Use of Current Sense Resistors for Battery Management in Automotive Applications

Use of Current Sense Resistors for Battery Management in Automotive Applications In automotive applications the requirement of electronic circuits for battery charge monitoring for the detection of the remaining battery level and over current protection has now seen a steep spike in demand with the recent proliferation of Hybrid and Electric vehicles.Typically these low ohm resistors are used in this applications for current sensing by connecting them in series with the load and the potential difference between both terminals is measured by an IC to determine the current flow. In recent years IC performance has improved substantially leading to vastly improved current detection accuracy by being able to measure even tiny potential differences.In order to exploit this feature, it necessitated the use of Ultra Low Ohmic Values which are capable of detecting large current with lower power consumption as compared to the resistive devices being used at present.Recent innovations have shown that Electron Beam Welded metal strip resistors offer Ultra Low Resistance values, enhanced Power Rating upto even 10 watts at negligible thermal dissipation as compared to thick film products .Being committed to being a partner to the automotive industry, HTR has introduced the following series to support the ever rising demand for this application and our IATF 16949:2016 certification reinforces this commitment.

Low Ohmic / Current Sense Resistors for Automotive Applications

Low Ohmic / Current Sense Resistors for Automotive Applications The demand for these types of resistors has increased in the automotive sector with the proliferation of Hybrid and Electric cars and in the sector in general due to the enhanced level of computerization and sophistication of various control systems.To meet this enhanced demand, HTR has introduced a wide variety of Electron Beam welded current sense resistors which have very superior size to power rating ratio , Ultra Low ohmic values which help in reducing circuit power consumption.These resistors are high precision devices featuring low temperature coefficient of resistance (TCR) thus making them very suitable over other devices in harsh temperature environments. The very nature of the physical configuration of these resistors having large copper terminals lend to rugged mounting, superior power to size ratio, both qualities which are considered so desirable in automotive applications. It is note worthy to point out that these Electron Beam shunts are now available from 2 watt rating to 10 watt rating and can dissipate in some cases over 200 amps without significant heating. The HTR series which support this application are in a variety of sizes from 2512 to 5930 and physical configurations to suit most PCB design requirements. A significant proportion of our production is for the automotive industry and our IATF 16949:2016 certification reinforces this.

Comparative Performance between Thick Film and Electron Beam Welded Metal Band Resistor

Comparative Performance between Thick Film and Electron Beam Welded Metal Band Resistor Technologies when used in Automotive Applications. These current sense resistors are predominantly used in automotive application in the DC/DC convertor output block and in battery management. The basic circuitry followed is that these low ohms resistors are connected in series with the load, and the potential difference between both terminals are measured by an IC to determine the quantum of current flow. The performance of IC’s available today has made great strides which enable them to measure current more accurately by being able to read ever diminishing potential differences. The result of this is that by using ultra low resistance values it is possible to detect even large currents in excess 160 AMP, with lower power consumption as compared to devices being used at present. Using the older thick film technology, these low ohms resistors are made by screen printing the resistive element and electrodes on an alumina substrate and generally speaking these thick film resistors which are available today have resistance range in tens of milliohms. The electron beam welded metal band resistors have a very rugged construction where the different resistance alloys selected are welded to the copper electrodes. The very nature of the construction of these resistors contributes to excellent heat dissipation as compared to the thick film variety. Using this technique it is possible to made devices with resistance range of several milliohms which mean a much lower resistance value as compared to thick film devices and with the characteristic of superior heat dissipation as compared to the thick film devices, hence lending itself to providing a smaller & more reliable device. Hence, the metal strip resistors offer higher power and very precise temperature co-efficient of resistance as compared to thick film devices. Further since these electron Beam welded metal band resistors can be made having resistance value much lower than thick film devices, they have the added advantage over thick film devices by being able to exploit the property of the latest IC’s which can now measure even the smaller potential differences. At HTR, being an IATF 16949:2016 company, we are committed to offering our automotive customers the full range of resistive devices using the latest electron beam technology to contribute to the quest of enhanced detection accuracy, reduction in the size of the devices and in conserving power consumption.