Thermal shutdown circuit with hysteresis and method of using
AssigneeSemiconductor Components Industries, LLC
InventorRobert N. Dotson
Life of this patent
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Abstract
An integrated circuit (10) includes a thermal shutdown circuit that incorporates hysteresis for shutting down a functional circuit (13) when its temperature exceeds a predefined value. First and second current sources (18, 17) respectively produce first and second reference currents (IREF1, IREF2) representative of first and second die temperatures of the integrated circuit. A current mirror (14) has an input (19) for summing the first and second reference currents and an output (15) for providing a mirror current (IMIRROR). A detection circuit (12) has an output coupled to the output of the current mirror for sinking the mirror current to produce a detection signal (VDET) as a function of the first and second die temperatures.
Claims18
An integrated circuit (10), comprising:
- first and second current sources (18, 17) respectively producing first and second reference currents (IREF1, IREF2) representative of first and second die temperatures of the integrated circuit;
- a current mirror (14) having an input (19) for summing the first and second reference currents, and an output (15) for providing a mirror current (IMIRROR) ;
- and
- a detection circuit (12) having an output coupled to the output of the current mirror for sinking the mirror current to produce a detection signal (VDET) that enables the second current source as a function of the first and second die temperatures.
A method of controlling a temperature of an integrated circuit, comprising the steps of:
- sensing a temperature of the integrated circuit to generate a detection current (IDET);
- summing first and second reference currents (IREF1, IREF2) at an input of a current mirror to provide a mirror current at an output of the current mirror;
- comparing the detection current to the mirror current to produce a detection signal when the detection current is equal to the mirror current;
- and
- switching the second reference current off with the detection signal when the temperature rises to a first predefined level.
An integrated thermal shutdown circuit, comprising:
- a temperature detector providing a detection current as a function of a temperature of the integrated thermal shutdown circuit and having an output for producing a detection signal when the detection current is greater than a mirror current;
- a current mirror having an input for receiving a first reference current indicative of a first die temperature, and an output coupled to the summing node for providing the mirror current;
- and
- a switch operating in response to the detection signal for supplying a second reference current indicative of a second die temperature to the input of the current mirror.
Dependencies are inferred from the claim text.