Current Sensors and Monitors
Silicon Labs' isolated AC, high-side DC current sensors and Isolated AC mains monitors provide current sensing solutions for a wide range of power applications. The Si85xx/Si890x family is ideal for a broad range of applications including ac-dc switching power supplies, isolated dc-dc supplies, UPS systems, motor control and electronic lighting ballasts.
The Si8920 is an isolated analog amplifier for current measurement. The differential, low voltage input connects directly to a current shunt resistor. Low signal delay across the isolation barrier insures that control loops can react quickly; important for stability and efficiency. Excellent offset and gain drift, linearity, and noise specifications ensure that accuracy is maintained in all operating environments. The device uses Silicon Labs’ proven isolation technology which supports up to 5 kV withstand and 1200 V working voltage.
The Si850x/1x devices are uni-directional isolated high frequency ac current sensors available in 10 and 20 A versions. The current sensors provide a large output signal level of 2.0 V and operate over a bandwidth of 50 kHz to 1 MHz. These products offer size and performance advantages over current transformers, Hall effect devices, DCR circuits and other approaches. The Si850x/1x isolators are extremely low loss, adding less than 1.3 mΩ of series resistance and less than 2 nH of series inductance in the sensing path at 25 ºC. Current-sensing terminals are isolated from the other package pins to a maximum voltage of 1 KVDC.
The Si8540 is a uni-directional, high-side current sense amplifier designed for use in applications that require current monitoring and control. This cost-effective high-side current sense amplifier operates with common mode voltages to 36 V (max). It operates over a frequency range of DC-20 KHz and can be configured to measure full-scale currents from 100 mA to 10 A.
The Si890x series of isolated monitoring ADCs are useful as linear signal galvanic isolators, level shifters, and/or ground loop eliminators in many applications including power-delivery systems and solar inverters. These devices integrate a 10-bit SAR ADC subsystem, supervisory state machine and isolated UART (Si8900), I2C/SMbus port (Si8901), or SPI Port (Si8902) in a single package.