Inexpensive peak detector requires few components

摘要

Requiring no rectifier diodes, the positive peak-detector circuits in figures 1 and 2 exploit the open-drain output of a Texas Instruments TLC372 fast comparator, IC{sub}1. Both versions of the detector are simple and inexpensive and provide a buffered, low-impedance output at V{sub}(our) In addition, the TLC372's high typical input impedance of 10{sup}12Ω eliminates any need for an input buffer stage. As Figure 1 shows, the detector's output voltage at the output of op amp IC{sub}(2A) applies a feedback signal for the comparator and acts as a reference level for comparison with the input signal's amplitude. Upon first application of input signal V{sub}(IN), the voltage on the hold capacitor, C{sub}1, is 0V, and V{sub}(OUT) is also 0V.