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I am using MCP73871 charging IC to charge 3.7 Li-Ion battery. This IC can take either input from charger or from battery and generate the output accordingly. TPS61032 is used to boost the output from MCP73871 to 5v to drive the remaining system. The system block diagram is shown below:

  • MCP73871 gives 5V when only charger/USB is connected MCP73871 gives
  • 5V when both charger/USB and battery is connected MCP73871 gives
  • battery voltage when only battery is connected

My questions are:

  1. do we still need a battery protection IC between battery and MCP73871.
  2. If we need, can anybody suggest any?
  3. Can i still input 5V to TPS61032 where datasheet define the input range from 1.8v-5.5v. Thanks

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3 Answers 3

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In an article by Sundar Krishnakumar dated 12/20/2019 titled BATTERY MANAGEMENT CIRCUIT USING MCP73871 States the following. There is much more to the article but this answers your question. states the following: "The battery IC under study (MCP73871) is linear type. This is suitable for charging Single-cell Lithium Ion( Li-ion) and Lithium Polymer(LiPoly) batteries in applications that demand less charging current (upto 500mA). A simpler version of this IC is available (MCP73831) with lesser parts and lesser functionalities." For the full article check: https://medium.com/@sundarkrish2010/battery-management-circuit-using-mcp73871-de4a213e9c0f

  1. No
  2. No need
  3. Yes
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It depends on your application. A BMS automatically shuts off the battery to prevent deep discharge and draws a few nanoAmps. Your charge controller draws 30 microAmps in shutdown. Also, it's not clear the software can shut off power to itself with this charge controller. If not, the battery would be quickly damaged due to deep discharge. When a battery reaches 0V, there's a good chance it will never charge again.

TI provides ICs that integrate both charge controller and booster IC.

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  • \$\begingroup\$ thanks, do you know any IC that integrate both charge controller and booster. i need 5v to drive my circuitry. @Dave. \$\endgroup\$
    – Sajjad
    Commented Aug 17, 2021 at 13:13
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To answer your question "do we still need a battery protection IC between battery and MCP73871"

1.We do not need Battery Protection IC because MCP73871 has charge termination feature to disable charging when the battery is fully charged 2. It also has Low Battery Output (LBO)feature to indicate to user battery is low and it needs charging ...

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