LM2664: Shutdown function

Dice-K

Mastermind 6330 points

Part Number: LM2664

Hello.

During shutdown, just stop switching, all four intenal switches do not turn off?

Is it that LM2664 stops in either of the states below and we do not know which way to go?

S1,S3 = ON
S2,S4 = OFF

S1,S3 = OFF
S2,S4 = ON

Regards,
Dice-K

over 5 years ago

0 Jasper Li over 5 years ago

TI__Mastermind 46905 points

i think all the switches turn off. you can measure the resistor between the V+, CAP+, CAP- and VOUT to confirm if the switcher is turned off. we can also do that, but it needs some times.

0 Dice-K over 5 years ago in reply to Jasper Li

Mastermind 6330 points

Hi Jasper,
Thank you for your reply.

At the experiment of my customer, all switches do not turn off.

Do you know the reason why does the following behavior occur?

S1,S3 = ON
S2,S4 = OFF

or

S1,S3 = OFF
S2,S4 = ON

Best regards,
Dice-K

0 Jasper Li over 5 years ago in reply to Dice-K

TI__Mastermind 46905 points

do you mean all the switches is turn off? otherwise the VIN shorts to GND

0 Dice-K over 5 years ago in reply to Jasper Li

Mastermind 6330 points

Hello Jasper.

All the switches do not turn off.

I have not confirmed the state of VIN, but I think that \SD is connected to Low.

Are the following experiment results of my customer correct?

S1,S3 = ON
S2,S4 = OFF

or

S1,S3 = OFF
S2,S4 = ON

Best regards,
Dice-K

0 Dice-K over 5 years ago in reply to Dice-K

Mastermind 6330 points

Hello Jasper.

I am happy if you let me know the result of your experiment.

Best regards,
Dice-K

0 Jasper Li over 5 years ago in reply to Dice-K

TI__Mastermind 46905 points

sorry for the delay. in my measurement, the S1, S3=ON, and S2, S4 = OFF. but i think it is possible that S1, S3= OFF and S2, S4 =ON, depending on the internal logic when the device stop oscillation.

may i know how does this behavior impact customer's operation?

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LM2664: Shutdown function