RIPPLE MONITORING

• US 20170153296A1
• Filed: 05/12/2016
• Published: 06/01/2017
• Est. Priority Date: 11/30/2015
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Linear Technology Corporation (Analog Devices, Inc.)
• Inventors: Engl, Bernhard Helmut, Chiacchia, Robert, Dobkin, Robert C.
• Granted Patent: US 10,641,837 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 19/0084 measuring voltage only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 31/40 Testing power supplies testing photovoltaic devices H02S50/10
• CPC Class Codes: G01R 31/42 AC power supplies
• CPC Class Codes: H03M 1/12 Analogue/digital converters H03M1/001 – H03M1/10 take precedence
• CPC Class Codes: H03M 1/1295 Clamping, i.e. adjusting the DC level of the input signal to a predetermined value
• CPC Class Codes: H03M 1/66 Digital/analogue converters H03M1/001 – H03M1/10 take precedence

Abstract

A ripple monitoring circuit may generate information indicative of a failing component in a power supply. At least one input may receive a ripple signal from the power supply that has a ripple component. A quantization circuit may repeatedly quantize the amplitude of the ripple component. A ripple amplitude statistics counter bank may count and store the number of times that different quantized amplitudes or different ranges of quantized amplitudes of the ripple component occurred.

A ripple monitoring circuit may generate information about a power supply. At least one input may receive a ripple signal from the power supply that has a ripple component. A ripple measurement circuit may measure a characteristic of the ripple component. A storage circuit may store information about the measurement. A comparison circuit may compare information stored in the storage circuit with a threshold value and indicate when the stored information meets or exceeds this threshold value.

Claims

1. A ripple monitoring circuit for generating information indicative of a failing component in a power supply, the ripple monitoring circuit comprising:

at least one input that receives a ripple signal from the power supply that has a ripple component;

a quantization circuit that repeatedly quantizes the amplitude of the ripple component; and

a ripple amplitude statistics counter bank that counts and stores the number of times that different quantized amplitudes or different ranges of quantized amplitudes of the ripple component occurred.

2. The ripple monitoring circuit of claim 1 wherein the quantization circuit includes an analog-to-digital converter that repeatedly converts the ripple component, each time into a digital word representative of the amplitude of the ripple component at the time of the conversion.

3. The ripple monitoring circuit of claim 2 wherein the ripple amplitude statistics counter bank maintains a count of the number of times that the ripple component is converted into each of the digital words.

4. The ripple monitoring circuit of claim 1 further comprising a signal conditioning circuit that conditions the ripple signal before it is counted by the ripple amplitude statistics counter bank.

5. The ripple monitoring circuit of claim 4 wherein the signal conditioning circuit includes a transformer.

6. The ripple monitoring circuit of claim 4 wherein the signal conditioning circuit includes a digital-to-analog converter having an output that is added to or subtracted from the ripple signal.

7. The ripple monitoring circuit of claim 4 wherein:

the ripple signal is a differential signal; and

the signal conditioning circuit includes;

a digital-to-analog converter that converts an input digital signal V_in into a differential analog output V_DAC; and

a dual input instrumentation amplifier that;

has a first pair of differential inputs that receives the differential signal of the ripple signal;

has a second pair of differential inputs that receives the differential analog output V_DAC from the digital-to-analog converter; and

produces an output that is equal to the sum of Vin time a non-zero gain factor and Vdac times a non-zero gain factor.

8. The ripple monitoring circuit of claim 7 wherein the signal conditioning circuit includes a digital filter that filters out unwanted ripples in the ripple signal, thereby preventing the amplitudes of these unwanted ripples from being counted by the ripple amplitude statistics counter bank.

9. The ripple monitoring circuit of claim 8 wherein the digital filter includes a low pass filter that filters out DC or low frequency ripples in the ripple signal.

10. The ripple monitoring circuit of claim 8 wherein the digital filter predicts linear voltage ramps to enable suppression of them.

11. The ripple monitoring circuit of claim 8 wherein the digital filter includes a low pass filter and a band pass filter.

12. The ripple monitoring circuit of claim 4 wherein the signal conditioning circuit includes a DC level restore circuit.

13. The ripple monitoring circuit of claim 12 wherein the DC level restore circuit includes switchable current sources coupled to the at least one input that receives the ripple signal.

14. The ripple monitoring circuit of claim 12 wherein the DC level restore circuit includes one or more bias resistors, each being coupled between the ripple signal and a bias voltage.

15. The ripple monitoring circuit of claim 14 wherein each bias resistor is coupled to a bias voltage by an electronic switch.

16. The ripple monitoring circuit of claim 15 wherein each electronic switch includes a MOSFET.

17. The ripple monitoring circuit of claim 1 further comprising computational circuitry that analyzes the counts in the ripple amplitude statistics counter that are relevant to determining whether a component in the power supply is failing.

18. The ripple monitoring circuit of claim 17 wherein the computational circuitry determines an amplitude slicing level below which counts of the amplitudes are ignored when determining whether a component in the power supply is failing.

19. The ripple monitoring circuit of claim 17 wherein the computational circuitry includes an arithmetic logic unit (ALU), accumulator registers, index registers, and a control state machine.

20. The ripple monitoring circuit of claim 17 wherein the computational circuitry issues an alert when it determines that a component in the power supply is failing.

21. The ripple monitoring circuit of claim 20 wherein the computational circuitry:

includes at least one inertia counter that increments for each ripple amplitude count that exceeds an alert threshold; and

issues an alert when the inertia counter reaches a threshold count.

22. The ripple monitoring circuit of claim 21 wherein the inertia counter decrements at time intervals until it reaches zero.

23. The ripple monitoring circuit of claim 1 wherein the ripple monitoring circuit includes a blanking input that, when enabled, stops the ripple amplitude statistics counter bank from continuing to count the number of times that each different quantized amplitude of the ripple component occurred.

24. The ripple monitoring circuit of claim 1 wherein the ripple monitoring circuit is contained in an integrated circuit.

25. A ripple monitoring circuit for generating information about a power supply, the ripple monitoring circuit comprising:

at least one input that receives a ripple signal from the power supply that has a ripple component;

a ripple measurement circuit that measures a characteristic of the ripple component;

a storage circuit that stores information about the measurement; and

a comparison circuit that compares information stored in the storage circuit with a threshold value and indicates when the stored information meets or exceeds this threshold value.

26. The ripple monitoring circuit of claim 25 wherein:

the ripple measurement circuit repeatedly measures a characteristic of the ripple component; and

the storage circuit stores information about each measurement.

27. The ripple monitoring circuit of claim 26 wherein the ripple measurement circuit includes an analog-to-digital converter that repeatedly coverts the ripple component, each time into a digital word representative of the characteristic of the ripple component.