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US 6,859,076 B2Granted
Combination triangular waveform generator and triangular to pseudo-sinusoidal waveform converter circuit
OwnerFutoshi Fujiwarainventor
Life of this patent
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Abstract
The present invention comprises an integral triangular voltage waveform generator (170, 180) and triangular to pseudo-sinusoidal current waveform converter (170, 180). The outputs of the present invention are preferably differential (130, 131), although the invention can easily be modified for single ended output. The frequency of the output waveforms corresponds to the frequency of the input reference clock.
Claims20
A waveform generator circuit, comprising:
- a triangular and pseudo-sinusoidal waveform generator adapted to accept clock signals and generate triangular waveforms;
- an amplitude control current responsively coupled to the triangular and pseudo-sinusoidal waveform generator operable to control the amplitude of the generated triangular waveforms;
- a reference voltage circuit responsively coupled to the amplitude control circuit, operable to generate reference voltages for the peak voltages of the triangular waveform;
- the triangular and pseudo-sinusoidal waveform generator operable to accept one or a plurality of clock signals;
- the triangular and pseudo-sinusoidal waveform generator further operable to generate triangular waveforms from the clock signals,
- the triangular and pseudo-sinusoidal waveform generator further operable to rectify the triangular waveforms;
- the triangular and pseudo-sinusoidal waveform generator further operable to smooth the triangular waveforms into pseudo-sinusoidal waveforms.
4 more elements
A method of generating a waveform, comprising:
- inputting a first clock signal and a second clock signal 90 degrees out of phase with the first clock signal into a waveform generator;
- inputting a reference current into the waveform generator;
- generating a first triangular waveform and a second triangular waveform that is 90 degrees out of phase from said first triangular waveform from said first clock signal and second clock signal;
- inputting said first triangular waveform and second triangular waveform to a first and second voltage-to-current converter;
- generating a first and second reference voltage in a reference voltage generator;
- summing the first and second reference voltages to the first and second voltage-to-current converters, respectively;
- inputting the first and second currents from the first and second voltage-to-current converters respectively and from the first and second waveform generators to a first and second switch, or plurality thereof, inside of the first and second voltage-to-current converters;
- driving the first and second switch or plurality thereof by the clock signal of the other side
- controlling the absolute value of the output by summing the output currents from the voltage-to-current converters at a node;
- providing the summed current to the input of a current comparator and current bias generator;
- comparing the input differential currents at an input node;
- increasing a reference current if the current is less than 0 at the input node and hence increasing the amplitude of triangular waveform;
- decreasing a reference current if the current is more than a predetermined amount at the input node and hence decreasing the amplitude of triangular waveform;
- and
- rectifying and shaping the triangular waveform to obtain a pseudo-sinusoidal waveform based.
12 more elements
Dependencies are inferred from the claim text.