DC/DC converter and controller therefor utilizing an output inductor current and input voltage
First Claim
1. A DC/DC converter for changing a coil current by controlling a switching means to control an output voltage, comprising:
- output voltage monitor means for setting the switching means to an ON state when the output voltage drops and reaches a predetermined voltage value;
coil current monitor means for setting the switching means to an OFF state when the coil current increases and reaches a reference current value; and
setting means for setting the reference current value, wherein said setting means sets the reference current based on an input voltage.
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Accused Products
Abstract
A switching element is controlled by a control circuit. When the switching element is in an ON state, a coil current IL ramps up. When the switching element is in an OFF state, the coil current IL ramps down. If an output voltage Vout is smaller than a predetermined output voltage value, a control circuit is informed of it. If the coil current IL rises to a peak current ILP set by a setting circuit, the control circuit is informed of it. The setting circuit sets the peak current ILP proportional to an input voltage Vin. The control circuit sets the switching element in the ON state when the output voltage Vout is smaller than the predetermined output voltage value, and sets the switching element in the OFF state when the coil current IL rises to the peak current ILP.
198 Citations
13 Claims
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1. A DC/DC converter for changing a coil current by controlling a switching means to control an output voltage, comprising:
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output voltage monitor means for setting the switching means to an ON state when the output voltage drops and reaches a predetermined voltage value; coil current monitor means for setting the switching means to an OFF state when the coil current increases and reaches a reference current value; and setting means for setting the reference current value, wherein said setting means sets the reference current based on an input voltage. - View Dependent Claims (2, 3, 4)
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5. A DC/DC converter having at least a light load mode and a heavy load mode as operation modes in supplying a load with an electric current, controlling a switching means by a method corresponding to each operation mode, and thereby controlling an output voltage with a coil current altered, comprising:
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light load mode control means for setting the switching means to an ON state when the output voltage drops and reaches a predetermined voltage value, setting the switching means to an OFF state when the coil current increases and reaches a reference current value, and thereby controlling the output voltage; heavy load mode control means for controlling the switching means by a predetermined method; mode switching means for switching the operation mode from light load mode to the heavy load mode when the output voltage cannot restore the predetermined voltage; and setting means for setting the reference current in such a way that an electric conversion efficiency can be optimum when the operation mode is switched, wherein said setting means sets the reference current based on an input voltage. - View Dependent Claims (6)
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7. A circuit for controlling an operation of a DC/DC converter for changing a coil current by controlling a switching means to control an output voltage, comprising:
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output voltage monitor circuit for setting the switching means to an ON state when the output voltage drops and reaches a predetermined voltage value; coil current monitor circuit for setting the switching means to an OFF state when the coil current increases and reaches a reference current value; and setting circuit for setting the reference current value based on an input voltage.
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8. A circuit for controlling an operation of a DC/DC converter having at least a light load mode and a heavy load mode as operation modes in supplying a load with an electric current, controlling a switching means by a method corresponding to each operation mode, and thereby controlling an output voltage with a coil current altered, comprising:
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light load mode control circuit for setting the switching means to an ON state when the output voltage drops and reaches a predetermined voltage value, setting the switching means to an OFF state when the coil current increases and reaches a reference current value, and thereby controlling the output voltage; mode switching circuit for switching the operation mode for light load mode to the heavy load mode when the output voltage cannot restore the predetermined value; and setting circuit for setting a reference current with respect to an input voltage, whereby an electric conversion efficiency is improved when the operation mode is switched from the light load mode to the heavy load mode.
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9. A DC/DC converter for changing a coil current by controlling a switching transistor to control an output voltage, comprising:
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a first comparator which monitors the output voltage and turns said switching transistor ON when the output voltage is below a predetermined voltage value; a second comparator which monitors an inductor current in an output inductor coupled to said switching transistor, said second comparator turning said switching transistor OFF when said inductor current is above a reference current value; and a reference current setting circuit which determines said reference current value in accordance with an input voltage to said DC/DC converter. - View Dependent Claims (12, 13)
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- 10. The DC/DC converter according to claim 10, wherein said reference current setting circuit sets the reference current in proportion to the input voltage.
Specification