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US 8,283,985 B2Granted
Automatic frequency compensation for pulse width modulated RF level control
AssigneeAmeritherm, Inc.
InventorIan Alan Paull
Life of this patent
Estimating the term…
Abstract
Preferred embodiments of the present invention provide systems and methods that automatically correct the desired on-time of switching elements as the resonant frequency changes, so as to maintain the correct proportional value.
Claims20
A method for automatically allocating to switching devices an on-time that is proportional to a cycle time, comprising:
- using a voltage controlled oscillator to output a first signal having a frequency that corresponds to a tune voltage;
- using a voltage controlled current source to charge a charge accumulating circuit by outputting a current that corresponds to the tune voltage or a scaled tune voltage;
- using a comparator that generates a second signal by comparing a voltage of the charge accumulating circuit to a pre-determined set point;
- and
- using a circuit configured to receive the first signal and the second signal to output a third signal that is a function of the first signal and the second signal,
- wherein the output of said circuit is coupled to the switching devices.
3 more elements
A system for automatically allocating to switching devices an on-time that is proportional to a cycle time, comprising:
- an oscillator configured to receive a tune voltage and configured to output a first signal having a frequency that corresponds to the tune voltage;
- a first circuit comprising a charge accumulating apparatus;
- a current source configured to receive the tune voltage or a scaled tune voltage and configured to charge the charge accumulating apparatus by outputting a current that corresponds to the received tune voltage or the received scaled tune voltage;
- a comparator configured to generate a second signal by comparing a voltage of the charge accumulating apparatus to a pre-determined set point;
- and
- a second circuit configured to receive the first signal and the second signal and configured to output a third signal that is a function of the first signal and the second signal, wherein the output of said second circuit is coupled to the switching devices.
3 more elements
A method for automatically allocating to switching devices an on-time that is proportional to a cycle time, comprising:
- producing a tune voltage;
- producing a first signal having a frequency that is dependent on the tune voltage;
- charging a charge accumulating apparatus using the tune voltage or a scaled tune voltage;
- producing a second signal, wherein the step of producing the second signal comprises comparing a voltage of the charge accumulating apparatus to a pre-determined set point;
- using the second signal to gate the first signal to the switching devices;
- and
- periodically discharging the charge accumulating apparatus.
4 more elements
Dependencies are inferred from the claim text.