Non-synchronous switching regulator with improved output regulation at light or low loads
First Claim
1. A switching regulator comprising:
- a highside power switch and a lowside switch coupled in series, the highside power switch coupled to a first voltage rail and the lowside switch coupled to a second voltage rail;
an inductor coupled to a node between the highside power switch and the lowside switch and an output capacitor; and
a control circuit that provides a switching signal to the highside power switch resulting in the generation of an operating current through the inductor that charges the output capacitor to provide a regulated voltage at an output terminal, the lowside switch provides a path for a reverse current that occurs at light loads on the output terminal wherein the lowside switch being substantially weaker than the highside power switch.
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Accused Products
Abstract
A switching power supply or switching regulator is provided with a control circuit that controls a switching signal to a first switch. The switching signal is also coupled to a second switch in an inverted state, such as the first and second switches are switched “ON” and “OFF” in opposing states. The first switch and the second switch are coupled through a common node. The second switch is also coupled to ground. An inductor is coupled to the common node and an output capacitor. The switching signal generates an operating current through the inductor that charges the output capacitor to provide a regulated voltage at an output terminal. The second switch is designed to handle the small reverse current that occurs when the first switch is turned off preventing the regulator from entering a discontinuous mode during light load conditions.
35 Citations
20 Claims
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1. A switching regulator comprising:
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a highside power switch and a lowside switch coupled in series, the highside power switch coupled to a first voltage rail and the lowside switch coupled to a second voltage rail;
an inductor coupled to a node between the highside power switch and the lowside switch and an output capacitor; and
a control circuit that provides a switching signal to the highside power switch resulting in the generation of an operating current through the inductor that charges the output capacitor to provide a regulated voltage at an output terminal, the lowside switch provides a path for a reverse current that occurs at light loads on the output terminal wherein the lowside switch being substantially weaker than the highside power switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A non-synchronous switching regulator comprising:
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a highside power Field Effect Transistor (FET) coupled to an input voltage and a common node;
a weak lowside FET coupled to a ground;
a first diode with an anode coupled to the common node and a cathode coupled to the weak lowside FET;
a second diode with an anode coupled to ground and a cathode coupled to the common node;
an inductor coupled to the common node and an output capacitor; and
a control circuit operative to control a duty cycle of an input signal provided to the highside power FET and the weak lowside FET resulting in the generation of a charge current through the inductor that charges the output capacitor to provide a regulated voltage at an output terminal, the lowside FET provides a path for a reverse current to prevent the regulator from entering a discontinuous mode that occurs at light loads on the output terminal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of operating a non-synchronous switching regulator, the method comprising;
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switching a highside power switch coupled to an input voltage and a common node to an “
ON”
state;
switching a lowside switch coupled to a ground and the common node to an “
OFF”
state;
generating a charge current through an inductor coupled to the common node and an output capacitor;
charging the output capacitor to a desired regulated output voltage;
switching the highside power switch to an “
OFF”
state and the lowside switch to an “
ON”
state;
providing an initial charging current to the inductor through a diode coupled to ground; and
allowing a reverse current of the inductor to flow through the lowside switch to ground, wherein the lowside switch being substantially weaker than the highside power switch. - View Dependent Claims (19, 20)
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Specification