Patent ID: 7746087
Filing Date: 2010-06-29
Classification: G01K

Abstract:
1. A temperature-sensing circuit comprising: a comparator that receives a sensing voltage and a reference voltage and generates a compare output; a voltage divider between a power supply and a compensation node, the voltage divider generating the reference voltage applied to the comparator; a sensing branch that senses a sensing current through a heating body to generate the sensing voltage; an isolation diode in the sensing branch to protect the comparator from damage due to high voltages; a sampling resistor in the sensing branch, the sampling resistor limiting the sensing current; a compensation branch between the power supply and a ground; a compensation diode in the compensation branch, the compensation diode for compensating the sensing voltage applied to the comparator for a voltage drop through the isolation diode; and a compensation resistor in the compensation branch to supply current to the compensation diode; wherein the compensation node of the voltage divider is a terminal of the compensation diode, whereby the compensation diode adjusts the reference voltage applied to the comparator by the voltage divider to compensate for the voltage drop through the isolation diode.