CN-122018623-A - Temperature correction circuit for reference voltage

Abstract

A temperature correction circuit for a voltage reference circuit includes two amplifiers each having an output that controls a respective transistor that generates a correction current for adjusting a reference voltage. Both amplifiers include one input coupled in a path to a reference voltage source and another input coupled in a path to a temperature sensing diode circuit. The output of one amplifier controls the conductivity of its respective transistor to adjust the reference voltage when the temperature exceeds the high temperature set point. The output of the other amplifier controls the conductivity of its respective transistor to adjust the reference voltage when the temperature is below a low temperature set point.

Inventors

• JOHN PIGGOTT

Assignees

• 恩智浦美国有限公司

Dates

Publication Date

20260512

Application Date

20251107

Priority Date

20241108

Claims (10)

1. 1. A circuit, the circuit comprising: A reference voltage source; an output coupled to the reference voltage source, the output for providing a reference voltage; A temperature sensing diode circuit; A first amplifier having a first input coupled in a path to the reference voltage source and a second input coupled in a path to an end of the temperature sensing diode circuit; A first transistor including a control terminal coupled to an output of the first amplifier and a first current terminal to provide a correction current for adjusting the reference voltage in response to the temperature sensing diode circuit indicating that a first temperature is exceeded; A second amplifier comprising a first input coupled in a path to the reference voltage source and a second input coupled in a path to the end of the temperature sensing diode circuit; A second transistor including a control terminal coupled to an output of the second amplifier and a first current terminal for providing a correction current for adjusting the reference voltage in response to the temperature sensing diode circuit indicating a temperature below a second temperature.
2. 2. The circuit of claim 1, wherein a second current terminal of the first amplifier is coupled to the first input of the first amplifier.
3. 3. The circuit of claim 2, wherein when the temperature sensing diode circuit indicates that the first temperature is exceeded, the first amplifier drives its output with a voltage to control the conductivity of the first transistor such that the voltage of the first input of the first amplifier matches the voltage of the second input of the first amplifier.
4. 4. The circuit of claim 1, wherein the first current terminal of the first transistor does not provide a correction current for adjusting the reference voltage when the temperature sensing diode circuit indicates that the first temperature is not exceeded.
5. 5. The circuit of claim 1, wherein the first amplifier controls an amount of correction current generated by the first current terminal of the first transistor such that when the first temperature is exceeded, a change in the amount of correction current is positively correlated with a temperature change.
6. 6. The circuit of claim 1, wherein a second current terminal of the second transistor is coupled to the second input of the second transistor.
7. 7. The circuit of claim 6, wherein when the temperature sensing diode circuit indicates that the temperature is below the second temperature, the second amplifier drives its output with a voltage to control the conductivity of the second transistor such that the voltage of the second input of the second amplifier matches the voltage of the first input of the second amplifier.
8. 8. The circuit of claim 1, wherein the first current terminal of the second transistor does not provide a correction current for adjusting the reference voltage in response to the temperature sensing diode circuit indicating that the temperature is not less than the second temperature.
9. 9. The circuit of claim 1, wherein the second amplifier controls an amount of correction current generated by the first current terminal of the second transistor such that a change in the amount of correction current is positively correlated with a negative temperature change when the temperature is below the second temperature.
10. 10. A circuit, the circuit comprising: A reference voltage source; An output path from the reference voltage source to a supply rail; an output connected to a node of the output path for providing a reference voltage; A temperature sensing diode circuit; A first amplifier having a first input coupled in a path to the reference voltage source and a second input coupled in a path to an end of the temperature sensing diode circuit; A first transistor including a control terminal coupled to an output of the first amplifier and a first current terminal to provide a correction current for adjusting the reference voltage in response to the temperature sensing diode circuit indicating that a first temperature is exceeded; A second amplifier comprising a first input coupled in a path to the reference voltage source and a second input coupled in a path to the end of the temperature sensing diode circuit; A second transistor including a control terminal coupled to an output of the second amplifier and a first current terminal for providing a correction current for adjusting the reference voltage in response to the temperature sensing diode circuit indicating a temperature below a second temperature; Wherein a second current terminal of the first amplifier is coupled to the first input of the first amplifier; wherein a second current terminal of the second transistor is coupled to the second input of the second transistor.

Description

Temperature correction circuit for reference voltage Technical Field The invention relates to a temperature correction circuit for a reference voltage. Background The reference voltage is used to provide a stable and predictable voltage in the electronic circuit. One type of reference voltage is a bandgap voltage. The bandgap voltage is generated by the bandgap reference circuit and is based on the bandgap of the semiconductor device of the bandgap reference circuit. Another type of reference voltage is a zener reference voltage. The zener reference voltage is generated by a zener reference circuit comprising a zener diode and is based on the breakdown voltage of the zener diode. For circuits designed to operate over a wide temperature range, the reference voltage may need to be relatively constant over the temperature range. Disclosure of Invention Features specifically illustrated or described with respect to one embodiment set forth herein may be implemented in other embodiments set forth herein. In one embodiment, a circuit includes a reference voltage source, an output coupled to the reference voltage source for providing a reference voltage, a temperature sensing diode circuit, a first amplifier having a first input coupled in a path to the reference voltage source and a second input coupled in a path to an end of the temperature sensing diode circuit, a first transistor including a control end coupled to an output of the first amplifier and a first current end to provide a correction current for adjusting the reference voltage in response to the temperature sensing diode circuit indicating that a first temperature is exceeded, a second amplifier including a first input coupled in a path to the reference voltage source and a second input coupled in a path to the end of the temperature sensing diode circuit, and a second transistor including a control end coupled to the second amplifier and a first current end to provide a correction current for adjusting the reference voltage in response to the temperature sensing diode circuit indicating that a second temperature is below the temperature sensing current. In yet another embodiment, a second current terminal of the first amplifier is coupled to the first input of the first amplifier. In yet another embodiment, when the temperature sensing diode circuit indicates that a first temperature is exceeded, the first amplifier drives its output with a voltage to control the conductivity of the first transistor such that the voltage of the first input of the first amplifier matches the voltage of the second input of the first amplifier. In yet another embodiment, the first current terminal of the first transistor does not provide a correction current for adjusting the reference voltage when the temperature sensing diode circuit indicates that the first temperature is not exceeded. In yet another embodiment, the first amplifier controls an amount of correction current generated by the first current terminal of the first transistor such that when the first temperature is exceeded, a change in the amount of correction current is positively correlated to a temperature change. In yet another embodiment, a second current terminal of the second transistor is coupled to the second input of the second transistor. In yet another embodiment, when the temperature sensing diode circuit indicates that the temperature is below a second temperature, the second amplifier drives its output with a voltage to control the conductivity of the second transistor such that the voltage of the second input of the second amplifier matches the voltage of the first input of the second amplifier. In yet another embodiment, the first current terminal of the second transistor does not provide a correction current for adjusting the reference voltage in response to the temperature sensing diode circuit indicating that the temperature is not below the second temperature. In yet another embodiment, the second amplifier controls the amount of correction current generated by the first current terminal of the second transistor such that when the temperature is below the second temperature, a change in the amount of correction current is positively correlated with a negative temperature change. In yet another embodiment, the output is provided by a node in an output current path, wherein the correction current provided by the first current terminal of the first amplifier and the correction current provided by the first current terminal of the second amplifier are provided by a resistive circuit across the output current path to adjust the reference voltage. In yet another embodiment, the circuit includes a resistive path from the reference voltage source to a supply rail, wherein the first input of the first amplifier is coupled to a first node of the resistive path and the first input of the second amplifier is coupled to a second node of the resistive path, wherein a resistive circuit is located in