Bootstrap circuit for H-bridge structure utilizing N-channel high-side fets
First Claim
Patent Images
1. A circuit for providing power, comprising:
- a switching circuit, including;
a first switching device;
a second switching device;
a third switching device; and
a fourth switching device, wherein the first switching device, the second switching device, the third switching device, and the fourth switching device are arranged to operate as an H-Bridge circuit, and wherein the first switching device and the second switching device are arranged as high-side switching devices;
a first driver circuit that is arranged to selectively drive the first switching device;
a first bootstrap capacitor that is arranged to provide power to the first driver circuit;
a second driver circuit that is arranged to selectively drive the second switching device;
a second bootstrap capacitor that is arranged to provide power to the second driver circuit; and
a cross-couple circuit that is arranged to enable charging of the first bootstrap capacitor via current through selectively either the cross-couple circuit or another current path that is distinct from the cross-couple circuit based, at least in part, on whether the fourth switching device is open or closed, wherein the cross-couple circuit is coupled between the first bootstrap capacitor and the second bootstrap capacitor.
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Abstract
The invention relates to an apparatus and method for driving high-side switching devices in an H-Bridge circuit. The apparatus includes first and second N-Channel high-side switching devices. Each of the high-side switching devices is associated with, and is selectively driven by, a driver circuit. Each of the driver circuits is associated with, and is powered from, a bootstrap capacitor. The apparatus further includes a cross-couple circuit that is arranged to charge each of the bootstrap capacitors based, at least in part, on whether the low-side switching device that is associated with the other bootstrap capacitor is open or closed.
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Citations
21 Claims
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1. A circuit for providing power, comprising:
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a switching circuit, including; a first switching device; a second switching device; a third switching device; and a fourth switching device, wherein the first switching device, the second switching device, the third switching device, and the fourth switching device are arranged to operate as an H-Bridge circuit, and wherein the first switching device and the second switching device are arranged as high-side switching devices; a first driver circuit that is arranged to selectively drive the first switching device; a first bootstrap capacitor that is arranged to provide power to the first driver circuit; a second driver circuit that is arranged to selectively drive the second switching device; a second bootstrap capacitor that is arranged to provide power to the second driver circuit; and a cross-couple circuit that is arranged to enable charging of the first bootstrap capacitor via current through selectively either the cross-couple circuit or another current path that is distinct from the cross-couple circuit based, at least in part, on whether the fourth switching device is open or closed, wherein the cross-couple circuit is coupled between the first bootstrap capacitor and the second bootstrap capacitor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A circuit for providing power, comprising:
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a switching circuit, including; a first switching device that is coupled between an input node and a first switch node; a second switching device that is coupled at least to a second switch node; a third switching device that is coupled between the first switch node and a common node; and a fourth switching device that is coupled between the second switch node and the common node; a first driver circuit having at least a first power terminal and a second power terminal, wherein the first power terminal of the first driver circuit is coupled to a first bootstrap node and the second power terminal of the first driver circuit is coupled to the first switch node; a first bootstrap capacitor that is coupled to the first bootstrap node and to the first switch node, wherein the first bootstrap capacitor is arranged to be charged via selectively either a current path between the first bootstrap node and a second bootstrap node or another current path that is distinct from the current path between the first bootstrap node and the second bootstrap node based, at least in part, on whether the third switching device is open or closed and on whether the fourth switching device is open or closed; a second driver circuit having at least a first power terminal and a second power terminal, wherein the first power terminal of the second driver circuit is coupled to the second bootstrap node and the second power terminal of the second driver circuit is coupled to the second switch node; and a second bootstrap capacitor that is coupled to the second bootstrap node and to the second switch node. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of providing power, comprising:
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employing a first driver circuit to selectively drive a first high-side N-Channel switching device of an H-Bridge circuit; employing a second driver circuit to selectively drive a second high-side N-Channel switching device of the H-Bridge circuit; selectively switching a first low-side switching device of the H-Bridge circuit, wherein the first low-side switching device is coupled to the first high-side switching device; selectively switching a second low-side switching device of the H-Bridge circuit, wherein the second low-side switching device is coupled to the second high-side switching device; charging a first bootstrap capacitor via selectively either a current path between the first bootstrap capacitor and the second bootstrap capacitor or another current path that is distinct from the current path between the first bootstrap capacitor and the second bootstrap capacitor based, at least in part, on whether the second low-side switching device is open or closed; charging a second bootstrap; employing the first bootstrap capacitor to power, at least in part, the first driver circuit; and employing the second bootstrap capacitor to power, at least in part, the second driver circuit.
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Specification