Temperature drift compensation
A voltage reference circuit includes a bandgap circuit and a temperature compensation circuit. The temperature compensation circuit includes a first trim circuit, a second trim circuit, and a resistive digital-to-analog converter. The resistive digital-to-analog converter is coupled to the first trim circuit, the second trim circuit, and the bandgap circuit. The resistive digital-to-analog converter is configured to generate a temperature compensation voltage, and to provide the temperature compensation voltage to the bandgap circuit.
1. A voltage reference circuit, comprising:
a bandgap circuit; and
a temperature compensation circuit, comprising:
a first trim circuit;
a second trim circuit;
a first resistive digital-to-analog converter coupled to the first trim circuit, the second trim circuit, and the bandgap circuit; the first resistive digital-to-analog converter configured to:
generate a temperature compensation voltage; and
provide the temperature compensation voltage to the bandgap circuit;
wherein the first trim circuit comprises a proportional to absolute temperature voltage generation circuit and a second resistive digital-to-analog converter.
2. The voltage reference circuit of claim 1 , wherein an output terminal of the second resistive digital-to-analog converter is coupled to an input terminal of the first resistive digital to analog converter.
3. The voltage reference circuit of claim 1 , wherein the proportional to absolute temperature voltage generation circuit is configured to generate a voltage proportional to absolute temperature as a function of output of the bandgap circuit.
4. The voltage reference circuit of claim 1 , wherein the proportional to absolute temperature voltage generation circuit is configured to generate a voltage proportional to absolute temperature as output voltage of the bandgap circuit less three diode drop voltages.
5. A voltage reference circuit, comprising:
a bandgap circuit; and
a temperature compensation circuit, comprising:
a first trim circuit;
a second trim circuit;
a first resistive digital-to-analog converter coupled to the first trim circuit, the second trim circuit, and the bandgap circuit; the first resistive digital-to-analog converter configured to:
generate a temperature compensation voltage; and
provide the temperature compensation voltage to the bandgap circuit;
wherein the second trim circuit comprises a complementary to absolute temperature voltage generation circuit and a third resistive digital-to-analog converter.
6. The voltage reference circuit of claim 5 , wherein an output terminal of the third resistive digital-to-analog converter is coupled to an input terminal of the first resistive digital to analog converter.
7. The voltage reference circuit of claim 5 , wherein the complementary to absolute temperature voltage generation circuit is configured to generate a voltage complementary to absolute temperature as a function of output of the bandgap circuit.
8. The voltage reference circuit of claim 5 , wherein the complementary to absolute temperature voltage generation circuit is configured to generate a voltage complementary to absolute temperature as two diode drop voltages.
9. A temperature compensation circuit, comprising:
a bandgap circuit;
a proportional to absolute temperature voltage generation circuit;
a complementary to absolute temperature voltage generation circuit;
a first resistive digital-to-analog converter coupled to an output of the proportional to absolute temperature voltage generation circuit;
a second resistive digital-to-analog converter coupled to an output of the complementary to absolute temperature voltage generation circuit;
a third resistive digital-to-analog converter coupled to:
an output of the first resistive digital-to-analog converter;
an output of the second resistive digital-to-analog converter; and
an input of the bandgap circuit.
10. The voltage reference circuit of claim 9 , further comprising:
a first switch that connects the first resistive digital-to-analog converter to the third resistive digital-to-analog converter;
a second switch that connects the second resistive digital-to-analog converter to the third resistive digital-to-analog converter; and
a third switch that connects the third resistive digital-to-analog converter to the bandgap circuit.