Or better yet, how much are you willing to pay?

 

[Roger Miller]

What is difference between LM2674 and LM2675. I think the specifications you mentioned here are of 2674
like
input voltage range : 6.5 V ~ 40 V
output voltage: 5V
And price mentioned for this product is 1.35$/unit

 

[onmyphd]

What is difference between LM2674 and LM2675. I think the specifications you mentioned here are of 2674
like
input voltage range : 6.5 V ~ 40 V
output voltage: 5V
And price mentioned for this product is 1.35$/unit

The LM2674 is just max 0.5 A. But for high efficiency, you can't get that price (in mouser is above 2€)
https://www.mouser.com/Search/Refine.aspx?Keyword=LM2674
not to mention the necessary components such as the inductor.

 

[asrock70]

How much do mean by really expensive? Or better yet, how much are you willing to pay?

OK look at the real price.
TI say price of LM2675 is 1,6$ for 1k pcs from this price Farnell in EU make 4.25$ for 10pcs and 3.4$ for 100pcs LM2675-Adj
Mouser have 3.4$ for 10pcs.
The idea is 2$ for order 10pcs and approximately 1.5$ for 100pcs.

 

[onmyphd]

OK look at the real price.
TI say price of LM2675 is 1,6$ for 1k pcs from this price Farnell in EU make 4.25$ for 10pcs and 3.4$ for 100pcs LM2675-Adj
Mouser have 3.4$ for 10pcs.
The idea is 2$ for order 10pcs and approximately 1.5$ for 100pcs.

Sorry. When I looked for similar products, the cheapest I could find were really the ones from TI.

 

[asrock70]

But this is sad, especially when one considers that on Ebay you can buy 20 pieces LM2575 for 8.8$, including shipping from China. Or at Mouser sell TINYSWITCH 4 for approx 1 Euro.

 

[Tahmid]

Take a look at L4971. Datasheet: https://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00001355.pdf

At Mouser, it costs $2.61 per piece for 10 pieces. https://www.mouser.com/ProductDetail/STMicroelectronics/L4971/?qs=sGAEpiMZZMvHdo5hUx%2bJYoAyMYAx4pVL

Also take a look at L4962. https://www.mouser.com/Search/Refine.aspx?Keyword=l4962

Observe the price of the L4962/A (PDIP package): $2.09 per piece for 10 pieces.

Hope this helps.
Tahmid.

 

[BradtheRad]

I hesitate to post this schematic because it will subject the load to overvoltage if abrupt changes are made. This could be lethal to sensitive devices.

However it has the advantage of being inexpensive.

Hysteresis-driven buck converter. Constructed as a simulation only, at this point.



Once Vref is set, regulation stays within 0.1 V for all loads.

The total load in the screenshot is 5 ohms.

The 100 m-ohm sense resistor is not essential, but it tightens regulation on the output voltage.

All values are flexible.

Disregard the 10k resistor across the diode.