LMR36503: Power management for battery and power supply

Stefan Frey

Part Number: LMR36503
Other Parts Discussed in Thread: LMR38010, TPS62826, TPS62840, TPS62177, TPS62175

Tool/software:

We are currently using the product LMR36503RFRPER in the series. We used as Buck converter for an output voltage of 3,3V and wide range input voltage nominal 4,5 – 28V. In Error case, for safety integrated max. input voltage 60V.
Now for a new product we need an input range from 2V – 3,8V in battery mode and wide range input from 4,2 – 60V in power supply mode. Both input range relate to the same wire on the board. Is there a converter how pass through the voltage of battery since 3,8V directly to sw pin, until 3,8V the converter should be switch off and should have a small quiescent current. Over 4,2V the converter switch on.

2 months ago

0 Richard Fu22 2 months ago

TI__Mastermind 31315 points

Hi Stefan,

Let me see if I understand correctly:

1) An input voltage range from 2V to 3.8V (where it passes through directly from input to output.

2) A converter that regulates from 4.2V to 60V down to 3.3V.

As I understand it, you would typically want a converter that has the UVLO. You can use this UVLO to have the converter turn on at 4.2V, and off otherwise.

Please examine the LMR38010. You can check according to formula 14 that your turn off voltage is around 3.7V, which is close to the 3.8V required. You can also parallel it with another device that turns on that allows you to pass the 3.8V directly to the output. That is most easily done using an MCU if that is how your application selects between battery mode and power supply mode.

Thanks,

Richard

0 Stefan Frey 2 months ago in reply to Richard Fu22

Prodigy 30 points

Richard Fu22 said:
LMR38010

We need a Buck Converter similar like TPS62826 or TPS62840.pdf

Hi Richard
I tried to describe it a little better, please have a look at pdf

Thanks

Stefan

0 Richard Fu22 2 months ago in reply to Stefan Frey

TI__Mastermind 31315 points

Hi Stefan,

I understand the use-case a bit better now- thanks.

I think there is a conflict between the input voltage ranges, in that a wide-input voltage range device typically will not have the battery-saving mode that you would see in the TPS62826 or TPS62840.

Unfortunately, I don't think we currently have a converter in our portfolio that has the specifications similar them besides the LMR3650x series.

Let me check with our team internally and check what we have. If you have a dedicated FAE, please contact them and let them know of the need and we can see if we have any products available that can support it.

Thanks,

Richard

0 Stefan Frey 2 months ago in reply to Richard Fu22

Prodigy 30 points

Hi Richard

The TPS62177 is Running to 30V max., i want to simulate with Pspice for Ti, but where have to connect ILIM Pin. I get an error with this Node: ERROR(ORPSIM-15141): Less than 2 connections at node N24677

0 Stefan Frey 2 months ago in reply to Stefan Frey

Prodigy 30 points

The minimum Inputvoltage of 4.75V of TPS62177 or TPS62175 is too high

0 Richard Fu22 2 months ago in reply to Stefan Frey

TI__Mastermind 31315 points

Hi Stefan,

I checked with the internal team and we currently do not have any devices that have the battery-saving mode seen in the TPS62177 or TPS62175. The reason for this is typically the trade-off between the device leakage current (due to the wider input-voltage necessitating larger FETs).

I recommend posting the PSPICE question with the SR-MVB forum.

Thanks,

Richard

0 Stefan Frey 2 months ago in reply to Richard Fu22

Prodigy 30 points

OK Thanks Richard

0 Richard Fu22 2 months ago in reply to Stefan Frey

TI__Mastermind 31315 points

Hi Stefan,

For now, I'll mark this thread as TI thinks resolved, since the thread has gone to a device in a different business unit.

Thanks,

Richard

0 Stefan Frey 2 months ago in reply to Richard Fu22

Prodigy 30 points

Hi Richard,

what about Buck converter with external Mosfet is there any components available

Thanks

Stefan

0 Richard Fu22 2 months ago in reply to Stefan Frey

TI__Mastermind 31315 points

Hi Stefan,

We do have controllers, please see the attached link:

https://www.ti.com/power-management/acdc-dcdc-controllers/products.html#1129=Buck%3BBuck%20Controller&238max=60%3B700&

Thanks,

Richard

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LMR36503: Power management for battery and power supply