BQ20Z655-R1: BQ20Z655R1 in production

Max

Intellectual 920 points

Part Number: BQ20Z655-R1
Other Parts Discussed in Thread: BQMTESTER, BQ40Z50-R1

I am planning to use BQ20Z655-r1 IC in designing a battery Pack.

Could the IC can be used for production,

Whether the software and other requirements(Queries) will be supported by Ti.

over 4 years ago

0 Shirish over 4 years ago

TI__Guru 57697 points

BQMTESTER software is provided by TI. It has good documentation. It requires additional hardware. Please refer the product page for more information.

0 Max over 4 years ago in reply to Shirish

Intellectual 920 points

I am designing a schematics for 4s1p Battery pack using BQ20z655r1.In this i have the following queries which is listed below

1.LED is not needed for indicating the battery percentage, So the LED pind and LED out can be grounded.

2.The PFIN pin is necessary to be connected to indicate the Secondary Protection input.

3.The DISP pin can be connected to ground if it is unused.

0 Shirish over 4 years ago in reply to Max

TI__Guru 57697 points

Please refer to the datasheet.

I did a quick search and see that DISP is active low, so it should not be connected to ground if unused.

0 Max over 4 years ago in reply to Shirish

Intellectual 920 points

I am designing a 4S1P Battery pack using BQ20Z655-r1.

In this i dont need the LED pins to display the battery percentage, So whether the LED1 to LED5 and DISP can be left floating.

2.PMS If connected to Pack Pin,The precharge can be carried out by Charge FET right??

3.CE can be left unconnected? whether it affects the design. Also Why CE is needed.. Could you breif it??

0 Shirish over 4 years ago in reply to Max

TI__Guru 57697 points

Hello Anandan,

LED output pins can be left floating.

I don't see PMS or CE in the pinout. General guidance is to connect all input pins.

0 Max over 4 years ago in reply to Shirish

Intellectual 920 points

Pin 6 and Pin 19 are those pins

0 Shirish over 4 years ago in reply to Max

TI__Guru 57697 points

Hello Anandan,

Sorry i was looking at the wrong part pinout. Both pins must be connected. Connect PACK to PMS to allow 0v precharge.

Connect CE pin based on desired functionality

The bq20z655 EVM design is the best reference. You can use those input connections if the described functionality is a don't care.

0 Max over 4 years ago in reply to Shirish

Intellectual 920 points

Hi Shrish

I have designed a Schematics for 4s1p Pack using BQ20z655r1,

Could you help me by reviewing my schematics

0 Shirish over 4 years ago in reply to Max

TI__Guru 57697 points

I will check if someone can help.

0 Max over 4 years ago in reply to Shirish

Intellectual 920 points

Waiting for your response.

Also I need to Know whether the FUSE can be connected after the FET i.e Between the FET and Charger Input

0 Max over 4 years ago in reply to Shirish

Intellectual 920 points

Waiting for your response.

Also I need to Know whether the FUSE can be connected after the FET i.e Between the FET and Charger Input

0 Shirish over 4 years ago in reply to Max

TI__Guru 57697 points

Hello Anandan,

The FUSE must be connected in the path of current flow. Load current must also flow through it. An example is shown in the datasheet under the heading of SYSTEM PARTITIONING DIAGRAM

0 Max over 4 years ago in reply to Shirish

Intellectual 920 points

HI Shirish

I have connected the FUSE as Follows in the Load Current Path.(Instead of connecting between Positive cell and FET,I have connected on other end between the pack voltage and FET)

Whether my design is correct ??

0 Shirish over 4 years ago in reply to Max

TI__Guru 57697 points

Hello Anandan,

There are multiple considerations for FUSE placement. The purpose is safety. The Positive cell is the first point from where current can flow. If the battery is designed such that there is no other short possibility(or application of external voltage) in the path between Positive cell and Pack, then I do not see an issue..

0 Max over 4 years ago in reply to Shirish

Intellectual 920 points

Hi Shirish

Thanks for the response.

Also while Pre charging can we use CHG FET instead of PRCHG FET (as used in BQ40Z50-r1).Shall we make DNP the ZVCHG Pins??

Regards

ANANDAN N

0 Shirish over 4 years ago in reply to Max

TI__Guru 57697 points

Hello Anandan, The answer depends on how you intend to use pre-charge function. Please make sure you have the PMS pin connected per the datasheet if you intend to use the CHG FET

0 Max over 4 years ago in reply to Shirish

Intellectual 920 points

Thanks Shirish

I have connected to PACK pin and I have made DNP the ZVCHG pins

0 Max over 4 years ago in reply to Max

Intellectual 920 points

i am using BQ20Z655-R1 IC for building 4s1p pack

In this i need to charge the battery during the precharge mode.

So I can use for CHG-FET for charging the battery during precharge based on the software configuration.

In that time can I make ZVCHG(precharge FET section as DNP. and connecting the PMS to VSS to disable 0V precharge.

will it be ok to use in the design as suggested.

0 Shirish over 4 years ago in reply to Max

TI__Guru 57697 points

I checked the datasheet and it looks like if you plan to use CHG-FET for precharge then PMS is to be connected to PACK.

See "Pin functions" section of datasheet which states "Connect to PACK to enable 0-V precharge using charge FET connected at CHG pin."

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BQ20Z655-R1: BQ20Z655R1 in production