大电流传感器

功能方塊圖:

特性曲線圖表: WCS1800

WCS27XX/1X00 使用說明

使用WCS27XX/1X00 系列產品去量測電流是非常簡單也很直接, 它不需外加任何元器件就可以直接運作, 首先將WCS27XX 以＂串聯＂方式將內部電流導體連接欲量測的電流路徑(或 將電線穿過WCS1X00中間的導體孔)並供給電壓5V 伏於 Vdd 與 Gnd 腳位之間(如上圖). 恭喜! 您已經完成了所有的硬體電路連接了.

過電流偵測:

上面應用電路可以偵測電流,進而保護珍貴的機器設備免於 過載或短路 所造成的損毀

直流量測:

1.零電流: 紀錄零電流通過時的輸出電壓 V0G (約

2.5V).

2.校正: 將一已知的直流電流(例如: 10 安培) 通過電流感測元件並記錄此時

的輸出電壓V10A. 如此即可精準算出目前使用的電流感測元件的靈敏度 靈敏度 = (V10A-V0G)/10 單位: V/A

3.開始量測電流: 藉由下列方程式得知目前通過的電流大小

電流 = (Vout-V0G)/靈敏度 (A)

交流量測(平均值):

交流電量測比直流電量測較為複雜一些, 但基本原理是一樣的

1.零電流: 紀錄零電流通過時的輸出電壓 V0G (約

2.5V).

2.軟體程式解決方案:

2.1將一已知交流電流(例如: 10 安培)流經電流感測元件

2.2直接將輸出信號Vout10A接入微處理器(micro-controller)類比輸入端

2.3 寫一程式來計算數個交流信號周期TT的積分面積.取樣次數越多越精準

2.4 將 “面積/TT＂ 即可求的此交流信號Vout10A的 平均值

Vout10A average=Average(Σ|Vout-V0G|) :取平均值

2.5 校正正確的靈敏度

靈敏度= Vout10A average /10 單位: V/A

2.6開始量測電流: 藉2.3同樣程式並由下列方程式可得知目前通過的電流大小 電流 = Vout/靈敏度 (A)

3.硬體方式解決方案:

3.1將一已知交流電流(例如: 10 安培)流經電流感測元件

3.2 將感測元計的輸出信號Vout10A接入下列AC 放大電路, 進行去DC位準

V0G 並放大, 放大倍數 =R2/R1

3.3取得Vout10A 的 平均值, 並計算靈敏度

靈敏度= Vout10A/10 單位: V/A

3.4開始量測電流: 藉由下列方程式得知目前通過的電流大小

電流 = Vout/靈敏度 (A)

Application 1. The ACS758 outputs an analog signal, V OUT , that varies linearly with the uni- or bi-directional AC or DC primary sampled current, I P , within the range specified. C F is for optimal noise management, with values that depend on the application.

ACS758xCB

Description

The Allegro ® ACS758 family of current sensor ICs provides economical and precise solutions for A C or DC current sensing. Typical applications include motor control, load detection and management, power supply and DC-to-DC converter control, inverter control, and overcurrent fault detection.

The device consists of a precision, low-offset linear Hall circuit with a copper conduction path located near the die. Applied current flowing through this copper conduction path generates a magnetic field which the Hall IC converts into a proportional voltage. Device accuracy is optimized through the close proximity of the magnetic signal to the Hall transducer. A precise, proportional output voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy at the factory.

High level immunity to current conductor dV/dt and stray electric fields, offered by Allegro proprietary integrated shield technology, guarantees low output voltage ripple and low offset drift in high-side, high voltage applications.

The output of the device has a positive slope (>V CC / 2) when an increasing current flows through the primary copper conduction path (from terminal 4 to terminal 5), which is the path used for current sampling. The internal resistance of this conductive path is 100 μΩ typical, providing low power loss.

The thickness of the copper conductor allows survival of the device at high overcurrent conditions. The terminals of the

ACS758-DS, Rev. 3

Thermally Enhanced, Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 100 μΩ Current Conductor

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Typical Application

Features and Benefits

▪ Industry-leading noise performance through proprietary amplifier and filter design techniques

▪ Integrated shield greatly reduces capacitive coupling from current conductor to die due to high dV/dt signals, and prevents offset drift in high-side, high voltage applications ▪ Total output error improvement through gain and offset trim over temperature

▪ Small package size, with easy mounting capability ▪ Monolithic Hall IC for high reliability

▪ Ultra-low power loss: 100 μΩ internal conductor resistance ▪ Galvanic isolation allows use in economical, high-side current sensing in high voltage systems ▪ 3.0 to 5.5 V , single supply operation

PSS Leadform PFF Leadform

Package: 5-pin package

Additional leadforms available for qualifying volumes

TÜV America

Certificate Number:U8V 09 05 54214 021