Delta-sigma pulse width modulator control circuit
AssigneeHewlett-Packard Company
InventorRichard S. Lewison
Life of this patent
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Abstract
A delta sigma pulse width modulator control circuit uses a delta sigma modulator as a first stage to create a sequence of pulses representing an input control signal. A pulse width modulator accumulates the sequence of pulses and defines a pulse width modulated output signal from the accumulated pulses. The pulse width modulated signal is given a randomly generated offset to the time of pulse value transition and an adjacent pulse value matching technique is used to reduce harmonically related noise generation.
Claims21
A control circuit for controlling power delivered to a load with reduced spurious electromagnetic energy generation, comprising:
- a delta sigma modulator accepting a first signal and generating a second signal representing said first signal with a plurality of digital pulses;
- and
- a pulse width modulator coupled to said delta sigma modulator, accumulating said second signal over a first time period, and generating a third signal coupled to the load and having a first magnitude value, said first magnitude value lasting for a second time period related to said second signal.
A method of controlling power delivered to a load with reduced spurious electromagnetic energy generation, comprising the steps of:
- accepting a first signal input to a delta sigma modulator;
- generating a second signal representing said first signal with a plurality of digital pulses;
- accumulating said second signal over a first time period;
- and
- generating a third signal coupled to the load and having a first magnitude value, said first magnitude value lasting for a second time period related to said second signal.
Dependencies are inferred from the claim text.