TPS2301: TPS2301

Hi Alexei,

Thanks for reaching out to us. I am looking into it and will get back to you by tomorrow morning (IST).

Hi Alexei,

Please populate 3.3 nF or more value of capacitor in the place of C652 to reduce the output voltage slew-rate. Kindly let us know that the startup is successfully happening or not after implementing this. An additional capacitance (Cg) is required between the gate of the external MOSFET and ground to limit the inrush current. According to the schematic, the current limit (ILMT) is set at 1.13 A. Therefore, the inrush current should be limited to maximum 60% of ILMT, which is 678 mA. Please see the below equations to calculate the value of Cg to limit the inrush current.

Hi Avishek,

Thank you for detailed answer. Please see below the waveforms after population of 3.3nF capacitor in place of C652.

Now it looks functional.

1st and 2nd pictures: Yellow - Vin, Green - Gate, Blue - Timer, Pink - Vout

3rd and 4th pictures: Yellow - Vin, Green - Gate, Blue - Timer, Pink - Enable

But I have similar issue on my other channel. Main different is Vin voltage [1V].

Also it's implemented on other side of device due the Low Voltage restrictions.

See below the scheme:

On this channel Gate capacitor 3.3nF didn't help [C677]. See below the start-up wave forms of 1V channel with 3.3nF gate.

1st and 2nd pictures: Yellow - Vin, Green - Gate, Blue - Timer, Pink - Vout

3rd and 4th pictures: Yellow - Vin, Green - Gate, Blue - Timer, Pink - Enable

Hi Alexei,

Thanks for sharing the update and glad to know that the circuit is working now. However, the recommended operating voltage for Channel 2 is in the range of 3 V to 5.5 V. Therefore, it may not work with 1 V input. 

Hi Avishek,

1V channel was implemented according to recommendations from TI application note document [SLVA110].

See below:

Did I understand it wrong?

Please update.

Thanks

Hi Alexei,

I don't find this application note. Please could you share the PDF file with me. 

TPS2301 Low Voltage Application.pdf

Hi Alexei,

Thanks a lot for sharing. Please let me go through it. I will get back to you be end of the day today (IST).

Hi Alexei,

I think we need to populate 3.3 nF ceramic capacitor at C677 to reduce the inrush current as discussed earlier in case of Channel 1. Please keep us posted the status, whether startup is happening or not.

Hi Avishek,

3.3nF capacitor is already populated on C677. Please see the last 4 scope screenshots. 

However, this change didn't resolve the issue.  

Alexei

Hi Alexei,

I am looking into the issue and will get back to you tomorrow. 

Hi Alexei,

Do you have EVM for TPS2301. Will you be able to test this on EVM?

Hi Avishek

Unfortunately I haven't the EVM.

And I see that this product is no longer manufactured. I'm talking about TPS2301EVM-153.

Yes Alesei... That's why I also don't have the EVM. I was thinking to to test this 1 V architecture in EVM. However, I will check once again the schematic in detail and get back to you.

Hi Alexei,

Is it a new design or old design you are testing? Please could replace the controller and check it. Is it failing to startup in one board or in all boards you have? 

Hi Avishek

It is a new design.

I have 3 additional boards with exactly same issue with 1V voltage.

Hi Alexei,

I am sending you friend request. Please accept that. We will communicate through private message.