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Why does the load run abnormally when the lithium battery is boosted without induction?

Hardware design
七月 13, 2020 by Haze 490

Power supply: 3.3V connected to lithium battery power supply.

Output: non-inductive boost 5V.

Output: Inductor boost 12V.

Load requirements: 5V load, 5V/50mA.

Load demand: 12V load, 12V/500mA.

problem:

    1. After removing the non-inductive booster part, the boosted 12V is completely normal, the boosted 12V voltage is stable, and the load operates normally.

    2. There is a non-inductive boosting part. 12V without load, the voltage of 12V is normal; after connecting the 12V load, the voltage becomes about 6V, and the load is not operating normally.


Load device: 12V/500mA DC fan.

所有评论

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Nicolaus 发表于 July 13, 2020

Non-integer multiple boost, try to avoid using charge pump, the efficiency is very low.


Among the requirements, 5V only requires 50mA. Consider the large-current SMD stack inductor. The 2.2uH packaged in 0805 can achieve several hundred milliamperes (a little more expensive than the I-core core inductor)


The problem may be related to the insufficient capacity of the 3.3V capacitor. 12V500mA is a big number for lithium booster power supply. It is recommended to increase to 12V first, and then to 5V.

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Fitzgerald 发表于 July 13, 2020

Have you independently tested that the non-inductive booster circuit is normal?

The output should be 10Uf, and you used 20Uf, have you confirmed that the voltage can be stable 5V output?

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Freida 发表于 July 13, 2020

Chip data When the current data is greater than 500ha, the voltage value that the chip can reach is around 6v, and the output voltage will increase when the current is small.

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