The circuit in Figure 1 uses current-feedback amplifiers to implement a wideband full-wave rectifier for applications such as a control/AGC system reference or as an amplitude indicator. Putting the full-wave-rectifier diodes in the feedback loop of an op amp works better than does using simple diode-based rectifiers. The op amp’s loop gain decreases the distortion [...]

Fig 1 shows a high-speed, full-wave rectifier-or absolute-value circuit-that uses a high-speed clamping amplifier, IC2. This circuit is faster and performs better than rectifiers employing diodes in their amplifiers’ feedback paths. These diode-based circuits have limitations at lower signal-input levels and higher bandwidths. These limitations show themselves most clearly as crossover distortion. This circuit cleanly [...]

Synchronous rectifiers are MOSFETs, driven in such a way as to perform a rectifying function. They often take the place of diodes in the output-rectification stage of switching power converters, because of their lower on-state power loss. In power circuits, synchronous rectifiers are often complicated to use because of timing issues…. Link