TPS65400: QRGZTQ1

Hi Yaqi,

Suggestions for you :
1. Please pay careful attention to the datasheet and User's Guide.
2. Please try to design according to the recommendations in the datasheet, including schematic , Layout example, and layout guidelines.
3. After completing the first version of the design, communicate in time and I will review it .

(Below pictures for your reference)

Best Regards,

Zhou

0121.TPS65400.pdf
Hello, the attachment is the schematic diagram I designed. Please check it. The input is FS56_V50. The PTA1 and PTA0 connected by I2C pull 3V3 elsewhere, so it is not reflected in this picture.
1. Are the SS1-SS4 pins used to connect capacitors to control the power-on sequence? Can I leave these four pins floating and use programming to control the power-on sequence?
2. How is the resistance value of the output voltage determined?
3. I2CADDR, I2CALERT, CLK_OUTRCLOCK_SYNC, PGOOD pins, I don’t know what function they should be connected to, please guide me.
4. What determines the size of the output current?

There are some inaccuracies in the picture. Please correct me. Thank you.

Hi Yaqi,

1.Yes. The TPS65400 has the ability to use an analog-based soft-start ramp based on external capacitors (one input for each switcher) or to use internal signals based on digital logics and DACs to perform the soft-start function.

2.Vout = Vref x (1 +RFB1/RFB2)        Default Vref in TPS65400 is 0.8 V

TI recommends to use a 1% tolerance resistor or better one to get higher output voltage accuracy.

3. About how to connect I2CADDR, I2CALERT, CLK_OUTRCLOCK_SYNC, PGOOD pins.  Recommended to connect according to the EVM Schematic Example. The specific functions of these pins, it is recommended to refer to the datasheet, which has a detailed introduction.

4. SW1, SW2 Iout: 4-A max ；SW3, SW4 Iout: 2-A max. The MOSFETs load characteristics of Buck itself determine the max value. The power consumption of the load determines the size of the output current.

Best regards,

Zhou

Hello, I have modified it according to your prompt, please check if there are any mistakes
The function I want to achieve is: connect to MCU through IIC, control the power-on timing through MCU programming, and output the corresponding voltage. Does my circuit diagram meet the requirements?
Thank you4578.TPS65400.pdf

Feedback to you later.

Hi Yaqi,

1. There is a problem: the 44  -CLCK_OUT pin is not connected correctly. If you don't need an internal clock, floating is recommended.
2. According to your connection method, there are two ways to achieve power-on timing : a. Control ENSWx through the I/O port of the MCU. b. Implemented by configuring internal sequence_order timing.

Best regards,

Zhou

hello
1. the 44  -CLCK_OUT pin  ，I saw that the instruction manual mentioned the need to pull up, so I connected to the 3.3V power supply.
But when I look at your reference picture, the picture on the left is incomplete. I can't see it clearly. It seems to be grounded after connecting a capacitor. Is the solution of connecting a capacitor to ground feasible? What parameters do capacitors need?

Thank you for your guidance