Power Management Integrated Circuit for Driving Inductive Loads
First Claim
1. An integrated circuit comprising:
- a first terminal;
a second terminal;
a third terminal;
a P-channel field effect transistor, wherein a source of the P-channel transistor is coupled to the first terminal, wherein a drain of the P-channel transistor is coupled to the second terminal;
an N-channel field effect transistor, wherein a drain of the N-channel transistor is coupled to the second terminal, wherein a source of the N-channel transistor is coupled to the third terminal, wherein an N type isolation structure is disposed between a substrate and the drain of the N-channel transistor; and
a tracking and clamping circuit that in a tracking mode provides a relatively low resistance path between the drain and the isolation structure such that when a voltage Vd on the drain is substantially positive that a voltage Viso on the isolation structure tracks Vd, whereas the tracking and clamping circuit in a clamping mode provides a relatively high resistance path between the drain and the isolation structure such that when Vd is substantially negative that Viso is clamped to be no more negative than approximately −
0.7 volts.
1 Assignment
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Accused Products
Abstract
A power management integrated circuit includes pairs of high-side and low-side drivers, sensing circuitry, and a processor. The high-side and low-side drivers are used in combination with external discrete NFETs to drive multiple windings of a motor. The N-channel LDMOS transistor of each high-side driver has an associated isolation structure and a tracking and clamping circuit. If the voltage on a terminal of the integrated circuit pulses negative during a switching of current flow to the motor, then the isolation structure and tracking and clamping circuit clamps the voltage on the isolation structure and blocks current flow from the substrate to the drain. An associated ESD protection circuit allows the voltage on the terminal to pulse negative. As a result, a large surge of current that would otherwise flow through the high-side driver is blocked, and is conducted outside the integrated circuit through a body diode of an external NFET.
30 Citations
23 Claims
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1. An integrated circuit comprising:
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a first terminal; a second terminal; a third terminal; a P-channel field effect transistor, wherein a source of the P-channel transistor is coupled to the first terminal, wherein a drain of the P-channel transistor is coupled to the second terminal; an N-channel field effect transistor, wherein a drain of the N-channel transistor is coupled to the second terminal, wherein a source of the N-channel transistor is coupled to the third terminal, wherein an N type isolation structure is disposed between a substrate and the drain of the N-channel transistor; and a tracking and clamping circuit that in a tracking mode provides a relatively low resistance path between the drain and the isolation structure such that when a voltage Vd on the drain is substantially positive that a voltage Viso on the isolation structure tracks Vd, whereas the tracking and clamping circuit in a clamping mode provides a relatively high resistance path between the drain and the isolation structure such that when Vd is substantially negative that Viso is clamped to be no more negative than approximately −
0.7 volts. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method comprising:
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(a) driving a control signal from a high-side driver onto a first terminal of an integrated circuit, wherein the high-side driver is a part of the integrated circuit, wherein the high-side driver includes an N-channel field effect transistor, wherein a drain of the N-channel field effect transistor is coupled to the first terminal of the integrated circuit, wherein a source of the N-channel field effect transistor is coupled to a second terminal of the integrated circuit, and wherein an N type isolation structure is disposed between the N-channel field effect transistor and a substrate; (b) in a tracking mode providing a relatively low resistance path between the drain and the isolation structure such that when a voltage Vd on the drain with respect to a voltage Vsub on the substrate is substantially positive that a voltage Viso on the isolation structure tracks Vd; and (c) in a clamping mode providing a relatively high resistance path between the drain and the isolation structure such that when Vd is substantially negative that Viso is clamped to be no more negative than approximately −
0.7 volts. - View Dependent Claims (8, 9, 10)
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11. An integrated circuit comprising:
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a first terminal; a second terminal; a third terminal; a P-channel field effect transistor, wherein a source of P-channel transistor is coupled to the first terminal, wherein a drain of the P-channel transistor is coupled to the second terminal; an N-channel field effect transistor, wherein a drain of the N-channel transistor is coupled to the second terminal, wherein a source of the N-channel transistor is coupled to the third terminal, wherein an N type isolation structure is disposed between the N-channel transistor and a substrate; and means for coupling the drain of the N-channel transistor to the isolation structure such that when a voltage Vd on the drain is substantially positive that a voltage Viso on the isolation structure tracks Vd, and for coupling the drain of the N-channel transistor to the isolation structure such that when Vd is substantially negative that Viso is clamped to be no more negative than a predetermined negative voltage. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A power management integrated circuit comprising:
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a plurality high-side drivers and low-side drivers organized in pairs, wherein each of the high-side drivers comprises; a P-channel field effect transistor; an N-channel field effect transistor having a drain that is coupled to a drain of the P-channel field effect transistor, wherein the N-channel field effect transistor has a source that is coupled to a terminal of the integrated circuit, wherein an N type isolation structure is disposed between the N-channel transistor and a substrate of the integrated circuit; and means for coupling the drain to the isolation structure such that when a voltage on the terminal is substantially positive that a voltage Viso on the isolation structure tracks a voltage Vd on the drain, and for coupling the drain and the isolation structure such that when the voltage on the terminal is substantially negative that Viso is clamped to be no more negative than a predetermined negative voltage; and a processor that outputs control information to the plurality of high-side drivers and low-side drivers and thereby causes the high-side drivers and the low-side drivers to output control signals onto terminals of the integrated circuit. - View Dependent Claims (19, 20)
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21. A power management integrated circuit comprising:
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a plurality high-side drivers and low-side drivers organized in pairs, wherein each of the high-side drivers comprises; a P-channel field effect transistor; an N-channel field effect transistor having a drain that is coupled to a drain of the P-channel field effect transistor, wherein the N-channel field effect transistor has a source that is coupled to a terminal of the integrated circuit, wherein an N type isolation structure is disposed between the N-channel transistor and a substrate of the integrated circuit; and means coupled to the isolation structure for preventing a large substrate surge current from flowing through the terminal and through the high-side driver when the voltage on the terminal spikes negative as a result of a switching of an inductive load coupled to the terminal; and a processor that outputs control information to the plurality of high-side drivers and low-side drivers and thereby causes the high-side drivers and the low-side drivers to output control signals onto terminals of the integrated circuit. - View Dependent Claims (22, 23)
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Specification