REDRIVER WITH OUTPUT RECEIVER DETECTION THAT MIRRORS DETECTED TERMINATION ON OUTPUT TO INPUT
First Claim
1. A method for operating a repeater to mirror a termination impedance to an input comprising:
- providing a connection to a first output termination resistance to an output of the repeater;
waiting for a measuring period of time to elapse after connecting the first output termination resistance to the output;
sensing the output to detect whether the termination impedance is connected; and
when connection of the termination impedance is detected, connecting an input termination resistance to an input of the repeater to mirror the termination impedance.
3 Assignments
0 Petitions
Accused Products
Abstract
A redriver chip is inserted between a transmitter chip and a receiver chip and re-drives differential signals from the transmitter chip to the receiver chip. The redriver chip has switched output termination that switches to a high value to detect far-end termination at the receiver chip, and to a low value for signaling. An output detector detects when the receiver chip has termination to ground and enables switched input termination to provide termination to ground on the lines back to the transmitter chip so that the far-end termination on the receiver chip is mirrored back to the transmitter chip, hiding the redriver chip. An input signal detector detects when the transmitter chip begins signaling and enables an equalizer, limiter, pre-driver, and output stage to re-drive the signals to the receiver chip. The input signal detector also causes the switched output termination to switch to the low value termination for signaling.
4 Citations
19 Claims
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1. A method for operating a repeater to mirror a termination impedance to an input comprising:
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providing a connection to a first output termination resistance to an output of the repeater; waiting for a measuring period of time to elapse after connecting the first output termination resistance to the output; sensing the output to detect whether the termination impedance is connected; and when connection of the termination impedance is detected, connecting an input termination resistance to an input of the repeater to mirror the termination impedance. - View Dependent Claims (2, 3, 4, 5)
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6. A repeater device comprising:
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a differential input including a true differential input and a complement differential input; a differential output including a true differential output and a complement differential output; a differential circuit, coupled to the differential input, for repeating data received to the differential output as re-transmitted data; and an impedance mirror circuit, coupled to the differential output, for detecting a termination impedance on the differential output and for controlling an input termination on the differential input to reflect the termination impedance detected on the differential output, wherein the termination impedance is re-detected after a period of time has elapsed. - View Dependent Claims (7, 8, 9, 10, 11, 12, 19)
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13. A system comprising:
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a transmitter; a receiver; and a repeater comprising, a differential input coupled to the transmitter, a differential output coupled to the receiver, a differential circuit coupled between the differential input and the differential output and configured for repeating data received at the differential input from the transmitter at the differential output for transmission to the receiver as re-transmitted data, the repeater further comprising an impedance mirror circuit coupled to the differential output and configured for detecting a termination impedance on the differential output and for controlling an input termination on the differential input to reflect the termination impedance detected on the differential output, wherein the termination impedance is re-detected after a period of time has elapsed. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification