Optical modules on a PCB are typically physically spread out and share the same onboard power supply. To ensure the quality of the transmitted optical signal, the optical modules have tight requirements on the integrity of their power supply, including a maximum permissible DC voltage drop from the power supply output to the module. Modules that are close to the power supply experience smaller voltage drops and better power-supply integrity. Modules that are further away can experience voltage drops large enough to violate specification. This disclosure describes a voltage sensing-line design that leverages the operating configurations of the optical-module array on a PCB to achieve distributed power integrity using a low number of sensing lines.

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This work is licensed under a Creative Commons Attribution 4.0 License.