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BQ25570EVM-206: Output voltage problem

Part Number: BQ25570EVM-206

Hi team

As shown in the attached picture, I use BQ25570EVM

Modifications on the EVM board:

       R10 has been modified and replaced with a 2.44M ohm resistor, so that the no-load voltage at the output is 3.3V;

External connection of EVM board:

       Input Vin: 2.3V voltage (obtained by self-powered module);

       Vstor: 2200uF, 16V capacitor;

       Vout: 100K resistance or 1K resistance;


When Vout is connected to a 1.5K resistor, the output Vout voltage can only reach more than 2V, and Vstor can only reach more than 2V;

When Vout is connected to a 100K resistor, Vstor can reach 4.2V after charging for a period of time, and the output Vout voltage can reach 3.3V, but after measuring the Vout or Vstor current with an ammeter, the Vout and Vstor voltages return to more than 2V, and the recharging starts.


If you want to use 2.3V voltage input and perform 3.3V discharge after charging, is there any problem with the connection method such as the accessory;

Is the sudden drop in voltage caused by too little charge stored in the capacitor? Or what reason? If so, are there any recommended solutions?

Thank you!