Crest detection circuit and crest detector

Abstract

The invention provides a crest detection circuit and a crest detector and belongs to the technical field of LED drive circuits. The crest detection circuit comprises a differential amplifier, a preset field-effect tube, a preset capacitor and a voltage division circuit. The first end of the differential amplifier is connected with the first end of the preset field-effect tube, and the second end of the differential amplifier is separately connected with the second end of the preset field-effect tube and the first end of the preset capacitor; one end of the voltage division circuit is connected with the first end of the preset capacitor; the differential amplifier is used for receiving an input signal, and inputting the input signal to the preset field-effect tube; the preset field-effect tube is used for outputting a first crest signal; the voltage division circuit is used for conducting voltage division processing on the first crest signal through the preset capacitor and generating a second crest signal. By means of the crest detection circuit and the crest detector, the PFC sine wave modulation function is achieved.

Description

technical field [0001] The invention relates to the technical field of LED drive circuits, in particular to a peak detection circuit and a peak detector. Background technique [0002] Light Emitting Diode (LED for short) is a kind of high-efficiency lamps and lanterns, which have been widely used in various indications, displays, decorations, backlights, general lighting and urban night scenes and other fields. LED lamps are generally required to have a power factor correction (Power Factor Correction, PFC for short) function, especially a high-power LED driver, which is an important component of the LED lamp. [0003] The first block in the PFC unit is the peak time detector, see figure 1 as shown, figure 1 A schematic structural diagram of a peak time detector provided in the prior art, the peak time detector 10 is composed of a preset peak detector 101 , a bias voltage source 102 , a comparator 103 and a single pulse generator 104 . Wherein, the preset peak detector 10...

AI Technical Summary

Problems solved by technology

At this time, some peak points will be missed, which will generate wrong PFC reference voltage, so that the function of PFC sine wave modulation cannot be realized.

[0004] Therefore, using the existing preset peak detector 101, the function of PFC sine wave modulation cannot be realized because the peak point is missed.

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