PWM signal generating circuit
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsMitsugu Makita, Yoshitaka Ojima, Yoshinobu Kume
Life of this patent
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Abstract
A PWM signal generating circuit according to the invention includes a digital PWM signal generating circuit that generates a digital PWM signal having a resolution of 2n based on a clock signal CLK and n-bits (n≧1) of digital information; a triangular wave generator that generates a triangular wave (e.g. ramp wave) synchronized with the clock signal CLK; and a comparator that compares the triangular wave with a threshold value. The PWM signal generating circuit increases the resolution of the digital PWM signal based on an output from the comparator.
Claims9
A PWM resolution increase signal generating circuit, comprising:
- a common PWM signal generating circuit portion that generates a common digital PWM signal having a resolution of 2n based on a clock signal CLK and n-bits (n≧1) of digital information;
- a triangular wave generator that generates a triangular wave synchronized with the clock signal CLK;
- and
- a comparator that compares the triangular wave with a threshold value, wherein
- the PWM resolution increase signal generating circuit increases the resolution of the common digital PWM signal based on an output from the comparator.
A high resolution PWM signal generating circuit, comprising:
- a counter that operates based on a clock signal CLK;
- a register that sets a duty ratio of a high resolution PWM signal;
- a first comparator that compares an output from the counter with an output from the register;
- a triangular wave generator that generates a triangular wave synchronized with the clock signal CLK;
- and
- a second comparator that compares the triangular wave with a threshold value, wherein
- the high resolution PWM signal generating circuit generates the high resolution PWM signal based on the output from the counter, an output from the first comparator, and an output from the second comparator.
Dependencies are inferred from the claim text.