Charge pump overshoot prevention for gate drivers
First Claim
1. A protection circuit, comprising:
- a pass gate including a drain configured to receive an input signal, a source configured to output the input signal, and a gate configured to control passing of the input signal between the drain and the source; and
a voltage boosting circuit including an output coupled to the gate of the pass gate, the voltage boosting circuit configured to generate a pass gate driving voltage on the output, the voltage boosting circuit further configured to passively control the pass gate driving voltage to a level less than a steady-state voltage level during start-up of the protection circuit, wherein the voltage boosting circuit includes;
an oscillator; and
a charge pump configured to generate the levels of the pass gate driving voltage in response to control by the oscillator;
wherein the oscillator includes a start-up oscillator bias control circuit configured to reduce a frequency of the oscillator during start-up of the protection circuit, the frequency reduced to frequencies less than a steady-state frequency to passively control the pass gate driving voltage.
1 Assignment
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Accused Products
Abstract
An over-voltage protection circuit and method may include a pass gate and a voltage boosting circuit for providing protection to start-up voltage-sensitive circuits during start-up conditions of a system including the voltage-sensitive circuits. The pass gate may include a drain, source, and gate, with the drain configured to receive an input signal and the source configured to output the input signal, in response to a pass gate driving voltage signal applied to the gate of the pass gate. The voltage boosting circuit may include an output coupled to the gate of the pass gate, the voltage boosting circuit configured to generate a pass gate driving voltage on the output. The voltage boosting circuit further configured to passively control the pass gate driving voltage to a level less than a steady-state voltage level during start-up of the protection circuit.
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Citations
15 Claims
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1. A protection circuit, comprising:
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a pass gate including a drain configured to receive an input signal, a source configured to output the input signal, and a gate configured to control passing of the input signal between the drain and the source; and a voltage boosting circuit including an output coupled to the gate of the pass gate, the voltage boosting circuit configured to generate a pass gate driving voltage on the output, the voltage boosting circuit further configured to passively control the pass gate driving voltage to a level less than a steady-state voltage level during start-up of the protection circuit, wherein the voltage boosting circuit includes; an oscillator; and a charge pump configured to generate the levels of the pass gate driving voltage in response to control by the oscillator; wherein the oscillator includes a start-up oscillator bias control circuit configured to reduce a frequency of the oscillator during start-up of the protection circuit, the frequency reduced to frequencies less than a steady-state frequency to passively control the pass gate driving voltage.
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2. A protection circuit, comprising:
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a pass gate including a drain configured to receive an input signal, a source configured to output the input signal, and a gate configured to control passing of the input signal between the drain and the source; and a voltage boosting circuit including an output coupled to the gate of the pass gate, the voltage boosting circuit configured to generate a pass gate driving voltage on the output, the voltage boosting circuit further configured to passively control the pass gate driving voltage to a level less than a steady-state voltage level during start-up of the protection circuit, wherein the voltage boosting circuit includes; an oscillator; and a charge pump configured to generate the levels of the pass gate driving voltage in response to control by the oscillator; wherein the oscillator includes a start-up oscillator bias control circuit configured to reduce a bias current to the oscillator during start-up of the protection circuit, the bias current reduced to levels less than a steady-state level to passively control the pass gate driving voltage.
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3. A protection circuit, comprising:
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a pass gate including a drain configured to receive an input signal, a source configured to output the input signal, and a gate configured to control passing of the input signal between the drain and the source; and a voltage boosting circuit including an output coupled to the gate of the pass gate, the voltage boosting circuit configured to generate a pass gate driving voltage on the output, the voltage boosting circuit further configured to passively control the pass gate driving voltage to a level less than a steady-state voltage level during start-up of the protection circuit, wherein the voltage boosting circuit includes; an oscillator; and a charge pump configured to generate the levels of the pass gate driving voltage in response to control by the oscillator; wherein the oscillator includes; a ring oscillator; and a current mirror of a plurality of transistors configured to supply a bias current to the ring oscillator; wherein the protection circuit includes a start-up oscillator bias control circuit configured to provide low-pass filtering of gates of the plurality of transistors in the current mirror. - View Dependent Claims (4, 5)
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6. An interconnection system, comprising:
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a first printed circuit board (PCB) node coupled to an external interface; a second PCB node coupled to an electronic circuit; and an over-voltage protection circuit coupled between the first PCB node and the second PCB node, the over-voltage protection circuit including; a pass gate including a drain configured to receive an input signal, a source configured to output the input signal, and a gate configured to control passing of the input signal between the drain and the source; and a voltage boosting circuit including an output coupled to the gate of the pass gate, the voltage boosting circuit configured to generate a pass gate driving voltage on the output, the voltage boosting circuit further configured to passively control the pass gate driving voltage to a level less than a steady-state voltage level during start-up of the protection circuit, wherein the voltage boosting circuit includes; an oscillator; and a charge pump configured to generate the levels of the pass gate driving voltage in response to control by the oscillator; wherein the oscillator includes a start-up oscillator bias control circuit configured to reduce a frequency of the oscillator during start-up of the protection circuit, the frequency reduced to frequencies less than a steady-state frequency to passively control the pass gate driving voltage. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method, comprising:
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generating bias current to a ring oscillator of an over-voltage protection circuit, a level of the bias current being less than a steady-state level during start-up of an over-voltage protection circuit; generating an oscillator signal at an output of the ring oscillator, the oscillator signal having a frequency based on the level of the bias current; boosting a reference voltage to a pass gate driving voltage to control a gate of a pass transistor of the over-voltage protection circuit; and driving the gate of the pass transistor with the pass gate driving voltage. - View Dependent Claims (13, 14, 15)
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Specification