Rectangular-wave-signal generating circuit and switching power supply
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorToshimasa Namekawa
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Abstract
A rectangular-wave-signal generating circuit according to an embodiment comprises: a sawtooth-wave output circuit; a first detector; a second detector; and a first PWM-signal output circuit. The sawtooth-wave output circuit is configured to generate and output a sawtooth-wave signal synchronized with a clock signal. The first detector is configured to detect a first timing at which a potential of the sawtooth-wave signal exceeds a bottom potential. The second detector is configured to detect a second timing at which a potential of the sawtooth-wave signal exceeds a potential of a first pulse-width instruction voltage signal. The first PWM-signal output circuit is configured to generate a first PWM signal based on a time difference between the first timing and the second timing.
Claims15
A rectangular-wave-signal generating circuit comprising:
- a sawtooth-wave output circuit configured to generate and output a sawtooth-wave signal synchronized with a clock signal;
- a first detector configured to detect a first timing at which a voltage of the sawtooth-wave signal exceeds a bottom voltage;
- a second detector configured to detect a second timing at which a voltage of the sawtooth- wave signal exceeds a voltage of a first pulse-width instruction voltage signal;
- and
- a first PWM-signal output circuit configured to generate and output a first PWM signal based on a time difference between the first timing and the second timing,
- wherein the sawtooth-wave output circuit comprises a first sawtooth-wave output circuit configured to generate a first sawtooth-wave signal having a period that is twice a period of the clock signal, and a second sawtooth-wave output circuit configured to generate a second sawtooth- wave signal whose signal value overlaps a time-proportional range of the first sawtooth-wave signal and a phase of which is different from that of the first sawtooth-wave signal by 180 degrees,
- the first detector detects the first timing based on the first sawtooth-wave signal or the second sawtooth-wave signal, and
- the second detector detects the second timing based on the first sawtooth-wave signal or the second sawtooth-wave signal, whichever the detection of the first timing was based on.
A rectangular-wave-signal generating circuit comprising:
- a sawtooth-wave output circuit configured to generate and output a sawtooth-wave signal synchronized with a clock signal;
- a first detector configured to detect a first timing at which a voltage of the sawtooth-wave signal exceeds a bottom voltage;
- a second detector configured to detect a second timing at which a voltage of the sawtooth-wave signal exceeds a voltage of a first pulse-width instruction voltage signal;
- and
- a first PWM-signal output circuit configured to generate and output a first PWM signal based on a time difference between the first timing and the second timing,
- wherein the bottom voltage is set based on a time-proportional range of the sawtooth-wave signal, and a rising rate of the voltage of the sawtooth-wave signal exceeding the bottom voltage is in a predetermined range.
A rectangular-wave-signal generating circuit comprising:
- a sawtooth-wave output circuit configured to generate and output a sawtooth-wave signal synchronized with a clock signal;
- a first detector configured to detect a first timing at which a voltage of the sawtooth-wave signal exceeds a bottom voltage;
- a second detector configured to detect a second timing at which a voltage of the sawtooth-wave signal exceeds a voltage of a first pulse-width instruction voltage signal;
- and
- a first PWM-signal output circuit configured to generate and output a first PWM signal based on a time difference between the first timing and the second timing,
- wherein the first PWM-signal output circuit sets a minimum pulse width of the first PWM signal to 0 when the voltage of the first pulse-width instruction voltage signal is lower than the bottom voltage.
Dependencies are inferred from the claim text.