Bootstrap diode emulator with dynamic back-gate biasing
First Claim
1. A bootstrap diode emulator circuit for use with a half-bridge switching circuit, the switching circuit including low-side and high-side transistors connected to one another in a totem pole configuration at a load node, the low-side and high-side transistors having respective gate nodes;
- a driver circuit electrically coupled to the gate nodes of the low-side and high-side transistors, the driver circuit being controllable by at least one control input;
a low-side voltage supply to produce a low-side voltage on a low-side supply node; and
a bootstrap capacitor coupled between a high-side supply node and the load node, the bootstrap diode emulator circuit comprising;
an LDMOS transistor having a gate, a back-gate, a source and a drain, the drain of the LDMOS transistor being coupled to the high-side supply node, the source of the LDMOS transistor being coupled to the low-side supply node;
a gate control circuit electrically coupled to the gate of the LDMOS transistor, and a dynamic back-gate biasing circuit electrically coupled to the back-gate of the LDMOS transistor;
wherein the gate control circuit is operable to turn on the LDMOS transistor in accordance with the at least one control input and the dynamic back-gate biasing circuit is operable to dynamically biases the back-gate of the LDMOS transistor when the LDMOS is turned on by applying a voltage to the back-gate of the LDMOS transistor that is close to but slightly lower than a voltage of the drain of the LDMOS transistor.
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Accused Products
Abstract
A bootstrap diode emulator circuit for use in a half-bridge switching circuit employing transistors connected to one another in a totem pole configuration, a driver circuit for driving the transistors, and a bootstrap capacitor for providing power to the high-side driver circuit. The bootstrap diode emulator circuit includes an LDMOS transistor having a gate, a back-gate, a source and a drain, the drain of the LDMOS transistor being coupled to the high-side supply node, the source of the LDMOS transistor being coupled to the low-side supply node; a gate control circuit electrically coupled to the gate of the LDMOS transistor, and a dynamic back-gate biasing circuit electrically coupled to the back-gate of the LDMOS transistor. The dynamic back-gate biasing circuit is operable to dynamically bias the back-gate of the LDMOS transistor when the LDMOS is turned on by applying a voltage to the back-gate of the LDMOS transistor that is close to but slightly lower than a voltage of the drain of the LDMOS transistor.
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Citations
12 Claims
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1. A bootstrap diode emulator circuit for use with a half-bridge switching circuit, the switching circuit including low-side and high-side transistors connected to one another in a totem pole configuration at a load node, the low-side and high-side transistors having respective gate nodes;
- a driver circuit electrically coupled to the gate nodes of the low-side and high-side transistors, the driver circuit being controllable by at least one control input;
a low-side voltage supply to produce a low-side voltage on a low-side supply node; and
a bootstrap capacitor coupled between a high-side supply node and the load node, the bootstrap diode emulator circuit comprising;
an LDMOS transistor having a gate, a back-gate, a source and a drain, the drain of the LDMOS transistor being coupled to the high-side supply node, the source of the LDMOS transistor being coupled to the low-side supply node;
a gate control circuit electrically coupled to the gate of the LDMOS transistor, and a dynamic back-gate biasing circuit electrically coupled to the back-gate of the LDMOS transistor;
wherein the gate control circuit is operable to turn on the LDMOS transistor in accordance with the at least one control input and the dynamic back-gate biasing circuit is operable to dynamically biases the back-gate of the LDMOS transistor when the LDMOS is turned on by applying a voltage to the back-gate of the LDMOS transistor that is close to but slightly lower than a voltage of the drain of the LDMOS transistor. - View Dependent Claims (2, 3, 4, 5, 6)
- a driver circuit electrically coupled to the gate nodes of the low-side and high-side transistors, the driver circuit being controllable by at least one control input;
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7. A half-bridge switching circuit to control low-side and high-side transistors electrically connected to one another at a load node in a totem pole configuration, the low-side and high-side transistors having respective gate nodes, a bootstrap capacitor being electrically coupled between a high-side supply node and the load node, the half-bridge switching circuit comprising:
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a driver circuit electrically coupled to the gate nodes of the low-side and high-side transistors, the driver circuit being controllable by at least one control input;
a low-side voltage supply to produce a low-side voltage on a low-side supply node; and
a bootstrap diode emulator circuit coupled to the low-side supply node and including an LDMOS transistor having source, gate, drain, and back-gate nodes, the LDMOS transistor being controllable to supply the high-side supply node with a voltage approximately equal to the low-side voltage when the low-side driver is operated, the bootstrap diode emulator being operable to dynamically bias the back-gate node of the LDMOS transistor by applying a voltage to the back-gate of the LDMOS transistor that is close to but slightly lower than a voltage of the drain node of the LDMOS transistor. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification