Bandgap reference circuits for providing accurate sub-1V voltages

Abstract

A reference voltage circuit includes a first PMOS device having a first source, a first gate, and a first drain, wherein the first source is coupled to a power supply node; and a second PMOS device having a second source, a second gate and, a second drain. The second source is coupled to the power supply node. The first and the second PMOS devices have constant source-drain currents. The reference voltage circuit further includes a third PMOS device having a third source, a third gate, and a third drain; and a resistor coupled between the third drain and the ground. The third source is coupled to the power supply node. The first, the second, and the third gates are interconnected. The first, the second, and the third drains are virtually interconnected.

Description

technical field [0001] The present invention relates generally to a reference circuit, and in particular to a bandgap reference circuit capable of providing a sub-1 volt reference voltage. Background technique [0002] Bandgap reference circuits are widely used in analog circuits to provide stable, voltage-independent and temperature-independent reference voltages. In most precision analog chips, bandgap reference circuits are important. [0003] FIG. 1 illustrates a circuit diagram of a known bandgap reference circuit, which includes an operational amplifier 100 and a PMOS device 106 . The drain (drain) of PMOS device 106 is coupled to resistors 108 and 114 . Resistor 108 is coupled to ground via diode 112 . Resistor 114 is coupled to ground via resistor 118 and a plurality of diodes 120 . Operational amplifier 100 has inputs 102 and 104, which are connected to nodes 110 and 116, respectively. [0004] The reference voltage V122 at node 122 of the circuit shown in FIG....

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Problems solved by technology

This cannot meet the needs of high accuracy applications

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