All sensing and control applications use shunt-based current sensing which is prone to resistive loss, amplification noise, and high-side, low-side polarity limitations. Why can't we just use Hall-effect ICs which seem easier to use?
I haven't looked lately but for all of my career the answer to that was:
- not good at low currents
- susceptible to external magnetic interference
The one good use for those is in the feedback type of current sensors such as made by LEM, but those are very expensive.
Two major advantages of a series resistor over a Hall-Effect IC are simplicity and reliability.
Simplicity. The resistor is a very common part, readily available from a large number of suppliers at much lower cost.
Reliability. The resistor is very simple and thus a very reliable component. When it fails, the resistor will almost certainly go open circuit and disconnect the load. The HE IC will not.
All sensing na udhibiti maombi kutumia shunt-msingi sasa sensing ambayo ni prone kwa hasara resistive, amplification kelele, na juu-upande, chini-upande polarity mapungufu. Kwa nini hatuwezi tu kutumia Hall-athari ICs ambayo kuonekana rahisi kutumia? "Hata hivyo, kwa sababu ya hali ya hewa, kwa sasa, hakuna uwezekano wa kuathiri athari za umeme wa nje, kwa hivyo, ""mfano wa LEM"" ni muhimu kwa ajili ya matumizi ya vifaa vya umeme." Faida mbili kuu za mfululizo resistor juu ya Hall-Effect IC ni unyenyekevu na kuegemea. Uwezo wa kufanya mambo kwa urahisi. Resistor ni sehemu ya kawaida sana, inapatikana kwa urahisi kutoka kwa idadi kubwa ya wauzaji kwa gharama ya chini sana. Kuaminika. The resistor ni rahisi sana na hivyo sehemu ya kuaminika sana. Wakati inashindwa, upinzani itakuwa karibu hakika kwenda mzunguko wa wazi na kuondoa mzigo. Hili ni jambo ambalo ICL haitafanya.