READOUT ARCHITECTURE FOR FMCW LIDAR

Provided is a readout integrated circuit of a FMCW LiDAR system includes a balanced PIN photo diode (340) configured to receive an optical signal, and convert the optical signal into a current signal, an optical mixer configured to receive the current signal from the balanced PIN photo diode (340), and convert the current signal into a mixed signal of high and low frequencies, a transimpedance amplifier (365) configured to, receive the converted current signal from the optical mixer; and convert the converted current signal into a voltage signal (367) including a low frequency sinusoidal waveform after filtered high frequency, a comparator to receive the voltage signal (367), and generate a pulse signal (385) from the voltage signal (367), a primary counter (395i) to receive a primary signal corresponding to the pulse signal (385), and count a number of pulses to generate primary counter data (387a), a reference counter (395r) to receive a reference signal, and count a number of pulses to generate reference counter data (387b), and an arithmetic logic unit (375) to receive the primary and reference counter data (387a, 387b), and calculate depth information corresponding to a distance of a target (130).