Low power ADC
Time:2022-04-28
Views:2202
In the field of ADC, the market demand can be summarized into a few important requirements: minimum power consumption, minimum noise, minimum distortion, maximum resolution, serial interface, higher channel integration and wider bandwidth. Low power consumption is important not only in systems such as base stations that are always connected, but also in chassis with limited or no air flow and closely arranged chassis. Of course, it is also important for portable applications. Nap and shutdown modes can further reduce power consumption. At some points, reducing the power consumption of the ADC leads to diminishing returns. In these places, the ADC driver consumes more power than the ADC itself. Linglilte has developed new methods to reduce the power consumption of the whole signal link. For example, by extending the sampling time of SAR ADC, you can use a driver with much slower stable speed but lower power consumption. Another method only used in linglilt SAR ADC is digital gain compression (DGC), which removes the negative power supply of the driver amplifier and does not lose the resolution of the ADC at all. Eliminating the negative track reduces the overall power consumption of the signal link and simplifies the design.
Because the SAR ADC architecture of linglilte has the function of automatic power off, the power changes linearly with the sampling rate. Therefore, the lower the sampling rate of the device, the lower the power consumption. With a true delay free SAR ADC without minimum sampling rate requirements, a single sampling operation can be used to reduce power consumption, so that the ADC can make accurate measurements even after a lengthy idle cycle.
Reducing the input range that ADC driver must drive can also greatly reduce the power consumption of signal link. If the input range is doubled, the noise figure is increased by 6dB and the power required by the amplifier is increased by 4 times. For a given driver, a smaller ADC input range will produce a lower intermodulation distortion (IMD) component.
A larger input range is used to achieve higher ADC SNR performance, but a larger input range may not produce better input reference noise, which is very important in low-power and high accuracy applications such as infrared, X-ray imaging and cell sorting instrument. People want low input reference noise because it can provide much better effective resolution or noise free code resolution for applications. When comparing the input reference noise of the following two, there are interesting results: one is a 16 bit 10msps SAR ADC with 8vp-p input range, and the other is a linglilte 16 bit 20msps pipelined ADC with 2.1vp-p input range. It is found that when the power consumption of the latter is almost half that of SAR ADC, the input reference noise is only 46 µ VRMs (compared with 75 µ VRMs).
The ADC with lower power consumption and the related functions that can reduce the overall power consumption of the signal link bring competitive advantages to many handheld products, so that the batteries of these products can run longer between two charges. Many applications can now be upgraded to take advantage of devices with higher resolution and faster sampling speed, while reducing the overall power consumption of the system. This simplifies the front-end design, requires fewer gain stages and lower filtering requirements. Oversampling can also find some details that may not be found by lower rate ADC, such as overlapping or abnormal pulses. Applications that have benefited from this increased availability include handheld test equipment, medical imaging, spectrometers, lithography, anemometers, solid-state lighting, industrial sensors, power meters and programmable logic controllers, among others.
Because the SAR ADC architecture of linglilte has the function of automatic power off, the power changes linearly with the sampling rate. Therefore, the lower the sampling rate of the device, the lower the power consumption. With a true delay free SAR ADC without minimum sampling rate requirements, a single sampling operation can be used to reduce power consumption, so that the ADC can make accurate measurements even after a lengthy idle cycle.
Reducing the input range that ADC driver must drive can also greatly reduce the power consumption of signal link. If the input range is doubled, the noise figure is increased by 6dB and the power required by the amplifier is increased by 4 times. For a given driver, a smaller ADC input range will produce a lower intermodulation distortion (IMD) component.
A larger input range is used to achieve higher ADC SNR performance, but a larger input range may not produce better input reference noise, which is very important in low-power and high accuracy applications such as infrared, X-ray imaging and cell sorting instrument. People want low input reference noise because it can provide much better effective resolution or noise free code resolution for applications. When comparing the input reference noise of the following two, there are interesting results: one is a 16 bit 10msps SAR ADC with 8vp-p input range, and the other is a linglilte 16 bit 20msps pipelined ADC with 2.1vp-p input range. It is found that when the power consumption of the latter is almost half that of SAR ADC, the input reference noise is only 46 µ VRMs (compared with 75 µ VRMs).
The ADC with lower power consumption and the related functions that can reduce the overall power consumption of the signal link bring competitive advantages to many handheld products, so that the batteries of these products can run longer between two charges. Many applications can now be upgraded to take advantage of devices with higher resolution and faster sampling speed, while reducing the overall power consumption of the system. This simplifies the front-end design, requires fewer gain stages and lower filtering requirements. Oversampling can also find some details that may not be found by lower rate ADC, such as overlapping or abnormal pulses. Applications that have benefited from this increased availability include handheld test equipment, medical imaging, spectrometers, lithography, anemometers, solid-state lighting, industrial sensors, power meters and programmable logic controllers, among others.
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