WCS current sensor Application note To precisely measure the current by using WCS series products is easy and straight forward. First connect the conductor in series with the current path you plan to measure (or pass conductor through the conductcor hole) and apply 5V between Vdd and Gnd (Fig. above). Then you already finish the hardware settlement of WCS series current sensor. Over current detection: The above circuit can detect current and protect your system from over current or short circuit. 育陞半導體股份有限公司 Copyright© DC Current measurement: 1. Zero current: measure the output’s voltage V0G when no current pass through. 2. Calibration: Pass an already known current (for example: 10A) through the current sensor and measure the output voltage V10A. The sensitivity of this current sensor is Sensitivity = (V10A-V0G)/10A unit: V/A 3. Start Measurement: you can measure any current by the following equation. Current = (Vout-V0G)/Sensitivity (A) AC Average Current measurement: 1. Zero current: measure the output’s voltage V0G when no current through. 2. Software Solution: 2.1 Pass an already known AC current (for example: 10A) through the current sensor 2.2 Connect sensor’s output signal Vout10A directly into analog input of micro-controller 2.3 Write a program to calculate the area of several TT periods of AC signal, the higher sampling rate per TT period the more precision you get. 2.4 Divide “Area/TT” and get the average value of Vout10A Vout10A average = Average(Σ|Vout-V0G|) 2.5 Calibrate the Sensitivity of current sensor by Sensitivity = Vout10A average /10 unit: V/A 2.6 Start Meaurement: Use the same program to measure any current by equation Current = Vout/sensitivity (A) 育陞半導體股份有限公司 Copyright© 育陞半導體股份有限公司 Copyright© 3. Hareware Solution: 3.1 Pass an already known AC current (for example: 10A) through the current sensor 3.2 Connect sensor’s output signal Vout10A into AC amplifier circuit listed below to remove DC part V0G and amplify it, Amplify Gain =R2/R1 3.3 Procure the average value of Vout10A and calculate sensitivity Sensitivity = Vout10A/10 unit: V/A 3.4 Start Meaurement: measure any current by the following equation Current = Vout/sensitivity (A) 育陞半導體股份有限公司 Copyright©