US 5,666,046 A · Reference voltage circuit having a substantially zero temperature coefficient

Abstract

A method for generating a programmable bandgap output reference voltage (V.sub.REF31) and a voltage reference circuit (31) have been provided. The voltage reference circuit (31) includes a pair of bipolar transistors (33, 34), a resistor (36), an operational amplifier (32) and a plurality of field effect transistors (38, 39, 41) configured to generate a current (I.sub.1 ') having a positive temperature coefficient. In addition, the voltage reference circuit (31) includes a resistor (46), an operational amplifier (44), another plurality of field effect transistors (47, 48) which, in conjunction with one (34) of the pair of bipolar transistors, generates a current (I.sub.2 ') having a negative temperature coefficient. The current (I.sub.1 ') having the positive temperature coefficient is summed with the current (I.sub.2 ') having the negative temperature coefficient to form a current having a zero temperature coefficient, which is used to develop a voltage having a zero temperature coefficient.

Claims22

Dependent claims

A reference voltage circuit, comprising:

a first amplifier circuit for generating a current having a positive temperature coefficient, the first amplifier circuit including a delta voltage generating circuit and having an output;
a second amplifier circuit for generating a current having a negative temperature coefficient, a portion of the delta voltage generating circuit common to the second amplifier circuit, the second amplifier circuit having an output, wherein the outputs of the first and second amplifier circuits are coupled to form a common electrode;
and
a summing circuit coupled to the common electrode.

1 more element

A reference voltage circuit, comprising:

a first operational amplifier having first and second inputs and an output;
means for generating a first current having a positive temperature coefficient, the means for generating a first current having a first current conducting electrode coupled to the first input of the first operational amplifier, a second current conducting electrode coupled to the second input of the first operational amplifier, and a reference node;
a first current mirror having a control node, a reference current electrode, a feedback electrode, and an output, the reference current electrode and the feedback electrode coupled to the first and second inputs of the first operational amplifier, respectively, and the control node coupled to the output of the first operational amplifier;
a second operational amplifier having a first input, a second input, and an output, the second input of the second operational amplifier coupled to the reference node of the means for generating a first current;
means for generating a second current having a negative temperature coefficient, the means for generating a second current having a first current conducting electrode coupled to the first input of the second operational amplifier;
a second current mirror having a control node, a reference current electrode, and an output, the control node of the second current mirror coupled to the output of the second operational amplifier, and the output of the second current mirror coupled to the output of the first current mirror;
and
a summing circuit having a first electrode coupled to a first power supply electrode and a second electrode coupled to the outputs of the first and second current mirrors.

5 more elements

Dependencies are inferred from the claim text.

Reference voltage circuit having a substantially zero temperature coefficient

Life of this patent

Reference voltage circuit having a substantially zero temperature coefficient

Life of this patent

Abstract

Claims22