TPS62140A: How much is the time for internal oscillator stable?

Kazuya Nakai59

Guru 21505 points

Part Number: TPS62140A

Hello guys,

One of my customers is considering using TPS62170A for their next products.

At this moment, they have the following questions.
Could you please give me your reply?

Q1.
How much is the time for internal oscillator stable?
They couldn't find it though they want to know.

Q2.
The device datasheet says "When EN is set to start device operation, the device starts switching after a delay
of about 50 µs, and VOUT rises with a slope controlled by an external capacitor connected to the SS/TR pin."
Does the internal oscillator switching become stable by this 50us?

Your reply would be much appreciated.

Best regards,
Kazuya.

over 1 year ago

0 Zixu Wang over 1 year ago

TI__Expert 8100 points

Hi Kazuya,

My colleague will give you reply next week!

BRs

Zixu

0 Shuai Fan over 1 year ago in reply to Zixu Wang

TI__Genius 13451 points

Hi Kazuya,

1. What kind of oscillator do you mean? This device is like COT control which doesn't have internal clock to keep switching frequency.

2. Same as Q1.

Shuai

0 Kazuya Nakai59 over 1 year ago in reply to Shuai Fan

Guru 21505 points

Hi Shuai, Zixu,

Thank you very much for your reply.
Could I ask you the following additional questions?

Q1.
When EN pin is connected to VIN(PVIN pin and AVIN pin), when does the device start switching after VIN powered up?

Q2.
Is the switching start timing which I ask as Q1 different at 3V VIN and 12V VIN?

Q3.
If you have the data of start timing at 3V and 12V VIN, could you please give me it?

Thank you again and best regards,
Kazuya.

0 Shuai Fan over 1 year ago in reply to Kazuya Nakai59

TI__Genius 13451 points

Hi Kazuya!

It is related to your VIN ramp up slew rate. The device start to switching only after EN> it rising threshold and VIN >it rising UVLO.

So it has no relationship with final stable VIN value.

0 Kazuya Nakai59 over 1 year ago in reply to Shuai Fan

Guru 21505 points

Hi Shuai,

Thank you very much for your strong supports.

We understood well!

Thank you again and best regards,
Kazuya.

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TPS62140A: How much is the time for internal oscillator stable?