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BQ25570: Inquiry About Low-Power Energy Harvesting with Photodiodes

Part Number: BQ25570

Tool/software:

Hello TI Community,

I am working with Essentim GmbH and the Technical University of Munich on a project to develop a sensorized implant, which we aim to wirelessly power using near-infrared (NIR) light.

For this, we are using a photodiode-based energy harvesting system that converts incoming NIR light into electrical energy. Based on our setup, the available electrical power will range between 1 mW and 50 mW, with operating voltages potentially as low as 120 mV.

The BQ25570 appears to be a suitable energy harvester for our application due to its ultra-low power startup and integrated buck converter. Before moving forward, I would like to ask the following questions:

Can the BQ25570 efficiently harvest energy within our given power range (1–50 mW) and voltage conditions (~120 mV and above)?
Are there any recommended circuit configurations or external components that would optimize its performance when used with a photodiode as the energy source?
Are there any available evaluation or development kits for the BQ25570 that would allow us to test its performance in our application?
Any insights, reference designs, or guidance on how to best implement this IC for our use case would be highly appreciated.

Thanks in advance for your help!

Best regards,
Paul Morandell

  • Hi Paul,

    It should be good in terms of Power (>0.005mW) and input voltage (>100mV) during normal charging operation. However, if you are starting from a discharged state (VSTOR < 1.9V) then the minimum required values for cold start are 15uW and 700mV at the input.

    For evaluation you can take a look at the BQ25570EVM and its user guide.

    Best Regards,

    Juan Ospina