CURRENT AND TEMPERATURE COMPENSATED VOLTAGE REFERENCE HAVING IMPROVED POWER SUPPLY REJECTION

摘要

A current and temperature compensated voltage reference circuit uses a power supply voltage as low as 1.3 Volts. A folded-cascode amplifier measures the temperature dependent voltages provided by first and second bias circuits, each including two series-coupled diodes or diode-connected bipolar junction transistors (BJTs), and provides a resulting proportional to absolute temperature (PTAT) current through a cascode-protected output transistor. A voltage reference circuit uses a PTAT current through a resistor to create A PTAT voltage in series with a diode-voltage. The resistor value is adjusted until the sum of these voltages is equal to the bandgap voltage of silicon, providing a temperature compensated voltage reference. The reference circuit is suitable for use with an implantable cardiac rhythm management system having a battery that provides a power supply voltage varying approximately between 1.3 Volts and 3.25 Volts. Cascode-protected current mirrors further improve rejection of such variations in the power supply voltage.