Electrical Fast Transient Burst Immunity Study Of Low-dropout Voltage Regulator

Low dropout regulator is the core component of power supply in electronic products that has been occupied the leading position in the power management chip market for a long time.It needs very small area of PCB,extremely low power consumption and other excellent performance comparing to other regulators,especially the ability to produce and remain independent,stable and predictable output Voltage with low noise.With the progress of technology and the worsening trend of electromagnetic environment,e-market urgently needs power modules with lower power consumption,less perpheral devices,better stability and anti-interfere nce ability,so that the electromagnetic compatibility of power part has received unprecedented attention nowadays.At the same time,electrical fast transient bursts,as a kind of easily triggered and complicated transient pulse interference with high damage frequency,seriously effect the performance of circuits.So from the perspective of reliability design of integrated circuits,immunity research on LDO to EFT has a lot of scientific significance.The main work of this paper is to deeply investigate the circuit characteristics of LDO voltage regulator and the signal characteristics of EFT interference.Furthermore,from the perspective of EMC performance evaluation,method for immunity test of LDO to EFT is realized and the LDO model under EFT sensitivity test is also formed.Then the failure mode and failure mechanism of the LDO under EFT interferenceare analyzed.First of all,the basic principle and structure of LDO voltage regulator are studied.Inside function modules of LDO voltage regulator are analyzed in detail and the design of circuit indicatorsare also discussed.Through the research of generation mechanism of the EFT interference pulse,the transmission mechanism and the harmful results of disturbance signal in circuits are analyzed.Secondly,after the study of current system level and integrated circuit level testing and measurement techniques of EFT immunity test,coupled with the study of the functional and structural characteristics of the LDO voltage regulator used in this paper,immunity research scheme of the LDO to EFT are proposed with specific implementation.Great emphasis is put on the set up of software and hardware platform,the design of the test chip adapter and the establishment of testing process.Eventually the immunity level of LDO under EFT interference is obtained,then the failure mode and failure mechanism are given through the analysis of the test results.Finally,according to parameter dates of discrete devices,combined with model parameters extracting by impedance testing and analysis,the simulation models of devices are established.Nonlinear characteristics and parasitic parameters of the tested chips are tested and analyzed,whichare used to deduce the EFT interference noise coupling mechanism inside the chip and to set up a high accuracy behavior model.Through the simulation analysis,high consistency between the model and the actual test are obtained.