Patent ID: 6783274
Filing Date: 2004-08-31
Classification: G01K

Abstract:
A semiconductor temperature measuring circuit, comprising:a first current mirror circuit and a second current mirror circuit, both connected to a positive power source, each of the first current mirror circuit and the second current mirror circuit having a control electrode, the control electrodes of the first current mirror circuit and the second current mirror circuit being commonly connected, and the second current mirror circuit having a first output terminal and a second output terminal; a third current mirror circuit provided between an output terminal of the first current mirror circuit and the ground, the third current mirror circuit including a first npn transistor having a first emitter size and a second npn transistor having a second emitter size, the first emitter size being larger than the second emitter size, an emitter electrode of the first npn transistor being connected to the ground via a first resistor, and an emitter electrode of the second npn transistor being directly connected to the ground; a third npn transistor having a collector electrode connected to the first output terminal of the second current mirror circuit and an emitter electrode connected to a negative power source, and a base electrode connected to the negative power source via a second resistor; an N channel transistor having a control electrode, a first signal electrode, and a second signal electrode, wherein the control electrode is connected to the first output terminal of the second current mirror circuit, the first signal electrode is connected to the second output terminal of the second current mirror circuit, and the second signal electrode is connected to the base electrode of the third npn transistor; and an operational amplifier that has a negative gradient with respect to temperature, the operational amplifier having a negative input terminal and a positive input terminal, the negative input terminal being connected to a node that is connected to the second output terminal of the second current mirror circuit and the first signal electrode of the N channel transistor, and to an output terminal of the operational amplifier via a resistor unit, and the positive input phase terminal being directly connected to the ground.