Use Wideband Balun To Test Pard Of DC Powersupply

DC Power Supply, which supplies stable DC power to the active device, is widely used in the industrial manufacture and research.PARD, Periodic and Random Deviation, is the AC distortion mixed in its DC output. And PARD will greatly affect the quality of power supply. So it is necessary to figure out the exact situation of PARD in the calibration of the DC power supply. However, to make the accurate test of PARD, the interferences for environment must be isolated or shielded. Only if the right method to taken, can we get close to the true situation of the PARD.Based on this theme, the paper analyzed the interferences which might take in places during the calibration of DC Power Supply’s PARD one by one. To improve the capability to resist the common mode interferences of calibration system for DC Power Supply, some reformations are taken in the traditional way to calibrate the PARD of DC Power Supply. A new method is introduced:Using wideband BALUN, as core accessary to resist common mode interferences, to test the exact PARD of DC Power Supply. After this wideband BALUN is developed, a test solution is given to make sure of its performance and specifications. Also the test data of this wideband BALUN is provided. At last, a whole test system is formed to validate the effect to anti-interference of this new method. In addition, two common methods-shielding cable method and differential detector method-are also performed as comparisons. The uncertainty analyze of these three methods are given. To sum up, this paper provides concrete data, new idea and references to the coming calibration method of DC Power Supply. And it help improving the quality of manufacture and development of DC Power Supply.