Abstract: A voltage sense circuit and method of providing an operating voltage to a low voltage integrated circuit are provided. The voltage sense circuit includes a switch responsive to a control signal. The switch is coupled between an input node and a power supply node, and a voltage drop circuit is coupled in parallel with the switch. The voltage drop circuit is configured to provide the operating voltage at the power supply node when a power supply voltage at the input node is approximately an operating voltage of a higher voltage integrated circuit. The voltage sense circuit also includes a control circuit coupled to the switch. The control circuit is configured to control the switch to substantially pass the power supply voltage to the power supply node when the power supply voltage is approximately the operating voltage of the low voltage integrate circuit.

Abstract: The present invention relates to a circuit capable of providing a negative temperature coefficient greater than that provided by discrete silicon integrated circuit components. A constant current source and a resistor divider network are added to a bipolar junction transistor, where the resistors and the constant current source function to increase the negative temperature coefficient of a bipolar junction transistor. The negative temperature compensation circuit formed in accordance with the present invention provides a sufficient negative temperature coefficient to offset the large positive temperature coefficient associated with high voltage avalanche breakdown diodes without requiring a high voltage integrated circuit.