Design and Test of Novel Programmable Digital Three Phases SPWM Chip

In order to improve the sinusoidal pulse width modulation (SPWM) control system's real time capability and reduce the system's complexity, a high precision programmable digital three phases SPWM chip based on variable sampling frequency method is designed. The chip can be "programmed" by MCU to set the needed parameters with great flexibility and can be interfaced with multiplexed and non-multiplexed data bus mode. To implement the high precision for any frequency sinusoidal power wave, an improved method is presented by changing the sampling clock frequency for different power frequency while keeping the sampling points constant. In addition, the pipeline structure also has improved the speed of the system. The chip is fabricated with 0.35 mum CMOS technology and the core area is 1755times1746 mum2. The test results show that the chip has reached its specifications. The control resolution for any power frequency is up to 16 bits, the system clock can reach 50 MHz, and the ROM operation period is up to 1.68 mus