An HMM Generator With Low Load Dependency for Alternative TLP-HMM

Various types of transmission line pulse-human metal models (TLP-HMM) have been proposed as alternatives to electrostatic discharge (ESD) generators for immunity testing of devices because TLP-HMM generates more stable discharge current waveforms than ESD generators. The output impedance of TLP-HMM differs from that of ESD generators due to their distinct discharge mechanisms. Therefore, we focused on an HMM generator via a coaxial cable that generates discharges using RC circuits, similar to ESD generators. However, ESD generators and the HMM generator differ in terms of their output structure and calibration target. This may cause the discharge current waveforms to vary when used on a device under test (DUT). In this study, the problems caused by the differences in the output structure and calibration target were identified through equivalent circuit modeling of the HMM generator corresponding to the discharge waveform measurement of two loads in simulating DUT. Subsequently, a low load dependency-human metal model (LLD-HMM) is proposed by addressing the problems to generate same-shaped discharge current waveforms for arbitrary resistive and certain capacitive loads with arbitrary cable lengths. The effectiveness of the LLD-HMM was verified through simulations and experiments.