BQ25185: Extra RC Circuit At Low Charge Currents

Gabe Ausfresser

Part Number: BQ25185

Tool/software:

Hello,

Section 8.1.1.4 of the datasheet, "ISET Pin Detection", says that when charge currents are set below 50 mA, an extra RC circuit using a 50 pF capacitance is recommended. Can you please show me a schematic example for this additional RC circuit?

Thanks,

Gabe

6 months ago

0 Alec Lehman 6 months ago

TI__Expert 7880 points

Hello Gabe,

You can find an example of this circuit in the schematic of the BQ25185 EVM, which is available in its User's Guide: BQ25185 EVM User's Guide

Let me know if you have any questions about this circuit.

Best regards,

Alec

0 Gabe Ausfresser 6 months ago in reply to Alec Lehman

Prodigy 83 points

Thanks, Alec. I assume that you are referring to R12 and C7 in the EVM schematic. Curious as to how those values are determined and why the datasheet says to use a 50 pF capacitor, but C7 is 4.7nF.

Gabe

+1 Alec Lehman 6 months ago in reply to Gabe Ausfresser

TI__Expert 7880 points

Hello Gabe,

Yes, R12 and C7 form the extra RC circuit referenced in the datasheet. This circuit acts as a pole-zero compensation network intended to help keep the ISET pin stable. However, in practice, we typically only recommend including it if stability problems arise in your design, as most customers don't use it and don't experience any issues.

Best regards,

Alec

0 Gabe Ausfresser 6 months ago in reply to Alec Lehman

Prodigy 83 points

Thanks again, Alec. Much appreciated.

Gabe

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BQ25185: Extra RC Circuit At Low Charge Currents