2.5 - Miniaturized 4x16 Thermopile Array Sensor with Integrated on Signal Conditioning on Chip

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings IRS² 2011
I2 - IR Arrays & lmaging
V. Kassovski, A. Grigorov, H. Hristov, P. Nedelev - MELEXIS BULGARIA LTD, Sofia (Bulgaria), B. Forg, F. Herrmann, W. Leneke, J. Schieferdecker - HEIMANN SENSOR GmbH, Dresden(Germany)
57 - 57


We present a 4x16 Thermopile Array (TPA) with 64 signal conditioning channels integrated on a CMOS silicon chip . Each channel consist of a low noise amplifier, a 2nd order Delta Sigma converter and a digital low-pass filter. The digitization resolution of the channel is 16-bit. Thanks to processing all pixels in parallel, the achieved Noise Equivalent Temperature Difference (NETD) can be limited to 0.2 ºC @1Hz frame rate.
Next to the 4x16 IR sensors a grid of 80 contact temperature sensors is implemented in the array. Thanks to these additional sensors, the temperature of each thermopile cold junction can be measured with an accuracy of 0.1 ºC. This information can be used by an external microcontroller to remove the distortion due to temperature gradients accross the slicon chip. The measurement results for all 64 IR and 80 contact temperature sensors are stored in onchip RAM and can be accessed through standard I2C communication, operating in Fast Mode Plus. For flexible control of the noise and speed, the chip supports refresh rates in very wide range: from 0.5 to 512 Hz frame rate, configurable by means of a command through I2C. . The TPA operates with a supply voltage in the range of 2.4 to3.6V and requres less than 4mA current. A power saving mode with a current consumption below 3uA can be triggered by a command through I2C.
The sensor comes in a standard 4-lead TO-39 package, and can be equipped with different lenses in order to customize the Field of View.. The sensor is intended for use in consumer applications like microwave ovens and aircondtioning systems, automotive applications like blind spot detection and air condtioning, and as a low cost alternative in applications like building isolation where normally high end bolometer cameras are used.