介紹

　　壓力，負(fù)載，溫度，加速度傳感器許多其他物理量往往采取的形式惠斯登電橋。這些傳感器可以是非常線性的隨著時間和溫度的穩(wěn)定。然而，最如果你不彎曲它們，自然界中的事物是線性的多。在一個負(fù)載細(xì)胞的情況下，虎克定律，材料中的應(yīng)變與所施加的應(yīng)力成正比—只要壓力沒有接近材料的屈服點(diǎn)（“不歸點(diǎn)”的材料永久變形的）。其后果是負(fù)載基于電阻應(yīng)變計的電池將有一個非常小電輸出往往只有幾毫伏。在盡管如此，儀器有100000個分辨率更多的可能。本申請說明高分辨率測量的一些新方法成為可能的線性技術(shù)的家庭20 -和24位Δ∑模數(shù)轉(zhuǎn)換器。

　　通常在實(shí)施20或24位的最大障礙電橋測量電路正在超越常規(guī)信號調(diào)理電路所需的12 -16位ADC。只需在電路中替換24位ADC專為12位ADC不保證一個4096倍分辨率增加。雖然性能可以提高，24位ADC可能只是揭示了局限性的模擬前端，并充分受益的24位ADC將無法實(shí)現(xiàn)。

　　In a typical 12-bit measurement system， the signal conditioning amplifier requires a very high gain in order to make use of the full ADC input range. A sensor with a 10mV fullscale output requires a gain of 500 to use the full input range of a typical 5V input ADC. A filter may be required to reduce noise at the expense of settling time. Additional difficulties arise when dealing with the large common mode voltage typical of a bridge sensor. Most instrumentation amplifiers have a large discrepancy between the typical CMRR and guaranteed minimum， which may require an additional trim.

　　Linear Technology’s differential input delta sigma ADCs address these concerns and make it possible to extract maximum resolution from a variety of bridge measurement devices. The outstanding resolution of these ADCs eliminates the need for amplification in many applications. Even in extreme cases where amplification is required， high resolution ADCs such as the LTC? 2440 allow very modest amplifier gains. A fully differential amplifier topology eliminates the differential-to-single-ended stage of a typical 3-amplifier instrumentation amplifier along with the CMRR limitations of this stage.