TPS61289: Power management forum

Hi Chen Chin,

The schematic looks ok.

It seems that the device encounters an over voltage.

The positive and negative spike both look high.

Could you give me the layout to have a review?

Also, could you provide more details about the parallel working?

Best Regards,

Fergus

Hi Fergus:

                1: layout as attached. 

                2: Vin 20V Vout 21.5V  Iout 4A

                3: I retest the short ground for measurment, The positive is 31V (Spec is 34V) and negative is -3V (7nS).

                    Does this measurement result meet the specification?

017138721513.zip  

Hi Chen chin,

The switching and the device are too far away, and the output capacitors are far.

This causes the large Parasitic inductance and causes high spike.

For the spike, it is now acceptable, but the situation can be much worse when heavy load.

Additionally, the spike of upper MOS (inside the device) can be high and causes damage.

Best Regards,

Fergus

Hi Fergus:

                 I close the switching and the device but the spike is same. Please see the attach a picture.

                 Than i close the output capacitors and it seems to have some effects. please attach a picture. 

                  Does this measurement result meet the specification?  or other suggestion for us?

                  Could you provide the demo board for us?

Hi Chen chin,

You are right about the output capacitors.

It absorbs the spike and influence the spike a lot.

It worth trying to work with paralleled devices.

I see that you are using TPS61289 for pure boost and I will recommend using TPS61287.

TPS61287 is just for pure boost use case.

I can send a paralleled TPS61287 for you.

Nevertheless, you can still use TPS61289 in this parallel board.

The device is to RTMed soon this year and please see its preliminary datasheet below.

3173.TPS61287 preliminary datasheet version 1.1.pdf

Regards,

Fergus

Hi Fergus:

                 We have no intention of trying paralleled devices, because we have not yet found the casue of the burned.

                 At first, I was worried that the temperature would be too high due to heavy load, but now there should be no problem when testing 

                 the temperature of a single device. 

                 Previously, you also suggested that we use TPS61287 but we couldn't get sample, so we used TPS61289. 

                 So since you want to provide TPS61287 samples to me, can the Demo board at the same time? 

                 Name: 陳金煌  Tommy chen

                 Phone: 0916050806  +886-2-8228-0505 ext: 1842

                 address: 17F., No.268, Liancheng Rd., Jhonghe District, New Taipei City 23533, Taiwan, R.O.C

                                 23553 新北市中和區連城路268號 17F

Thanks~

Hi Tommy,

I still have a small question.

your input is 20V and output is 21.5V and Io is 4A, why you need a paralleled TPS61289? One is enough.

Also, we have other device like TPS61377 fit for this application.

Do you need one TPS61287 evaluation board or paralleled board?

Regards,

Fergus

Hi Fergus:

                Because we use OLED MNT, the ambient temperature is very higt, so we reseved the parallesd device. 

                So what you said is right,  one is enough. 

                I need TPS61287 samples and evaluation board. 

Thanks~~

Hi Tommy,

I will send you the TPS61287EVM to you.

Could you place a ZS order as the device is not released？

Best Regards,

Fergus

Hi Fergus:

                I don't know what ZS order is?

                Do you mean that both EV board and samples require payment?

thanks~

Hi Tommy,

The ZS order is our system for ordering unreleased device, and I will fill it for you.

It is for free.

Please provide your company name and email address.

Best Regards,

Fergus

Hi Fergus:

                 AmTRAN Technology Co., Ltd. 

                 瑞軒科技股份有限公司

                 tommy.chen@amtran.com.tw

thanks~~

Hi Tommy,

Thanks for the informartion.

I will send the model to you soon.

Regards,

Fergus

Hi Fergus:

                I have receivied the demo baord you sent, can you provide the circuit of the demo board?

thanks~