Single analog-to-digital converter and digital to analog converter are widely used in control system, but the split configuration can not solve the shortcomings of controller design under the trend of integration. After years of development, the traditional split configuration has actually been called excellent and efficient. However, there are too many variations of control products, and the split configuration is far from being “agile”.
Integration is still the most critical concept. Through integration, the channel design of control system is simplified, the size is reduced and the performance is improved. For example, there are many integrated applications of adc/dac on the fixture at the end of industrial robot. This integrated a / D and D / a converter is often combined with other technologies to provide a comprehensive set of functions. Whether in terms of configurability, reliability or detectability, it is often better than the vertical configuration.
Adc/dac high density integration
The system with highly integrated devices, regardless of the performance index of each component, can greatly reduce the number of components, simplify the design of the whole system, and generally meet the requirements of space constrained applications in terms of size. A multi-channel analog-to-digital converter, a multi-channel digital to analog converter with programmable output range, multiple gpios, an internal reference voltage and a local temperature sensor channel, such a high-density integration scheme (optional channel number and resolution) can combine many complete analog monitoring and control series.
Here we choose ti’s amc7836 as an example. Its monotonic 12 bit DAC has a selectable voltage range of ± 10V, current driving capacity up to ± 15mA, and is equipped with automatic range detection. The integrated ADC is a 12 bit SAR ADC. Among the 21 external analog inputs, 16 are bipolar inputs and the remaining 5 are high-precision inputs. As the head manufacturer of data converter, Ti selects ADC and DAC whose performance is strong enough. This high-density A / D / a conversion integration is bound to be inseparable from deep technical accumulation.
The high-density integrated devices can adapt to the multi-channel applications with strict size requirements. While reducing the number of components, the closed-loop system design is simplified. The extremely wide operating temperature also allows the devices to adapt to more industrial occasions. In terms of packaging, the thin package with heat-resistant enhancement also greatly widens the operating temperature of the IC.
This kind of high-density integration can be applied not only to the integration with power amplifier, but also to low-cost bias control circuit in multi-channel RF communication system. At the same time, with the flexible DAC output range, the device can be applied to a variety of bias solutions for transistor technology, as well as general-purpose monitor and control systems.
Single chip integration of discrete signal chain and data conversion
The ad74413r includes a 16 bit Σ-Δ The analog-to-digital converter and four configurable 13 bit analog-to-digital converters can provide four configurable input / output channels and a set of diagnostic functions. The ad74413r can provide a variety of modes, including voltage output, current output, voltage input, current input of external power supply, current input of loop power supply, external RTD measurement, digital input logic and digital input of loop power supply. At the same time, it contains a high-precision 2.5 V reference voltage source to drive DAC and ADC.
16 bits Σ-Δ The analog-to-digital converter has optional 50Hz and 60Hz suppression performance, and the DAC is a 13 bit monotonic DAC. The device can realize a true zero voltage output charge pump. The four software configurable channels of ad74413r are different from the discrete implementation method. This integrated and configurable i/o can quickly iterate and shorten the development time. Both hardware and software design have changed from resource intensive, lengthy and multi product variant development to a single design to meet many needs, which can reduce R & D time and cost, while maintaining the high reliability and robustness of the mature architecture. The integrated configuration design can achieve the above-mentioned effect of “various functions can be realized on any pin”.
In addition, due to the reduction of the number of components, the PCB size can be reduced by up to 40%, and the mounting cost in production will also be reduced. In addition, because software configurable i/o supports design reuse, controller manufacturers will need more PCBs of the same type. It seems to be a better choice for the overall cost.
This highly integrated adc/dac combination that integrates discrete signal chains into a single chip is not common in the market. However, its superb technology has brought about a great improvement in the performance and cost of the device. Driven by it, not only the control system, many automation applications have become more “agile”.