Feature: Analogue design


Figure 6: Venable Instruments Model 5060A vintage network analyzer used for high-side floating noise injection and measurement of LED driver


Figure 7: Noise injection and measurement points on the LT3950 LED driver


Figure 8: Bode plots for the LT3950 LED driver on a DC2788A demonstration circuit. The plots generated through LTspice simulation (blue line) have a strong correlation to those generated using a network analyzer (green line)


Table 1: Bode plot measurement data comparison of LTspice vs. network analyzer for the LT3950 LED driver


LTspice data is useful for relatively quickly narrowing the field of components and predicting general circuit behaviour, even without perfect component modelling. A working simulation helps guide the design engineer before transitioning to hardware implementation, saving overall design time. Once rough component choices have been made, measurements using a built board with a network analyzer can confirm or contrast the simulation results as a means of hardware validation during development.


30 May 2022 www.electronicsworld.co.uk


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