The design of 20 bit DAC adopting the pulse width and modulating technology
The device products of DAC are various in style at present, performance is better and better, but the DAC products on the market, have 18 bit only a few audio frequency of more than products to deal with the device.20 DAC that the main research of this text can output the direct current of 0 ～10V, demand to have 20 effective resolution ratios, outputting the voltage can reach 10V. Because this converter only deals with the setting-up problem that the direct current voltage, it is not very high to the speed demand, but expect much to resolution ratio, changing the precision, temperature coefficient, etc.. This text has adopted pulse width modulation technology in the design, it is Setting Value than to mean setting up that this technology modulates the accurate reference voltage and is duty ratio, the range is equal to the rectangle wave of the basic voltage, then filter AC components through the low pass filter, produce the direct current voltage. The key that the circuit is designed lies in four respects: Stability degree of the direct current basic voltage, the precision in pulse width Modulate, Performance of the analog switch, Result of low pass filter. This text adopts the technology of average of voltage in the design of direct current basic voltage, it make by the stability degrees of basic voltage reaching 2 ×10-6 /year. Modulating the circuit adopting double channel pulse width modulate technology, it is up to 1 ×10-7 to modulate the resolution ratio. It is low pass filter to strain the wave unit and adopt seventh-order low pass filter to be designing. The analog switch adopts two MOSFET through screening strictly. In the past year, test the data and show, this effective resolution ratio of converter reaches 20 bit, 10V outputs the stability to reach 6×10-6 /year, the linear index is 5×10-6.
pulse width modulation resolution ratio the linear indez the stability
LI li
92941 Armies and 96 Elements, Huludao City, Liaoning,125000
国际会议
第八届国际测试技术研讨会(8th International Symposium on Test and Measurement)
重庆
英文
3150-3153
2009-08-01（万方平台首次上网日期，不代表论文的发表时间）