Patent ID: 6916415
Filing Date: 2005-07-12
Classification: G01N

Abstract:
1. A drive circuit for a gas sensor having a resistive heating element with an incoming line branch and an outgoing line branch connected to a reference potential, comprising; a feed voltage source producing a feed voltage; a supply branch having said feed voltage applied thereto; a first controllable switching element connected to said supply branch and to the incoming line branch of the heating element; a measuring voltage Source; a second controllable switching element connected to said measuring voltage source; a measuring resistor having: a current heating path flowing, when said first switching element is turned on, from said supply branch through said first switching element, the incoming line branch of the heating element, the heating element, and the outgoing line branch to the reference potential; and a measuring current path leading from said measuring voltage source through said second switching element and said measuring resistor into said supply branch, said measuring current path being closed when said first switching element is turned off and said second switching element is turned on; and a measuring device having: