DRV8305-Q1: spike current PVDD line

Hi Kura,

How is PVDD being supplied and what is its voltage level when these spikes are being scene?

Also, are there any other component actively switching on the board, like a buck for example?

Best,

Joshua

Joshua-san

Thank you for your reply.

Below is their answer for your question.

>How is PVDD being supplied and what is its voltage level when these spikes are being scene?

Because it is supplied from a 12V stabilized power supply through a rectifier diode, the voltage of PVDD will be about 11V.

>Also, are there any other component actively switching on the board, like a buck for example?

Nothing in particular. A power supply IC that steps down from 12V to 5V is used on the board, but it is LDO (linear regulator).

Regards,

Kura

Hi Kura-san,

kura said:

In the image below, the external FET is stopped, SPI communication is also stopped,

Just to make sure are you unable to perform SPI read and writes or do you just mean that no SPI communication is occurring?

1. Are you seeing any faults being reported?

2. Can you see this pulse on the VCPH pin as well?

Best,

Joshua

SPI communication is not always performed at their puroduct.  (SPI communication is not running in the attached image)
SPI communication is executed only when the power is turned on and when the nFAULT is fixed to Low.

Below is answer for your question.

1. Are any failures reported?
-> There is no report of failure

2. Do you also see this pulse on the VCPH pin?
-> Unconfirmed.

     Please let us know  about the background of your question.

     Does the charge pump circuit of this part operate intermittently with a period of about 128 us ?

regards,

Kura

Hi Kura,

The background to the VCPH pin question was to see if the pulsing on PVDD was visible at other pins of the device. VCPH was chosen because the charge pump uses PVDD as an input and VCPH connected to PVDD by a capacitor so it had the best chance of also having the pulsing.

Could I ask why this pulsing is a concern, has it been affecting the operation of the device in any way?

Regards,

Joshua

Joshua-san

Thank you for your support.

We got following answer from customer.

They understand the background of your question.

Also, even if a pulse-shaped current waveform derived from VCPH is superimposed on the PVDD line,

it is within the specification range and there is no problem.

1.Please advise us if there is any mistake in their understanding.

>Could I ask why this pulsing is a concern, has it been affecting the operation of the device in any way?

--->There are no particular problems with the operation of the device.
There was a high peak current flowing, so they just wanted to know that there was no problem with their usage and that it was operating within specification.

Regrards,

Kura