Bristol Nano Dynamics specializes in atomic force microscopy, involving laser based sensor systems requiring extreme accuracy. To adapt an early proof-of-concept for a thermal imaging system, Ingeniunda was commissioned to design the analog front-end circuits.
With stability and noise characterisation essential aspects of the project, Ingeniunda designed the analog circuits using the most sophisticated commercially available components. Several solutions were developed and implemented in SPICE for a complete simulation of system parameters, including transient response functions and frequency stability. The circuit designs were then updated using the information acquired through SPICE simulation. Before moving to physical prototyping, the complex circuit topology involving numerous discrete transistors, current mirrors, and operational amplifiers was completely characterised.
A circuit board layout was proposed by Ingeniunda for experimental verification in a prototype. Safeguards were included in the design to protect the extremely sensitive thermal probes during the experiments. Specific attention was given to noise immunity during the PCB design, with noise suppression features being added to the design where applicable. Prototype circuit boards were manually assembled by Ingeniunda engineers and thoroughly subjected to functional testing before integration in the microscope prototype. Thanks for the experience of the Ingeniunda engineering team and accurate SPICE modelling, the first prototype implementation was found to be immediately usable, with only minor stability adjustments needed for the second and final version.
