BQ34Z100-R2: Best way to power device with 12S-14S battery

SAERO

Part Number: BQ34Z100-R2
Other Parts Discussed in Thread: BQ34Z100, TPSM365R15, TPSM365R1

Tool/software:

Hello,

We are looking for best way to power BQ34Z100-R2. Datasheet suggests a Zener diode method and I'm reading few forum posts and I see suggestions to use LDO.

Option1: We have a TPSM365R15F(5V fixed) on the PCB and we can use a 3.3V LDO and power it

Option 2: LDO from 60V to 3.3V directly

Option 3: Stick to Zener method.

Looking for suggestions. We need the best efficient method to power the device.

Thank You

11 months ago

0 SAERO 11 months ago

Intellectual 361 points

Awaiting response!

0 Adrian 11 months ago in reply to SAERO

TI__Mastermind 37981 points

Hello Zero,

We would recommend option 3, the Zener method.

Regards,

Adrian

0 SAERO 11 months ago in reply to Adrian

Intellectual 361 points

Can you please provide reason for better understanding?

Thank you!

0 Diego 11 months ago in reply to SAERO

TI__Mastermind 29025 points

Hi,

LDOs would be less efficient, due to the loss in energy from heat.

Regards,

Diego

0 SAERO 11 months ago in reply to Diego

Intellectual 361 points

How about switching regulator with low quiescent current?

say TPSM365R15F?

0 Diego 10 months ago in reply to SAERO

TI__Mastermind 29025 points

Hi,

looping in some from buck/boost team.

Regards,

Diego

0 Richard Fu22 10 months ago in reply to SAERO

TI__Mastermind 31315 points

Hi Saero,

Can you provide a little more insight to your application? If I understand it correctly, the current drawn from the 3.3V supply is in the order of 100's of uA's right? In that case, a LDO will be fine. It will reduce your overall design complexity and additional noise generated with little trade-off in terms of loss. (maybe 100-300uW).

Thanks,

Richard

0 SAERO 10 months ago in reply to Richard Fu22

Intellectual 361 points

Application is Battery management system with BQ34Z100. We need to power BQ34Z100 and are looking for best ways to power it.

0 Richard Fu22 10 months ago in reply to SAERO

TI__Mastermind 31315 points

Hi Saero,

It looks like the current draw for the BQ34Z100 is in the 100s of uAs. In that case, the LDO may be the best option.

Thanks,

Richard

0 SAERO 10 months ago in reply to Richard Fu22

Intellectual 361 points

Is switching regulator okay if I have 3.3V output?

I'm looking at TPSM365R15 which gave low quiescent current.

0 Richard Fu22 10 months ago in reply to SAERO

TI__Mastermind 31315 points

Hi Saero,

Yes, it should be fine. I was misunderstanding the situation in that you were using a 5-V switcher already.

We have an existing EVM that can help you evaluate the TPSM365R15, including a 3.3V option that supports up to 65-V output:

https://www.ti.com/tool/TPSM365R15EVM

Let me know if that works.

Thanks,

Richard

0 SAERO 10 months ago in reply to Richard Fu22

Intellectual 361 points

We initial planned to use LDO from 5V to 3.3V. But looks like we don't need 5V supply anywhere for this design. So we are planning to have 3.3V switching regulator.

I couldn't find 3.3V fixed switching regulator similar to TPSM365R1 OR R15. Any suggestions?

Thank you!