Other Parts Discussed in Thread: SWITCHERPRO, ,
Hello,
I've spent the last five months designing and creating the attached SwitcherPro Design schematic using the TPS40055. After many weeks of debugging, I've found that your generated design has some faults. I'm hoping someone will be able to help salvage this board so that I can still get it to work.
I'll go step by step through the information identified.
- VFP is 0.2V with the output scaled by 10x, this is to be expected due to the R1 and R2 resistors in the COMP network.
- There are no Gate Drive signals generated by the TPS
- When probing the signals, a random non-PWM signal appears at a consistent frequency.
- BP10 is at 10V
- BP5 is at 5V
- These two voltages tell me the chip is working. (I've also replaced it already with the same results)
I have triple checked all components in the COMP network, and everything is correct, as well as all resistors.
Now I have a few questions regarding design decisions.
- What is the use of the RC filter before the output connected to the inductor? In the datasheet, this is after, which makes sense for an RC filter.
- Why is there a Diode connecting LDRV to KFF. There is no such diode needed in the "Typical Application" section of the datasheet.
Finally, when searching this component with the parameters
- TPS40055
- 10-25V INPUT
- 7V OUTPUT
- 15A OUTPUT
into your WEBENCH tool, nothing appears... has this design been removed? If so, why is it still possible to use your SwitcherPro Software? www.ti.com/.../SWITCHERPRO
I am incredibly frustrated and would like some help. Calling your customer support line resulted in me being rejected since I purchased this TPS chip from DigiKey, not you guys directly.
Any support with this issue would be appricated.
Austin
