Synchronous Current Switching Technique For Adjusting The Cmos Ring Oscillator Duty Cycle

The present work proposes a low cost, synchronous current switching technique for adjusting a 60MHz, medium frequency, oscillator duty cycle. Current switching is necessary due to the use of both charge and discharge delays of the oscillator topology. Added circuitry consists on trimmable current mirrors and synchronizing circuitry. Main goal is not to affect the functionality of the system, nor initial frequency or duty cycle variation. The circuit is designed using sub micrometer technologies, for a supply voltage range between 1.6V and 2V.