Constant-ratio timing circuit for trailing edge timing

Abstract

The invention provides a constant-ratio timing circuit for trailing edge timing. The circuit comprises a first resistor, a second resistor, a capacitor and a comparator. One end of the second resistoris connected with a direct-current power supply, and the other end of the second resistor is connected with one end of the first resistor and the first input end of the comparator and then grounded through the capacitor. A second input end of the comparator is connected with the other end of the first resistor and an input signal of the constant-ratio timing circuit. An output end of the comparator serves as an output end of the constant-ratio timing circuit. The direct-current power supply and the input signal have the same direct-current component. According to the invention, only the pulsesignal is attenuated, and the direct current component remains unchanged, so that the stability of the circuit is improved compared with the attenuation of the direct current component and the pulsesignal in the traditional constant-ratio timing circuit. In addition, the attenuation and the time delay are achieved only through one RC network. Compared with a traditional constant-ratio timing circuit in which quantity signals are divided into two paths to be attenuated and delayed respectively, the structure is simpler.

Description

technical field

[0001] The invention belongs to the technical field of analog integrated circuits, in particular to a constant-ratio timing circuit with trailing edge timing. Background technique

[0002] Constant ratio timing is a timing method with a constant trigger ratio. The constant ratio timing circuit is mainly used in the laser ranging radar chip. Its function is to detect the reflected optical pulse signal and record the generation time of the reflected pulse, so as to provide the system to calculate the laser transmission distance and achieve the effect of ranging. In order to ensure the accuracy of the distance measurement, it is necessary to ensure that the time point when the comparator triggers each pulse signal on the receiving surface is the same.

[0003] In the traditional constant-ratio timing circuit, the constant-ratio point at the leading edge of the input analog signal is used for timing triggering to form a standard digital signal. The point at whi...

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