Hi dialog,
I meet a strange start-up problem about DA14580 recently.
I check the components of my board by exchanging them to the normal board. However, the board doesn't start up after changing the main components such as the resistance , inductance and IC. Then I check the voltage around the DA14580 . The buck VDCDC is about 0 when the VDCDC of the normal board is 1.41V .
The resistance between VDCDC to groud of the abnormal board is 270Ω when the normal one is about 10 MΩ . That the external 1.41V is added to VDCDC for several seconds can solve the problem surprisingly . The problem hasn't recurred yet since I add the exteranal 1.41V to the VDCDC to resolve the matter.
Can you explain the reason of the problem?
Device:
Hi Beyondpan,
I am sorry, i dont understand the issue you are describing, your reference is a "normal board" (what do you mean by normal board ?), you mentioned that you ve changed the components (resistance, inductance and IC), have you used the recommended values of the external components needed for the function of the 580 (described in the datasheet and in the documents of our reference designs) ? You also mention that you solve the problem by applying an external voltage source on the VDCDC pin of the 580 ? The 580 includes an DCDC converter which can be configured either as buck or boost depending on the power supply of the device, you dont have to apply an external source, unless you would like to bypass the DCDC.
Thanks MT_dialog
Hi dialog，
The normal board is a product board in good working condition. The board in this topic can't not start up .
I design the PCB by referring to the datasheet design , and the value of components is the same as the reference designs. After I exchanged the components of the proper working board and the badly working one , the problem remained the same .
The voltage I add to 580 is 2.8V , so the DCDC converter is configured as buck mode . The output of the buck converter is about 1.41V in normal working condition , however , the voltage of the abnormal one which we are talking about is about 0.
I try to fix the abnormal board and find out the reason of the problem . When I add the external 1.4V to the VDCDC pin for several seconds , the 580 can work in good condition . After I remove the external voltage and restart the system , the 580 also work properly .
I guess that some of the DCDC converter doesn't work because the internal module of 580 isn't activated until we add the 1.4V to the VDCDC pin .
Hi Beyondapn,
You mean that in order for the device to work you need to jump start the device via applying 1.4V on the DCDC output ? I dont see something obvious from what you are mentioning, but as far as i can tell this is either due to a faulty PCB design or a faulty assembly problem, a short circuit between pads most probably.
Thanks MT_dialog