System for adjusting slew rate on an output of a drive circuit by enabling a plurality of pre-drivers and a plurality of output drivers
First Claim
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1. A drive circuit, comprising:
- a plurality of selector circuits;
a plurality of control inputs;
a plurality of pre-driver groups having a plurality of pre-drivers, each pre-driver group coupled to a corresponding one of the plurality of selector circuits, each pre-driver group coupled to the plurality of control inputs, the control inputs to enable one or more of the plurality of pre-drivers within each pre-driver group; and
a plurality of output drivers, each output driver having an input and an output, each input of an output driver coupled to a corresponding one of the plurality of pre-driver groups, the selector circuits to enable one or more of the plurality of output drivers, the outputs of the plurality of output drivers coupled together and having a slew rate, the slew rate determined by a first number of the plurality of pre-drivers that are enabled and by a second number of the plurality of output drivers that are enabled.
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Abstract
An interface circuit providing a high speed bus. According to one embodiment, the interface circuitry includes a plurality of I/O pins coupled to a plurality of bus drivers, wherein each bus driver is configured to adjust the rise time, fall time, and drive strength of outputs signal on the I/O pins based on process-voltage-temperature ("PVT") conditions. The circuitry used to adjust the I/O outputs includes a slew rate control circuit, a current control circuit, and a delay lock loop ("DLL").
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Citations
24 Claims
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1. A drive circuit, comprising:
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a plurality of selector circuits; a plurality of control inputs; a plurality of pre-driver groups having a plurality of pre-drivers, each pre-driver group coupled to a corresponding one of the plurality of selector circuits, each pre-driver group coupled to the plurality of control inputs, the control inputs to enable one or more of the plurality of pre-drivers within each pre-driver group; and a plurality of output drivers, each output driver having an input and an output, each input of an output driver coupled to a corresponding one of the plurality of pre-driver groups, the selector circuits to enable one or more of the plurality of output drivers, the outputs of the plurality of output drivers coupled together and having a slew rate, the slew rate determined by a first number of the plurality of pre-drivers that are enabled and by a second number of the plurality of output drivers that are enabled. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An interface circuit, comprising;
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a plurality of drive circuits, each of the plurality of drive circuits having a first input, a second input, and an output; a first control circuit coupled between the first input and the output of at least one of the plurality of drive circuits, the first control circuit to control a current flow on the output of the at least one of the plurality of drive circuits, the current flow based on an output voltage on the output of the at least one of the plurality of drive circuits; and a second control circuit coupled to the second input of the at least one of the plurality of drive circuits, the second control circuit to control a slew rate on the output of the at least one of the plurality of drive circuits. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A data transfer system, comprising:
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a bus having data lines, a first clock, and a second clock; a first device and a second device coupled to the bus, each device having an interface circuit, the interface circuit further comprising; a plurality of drive circuits, each of the plurality of drive circuits having a first input, a second input, a first clock input, a second clock input, and an output; a clock circuit coupled to the first and the second clock inputs, the clock circuit to synchronize the first clock and the second clock, the clock circuit to transmit the synchronized first and second clocks to the first and the second clock inputs; a first control circuit coupled between the first input and the output of at least one of the plurality of drive circuits, the first control circuit to control a current flow on the output of the at least one of the plurality of drive circuits; and a second control circuit coupled to the second input of the at least one of the plurality of drive circuits, the second control circuit to control a slew rate on the output of the at least one of the plurality of drive circuits. - View Dependent Claims (19, 20)
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21. A method of adjusting slew rate on an output of a drive circuit, comprising;
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generating a plurality of drive control signals based on a calibration signal; generating a current control signal based on a voltage of the output of the drive circuit; and enabling a plurality of pre-drivers using the plurality of drive control signals, the plurality of pre-drivers coupled to a corresponding plurality of output drivers, the plurality of pre-drivers enabled to adjust the slew rate on the output of the drive circuit. - View Dependent Claims (22, 23, 24)
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Specification