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US 7,679,348 B2Granted
Switching regulator
AssigneeRicoh Company, Ltd.
InventorShohtaroh Sohma
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AssigneeRicoh Company, Ltd.
InventorShohtaroh Sohma
Estimating the term…
A switching regulator is disclosed that is able to operate with low power consumption and able to prevent variation of an output voltage. The switching regulator operates in a PWM control mode and a PFM control mode, and includes a switching unit; an error amplification circuit for amplifying an error voltage between an output voltage and a first reference voltage; a slope circuit for generating a slope signal; a reference voltage generation circuit for generating a second reference voltage for determining a time interval of an ON state in the PFM control mode; a multiplexer for outputting one of the second reference voltage and an output voltage from the error amplification circuit; a comparison circuit for comparing an output voltage from the slope circuit to an output voltage from the multiplexer; and an oscillation circuit for determining a timing of the ON state in the PWM control mode.
A switching regulator operating in one of a PWM control mode and a PFM control mode, comprising:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Using semiconductor devices only: with automatic control of output voltage or current, e.g. switching regulators
Apparatus for conversion between ac and ac, between ac and dc, or
About 1 year 5 months of term left · ends 28 Mar 2028 (estimated)
1. Field of the Invention
The present invention relates to a switching regulator having low power consumption and able to operate efficiently under low workload conditions.
2. Description of the Related Art
FIG. 1 is a block diagram illustrating a switching regulator 100 according to a first embodiment of the present invention;
FIG. 2A through FIG. 2H are waveform diagrams illustrating operations of the switching regulator 100 in the PWM control mode;
FIG. 3A through FIG. 3G are waveform diagrams illustrating operations of the switching regulator 100 in the PFM control mode;
Below, preferred embodiments of the present invention are explained with reference to the accompanying drawings.
In the present invention, the switching regulator includes an oscillation circuit that determines a timing of the ON state in the PWM (Pulse Wide Modulation) control mode, a reference voltage generation circuit that generates a reference voltage for determining a time interval of an ON state in the PFM (Pulse Frequency Modulation) control mode, a multiplexer that outputs one of the reference voltage from the reference voltage generation circuit and an output voltage from an error amplification circuit. In the PWM control mode or the PFM control mode, the multiplexer switches the voltage input to a comparison circuit, thereby, determining the ON timing in the PWM control mode or the ON state time interval in the PFM control mode.
FIG. 1 is a block diagram illustrating a switching regulator 100 according to a first embodiment of the present invention.