Detection of disturbances of a power supply

Patent metadata

Field	Value
Publication number	US-10067200-B2
Application number	US-201615076955-A
Country	US
Kind code	B2
Filing date	Mar 22, 2016
Priority date	Oct 27, 2015
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A circuit includes, in series between a first terminal and a second terminal of application of a power supply voltage, and first and second branches. The first branch includes a first transistor and a first current source coupled to the first transistor. The second branch includes a resistive element, a second transistor coupled to the resistive element and forming a current mirror with the first transistor and a second current source coupled to the second transistor. The resistive element conditions a threshold of detection of a variation of the power supply voltage.

First claim

That which is claimed is:

1. A detection circuit, comprising:
a current mirror comprising a first transistor and a second transistor, wherein a gate terminal of the first transistor, a drain terminal of the first transistor, and a gate terminal of the second transistor are coupled as a first node, wherein a source terminal of the first transistor and a power supply terminal are coupled as a second node, wherein the power supply terminal is configured to receive a power supply voltage;
a first current source comprising a first terminal and a second terminal, wherein the first terminal of the first current source and the drain terminal of the first transistor are coupled as a third node, and wherein the second terminal of the first current source is coupled to a ground potential;
a first resistor coupled between a source terminal of the second transistor and the power supply terminal; and
a second current source coupled between a drain terminal of the second transistor and the ground potential, wherein the first resistor is configured to set a threshold of detection of a variation of the power supply voltage at the power supply terminal, and wherein an output voltage of the detection circuit, drawn from a node between the drain terminal of the second transistor and the second current source, is configured to vary in response to the variation of the power supply voltage at the power supply terminal, and
a first capacitive element coupled between the first node and the ground potential.

2. The detection circuit of claim 1 , further comprising:
a second resistor coupled between the first resistor and the power supply terminal; and
a second capacitive element coupled between a fourth node and the ground potential, wherein the fourth node is located between the first resistor and the second resistor.

3. The detection circuit of claim 1 , wherein the first transistor and the second transistor comprise MOS transistors.

4. The detection circuit of claim 1 , wherein the first transistor and the second transistor comprise bipolar transistors.

5. The detection circuit of claim 1 , wherein the first current source comprises a current transistor.

6. The detection circuit of claim 5 , wherein a ratio of a width of a gate of the first transistor to a length of the gate of the first transistor is different from a ratio of a width of a gate of the current transistor to a length of the gate of the current transistor.

7. The detection circuit of claim 1 , wherein the first resistor comprises a programmable resistor.

8. A device, comprising:
a power supply regulator configured to provide a power supply voltage and a ground potential;
a main circuit comprising a first terminal coupled to the power supply regulator and configured to receive the power supply voltage, the main circuit further comprising a second terminal coupled to the power supply regulator and configured to receive the ground potential; and
a detection circuit configured to provide the main circuit an indication signal in response to a disturbance in the power supply voltage, the detection circuit comprising:
a current mirror comprising a first transistor and a second transistor, wherein a gate terminal of the first transistor, a drain terminal of the first transistor, and a gate terminal of the second transistor are coupled as a first node, wherein a source terminal of the first transistor and a power supply terminal of the detection circuit are coupled as a second node, wherein the power supply terminal is configured to receive the power supply voltage from the power supply regulator;
a first current source comprising a first terminal and a second terminal, wherein the first terminal of the first current source and the drain terminal of the first transistor are coupled as a third node, and wherein the second terminal of the first current source is coupled to the ground potential;
a first resistor coupled between a source terminal of the second transistor and the power supply terminal; and
a second current source coupled between a drain terminal of the second transistor and the ground potential, wherein the first resistor is configured to set a threshold of detection of the disturbance in the power supply voltage at the power supply terminal, and wherein the indication signal, drawn from a node between the drain terminal of the second transistor and the second current source, is configured to vary in response to the disturbance in the power supply voltage, and
a first capacitive element coupled between the first node and the ground potential.

9. The device of claim 8 , wherein the detection circuit further comprises:
a second resistor coupled between the first resistor and the power supply terminal; and
a second capacitive element coupled between a fourth node and the ground potential, wherein the fourth node is located between the first resistor and the second resistor.

10. The device of claim 8 , wherein the first transistor and the second transistor of the detection circuit comprise MOS transistors.

11. The device of claim 8 , wherein the first transistor and the second transistor of the detection circuit comprise bipolar transistors.

12. The device of claim 8 , wherein the first current source of the detection circuit comprises a current transistor.

13. The device of claim 12 , wherein a ratio of a width of a gate of the first transistor to a length of the gate of the first transistor is different from a ratio of a width of a gate of the current transistor to a length of the gate of the current transistor.

14. The device of claim 12 , wherein the first resistor of the detection circuit comprises a programmable resistor.

15. A device, comprising:
a power supply regulator configured to provide a power supply voltage and a ground potential, the power supply voltage being generated based on a batteiy voltage received by the power supply regulator;
a main circuit comprising a first terminal coupled to the power supply regulator and configured to receive the power supply voltage, the main circuit further comprising a second terminal coupled to the power supply regulator and configured to receive the ground potential; and
a detection circuit configured to provide the main circuit an indication signal in response to a variation in the battery voltage, the detection circuit comprising:
a current mirror comprising a first transistor and a second transistor, wherein a gate terminal of the first transistor, a drain terminal of the first transistor, and a gate terminal of the second transistor are coupled as a first node, wherein a source terminal of the first transistor
and a power supply terminal of the detection circuit are coupled as a second node, wherein the power supply terminal is configured to receive the battery voltage;
a first current source comprising a first terminal and a second terminal, wherein the first terminal of the first current source and the drain terminal of the first transistor are coupled as a third node, and wherein the second terminal of the first current source is coupled to a ground potential;
a first resistor coupled between a source terminal of the second transistor and the power supply terminal; and
a second current source coupled between a drain terminal of the second transistor and the ground potential, wherein the first resistor is configured to set a threshold of detection of the variation in the battery voltage, and wherein the indication signal, drawn from a node between the drain terminal of the second transistor and the second current source, is configured to vary in response to the variation of the power supply voltage

Assignees

• St Microelectronics Alps Sas

Inventors

• Leduc Bruno
• Bernon Pascal
• Clin Stephane

Classifications

• G01R3/00

  Apparatus or processes specially adapted for the manufacture {or maintenance} of measuring instruments {, e.g. of probe tips} · CPC title

• G01R19/165 Primary

  Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values · CPC title

• G01R15/14

  Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks · CPC title

• G01R31/40 Primary

  Testing power supplies (testing photovoltaic devices H02S50/10) · CPC title