Current-sense and power amps
7 parts
Two behavioural difference-amp macromodels doing their day jobs. The current-sense amp watches a 0.1 Ω low-side shunt in a 47 Ω load line: as the supply sweeps 4–12 V the differential probe measures 8.49–25.48 mV across the shunt and the amp's ground-referenced copy measures 0.4236–1.2470 V — a ratio of 49.88 at the bottom of the swing and 48.95 at the top, against a nominal gain of 50. The power amp takes a 1 V sine into an 8 Ω load and peaks at ±13.051 V, drawing ±1.631 A. Both parts are macromodels: a fixed differential gain into a tanh soft clamp at ±V_sat, which is exactly why the top of each swing compresses — there is no bandwidth or slew limit, no common-mode range or CMRR, no output impedance, and no crossover distortion.
- V1 4V·1kHz
- R1 47Ω
- R2 100mΩ
- CSA1 ×50
- V2 1V·1kHz
- PA1 ×20
- R3 8Ω
