Using iMX27 with MC13783 Power Management, no Switcher outputs!

[DarrenHarrold]

I have a development card using an iMX27 processor and an MC13783 Power Management device to provide the LDO and Switcher rails that I require to power the iMX27. I have configured the PUMS pins on the MC13783 to provide +1V2 on SW1 and +1V8 on SW2 but I'm not getting any outputs from these 2 switchers. Both PUMS1 and PUMS2 are connected to GND, and PUMS3 is floating - I have followed the MC13783 User guide, specifically section 5.3 of the document. The LDO's are present and SW3 (unused) is also up and running. SW1 and SW2 are both configured for 'Parallel use' to provide up to 1A. Has anyone else had issues with the MC13783 power management device used in this manner with the iMX27? 

Regards,

Darren

[DarrenHarrold]

My email address is darren.harrold@vislink.com if you want to communicate directly.

Darren

Chuck Farago said:

Hello Darren,

Yes, the missing terminations are the reason for your switcher issues.  In particular, the charger related connections and the VINCAM connection are important for proper switcher operation.  Please see the enclosed unused charger and unused pin list documents, and ensure that your entire design complies with the info in these documents.  If you have further questions, please let us know.

Thanks & Regards,

Chuck

 

Darren Harrold said:

Hi Chuck,

I'm using the MC13783VK5 device. Yes I did see this document on the Freescale website and I think I have my circuit wired for the VK5 part with both SW1 and SW2 set for 'Parallel mode'. The pages from my schematic where the MC13783 is used are attached for you to look at. One document that was pointed out to me was AN3276 - Interfacing iMX31 to MC13783. In this document section 6.4.1 states recommendations for terminations related to unused functions. On my circuit I don't have VINVIB or VINCAM connected to +3V3. Also it states that the pins CHRGISNSP, CHRGISNSN, BATTISNS and BATT should be tied to +3V3 but again I haven't connected these pins to anything. I have connected CHRGMOD0 to GND and CHRGMOD1 to VATLAS. Could these missing terminations be the reason why I'm not having the correct voltages from SW1 and SW2??

Regards,

Darren 

[DarrenHarrold]

Hi Chuck,

Ok thank you for the reply and the attached documents. I will modify the next revision of my design and incorporate the changes as per the documentation.

Is it possible to email you directly at Freescale so I can send you the schematics for the next revision of my design, so you can confirm I've connected the missing unused pins correctly?

Regards,

Darren

[ChuckFarago]

Hello Darren,

Yes, the missing terminations are the reason for your switcher issues.  In particular, the charger related connections and the VINCAM connection are important for proper switcher operation.  Please see the enclosed unused charger and unused pin list documents, and ensure that your entire design complies with the info in these documents.  If you have further questions, please let us know.

Thanks & Regards,

Chuck

 

Darren Harrold said:

Hi Chuck,

I'm using the MC13783VK5 device. Yes I did see this document on the Freescale website and I think I have my circuit wired for the VK5 part with both SW1 and SW2 set for 'Parallel mode'. The pages from my schematic where the MC13783 is used are attached for you to look at. One document that was pointed out to me was AN3276 - Interfacing iMX31 to MC13783. In this document section 6.4.1 states recommendations for terminations related to unused functions. On my circuit I don't have VINVIB or VINCAM connected to +3V3. Also it states that the pins CHRGISNSP, CHRGISNSN, BATTISNS and BATT should be tied to +3V3 but again I haven't connected these pins to anything. I have connected CHRGMOD0 to GND and CHRGMOD1 to VATLAS. Could these missing terminations be the reason why I'm not having the correct voltages from SW1 and SW2??

Regards,

Darren 

[DarrenHarrold]

Hi Chuck,

I'm using the MC13783VK5 device. Yes I did see this document on the Freescale website and I think I have my circuit wired for the VK5 part with both SW1 and SW2 set for 'Parallel mode'. The pages from my schematic where the MC13783 is used are attached for you to look at. One document that was pointed out to me was AN3276 - Interfacing iMX31 to MC13783. In this document section 6.4.1 states recommendations for terminations related to unused functions. On my circuit I don't have VINVIB or VINCAM connected to +3V3. Also it states that the pins CHRGISNSP, CHRGISNSN, BATTISNS and BATT should be tied to +3V3 but again I haven't connected these pins to anything. I have connected CHRGMOD0 to GND and CHRGMOD1 to VATLAS. Could these missing terminations be the reason why I'm not having the correct voltages from SW1 and SW2??

Regards,

Darren 

[ChuckFarago]

Hello Darren,

Can you please provide the top markings of the MC13783 ICs that you are using?  Also, please ensure that your schematic follows the recommendations in the enclosed application note AN3417 for your IC version.  You can also find this app note on www.freescale.com.

Thanks and Regards,

Chuck

PMIC Applications

Freescale Semiconductor