ON Semiconductor - Current mirror with switch controller and SENSEFET Power MOSFETs

System level power management solution supports integrated, low power current monitoring for portable computers and networking equipment

Exact control and matching of the SENSEFET’s SENSE output with the KELVIN voltage leads by the CAT2300 ensures accurate current monitoring over the SENSEFET’s entire operating range.

The CAT2300 offers a single chip alternative to a discrete circuit approach and is able to provide sensorless precision current measurement of 0.9 volt (V) to 5 V power supply rails. The new device performs current mirroring to 70 milliamperes (mA) – which equates to 25 amperes (A) of measured current - and integrates logic level ON /OFF control of the power MOSFET and its own circuitry, reducing power consumption to virtually zero. A soft-start function is also included. Current consumption is less than one microampere (µA) in shutdown mode supporting long life in battery powered applications. Housed in a space saving, low profile 2 mm x 3 mm TDFN-8 package, the CAT2300 is suitable for use over the full -40 ºC to +85 ºC operating temperature range.

The NTMFS4833NS and NTMFS4854NS are 30 V, N-Channel SENSEFET MOSFETs that provide lossless current sensing with improved accuracy. They also combine low on-resistance, low capacitance, and low gate charge to minimize conduction, driver, and switching losses. The NTMFS4833NS and NTMFS4854NS are rated at 26 A and 24 A respectively.

“Replacing multiple component discrete solutions with integrated devices can bring benefits such as PCB real estate savings, lower power consumption and enhanced reliability,” said Paul Leonard, vice president of Power MOSFETs at ON Semiconductor. “The CAT2300, which has been optimized for use with our SENSEFET devices, supports a simple, compact, and highly efficient solution for accurate current monitoring in a wide range of fixed and portable equipment applications.”