LM51770: Circuit design recommendations

Allen yang

Part Number: LM51770
Other Parts Discussed in Thread: LM5177, LM5118

Hi Team,

Please provide complete design suggestions, given the following design requirements.

Power Supply
Nominal voltage: 9~36V (ATC 3540-IP7-4C); 24V for rail
(ATC 3540-IP7-AI4CR)
Cranking voltage: 6V~9V (less than 20 sec)
OCP & UVP (shut down once exceeding 37V)
gnition on/off control & programmable on/off delay timer
Opional for remote power on/off control

ATC 3540-IP7-4C_AI4CR.pdf

1 month ago

0 Stefan Schauer 1 month ago

TI__Guru 60891 points

Hi Allen,

the LM51770 would fit here very well.

A good starting point would be the EVM:

https://www.ti.com/tool/LM5177EVM-HP

(Note: this EVM is still using the LM5177 which is pin compatible with the LM51770. Would recommend to use the LM51770 for new design due to the performance improvements.

For design optimizations i recommend to use the QuickStart calculator:

LM51770-QUICKSTART-CALC Calculation tool | TI.com

Best regards,

Stefan

0 Allen yang 29 days ago in reply to Stefan Schauer

Expert 1045 points

Hi Stefan,

How should the following function be designed?

Cranking voltage: 6V~9V (less than 20 sec)

The LM5177 is a bit complicated in terms of functionality. Could you please recommend a simpler IC?

Thanks

0 Stefan Schauer 29 days ago in reply to Allen yang

TI__Guru 60891 points

Hi Allen,

when considering a time of 20 seconds then you need to use also the 6V-9V as normal operation voltage range.

Unless your output power is less the 70W (which would allow an Flyback or SEPIC) design, you need to use a 4-Switch BuckBoost controller.

If your output power is less then 150W you might could use a async 4-Switch BuckBoost (LM5118).

If your output power is higher then a 4-Switch BuckBoost like the LM51770 is the right choice.

I am not sure what you think is complicated on this design. It is really easy to use.

Best regards,

Stefan

0 Allen yang 27 days ago in reply to Stefan Schauer

Expert 1045 points

Hi Stefan,

gnition on/off control & programmable on/off delay timer

Opional for remote power on/off control

Does the above function require MCU control?

0 Stefan Schauer 27 days ago in reply to Allen yang

TI__Guru 60891 points

Hi Allen,

really sorry but I do not understand your questions.

Can you please rephrase and add more details?

Best regards,

Stefan

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LM51770: Circuit design recommendations