A Design For Test Circuit Of Switching Power Controller

Switching power supply has become the main power supply of a portable electronic device. The core parts is the control chip. With the increasing degree of integration, there are more faults in the control chip when manufacturing, and testing issues become more complex, so test cost in the proportion of the total cost is increasing. In order to quickly and effectively detecting defects in the control chip, The study of the switching power supply design for testability is required.This paper analyzes the development of the design for testability about the PSR digital switching power controller and the design methods of measuring technology. Based on PSR digital switching power controller, proposes a testing method suiting for switching power controller. Then this paper also studies the various disturbances that may exist in actual using, and designs circuit to eliminate interference. To reduce the manufacturing cost of ICs, the technology of pin with multiple functions is applied in design for testability, and the technology is applied in the test circuit. Using the existing circuits in chip to realize the function of test mode substantially reduce the area of the test circuit, and reduce the cost of testing, also improve the utilization of the circuit. In addition, this paper also studied the effective ways to reduce testing time. Finally, according to the testing specifications of a switching power supply controller, this paper design a test circuit and layout. The area of the test circuit is 11869.8μm2.The simulation results show:The test mode longest is three hundred and thousands of unit. The test mode need only two sets of test vectors, the fault coverage is greater than 96%, and on-time controlling the clock and the reset signal is achieved. The simulation results also show that the test circuit can effectively resist outside interference, to ensure the test circuit working properly. In addition, the test circuit also set aside test mode expansion ports, which will make this design has better flexibility and compatibility.