Supply voltage modular photodiode bias
AssigneeAvago Technologies General IP (Singapore) Pte. Ltd.
InventorsGeorgios Asmanis, Faouzi Chaahoub, Michael A. Robinson
Life of this patent
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Abstract
An optical communication system, circuit, and Integrated Circuit (IC) chip are disclosed. The disclosed optical communication system includes a photodiode configured to receive light energy and convert the light energy into an electrical signal, an amplifier configured to receive the electrical signal from the photodiode and output an amplified electrical signal, and a control circuit comprising a biasing network that generates a modular logic level that scales with a bias voltage of the photodiode.
Claims20
An optical communication system, comprising:
- a photodiode configured to receive light energy and convert the light energy into an electrical signal;
- an amplifier configured to receive the electrical signal from the photodiode and output an amplified electrical signal, wherein the amplifier is driven by a supply voltage Vcc;
- and
- a control circuit comprising a biasing network having a plurality of switching elements connected in series between a photodiode biasing supply voltage Vpd and a bias resistor that is connected to a common reference voltage or ground, wherein the supply voltage Vcc is less than the photodiode biasing supply voltage Vpd, wherein the amplifier is also connected to the common reference voltage or ground, and wherein the biasing network provides a balanced high frequency ground path between the photodiode and the amplifier.
A circuit, comprising:
- a photodiode that receives optical signals and produces electrical signals in response thereto, wherein the photodiode is driven by an external supply voltage Vpd;
- a trans-impedance amplifier that receives the electrical signals produced by the photodiode, wherein the trans-impedance amplifier is driven by a supply voltage Vcc that is less than the external supply voltage Vpd;
- and
- a filter circuit that biases the photodiode to provide a balanced high frequency ground path between the photodiode and the trans-impedance amplifier, wherein the filter circuit receives a biasing voltage from a control circuit that shares a common reference or ground voltage with the trans-impedance amplifier, wherein the control circuit comprises a plurality of switching elements connected in series between the external supply voltage Vpd and a bias resistor, wherein the bias resistor is connected to the common reference or ground voltage, and wherein the control circuit is driven by the external supply voltage Vpd.
An Integrated Circuit (IC) chip, comprising:
- a trans-impedance amplifier configured to receive an input electrical signal from a photodiode and provide an amplified version of the input electrical signal as an output, wherein the trans-impedance amplifier is driven by a supply voltage Vcc, wherein the photodiode is driven by an external supply voltage Vpd, and wherein the external supply voltage Vpd is greater than the supply voltage Vcc;
- a control circuit that controls a bias voltage of the photodiode when the IC chip is connected to the photodiode, that is also driven by the external supply voltage Vpd, and that shares a common reference or ground voltage with the trans-impedance amplifier, wherein the control circuit comprises a plurality of switching elements connected in series between the external supply voltage Vpd and a bias resistor, and wherein the bias resistor is connected to the common reference or ground voltage;
- and
- a filter circuit that biases the photodiode to ensure a balanced high frequency ground path between the photodiode and the trans-impedance amplifier.
Dependencies are inferred from the claim text.