Device monitoring using satellite ADCs having local capacitors

Patent metadata

Field	Value
Publication number	US-10705144-B1
Application number	US-201916535713-A
Country	US
Kind code	B1
Filing date	Aug 8, 2019
Priority date	Aug 8, 2019
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

Systems and methods for monitoring operating conditions of a programmable device are disclosed. The system may include a root monitor configured to generate a reference voltage, a plurality of sensors distributed across the device, and a plurality of satellite monitors distributed across the device. Each of the satellite monitors may be coupled to a corresponding sensor via a local interconnect, and may be configured to convert analog signals generated by the sensor into digital data indicative of one or more operating conditions of an associated circuit. In some implementations, each satellite monitor may include a circuit to store a local reference voltage, an analog-to-digital converter (ADC) to convert the analog signals into digital codes, a calibration circuit to generate a correction factor indicative of errors in the digital codes, and a correction circuit to correct the digital codes based on the correction factor.

First claim

What is claimed is:

1. A programmable device, comprising:
programmable logic including a plurality of configurable logic resources;
a root monitor including a bandgap voltage generator configured to generate a temperature-independent reference voltage;
a plurality of sensors distributed in various locations across the programmable device, each of the sensors configured to generate analog signals indicative of measured operating conditions of one or more associated circuits in a vicinity of a corresponding one of the various locations; and
a plurality of satellite monitors distributed across the programmable device in the various locations, each of the satellite monitors coupled to one or more associated sensors via one or more local signal lines and comprising:
a voltage store configured to store a local reference voltage based on the temperature-independent reference voltage generated by the bandgap voltage generator;
an analog-to-digital converter (ADC) including a reference terminal to receive the local reference voltage and configured to convert the analog signals generated by the one or more associated sensors into digital codes indicative of the measured operating conditions;
a calibration circuit configured to generate a correction factor indicative of errors in the digital codes; and
a correction circuit configured to correct the digital codes based on the correction factor.

2. The programmable device of claim 1 , wherein the local reference voltage is at least one order of magnitude less accurate than the temperature-independent reference voltage generated by the bandgap voltage generator.

3. The programmable device of claim 1 , wherein the voltage store comprises a capacitor.

4. The programmable device of claim 1 , wherein the errors in the digital codes are associated with deviations of the local reference voltage from the temperature-independent reference voltage.

5. The programmable device of claim 1 , wherein the correction factor is based on differences between a reference code generated by the ADC in response to sampling the temperature-independent reference voltage and a predetermined digital code indicative of the temperature-independent reference voltage.

6. The programmable device of claim 1 , further comprising:
a network-on-chip (NoC) interconnect system spanning the programmable logic and configured to selectively route digital data from each of the plurality of satellite monitors to the root monitor.

7. The programmable device of claim 6 , wherein the root monitor further comprises:
a memory configured to store the digital data received from the plurality of satellite monitors via the NoC interconnect system; and
a controller configured to determine whether the measured operating conditions embodied by the digital data are within a range.

8. The programmable device of claim 6 , further comprising:
one or more analog channels configured to distribute the temperature-independent reference voltage from the root monitor to each of the plurality of satellite monitors.

9. The programmable device of claim 8 , wherein the NoC interconnect system comprises the one or more analog channels.

10. The programmable device of claim 8 , wherein each of the satellite monitors further comprises:
a first switch including a first input terminal coupled to receive the temperature-independent reference voltage from the one or more analog channels, a second input terminal coupled to receive the analog signals generated by the one or more associated sensors, a control terminal coupled to receive a control signal, and an output terminal coupled to an input terminal of the ADC within the satellite monitor.

11. The programmable device of claim 10 , wherein each of the satellite monitors further comprises:
a second switch including an input terminal coupled to receive the temperature-independent reference voltage from the one or more analog channels, a control terminal coupled to receive the control signal, and an output terminal coupled to the voltage store.

12. The programmable device of claim 11 , wherein during a calibration operation:
the first switch provides the temperature-independent reference voltage as an input signal to the ADC;
the second switch charges the voltage store and then isolates the voltage store from the temperature-independent reference voltage; and
the ADC samples the temperature-independent reference voltage to generate a reference code.

13. The programmable device of claim 12 , wherein during a monitoring operation:
the first switch provides the analog signals from the sensors as input signals to the ADC;
the second switch periodically provides the temperature-independent reference voltage to the voltage store; and
the ADC samples the analog signals from the one or more associated sensors to generate the digital codes.

14. The programmable device of claim 11 , wherein the root monitor is configured to generate the control signals based at least in part on a timing schedule for calibrating the plurality of satellite monitors.

15. The programmable device of claim 14 , wherein the timing schedule is configured to sequentially enable calibration of each of the plurality of satellite monitors by providing the temperature-independent reference voltage to only one of the satellite monitors at a time.

16. A method of monitoring operating conditions of a plurality of circuits distributed in various locations across a programmable device, the method comprising:
generating a plurality of analog signals indicative of the operating conditions of each of the plurality of circuits using a corresponding one of a plurality of sensors distributed in the various locations across the programmable device;
providing each of the analog signals to a corresponding one of a plurality of satellite monitors distributed in the various locations across the programmable device;
storing, in each of the plurality of satellite monitors, a local reference voltage based on a temperature-independent reference voltage;
converting, in each of the plurality of satellite monitors, a corresponding one of the plurality of analog signals into a digital code using an analog-to-digital converter (ADC) based on the local reference voltage;
distributing the temperature-independent reference voltage from a root monitor to each of the plurality of satellite monitors;
correcting the digital code generated by the ADC within each of the plurality of satellite monitors based at least in part on the distributed temperature-independent reference voltage; and
selectively routing the corrected digital codes from each of the plurality of satellite monitors to the root monitor.

17. The method of claim 16 , wherein:
the corrected digital codes are selectively routed from the plurality of satellite monitors to the root monitor using a network-on-chip (NoC) interconnect system spanning the programmable device; and
the temperature-independent reference voltage is distributed from the root monitor to the plurality of satellite monitors using one or more analog channels spanning the programmable device.

18. The method of claim 17 , wherein the storing comprises:
selectively charging a capacitor provided within a respective satellite monitor using the temperature-independent reference voltage distributed by the one or more analog channels.

19. The method of claim 16 , wherein distributing the temperature-independent reference voltage further comprises:
sequentially enabling each of the plurality of satellite monitors to access the tempe

Assignees

• Xilinx Inc

Inventors

• Jennings John K

Classifications

• G01R31/318516

  Test of programmable logic devices [PLDs] · CPC title

• H03M1/1009

  Calibration · CPC title

• H03M1/12

  Analogue/digital converters ({H03M1/001 – } H03M1/10 take precedence) · CPC title

• H03K19/17724 Primary

  Structural details of logic blocks · CPC title

• G01R31/31712

  Input or output aspects · CPC title