Capacitive trans-impedance amplifier circuit with pure digital output for weak light detection

Abstract

The invention belongs to the field of optical detection, and particularly relates to a capacitive trans-impedance amplifier circuit with pure digital output for weak light detection. The capacitive trans-impedance amplifier circuit comprises a signal generating circuit, a CTIA-based optical detecting circuit and a two-stage inverter; and furthermore the signal generating circuit, the CTIA-based optical detecting circuit and the two-stage inverter are successively connected. The signal generating circuit comprises a sampling signal SELECT circuit and a square wave reset signal RESET circuit. An original square wave signal is input into the input end of the sampling signal SELECT circuit. The original square wave signal is transmitted to a first delay unit and then is transmitted to one input end of an XOR gate, and the original square wave signal is input to the other input end of the XOR gate. AND operation between the pulse signal which is output from the XOR gate and the original square wave signal is performed for obtaining a sampling signal SELECT. The square wave reset signal RESET is obtained from the original square wave signal through a three-stage delay unit. The capacitive trans-impedance amplifier circuit is advantageous in that pure digital output can be realized in detecting the weak light, thereby facilitating processing by a following circuit.

Description

technical field [0001] The invention belongs to the field of light detection, in particular to a capacitive transimpedance amplifier circuit with pure digital output for weak light detection. Background technique [0002] With the maturity of microelectronics technology, there are more and more ways to acquire sensitive information for integrated circuits and information systems, which can generally be divided into non-invasive attacks and intrusive attacks. Among them, the intrusive attack destroys the chip package by opening the cover, drilling, corrosion and other means, and uses technologies such as photography and microprobes to extract important information such as layout and passwords, and the destruction of the package will expose the chip to light. under. Therefore, in order to enhance the anti-attack capability of chips or systems, weak light detectors are often designed to sense information such as cover opening and drilling, and provide early warning signals for...

AI Technical Summary

Problems solved by technology

However, since the purpose of this circuit is to detect weak light, in order to facilitate the processing of the alarm signal by the subsequent circuit, the ideal output alarm signal is a pure digital output, while the PWM signal needs to use a counter to convert the duty ratio information into a high level or Low-level signals, and doing so increases system complexity on the one hand, and increases system power consumption on the other hand

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