OPERATION DETECTION DEVICE FOR PELTIER ELEMENT

摘要

PROBLEM TO BE SOLVED: To detect the operation conditions of a Peltier device in operation based upon a PWM signal. SOLUTION: An H bridge circuit 11 is formed with a plurality of FET transistors to which a switching signal based on a PWM signal is applied. the Peltier device 1 is connected between those FET transistors for executing heating operation or cooling operation depending upon the direction of a flowed driving current. A controller 23 outputs a PWM control signal on the basis of a measured value and a set value inputted through a sensor 3 and an input section 5. A driving section 9 outputs a switching signal based on the PWM signal to the H bridge circuit 11. The H bridge circuit 11 switches the direction of the driving current to the Peltier device 1 connected thereto. A switch section 27 inputs an electric potential on the Peltier device in a first off period during a predetermined period in the PWM signal upon heating operation or cooling operation. A detector section 29 detects first Zeebeck voltage from an input electric potential.