Circuits and methods for photoplethysmographic sensors

Some embodiments relate to a device, method, and/or computer-readable medium storing processor-executable process steps to remove a component of a signal corresponding to ambient light in a photoplethysmographic sensor device, including capturing a first detected light signal representing an ambient light at a first time, causing a light emitter to generate a source light signal driven at a first level, capturing a second detected light signal representing the source light signal after interacting with a user's tissue plus the first detected light signal, generating a first output signal based on the second detected light signal adjusted by the first detected light signal, causing the light emitter to generate a source light signal driven at a second level, capturing a third detected light signal representing the source light signal driven at the second level after interacting with the user's skin plus the first detected light signal, and generating a second output signal based on the third detected light signal adjusted by the first detected light signal.