| 摘要 |
The specification relates to a thermal shutdown circuit for an integrated circuit. Two matching thermal sensing resistors are used to develop a voltage representing the relative differential temperature between the two resistors. One resistor is fabricated within the integrated circuit dissipating device dielectric isolation tub and therefore its temperature closely follows the temperature of the dissipating device. The second thermal sensing resistor reflects the ambient temperature of the integrated circuit. A third thermal sensing device is used to obtain actual absolute temperature at the location of the second thermal sensing resistor. By algebraically adding a voltage representing actual absolute temperature at an ambient temperature location with a voltage representing the relative differential temperature between thermal sensing resistors, a voltage representing the actual absolute temperature of the dissipating device is produced. The resulting voltage is compared to a reference voltage, the reference voltage representing a high temperature setpoint, so that when the temperature of the dissipating device exceeds the high temperature setpoint, a thermal shutdown signal is actuated.
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