| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 102 === One of the key techniques of electric vehicles (EVs) is battery management systems,
which demand the development of battery modules, the measurement circuits of batteries,
and so on. This thesis investigates a high-voltage operational amplifier with rail-to-rail
input and output ranges, and an 8:1 analog high-voltage multiplexer for the battery voltage
measurement.
This thesis proposes a high-voltage operational amplifier with rail-to-rail input and
output ranges to meet the required amplifier for the aforementioned technology. It also
carries out the signal transfer circuit design for battery management systems, such as subtractor,
analog to digital converter. Since the input range of the design could be up to 30
V, and the output range is 0 ∼ 29.57 V, ADC with a high input range is no longer needed
hereby. Although the dc gain is 41 dB, the gain error can be corrected by using low-bit
ADCs. Finally, this design is expected for battery management systems to attain accurate
SOC estimation .
Another key circuit is the high-voltage multiplexer. This thesis proposes a 8:1 highvoltage
analog multiplexer which can be used to measure the voltage of a single cell in
a battery string. If the battery modules consists of eight batteries connected in series and
the voltage of a battery cell is 2.5 V to 4.5 V, the input voltage range is 0 ∼ 36 V. To
resolve the high input voltage problem, this thesis demonstrates a 8:1 high-voltage analog
multiplexer, where the output voltage range is in line with SAR ADC input voltage range
of 1.5 ∼ 3.5 V.
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