CD1020&1030

[ONUR]

Hello, I am using 2 CD1020 and 1 CD1030 integrations. The integrations are daisychain connected to each other. INT_B pins are common.AMUX channel is not connected. I want to create SHORT TO BATTERY diagnostics when I give 24 V from outside to an SP pin set to ACTIVE LOW (SWITCH TO GROUND DETECTION).How can I do it ?
Thank you.

[ONUR]

Hello David,

I understand you, but the customer wants to configure the SP pin as switch to GND and wants 0 in float state (4-6 volts), 1 in gnd state, short to bat fault detection in short to bat (6-36 volts) state. They say that there is MC33978 in the current benchmark and that this is done software.Can you help with this?

Regards,
ONUR

[diazmarin09]

Hello ONUR,

I don’t think MC33978 can support it when configured as a switch to GND channel. The comparator in MC33978 is 4V threshold.

0-- in float state (4-6 volts)

1-- in GND state, short-to-bat fault detection in short-to bat (6-36 volts) state.

Please accept my apologies. 

Regards,

David 

[ONUR]

Hello David,

"It seems customer configure the SP as switch to GND , and they wants to detect the VBAT short to SP fault using software , right?"

Yes, that's exactly it. Can I do that? Can you help me? Thanks.

Regards,
ONUR

[diazmarin09]

Hello ONUR,

I am pleased to contact you again. 

Please review the response from our specialist below:

We haven't done this before. Here are my comments: CD1020 uses 4V threshold to detect the OPEN/CLOSE status of the switch. When SP is configured as switch to GND, If the level on SP is >4V, it will be detected as open; and if the level on SP is <4V, it will be detected as closed. So short to  battery fault will be reported as OPEN by software.

I hope this information will be useful for you. 

Regards,

David 

[ONUR]

Hello diazmarin09,

Thank you for sharing the document.I'll look into it.

But what I wanted to ask you;

I configured the sp pin as a short to gnd, there are 6 volts on the pin in float state and the pin status is 0. If I short to GND, it becomes 1. There is no problem here. I want to detect the battery short in the software when I give more than 6 volt. Can I do this? Does IC support it ? Or do you have a msdi that does?

Thank you diazmarin09.

Regards,
ONUR

[diazmarin09]

Hello ONUR,

Please review the response from our specialist below:

If SP pin is configured as switch to battery , yes , customer can apply VBAT to the SP channel, please refer to below plot  .

But if SP is configured as switch to GND, I don’t think the SP pin has the risk to short to VBAT. 

It seems customer configure the SP as switch to GND , and they wants to detect the VBAT short to SP fault using software , right?

CD1020 use 4V threshold to detect the OPEN/CLOSE status of the switch. So if the level on SP is >4V , it will be detected as open; and if the level on SP is <4V , it will be detected as closed.  So short to  battery fault will be reported as OPEN .  Any other questions, please let me know.

I hope this information will be useful for you.

Regards,

David

[ONUR]

Hello diazmarin09,

I didn't see it, can you help me?
Thank you.

Regards,
ONUR

[diazmarin09]

Hello ONUR,

CD1020 is low-cost MC33978 and they are pin-to-pin compatible.

I emailed you the  MC33978 Electrical Over Stress Performance document, and it works for CD1020 and CD1030.

You can refer to it.  Any other questions, please let me know.

Regards,

David 

[ONUR]

I use two state switches. The switch is connected as Float and GND. I want to detect when short to bat in float state, how do I do it ?

[diazmarin09]

Hello ONUR,

I hope all is great with you. Thank you for using the NXP communities.

Please review my last response on the case created. I shared some useful material. 

I hope this information helps.

Regards,

David