Therefore, it becomes mandatory to measure and monitor the current flow in order to reduce losses and improve overall efficiency. And, the most cost-effective solution of current monitoring can be achieved with the help of current Sense Resistors, also known as Shunt resistors.
Usually, a current sensing resistor will be placed in series with the electrical load whereby all the current to be measured will flow through it.
Then, by measuring the voltage drop across the resistor, accurate measurements of current are calculated by applying Ohm’s law. Since these resistors will have very low values, they will cause only an insignificant voltage drop of 10 to 130 mV in the application.
Stackpole Electronics Inc, a leading global manufacturer of resisting components has specifically designed CSS/CSSH Series Resistors for high current, high power, high temperature, and high precision current sensing requirements.
A CSS/CSSH Series Resistor. Image courtesy Stackpole
The CSS/CSSH series is specifically designed as an all-metal component to eliminate problems with part or solder-joint cracking, issues that are a major concern for larger chip sizes. These current sense resistors are available in chip sizes from 1206 to 4527 and power ratings from 0.5 W to 5 W. These current sensing resistors are available in resistance values down to 0.25 mΩ.
Since the metal plate element and unique trimming process yields a highly stable device at high currents, these resistors are capable of operation at full rated power up to +100°C.
High Power Sensing
Stackpole’s CSS/CSSH series resistors have very high power ratings when compared to a standard resistor. For example, CSS4527 is a 5-watt surface-mount current sense resistor capable of handling up to 100 amps of continuous current whereas CSS2725 has a maximum power rating of 4-watt that can withstand a high current of up to 126 amps. Since these resistors offer tolerance of 0.5% to 1%, they are ideal for a wide variety of applications that require high power monitoring and control.
CSS/CSSH series resistors have low TCR (Temperature Coefficient of Resistance), which means the resistance hardly changes at all with any variation in temperature. Therefore, these resistors can withstand a high temperature of up to +225°C (normal) and up to +275°C (with proper precautions). For instance, the TCR of CSSH2728, CSS2728 are ±15 ppm/ºC and ±15 ppm/ºC respectively. In order to achieve a very low TCR, these CSS/CSSH resistors are designed using a specially formulated resistive alloy.
Stackpole's CSS / CSSH Series is Ideal for many types of motor controls and industrial power supplies that have harsh environmental conditions such as high temperatures. They can be also used in other types of residential, medical, and automotive applications including:
Power supplies and regulators
Smart electricity meters
Battery management systems
Gasoline or diesel engine controllers
A High-Efficiency Current Sensor
Whether it is used in a handheld portable device such as a smartphone or a sophisticated piece of medical equipment in a hospital, there is always a need to achieve maximum efficiency.
Since Stackpole’s CSS/CSSH Series can provide high measurement accuracy with low resistance values, it is ideal for measuring the current in various applications, varying from a simple phone battery to a complex electrical circuit, to reduce losses and improve the overall efficiency of the system.