Residual voltage on VBUS on nPM1300.

[Jose Juan]

Hi,

I'm working with a custom PCB, with nPM1300 and a microcontroller.

The problem is that working only with battery the nPM1300 VBUS pin show 2.4V and I cannot put the nPM1300 in Ship Mode.

Any hint?

[Asbjørn]

Hello Jose,

I think you need to share a bit more about your setup and issue to be able to assist you.

Q1: When you have battery connected to the nPM1300 output you only see 2.4V on the VBUS pin, but when there's no battery you measure the full 5V?

Q2: What are you doing to the nPM to put it into ship mode? How are you configuring it and are other configurations of the nPM possible with the same setup?

Best regards

Asbjørn

[Jose Juan]

Hello Asbjørn,

Thank you for your interest.

The schematics.

Q1: When you have battery connected to the nPM1300 output you only see 2.4V on the VBUS pin, but when there's no battery you measure the full 5V?

Yes, when USB its connected I measured 5V. When it´s not connected I measure 2.41V and the content of register VBUSINSTATUS is 0x09 (VBUS present and Undervoltage)

Q2: What are you doing to the nPM to put it into ship mode? How are you configuring it and are other configurations of the nPM possible with the same setup?

I sent shipmode command through i2c. Must be something in design, because I try a new prototype board with no programming and no nPM1300 configuration and VBUS with no USB present measure 2.41V.

[Asbjørn]

Hello Jose,

With the VBUS still present, are you wanting for the EVENTSVBUSINOSET?  https://docs.nordicsemi.com/bundle/ps_npm1300/page/chapters/core_components/ctrl_reg/doc/main-registers.html#ariaid-title24

https://docs.nordicsemi.com/bundle/ps_npm1300/page/chapters/core_components/ship/doc/ship-mode.html

"The host software must wait until EVENTSVBUSIN0SET to ensure VBUS is disconnected and discharged before writing to the register."

What have you configured the SHPHLDCONFIG debounce duration to be? https://docs.nordicsemi.com/bundle/ps_npm1300/page/chapters/core_components/ship/doc/ship-mode.html#ariaid-title8

Jose Juan said:

I try a new prototype board with no programming and no nPM1300 configuration and VBUS with no USB present measure 2.41V.

Where exactly are you measuring, just to be sure.

Best regards

Asbjørn

 

[Jose Juan]

Hello Asbjørn,

Thank you for your help.

It has made me think more about design and the way it works.

In the end the bus voltage came from the double rail-to-rail ESD protection diode PRTR5V0U2X, which input de voltage from pin D+ of microcontroller.

Sorry for the inconvenience.

Best regards.