I am using The BQ25504' EVM to do my master thesis "A energy automunous wireless temperature sensor module", I have changed the OV UV, and OK voltage threshhod. The OK voltage si set to be nearly 3.3V. The the output voltage is OK under light load (>5.1k), But it could output 3.3V under a load heavier than 1k until the input voltage is as large as 2V. I am not sure whether it is a issur or not. The schematic diagram is enclosed.
no body could help me? It is very important for me!
Your question is not clear.
My understanding of your post: you mean to say "at higher loads (resistance < 1k ohms), the BAT voltage falls below 3.3V (does NOT reach BAT_OK voltage of 3.3V)." Your question is: is that normal?
My answer is: the output current at 3.3V and 1k ohms is 33mA. The bq25504 has a peak input power of PIN_PK of 200ma. (I don't see a max output power rating.) Allowing for some losses, it seems like the bq25504 should deliver 33mA if the input power is 200mA.
But you did not say what your input power is. If the input power is not enough, the output voltage cannot be sustained.
The data sheet says in many places that you may need to manage (periodically disconnect) the load. That is, pulse power to a high load.
I am not an electrical engineer, so I could be mistaken.
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