Boost regulator

danadak

Well-Known Member

Most Helpful Member

• Oct 6, 2023

• #2

Is your battery capable of delivering energy at 1.5V ? What is your energy source ?


Regards, Dana.

 

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Tom120

New Member

• Oct 6, 2023

• #3

Hi Dana. Yes I'm using a 1.5v battery in good condition.(Tom)

 

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Tony Stewart

Well-Known Member

Most Helpful Member

• Oct 6, 2023

• #4

What deviations to the App Note such as figure 2 and the values did you make? and why?
https://www.analog.com/media/en/technical-documentation/data-sheets/3400fa.pdf

 

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sagor1

Active Member

• Oct 6, 2023

• #5

What is the load? Note that in the spec sheet (Minimum Start-Up Voltage vs Load Current), if the load is around 100mA, the startup voltage required is around1.3V

 

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Tom120

New Member

• Oct 7, 2023

• #6

Thanks for replying. My circuit differs from the app example only in resistors R1 and R2. R1 is 1.5M and R2 is 620K to produce 4.2v output. I've been testing the circuit with a light load - about 1mA.

 

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tepalia02

Active Member

• Oct 7, 2023

• #7

Tom120 said:

Thanks for replying. My circuit differs from the app example only in resistors R1 and R2. R1 is 1.5M and R2 is 620K to produce 4.2v output. I've been testing the circuit with a light load - about 1mA.

Click to expand...

Have you performed any tests in no load condition?

 

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Tom120

New Member

• Oct 7, 2023

• #8

Yes. Same result with zero load. (4.2 volts with 2volt input but only 1.2 volts with 1.5 volt input)

 

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rjenkinsgb

Well-Known Member

Most Helpful Member

• Oct 7, 2023

• #9

The data sheet mentions the extra Schottky diode is used for the graph showing 1.5V operation.

Also, due to the high operating frequency the type of capacitors may be critical - try adding 0.1uF ceramics across the input & output caps??

 

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Tom120

New Member

• Oct 11, 2023

• #10

Thanks for that. I tried the extra caps also the schottky diode but no change unfortunately.

 

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Lightium

Active Member

• Oct 11, 2023

• #11

You should have a cap across the source voltage when using anything on its low voltage end.

 

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rjenkinsgb

Well-Known Member

Most Helpful Member

• Oct 11, 2023

• #12

Tom120 said:

Thanks for that. I tried the extra caps also the schottky diode but no change unfortunately.

Click to expand...

How is the circuit built? If there are long connections between any components in the high frequency current path, that could affect efficiency?

 

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Lightium

Active Member

• Oct 11, 2023

• #13

Without a pic or schematic it's tuff to tell what's drawing all the current.

 

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Tom120

New Member

• Apr 16, 2024

• #14

Hi. Just thought I'd let you know the result of this one. Later I read that overheating the chip through careless soldering might degrade performance. I got another LTC3400 and soldered it carefully. This time the circuit worked fine. All the way down to 0.8volt input producing a 4 volt output. (Tom120)

 

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