BQ40Z50-R2： About delay time of OCD, OCC, etc.

user5768972

Part Number: BQ40Z50-R2
Other Parts Discussed in Thread: BQ40Z50

There is an application that uses bq40Z50.

When I contacted TI about the delay time of OCC and OCD about the application, "The delay time of the actual operation is the delay time set in the gauge IC + 1 to 2 seconds.
The reason is that OCD and OCC sample the current four times (at intervals of 250 msec) and calculate the average value. Therefore, sampling time + calculation time is required. Was said.

1. 1. Is this true?
Why is there a large range of 1 to 2 seconds?
I don't think the sampling time and calculation time will fluctuate so much.

2. 2. Is the delay time measurement done by counting the clock?
Do you have this much time fluctuation range because you are using a CR timer?

over 5 years ago

0 Kang Kang over 5 years ago

TI__Mastermind 24870 points

Hello User,

1. No, these are HW protections, there should be no delay.

2. The HW protections are triggered off of some HW timing. Please check your test setup and make sure you are measuring the thresholds accurately to determine timing.

0 user5768972 over 5 years ago in reply to Kang Kang

Intellectual 450 points

I hear that AOLD is HW protection, but OCD and OCC are SW protection.
Does it mean that there is no delay other than the delay time set in SW?

Is the set Delay time measured by the clock count?

0 Kang Kang over 5 years ago in reply to user5768972

TI__Mastermind 24870 points

Hello User,

For FW protection, 1 or 2 seconds of delay is normal.

The delay time is measured when the gauge runs the protection checks. It is not directly based on clock cycle, but when the gauge runs the protection check code. It is run periodically. That is all the detail we can share on the forums.

0 user5768972 over 5 years ago in reply to Kang Kang

Intellectual 450 points

The set delay + 1 to 2 sec is normal.
-The reason is the current sampling time + the timing when the gauge executes the protection check code.
・ It will always be +1 to 2 seconds for the set delay time.
・ You can't explain any more in the forum
Is this OK?

0 Kang Kang over 5 years ago in reply to user5768972

TI__Mastermind 24870 points

Hello User,

My only other suggestion would be to test this on an EVM. Make sure you are measuring when you expect the protection to trip with a current probe and look at the actual delay.

However, FW based protections will have delays since we filter the voltage and current values.

0 user5768972 over 5 years ago in reply to Kang Kang

Intellectual 450 points

I am asking this question because the measured value is delayed with respect to the set value.
In addition, the customer is asking "Why is there a delay of +1 to 2 seconds in the set value?"

I will write the question again.
The set delay + 1 to 2 sec is normal.
-The reason is the current sampling time + the timing when the gauge executes the protection check code.
・ It will always be +1 to 2 seconds for the set delay time.
・ You can't explain any more in the forum
Is this OK?

0 Kang Kang over 5 years ago in reply to user5768972

TI__Mastermind 24870 points

Hello User,

That delay is unavoidable. Our gauge reads AFE values at certain intervals, based on timing, there will be delay. Should be around 1 second.

0 user5768972 over 5 years ago in reply to Kang Kang

Intellectual 450 points

I understand your answer.
Thank you for your kind explanation.

Best regards

Power management

Power management forum

BQ40Z50-R2： About delay time of OCD, OCC, etc.