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US 11,114,820 B2Granted
Push-pull circuit with driving assisted by asymmetric charge sharing
AssigneeHewlett Packard Enterprise Development LP
InventorsZhubiao Zhu, Clinton Harold Parker, Daniel Alan Berkram
Life of this patent
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Abstract
A push-pull circuit for an opto-electronic device includes: an output node; a pull-up circuit that, in operation, controls a falling edge rate of an input signal to the opto-electronic device while sharing charge with the output node; and a pull-down circuit that, in operation, controls a rising edge rate of the input signal to the opto-electronic device while sharing charge with the output node.
Claims14
A push-pull circuit for an opto-electronic device, comprising:
- an output node connected to a common node, wherein an input signal is transmitted over a line from the common node to the output node;
- a pull-up circuit connected to the output node that, in operation, controls a falling edge rate of the input signal to the opto-electronic device while sharing charge with the output node, the pull-up circuit comprising:
- a current source;
- a variable capacitance capacitor in parallel with the current source;
- and
- a controllable switch in series with the current source and the variable capacitance capacitor to connect and disconnect the current source and the variable capacitance capacitor to and from the output node;
- and
- a pull-down circuit connected to the output node that, in operation, controls a rising edge rate of the input signal to the opto-electronic device while sharing charge with the output node, the pull-down circuit comprising:
- a current sink;
- a variable capacitance capacitor in parallel with the current sink;
- and
- a controllable switch in series with the current sink and the variable capacitance capacitor to connect and disconnect the current sink and the variable capacitance capacitor to and from the output node,
- wherein the pull-up circuit and the pull-down circuit is configured to convert the input signal at the output node to an output signal to the opto-electronic device that equalizes the output signal of the electro-optic device based on a difference in the falling edge rate of the input signal caused by the pull-up circuit and the rising edge rate of the input signal by the pull-down circuit.
10 more elements
An apparatus comprising:
- an opto-electronic device;
- a driver circuit that, in operation, asymmetrically drives an input signal to the opto-electronic device to equalize output from the electro-optic device, the driver circuit including:
- an output node connected to a common node, wherein the input signal is transmitted over a line from the common node to the output node and the input signal is transmitted to the opto-electronic device through the output node;
- a pull-up circuit connected to the output node including:
- a current source;
- a first variable capacitance capacitor in parallel with the current source;
- and
- a first controllable switch in series with the current source and the first variable capacitance capacitor to connect and disconnect the current source and the first variable capacitance capacitor to and from the output node, the pull-up circuit sharing charge between the output node and the first variable capacitance capacitor to control the falling edge rate of the input signal to the opto-electronic device when connected to the output node;
- and
- a pull-down circuit connected to the output node including:
- a current sink;
- a second variable capacitance capacitor in parallel with the current sink;
- and
- a second controllable switch in series with the current sink and the second variable capacitance capacitor to connect and disconnect the current sink and the second variable capacitance capacitor to and from the output node, the pull-down circuit sharing charge between the output node and the second variable capacitance capacitor to control the rising edge rate of the input signal to the opto-electronic device when connected to the output node,
- wherein the driver circuit asymmetrically drives the input signal based on a difference in the falling edge rate of the input signal caused by the pull-up circuit and the rising edge rate of the input signal by the pull-down circuit at the output node to output an output signal that asymmetrically drives the input signal to the electro-optic device.
12 more elements
A method comprising:
- generating an input signal for an opto-electronic device from a push-pull driver circuit;
- sharing charge in the push-pull driver circuit between the input signal and at least one variable capacitance capacitor to control at least one of the rising edge rate or the falling edge rate of the input signal, wherein each of the at least one variable capacitance capacitors is connected to an output node, the output node connected to a source of the input signal;
- and
- asymmetrically driving the opto-electronic device with the controlled-edge input signal to produce an equalized optical output signal from the opto-electronic device,
- wherein a first variable capacitance capacitor of a push portion of the push-pull driver circuit is in parallel with a current source, and a second variable capacitance capacitor of a pull portion of the push-pull driver circuit is in parallel with a current sink, and
- wherein asymmetrically driving the opto-electronic device with the controlled-edge input signal is based on a difference in the falling edge rate of the input signal and the rising edge rate of the input signal on the output node to output an output signal that equalizes the output of the opto-electric device.
3 more elements
Dependencies are inferred from the claim text.