# ZXCT1009 as a current monitor

I am currently using ZXCT1009 high side monitor for monitoring the current consumption on a bus line for an embedded system we are developing. I am currently using tek scope with Labview for automation purpose. Works good at our lab.

Now I am thinking of implementing this ZXCT1009 in the embedded design itself and somehow sensing the voltage across the output resistor.

ZXCT1009 data sheet -http://www.diodes.com/datasheets/ZXCT1009.pdf

I am not sure how to move forward along the lines of using ZXCT1009 as a battery current monitor.

## 1 Answer

The datasheet itself provides the schematic for implementing the ZXCT1009 as a current monitor:

• Select Rsense such that the expected maximum possible current generates just under 1.1 Volts across Rsense (Rsense = 1.1 / Imax) - going by the limits in the first graph on Page 3, not by the 2.5 Volt specified in the table on Page 2.
• Select a suitable value of Rout, to give a Vout range suitable to one of the available ADC channels of the microcontroller, for a full-scale Iout of around 10 mA (Rout = 5 / 0.01 assuming a full-scale of 5 Volts)

As the current flowing through Rsense changes, so will Vout. Read this into the ADC, process as required.

• Wow, that's rough... you have to tolerate a 1.1V drop before your load comes into play... I guess "Load" could be a regulator or step-up converter and you'd increase V_in accordingly to use this part. Jan 28 '13 at 16:55