Single-Cell Reverse Polarity Protection for MP2632

Battery Management
1

Hi everyone,

We are working on a project that uses the MP2632 to charge and manage a single-cell lithium-ion battery (3.7V nominal). Is it possible to implement reverse polarity protection to safeguard the system in case the user accidentally connects the battery backwards while ensuring the charging functionality works seamlessly?

Right now, we have two ideas:

  1. Fast blow fuse + diode: A fuse in series with the battery and a diode in parallel for reverse polarity. However, we’re hesitant as this is a one-time solution and not ideal for long-term use.

  2. High-Side P-MOSFET: This is an alternative solution for reverse polarity protection based on some research. It allows current flow during both charging and discharging, but we’re unsure how it might impact the MP2632’s charging functionality or if there is a nuisance to configuring it for the MP2632 to allow for seamless charging.

Would a high-side P-MOSFET solution work here without interfering with charging, or are there better alternatives for handling both charging and discharging currents (≤1A charging, 40mA-100mA discharging)?

Thanks in advance for any guidance or suggestions!

2

Hi Strom,

Welcome to the MPS Forum!

Yes, although typically the PMOS solution is aimed towards higher currents, it should be adequate for your application. See the attached article from MPS regarding designing a reverse polarity circuit and key considerations when implementing.

Designing a Reverse Polarity Protection Circuit (Part I) | Article | MPS

Designing a Reverse Polarity Protection Circuit (Part II) | Article | MPS

3

Hi Stephen,

Thanks for the links and feedback. We will go through them and implement on our side. I’ll send an update message when we get a pilot board back from the fab.

Thanks again.

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