Current Mode vs Voltage Mode Pyros
Date Announced: 10 Jun 2015
Pyroelectric detectors have become a staple in the IR industry for countless applications and for good reasons; pyroelectrics are cheap, reliable, and sensitive enough for applications ranging from motion detection to FTIR spectrometry. Experienced users will be very familiar with how pyroelectric detectors operate under the most commonly used mode; voltage mode (VM).
Voltage mode detectors are simple JFET source follower based devices converting a high impedance input to a low impedance output. Voltage mode operation does have the advantage of being capable of giving the highest D* (@10Hz) with a relatively simple circuit with very flexible amplification. VM devices are not without their failures; producing relatively low signal (especially at high frequencies) and a strongly temperature dependent offset.
Current mode operation provides a higher responsivity with a low offset with a low temprature dependence. In current mode an op-amp is used in conjunction with a negative feedback loop. CM also provides a low electrical time constant and faster recovery times allowing you to use current mode devices at much higher frequencies than VM devices with less signal loss.
At LASER COMPONENTS we manufacture both voltage mode and current mode devices in a wide range of standard products, but can provide the solution fitted to your needs.
Contact
LASER COMPONENTS (UK) Ltd
Goldlay House, 114 Parkway, Chelmsford, Essex. CM2 7PR. UK
Tel: 01245 491499, Fax: 01245 491801
E-mail: info@lasercomponents.co.uk
Web Site: www.lasercomponents.co.uk
