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.
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
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
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
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
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
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
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
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