Passive infrared sensor apparatus and method with DC offset compensation
US6307200A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 10, 1999 |
| Grant date | Oct 23, 2001 |
| Priority date | — |
| Expiry date | Mar 10, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/24
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A PIR sensor apparatus and method make use of a dc amplifier circuit. The dc amplifier circuit amplifies a dc-coupled sensor signal generated by a PIR sensor for analysis. For improved accuracy, the dc amplifier circuit is controlled to compensate for dc offset in the sensor signal. In this manner, the dc amplifier circuit is capable of reducing false triggering and inhibited triggering due to excessive dc offset. The amplifier is dc-coupled to an output of the PIR sensor to receive the sensor signal. A detector detects a level of dc offset within the sensor signal. A controller controls the amplifier to compensate for the detected level of dc offset The amplifier may include a differential amplifier having a first input that receives the sensor signal and a second input that receives a reference voltage. A resistor-capacitor circuit can be provided to set the reference voltage received by the second input of the amplifier. The detector and controller may be realized by a processor that detects the level of dc offset in the sensor signal, and charges the capacitor in the resistor-capacitor circuit at a duty cycle selected to adjust the reference voltage to compensate for the dc off…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.