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Tonny
Level 3
Level 3
First solution authored 25 sign-ins 10 replies posted

Hi Infineon Expert:

We have use TC387 EVADC module for phase current sampling on FOC motor ECU. The ADC converter started by trigger signal from TOM module. The function of AD converter trigged by TOM channel worked correct. But the time gap from the trigger point to AD converter result interrupt nearly 4us. When we add one convert channel the time gap will increase nearly 3.5us, and the test result as shown below. We have two questions about the conversion.

1: How to reduce the time consumption about 4us for one channel convert. This is very important for FOC system.

2: In TC3xx user manual had describe the convert speed is 2.6M/S, but We had test when add one channel conversion, the consumption time will increase 3.5us. Why the conversion is so slowly and where did the time spend. 

look for your reply!

Best wishes! 

 

Add Convert channel from one to eightAdd Convert channel from one to eight

 

 

Trig and converter interrupt figureTrig and converter interrupt figure

 

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dw
Moderator
Moderator
Moderator
100 likes received 750 replies posted 10 likes given

dw_0-1671076527742.png

Hi Tonny, as above table showed, 375ns(0.375us) is calculated which is equal near 2.6MS/s

You said there is 4us between trigger ADC and the result conversion is done, it looks incorrect.

So after the result conversion is done, the trigger is started immediately, right?

 

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Tonny
Level 3
Level 3
First solution authored 25 sign-ins 10 replies posted

Hi dw, the trigger signal is a rising edge which from TOM, the time gap of the rising edge is 100us, that is mean that ad sampling is started every 100us begging. 

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dw
Moderator
Moderator
Moderator
100 likes received 750 replies posted 10 likes given

Hi Tonny, from your trigger point to ADC conversion done, there is 4us right? It should be 0.4us. Could you check below image?

dw_0-1671080604177.png

 

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Tonny
Level 3
Level 3
First solution authored 25 sign-ins 10 replies posted

yes, as your labeled, the gap is 4us, not 0.4us.

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Tonny
Level 3
Level 3
First solution authored 25 sign-ins 10 replies posted

Hi dw, the calculate formula you showed, 112.5+243.5+18.75=375ns, excluding [NRS × tNR] + [tPC]. How can this two consumption parts disabled by code. 

 In user manual calculate formula is :

tC12 = [(2 + STC) × tADCI] + [13 × tADCI] + [NRS × tNR] + [tPC] + [3 × tADC].
 

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