Signal driver slew rate control
AssigneeIntegrated Device Technology, Inc.
InventorsZhigang Hu, Hui Yu, Shaokang Wang, Yuan Zhang, Yue Yu
Life of this patent
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Abstract
An apparatus includes a first circuit and a second circuit. The first circuit may be configured to (i) generate a plurality of delayed signals each as a copy of an input signal shifted in time by a sequence of respective delays based on a control signal and (ii) change a number of driver signals that are active during each delay in the sequence of respective delays based on the input signal and the plurality of delayed signals to control a slew rate of an output signal. The second circuit may be configured to drive the output signal in response to the driver signals.
Claims18
An apparatus comprising:
- a first circuit configured to (i) generate a plurality of delayed signals each as a copy of an input signal shifted in time by a sequence of respective delays based on a control signal and (ii) change a number of driver signals that are active during each delay in said sequence of respective delays based on said input signal and said plurality of delayed signals to control a slew rate of an output signal;
- and
- a second circuit configured to drive said output signal in response to said driver signals, wherein (i) an initial delay in said sequence of respective delays has a fixed duration that maintains said slew rate of said output signal at a constant rate until said output signal crosses a threshold voltage and (ii) at least one subsequent delay after said initial delay in said sequence of respective delays has a programmable duration that adjusts said slew rate of said output signal after said output signal has crossed said threshold voltage.
A method for signal driver slew rate control, comprising the steps of:
- generating a plurality of delayed signals each as a copy of an input signal shifted in time by a sequence of respective delays based on a control signal;
- changing a number of driver signals that are active during each delay in said sequence of respective delays based on said input signal and said plurality of delayed signals to control said slew rate of an output signal;
- and
- driving said output signal in response to said driver signals, wherein (i) an initial delay in said sequence of respective delays has a fixed duration that maintains said slew rate of said output signal at a constant rate until said output signal crosses a threshold voltage and (ii) at least one subsequent delay after said initial delay in said sequence of respective delays has a programmable duration that adjusts said slew rate of said output signal after said output signal has crossed said threshold voltage.
An apparatus comprising:
- a first circuit configured to (i) generate a trim signal based on a fabrication process parameter of said apparatus and (ii) generate a control signal that determines a slew rate of an output signal based on both said trim signal and a target signal, wherein (a) said target signal provides a programmable offset to said trim signal and (b) said first circuit comprises an adder configured to generate said control signal as a sum of said trim signal and said target signal;
- and
- a second circuit configured to drive said output signal at said slew rate in response to an input signal.
Dependencies are inferred from the claim text.