# AFE(MC33772) Coulombmeter use problem

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## AFE(MC33772) Coulombmeter use problem

155 Views
Contributor II

MC33772B coulombmeter and overcurrent detection have some questions to ask:

1. How to set or distinguish the positive and negative current overcurrent thresholds in sleep mode?

2. How does TH_COULOMB_CNT reflect positive and negative values of coulommeter?

3.TH_COULOMB_CNT What value indicates 1 coulomb?

4. What is the conversion relationship between COULOMB_CNT and TH_COULOMB_CNT?

5. If COULOMB_CNT is enabled, how can Coulomb_CNt be converted into coulomb_CNt after waking up?

2 Replies
71 Views
NXP TechSupport

Hello,

Sorry for the delay in replying.

1. It can't be distinguished. In sleep mode the over-current is related to the self-consumption of the IC, not to the strong current drawn from or injected by the power inverter module. In sleep mode the current is always positive and weak. If the IC consumption gets anomalous for any reason, then the IC can wake up the MCU.
2. I guess you refer to the CC in sleep mode, as in point #1. If so, the answer is exactly the same. The CC threshold is meant positive: as the self-consumption current is positive, the accumulated value has same sign.
3. your question is unclear to me. Please, rephrase it.
4. COULOMB_CNT and TH_COULOMB_CNT use same resolution. It is written in datasheet:
"Resolution is V2RES". Of course, the register data is an integer, but this represents a physical value (the shunt voltage) that you can get multiplying the integer by V2RES.
5. Cryptic question. what do you mean?
137 Views
Contributor II

1. How does the TH_ISENSE_OC overcurrent threshold reflect the incoming or outgoing current in sleep mode? The purpose is to measure the amount of electricity flowing through. This electricity has an inflow and outflow, can it be understood that there are positive and negative points, how to distinguish between positive and negative values when setting this threshold? (It is currently possible to set the threshold of overcurrent, but it is not certain whether the threshold set belongs to the detection of outgoing or incoming current)

2. The overflow threshold can be set before the coulomb is hibernated. Let the coulomb meter in the AFE in the sleep cycle detection mode to detect the flowing power, the customer feedback this power has inflow, outflow, should be positive and negative points, the customer wants to ask is how to distinguish the positive and negative values when setting this threshold; The purpose is to read the static current data after MCU restart;

3.  If MC33772B enables COULOMB counting to wake up over the threshold, how to convert the COULOMB CNT meter value into the corresponding power after waking up? How to achieve the specific operation method?

With COULOMB counting enabled in the MC33772B data book, what is the conversion relationship between COULOMB CNT and TH COULOMB CNT?

4. If the Coulomb count function is enabled in MC33772B, what is the value of 1 Coulomb when TH_COULOMB_CNT is accumulated? TH COULOMB CNT At this time, how does the value reflect the incoming current or the outgoing current, that is, how to determine the current direction?