TIDA-010216: TIDA-010216

Utku Kir

Part Number: TIDA-010216
Other Parts Discussed in Thread: TPS54308, BQ76972, UCC27524

Tool/software:

Hello,

I have two questions about design of TIDA-010216:

1- What is the reason of using 5 Mosfets for each CHG and DCHG channel separately, is it to create redundancy and to reduce the load on each mosfet? Because each mosfet can tolerate 200A continuous current which is usually enough for charging 16 cells. Does it have dramatic effect on board's thermal performance? What if we use 2 Mosfets instead of 5 mosfets?

2- I am trying to estimate the cost of the circuit. Can you recommend an alternative iso transformer instead of 750344754 which is used in the TPS54308DDCR circuit? We will be manufacturing 6500 units/month, we need to be using a transformer which does not have production and lead time problems.

Thank you.

Utku

7 months ago

0 Ryan Tan 7 months ago

TI__Expert 3345 points

Hi Utku,

See below:

1. Yes, more MOSFETs helps a lot on the thermal. If using the same MOSFET (2mR ohms Rds_on) with TIDA-010216, 200A generates 80W which is too large. Suggest to add more MOSFETs based on your cooling conditions and system requirements.

2. We only tested 750344754 in our board. I don't see it quite complicated to design the transformer, maybe you can find some other transformer manufactures to help you with a new transformer design, you can find TPS54308 calculation tools through below: https://www.ti.com/tool/download/SLUC685.

Ryan Tan

0 Utku Kir 7 months ago in reply to Ryan Tan

Prodigy 20 points

Hi, with this particular design, can we control and limit charge and discharge current through PWM signals on CHG,DSG pins?

0 Kian Lin 7 months ago in reply to Utku Kir

TI__Intellectual 2350 points

Hi Utku,

AFE doesn't have this feature integrated, but you could use host to control AFE through DEFTOFF/CFETOFF pins to achieve this. More details you can refer to 7.7.4 of BQ76972 TRM https://www.ti.com/lit/ds/symlink/bq76972.pdf?ts=1719130822796&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ76972 .

BRs

Kian

0 Utku Kir 7 months ago in reply to Kian Lin

Prodigy 20 points

Hi,

UCC27524AD gate driver supports PWM signals through Vinx pins. So it must be able to switch the Mosfet groups in CHG and DSG channels using PWM. That must be limiting the current flowing through V- line. Can you be more specific on how AFE does not support current adjustment? We are not using BQ76972 yet, we consider to use MOSFET part in one of our commercial products. But we may switch to BQ76972 if there is a way to control current.

Thank you.

0 Kian Lin 7 months ago in reply to Utku Kir

TI__Intellectual 2350 points

Hi Utku,

Yes, UCC27524 can support PWM input but AFE can't output PWM signals automatics via DSG/CHG pins. So you need use host to control the FET manually to generate a PWM signals.

BRs

Kian

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TIDA-010216: TIDA-010216