Micrel, Incorporated

Paul Ad Smith

Paul Wilson

John Shaw

A thermal sensor for an integrated circuit including a bandgap reference circuit. The thermal sensor includes a comparator that compares a temperature dependent voltage generated by the bandgap reference circuit to a temperature independent voltage, where both temperatures are referenced to the bandgap reference voltage generated by the bandgap reference circuit. The thermal sensor generates a digital output control signal based on a predetermined relationship between the temperature dependent voltage and the temperature independent reference voltage. When used as a thermal shutdown circuit, the comparator generates a thermal shut-down signal when the dependent temperature voltage decreases (or increases) with rising system temperature to equal to the temperature independent reference voltage. The comparator is implemented using an operational amplifier that is connected to existing circuitry associated with the bandgap reference circuit.

Bandgap-referenced thermal sensor

A voltage multiplier circuit includes a control circuit and a first voltage multiplier stage. The control circuit receives a power supply voltage and a reference voltage and provides a first output voltage being the difference between a first selected voltage and the power supply voltage where the first selected voltage is a function of the reference voltage and is independent of variations in the power supply voltage. The first voltage multiplier stage receives the first output voltage and a clock voltage signal having a clock voltage value and provides a second output voltage being the sum of the first output voltage and the clock voltage value. When the clock voltage value is equal to the power supply voltage, the second output voltage of the first voltage multiplier stage is the first selected voltage independent of any power supply voltage variations.

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Glasgow, United Kingdom

Paul Ad Smith