DUAL TEST SIT ISOLATION VOLTAGE TESTER
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2002-Feb-11
Optoisolator applications have stringent requirements for isolation voltage. To succcssMly market optoisolators, they must have the approval of regulatory agencies. In the consumer market, Underwriters Laboratories (UL) and the Canadian Standards Association (CSA) approv- als arc required. The multinational industrial market demands VDE approval for most applications. Prior to 1992, UL, CSA, and VDE required that a isolation test be performed on 100 percent of all product manufac- tured. This isolation voltage test stressed the device with a high voltage potential and detected any leakage cur- rents associated with insulation breakdown. In 1992 VDE imposed a partial discharge test to replace the isolation voltage test. Unfortunately, UL and CSA did not accept the partial discharge test method. This situation has letI the optoisolator manufacturer with both test require- ments. Having to perform both of these tests is not only Input expensive in terms of capital investment, but also in terms of manufacturing costs. Each test must be performed for one second, this effectively doubles the cost of regulatory testing.