A 100kHz Zero Droop Peak Detector

Here’s an inexpensive precision peak detector circuit that accurately tracks the peak voltage of input signals at frequencies up to 100kHz and has zero voltage droop over an indefinite period of time…no microcontrollers required!

The following circuit uses a dual comparator, three op amps, and a digital potentiometer to provide two peak detection outputs: one “real-time” peak output, accurate to within 2% for input signals up to 100kHz, and one maximum peak output which outputs the maximum peak voltage seen since the last reset:

Precision zero-droop 100kHz peak detector circuit

Precision zero-droop 100kHz peak detector circuit

References and additional reading:

Description Reference
A comparator based peak detector LM311 Datasheet, Texas Instruments, Figure 28
A droopless peak detector using a digital potentiometer Application Note 1163, Maxim Inetgrated
Wide bandwidth precision peak detector Precision Peak Detector Uses No Precision Components, Jim McLucas, EDN
High speed peak detector design Peak Detectors Gain in Speed and Performance, John Wright, Linear Technologies, Design Note 61