System and method for providing a thermal shutdown circuit with temperature warning flags
AssigneeNational Semiconductor Corporation
InventorKern W. Wong
Life of this patent
Estimating the term…
Abstract
A system and method is disclosed that provides a thermal shutdown circuit that generates a plurality of temperature warning flag signals. Each temperature warning flag signal represents a different temperature. The thermal shutdown circuit comprises a plurality of inverter circuits in which each inverter circuit has a different temperature turn-on threshold. A temperature to binary code converter receives the temperature warning flag signals from the inverter circuits and generates a plurality of binary coded signals that represent a temperature that is detected by the thermal shutdown circuit. A host controller unit uses the temperature information from the binary coded signals to shut down subsystems in advance of an abrupt thermal shutdown of a system.
Claims20
A thermal shutdown circuit comprising circuitry that generates a plurality of thermal warning flag signals in which each thermal warning flag signal represents a different temperature wherein said circuitry that generates said plurality of thermal warning flag signals comprises:
- a first current source;
- a first diode coupled to an output of said first current source;
- and
- a plurality of inverter circuits, wherein an input of each inverter circuit is coupled to a node between said output of said first current source and an input of said first diode;
- wherein each inverter circuit is capable of turning on at a different temperature and generating a temperature warning flag signal that represents a detection of a said temperature.
A thermal shutdown circuit comprising:
- a first current source;
- a first diode coupled to an output of said first current source;
- a second diode coupled to an output of said first diode;
- a plurality of inverter circuits, wherein an input of each inverter circuit is coupled to a node between said output of said first current source and an input of said first diode;
- wherein each inverter circuit is capable of turning on at a different temperature and generating a temperature warning flag signal that represents a detection of said temperature;
- and
- a second current source;
- a resistor coupled to an output of said second current source;
- and
- a comparator circuit having an inverting input coupled to a node between said output of said first diode and said input of said second diode, and having a noninverting input coupled to a node between said output of said second current source and said resistor.
A thermal shutdown system comprising:
- a host controller unit;
- and
- a plurality of thermal shutdown circuits coupled to said host controller unit;
- wherein each thermal shutdown circuit of said plurality of thermal shutdown circuits comprises circuitry that generates a plurality of thermal warning flag signals in which each thermal warning flag signal represents a different temperature wherein each thermal shutdown circuit comprises:
- a first current source;
- a first diode coupled to an output of said first current source;
- and
- a plurality of inverter circuits, wherein an input of each inverter circuit is coupled to a node between said output of said first current source and an input of said first diode;
- wherein each inverter circuit is capable of turning on at a different temperature and generating a temperature warning flag signal that represents a detection of a said temperature.
Dependencies are inferred from the claim text.