Transmitter architecture for photoplethysmography systems
US10187940B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 18, 2016 |
| Grant date | Jan 22, 2019 |
| Priority date | — |
| Expiry date | Jul 4, 2036 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/30
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An LED (light-emitting diode) driver for a photoplethysmography system, including a switched-mode operational amplifier for driving a driver transistor with a source-drain path in series with the LED. In a first clock phase in which the LED is disconnected from the driver transistor, the amplifier is coupled in unity gain mode, and a sampling capacitor stores a voltage corresponding to the offset and flicker noise of the amplifier; the gate of the driver transistor is precharged to a reference voltage in this first clock phase. In a second clock phase, the sampled voltage at the capacitor is subtracted from the reference voltage applied to the amplifier input, so that the LED drive is adjusted according to the sampled noise. A signal from the transmitter channel is forwarded to a noise/ripple remover in the receiving channel, to remove transmitter noise from the received signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.