My questions relate to the current-sensing aspect of your Profets, in particular the TO-252-5 form factors (BTS6133, BTS5014 etc).
We've been testing with several BTS6133s and have found that the current sense is fairly innacurate at low currents - this device a nominal load of 10A, I'm talking about currents under around 500mA.
Figure 6b in the datasheet shows the Current Sense Ratio (KILIS)as nominally 10,000 but with larger errors at the lower end, and no values at all on that graph under about 750mA. The datasheet also says "Approximate solution for worst case minimum detectable load current is IIS(LH) * KILIS - for this device IIS(LH) ranges from 1uA to 60uA, so worse case is 600mA.
My questions are:
1. Are there other devices in the same range and form factor that give higher accuracy at the lower end? For example, the BTS5014 - this has a nominal load of 6A, the range of IIS(LH) is 0.1uA to 1uA, and there's no mention of the "worse case minimum detectable load current". Also, the graphs showing KILIS extend closer towards zero:
Is the BTS5014 part really more accurate at lower currents than the BTS6133, or am I misreading the datasheets?
2. The Application Note "Advanced Sense Calibration", does this apply to these devices? It refers to Profets with "ADVANCED SENSE" but I can't find this exact phrase in the datasheets, so I'm not sure if this applies to any Profet with a Sense (Is) pin, or just some subset.
3. While prototyping we've stressed these devices a bit, mainly thermally by reworking etc. At least one will now switch on and conduct current, but report nothing on the sense pin. This isn't a good failure mode for us as we're using these as soft fuses on a vehicle - no current sense means we can't blow the fuse if there's a short, and bad things could happen as a result. I can't find any reference of this sort of failure mode in your literature, is this something we should expect during normal use of the device (say after N hours, or after a period of high current exposure), or is it the sort of thing that only happens when a device is thermally stressed beyond it's design?
Thanks in advance.
Cheers... Mike
We've been testing with several BTS6133s and have found that the current sense is fairly innacurate at low currents - this device a nominal load of 10A, I'm talking about currents under around 500mA.
Figure 6b in the datasheet shows the Current Sense Ratio (KILIS)as nominally 10,000 but with larger errors at the lower end, and no values at all on that graph under about 750mA. The datasheet also says "Approximate solution for worst case minimum detectable load current is IIS(LH) * KILIS - for this device IIS(LH) ranges from 1uA to 60uA, so worse case is 600mA.
My questions are:
1. Are there other devices in the same range and form factor that give higher accuracy at the lower end? For example, the BTS5014 - this has a nominal load of 6A, the range of IIS(LH) is 0.1uA to 1uA, and there's no mention of the "worse case minimum detectable load current". Also, the graphs showing KILIS extend closer towards zero:
Is the BTS5014 part really more accurate at lower currents than the BTS6133, or am I misreading the datasheets?
2. The Application Note "Advanced Sense Calibration", does this apply to these devices? It refers to Profets with "ADVANCED SENSE" but I can't find this exact phrase in the datasheets, so I'm not sure if this applies to any Profet with a Sense (Is) pin, or just some subset.
3. While prototyping we've stressed these devices a bit, mainly thermally by reworking etc. At least one will now switch on and conduct current, but report nothing on the sense pin. This isn't a good failure mode for us as we're using these as soft fuses on a vehicle - no current sense means we can't blow the fuse if there's a short, and bad things could happen as a result. I can't find any reference of this sort of failure mode in your literature, is this something we should expect during normal use of the device (say after N hours, or after a period of high current exposure), or is it the sort of thing that only happens when a device is thermally stressed beyond it's design?
Thanks in advance.
Cheers... Mike
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