TPS65311-Q1：TPS65311-Q1 is no working, can you help me to check the schematic? I also can't use MCU communication with it by spi. Is any wrong with my schematic?

Hello,

It is very difficult to follow your schematic diagram. can you please clarify:

- Where did you connect PH1? I dont see connection from L9, Q9/Q10 junction to PH1 pin. Without this device will not power up.

- Did you connect VIO input to 3.3V supply?

- Did you set BUCK2 output to 7V and its input is 5V? If so, this will not work.

-Remove filter capacitors on Vsensex pins.

- Add atleast 4.7uF ceramic capacitor on VINPROT line and you may need more capacitors on VIN/VINPROT line depending on ripple requirements.

- Connect HSSENSE to VINPROT if HSSENSE is not used in your application.

- Did you configure the WD signal correctly from your MCU?

- What is connected to EXTSUP?

-What is connected to COMP3 and COMP2

-What is connect to VSUP2 and VSUP3, VSUP4, VSUP5?

- Send me the BUCK1, BUCK2, BUCK3 startup wave forms. Please refer to the datasheet "Power-up Sequencing" diagram and check whether regulator is powering up according to this sequence.

Regards,

Murthy

Dear Murthy，

     Thanks for you reply ! That is very important for us to debug the power board. We have replied one by one according to your suggestion, as follows.

     1. PH1 didn't connected to the junction . After I connected the PH1 to the L9,Q9/Q10 junction, the PMIC was going to work.  The BUCK1 is ourput 7V, BUCK2/BUCK3/BOOST/LDO  are all get working normally.

     2. We didn't give the VIO power, we don't know how to connect the VIO. Does VIO should connect to the MCU's power line? The MCU is powered by 5V .

     3. We had designed the schematic diagram was BUCK2 output to 7V and its input is 5V. but we found the part was wrong, so we modified the schematic diagram,  now the BUCK1 is output to 7V and BUCK2 is output to  5V.

     4. We have removed the filter capacitors on Vsensex pins in PCBA.

     5. Can we use replace the ceramic capacitor by Electrolytic capacitor on VIN/VINPROT line?

     6. HSSENSE is not used in our application. we will take your advice to connect HSSENSE to VINPROT. Should I connect a current-limiting resistance  between the  HSSENSE and VINPROT？

     7.HOW should I configure the WD signal  from  MCU?

     8. EXTSUP is connected to nothing.

     9. COMP3 and COMP2 are connected to  GND.

     10. VSUP2 and VSUP3, VSUP4, VSUP5 are connect to BUCK1. Can we connect VSUP2 and VSUP3, VSUP4, VSUP5 to VINPROT line?

     11. We can't give your the BUCK1, BUCK2, BUCK3 startup wave forms, because we had  a re-make a sample, when we get the test after the sample is ok.

   Your reply is very helpful to us, thank you very much! Looking forward to your reply again !

Hi,

Can you please let me know your project and customer details? Is this for autmotive application or some other application?

Regarding VIO: You can connect it to 5V if you don't have 3.3V available. But ABS max rating of VIO pin is 5.5V and so, make sure that this is not violated at any conditions. So, we recommend 3.3V for VIO.

Capacitors on VINPROT pin: It is important to have ceramic capacitors there (at least 2 or more 2.2uF/50V or 4.7uF/50V). Please use ceramic capacitors and electrolytic capacitor can be still there.

WD signal: MCU should generate PWM signal to service the WD within 200ms after power up. I have attached one slide explaining this.

VSUP2,3,4,5 connection: Please keep the connection to BUCK1. How much is your input supply? You are operating at very high duty cycle for BUCK1, BUCK2/3 and please check every device pin abs max rating and datasheet specification table to make sure that you are not violating the specifications. Usually this device is used in 12Vin application with BUCK1 configured for 3.3V and BUCK2/3 for 1.8V and 1.2V or something like this..

Regards,

Murthy

4073.TPS65311_Watchdog.pptx

Dear Murthy，

Thanks for your reply again!

These days we are debug the part circuit, because we find a new problem。

When 3.6V is divided by a resistor on the WAKE pin, the PMIC works normally, and BUCK1, BUCK2, and BUCK3 output normally, but the WD pin is  connected nothing. Will this cause repeated operations of turning on and off the GPFET?

hello，We now have a collaborative project to design charging piles for private electric vehicles, our company is located in Nanjing ，we We really need technical support 。Thanks very much for your reply!

Hello,

Without WD signal device will go to LPM0 state after around 2 seconds and when Wake pin is set to around 3.6V, then device detects high on wake pin and wakes up again and this cycle will repeat. So, you will have cyclic reset of the device and this is expected. Please see the datasheet operating mode transitions diagram.

Regards,

Murthy

Hello,

Also for next two weeks, our E2E support will be very limited and I request you to look in the device datasheet to understand the device functionality if you run in to some issues.

Regards,

Murthy

Dear Murthy,

Thanks for your reply! we had solved the problem after the MCU send  the WD signal to the PMIC .

Can you provide the failure analysis report of the electronic components of this chip? Which is need by our project. Or where can i get it by myself ?

Thank you very much again!

Hello，

Could you please tall me how can I find the MTBF of TPS65311-Q1?  I can't find the MTBF on the datasheet. 

Hello,

Murthy is out of office and will be returning next week. Please accept a delay in his response.

Best regards,

Layne J

Hello,

This device was not developed according to ISO26262 development process and it is just quality managed device. It is true that this device has some build it protection mechanisms, but we have very limited documentation support to this device as far as safety is concerned. We don’t support safety related topics on E2E and please send me an email by proving business case numbers, what exactly you need for this device and  why you need this documentation. I will forward your email to our management to see what best we can do for you.

My email address: kmurthy.hegde@ti.com

Regards,

Murthy