Design of a wide range and high precision phase/duty-cycle correction circuit for modulation driving of 2D/3D image sensors

For 2D/3D image sensors, the phase and duty-cycle deviations of the modulated signal reduce depth errors. This article proposes a wide-range and high-precision phase/duty cycle correction circuit for modulation driving of 2D/3D image sensors. A self-compensating current-steering charge pump structure is proposed in the phase/duty-cycle correction circuit to minimize the current mismatch in the charge pump. In addition, a high-speed parasitic compensation (PC) circuit with an AC-coupled resistor feedback inverter is proposed to extend the correction range. The proposed correction circuit is designed with a 0.11 μm CMOS process, and its area is 0.0143 mm2. The post-simulation results show that the circuit has a wide range of phase and duty-cycle correction (−0.5 %–99.5 % and 0.4 %–98.3 %) with small accuracy errors (−0.945 %&+1.312 %, −0.875 %&1.175 %).