Narrow pulse peak value sampling hold circuit and control method thereof

Abstract

The invention discloses a narrow pulse peak value sampling hold circuit and a control method thereof. The circuit comprises a peak signal sampling and holding part, a comparator control part, a capacitor voltage compensation part, a following output part and a DSP signal control processing part, wherein the comparator control part, the capacitor voltage compensation part, the following output partand the DSP signal control processing part are respectively connected with the peak signal sampling and holding part; the comparator control part comprises a second operational amplifier and a fifthresistor and is used for controlling a second analog switch of the peak signal sampling and holding part to be turned off at a peak value and cutting off a leakage current channel of a sampling capacitor of the peak signal sampling and holding part; the capacitor voltage compensation part comprises a first junction field effect transistor, a third resistor and a first capacitor, and is used for compensating voltage loss of a sampling capacitor caused by junction capacitor charging of a second junction field effect transistor of the peak signal sampling and holding part. The circuit has the characteristics of high speed and high precision, and is suitable for occasions of extracting high-speed narrow pulse peak values.

Description

technical field [0001] The invention relates to the technical field of power device junction temperature monitoring, in particular to a narrow pulse peak sampling and holding circuit and a control method thereof. Background technique [0002] In the on-line monitoring of power device junction temperature, it is a new method to extract the junction temperature by using the electrical parameter method. The induced voltage peak generated by the parasitic inductance of the source is related to its junction temperature when the device is turned off. The turn-off time of general devices is hundreds of nanoseconds, and high-speed devices are even as low as tens of nanoseconds, and the rise time of pulse peaks generated during the period will be shorter, and the amplitude will also change, so design a high-precision nanosecond A high-speed narrow-pulse peak sample-and-hold circuit is one of the necessary conditions for using this method to realize online monitoring of junction temp...

AI Technical Summary

Problems solved by technology

[0003] However, the existing peak sample-and-hold circuit has the disadvantages of insufficient bandwidth, slow tracking speed, and insufficient precision

In order to meet the speed requirements, the sampling capacitors used are mostly pF-level small capacitors. After reaching the peak value, the parasitic capacitance of the diode will cause its charge to leak, and the voltage held by the sampling capacitor will drop to a certain extent, which affects the sampling peak value. precision

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