Hello,
I made a device where I am using Texas Instruments LM2700 boost converter (2.7-4.2V to fixed 5V output, or in other words 18650 battery to 5V.) I have already made the PCB (according to the datasheet example) and assembled all the components. However, I face a really strange output voltage behavior. When there is no load, I get my expected 5V output, but when I load the LM2700 with the intended 1W load, my output voltage drops to 2.2V something volts... This should not happen, because this IC is advertised to supply up to 2.5A of current (headline of the datasheet), and my load is consuming just a bit more than 200 mA (at 5V). I had a feeling that the suggested 2.2 uH inductor might be a bit to small, changed it for 10 uH, 50 uH, 100uH and finally even 1 mH. But with 1mH inductor I was still getting only 4.05 volts at the output (inductor was orders of magnitude larger than the datasheet recommendation.) I dont have much experience in power electronics, and it seems I have reached my edge of knowledge here. Thank you in advance for any help and ideas provided.
I made a device where I am using Texas Instruments LM2700 boost converter (2.7-4.2V to fixed 5V output, or in other words 18650 battery to 5V.) I have already made the PCB (according to the datasheet example) and assembled all the components. However, I face a really strange output voltage behavior. When there is no load, I get my expected 5V output, but when I load the LM2700 with the intended 1W load, my output voltage drops to 2.2V something volts... This should not happen, because this IC is advertised to supply up to 2.5A of current (headline of the datasheet), and my load is consuming just a bit more than 200 mA (at 5V). I had a feeling that the suggested 2.2 uH inductor might be a bit to small, changed it for 10 uH, 50 uH, 100uH and finally even 1 mH. But with 1mH inductor I was still getting only 4.05 volts at the output (inductor was orders of magnitude larger than the datasheet recommendation.) I dont have much experience in power electronics, and it seems I have reached my edge of knowledge here. Thank you in advance for any help and ideas provided.
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