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I'm experimenting with the BTS50010-1TAD high side smart switch. However I'm experiencing very scattered values on the current feedback pin. I have connectedb the BTS to a ESP32 MCU.
I also don't understand how the dkILIS vs Rsense is calculated, because the values that is being read is not what I expected. With a 10K Rsense I was expecting 18500 µV per Amp = 18,5 mV per Amp = 0,05 Amp per mV. But what I get is notthis, and with a very inconsistent ratio between Vsense and the actual current measured thru the MOSFET.
Also the Vsense value can easily rise above any commonly available ADC Vmax value, usually 3V3 or 5V. But there is no zener or any other protection circuit recommended in the datasheet for the BTS50010-1TAD. What is the idea here?
This is my circuit:
Results from Vsense measured at IS versus actual mA flowing:
µV | mA | Ratio |
2851941 | 13700 | 208.17 |
1883296 | 11400 | 165.20 |
1755164 | 10700 | 164.03 |
1802710 | 11000 | 163.88 |
1766447 | 10800 | 163.56 |
1774505 | 10900 | 162.80 |
1704395 | 10700 | 159.29 |
1693113 | 10750 | 157.50 |
1220073 | 8000 | 152.51 |
1061318 | 7000 | 151.62 |
1095970 | 7500 | 146.13 |
917875 | 6300 | 145.69 |
986373 | 6800 | 145.05 |
826813 | 5800 | 142.55 |
948498 | 6700 | 141.57 |
875970 | 6200 | 141.29 |
904175 | 6500 | 139.10 |
828425 | 6000 | 138.07 |
832454 | 6100 | 136.47 |
747838 | 5500 | 135.97 |
730915 | 5400 | 135.35 |
697069 | 5200 | 134.05 |
743809 | 5600 | 132.82 |
647912 | 4900 | 132.23 |
617289 | 4700 | 131.34 |
641465 | 5000 | 128.29 |
567326 | 4500 | 126.07 |
535091 | 4300 | 124.44 |
564908 | 4600 | 122.81 |
531062 | 4400 | 120.70 |
461758 | 4000 | 115.44 |
383589 | 3500 | 109.60 |
413406 | 3800 | 108.79 |
277216 | 3000 | 92.41 |
251428 | 2800 | 89.80 |
218388 | 2700 | 80.88 |
199047 | 2500 | 79.62 |
173260 | 2350 | 73.73 |
137802 | 2150 | 64.09 |
112820 | 2000 | 56.41 |
88644 | 1900 | 46.65 |
75750 | 1800 | 42.08 |
68498 | 1700 | 40.29 |
59633 | 1600 | 37.27 |
52380 | 1500 | 34.92 |
41904 | 1400 | 29.93 |
30622 | 1300 | 23.56 |
16923 | 1000 | 16.92 |
15311 | 1150 | 13.31 |
12087 | 1100 | 10.99 |
5641 | 1000 | 5.64 |
4029 | 1000 | 4.03 |
800 | 900 | 0.89 |
0 | 800 | 0.00 |
0 | 700 | 0.00 |
0 | 600 | 0.00 |
Thank you in advance.
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Hello Tobbera,
Thank you for posting on Infineon Community.
dkILIS is not exactly a function of Rsense. It mainly depends on Vs, difference between Vs & Vis, and Tj. A typical value of 1kohm is recommended for Rsense value in the datasheet. With this the measured Vsense can be kept below the uC measurement range.
The current through Is pin is given by below formula:
IIS =IL/dkILIS+ IIS0
The wide variation in the ratio is contributed by the tolerance of both dkILIS & IIS0. IISO values at different Tj is given in "Table 6 Electrical Characteristics: BTS50010-1TAD" and dkILIS vs Tj is provided in the section 6.2.
Kindly consider all these tolerance while analyzing the accuracy of Sense.
Request you to repeat your experiment with Rsense of 1kohm and let us know your observation. Also please share the specifications of input and output voltage to analyze the behavior further.
Thanks,
Meghana R
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Hello Tobbera,
Thank you for posting on Infineon Community.
dkILIS is not exactly a function of Rsense. It mainly depends on Vs, difference between Vs & Vis, and Tj. A typical value of 1kohm is recommended for Rsense value in the datasheet. With this the measured Vsense can be kept below the uC measurement range.
The current through Is pin is given by below formula:
IIS =IL/dkILIS+ IIS0
The wide variation in the ratio is contributed by the tolerance of both dkILIS & IIS0. IISO values at different Tj is given in "Table 6 Electrical Characteristics: BTS50010-1TAD" and dkILIS vs Tj is provided in the section 6.2.
Kindly consider all these tolerance while analyzing the accuracy of Sense.
Request you to repeat your experiment with Rsense of 1kohm and let us know your observation. Also please share the specifications of input and output voltage to analyze the behavior further.
Thanks,
Meghana R
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Hello Tobbera,
Do you have any further query regarding this topic? If there are no questions, can we close this thread?
Regards
Meghana