A New Delay-Line Sharing Based CMOS Digital PWM Circuit

Abstract

This paper presents a new circuit design for digital pulse-width modulators (DPWM). This method improves the structure of hybrid DPWM to a more compact architecture by utilizing the separation of MSB (most significant bit) and LSB (least significant bit) groups. In addition, a delay-line function block is shared with MSB and LSB groups to reduce power consumption. HSPICE post-layout simulation shows that this new DPWM circuit operates successfully at 200 MHz clock frequency and has 1.55-mW power consumption. An experimental chip had been fabricated by using a standard 0.18 micron CMOS process. The layout area of the chip including I/O pads is 461 m×370 m. The new DPWM design carries the advantages of smaller chip area and low power consumption especially for the high resolution required.