Digitally controlled wide range pulse width modulator

摘要

The present invention provides a digitally controlled, current starved, pulse width modulator (PWM). In the PWM of the present invention, the amount of current from the voltage source to the ring oscillator is controlled by the proposed header circuit. By changing the header current, the pulse width of the switching signal generated at the output of the ring oscillator is dynamically controlled, where the duty cycle can vary between 50% and 90%. A duty cycle to voltage converter is used to ensure the accuracy of the system under process, voltage, and temperature (PVT) variations. The proposed pulse width modulator is appropriate for dynamic voltage scaling systems due to the small on-chip area and high accuracy under process, voltage, and temperature variations.

主权项

1. A pulse width modulator, comprising:
a ring oscillator comprising an odd plurality of delay stage inverters coupled in a sequential loop; and a header circuit coupled between a power source and every other delay stage inverter of the odd plurality of delay stage inverters, every other delay stage inverter including the first delay stage inverter and the last delay stage inverter of the sequential loop, the header circuit configured to control a current flow from a power source to every other delay stage inverter of the ring oscillator.