Method and apparatus for digital leak detection in liquid-cooled information handling systems

1. An apparatus comprising:

a transmitter circuit configured to provide a transmitted waveform at a transmitter output;

a first microstrip differential trace extending from a first microstrip differential trace first end to a first microstrip differential trace second end;

a first resistor having a first resistor first end coupled to the transmitter output and a first resistor second end coupled to the first microstrip differential trace first end;

a second microstrip differential trace extending from a second microstrip differential trace first end to a second microstrip differential trace second end;

a second resistor having a second resistor first end coupled to the transmitter output and a second resistor second end coupled to the second microstrip differential trace first end;

a first receiver circuit having a first receiver circuit input coupled to the first microstrip differential trace second end, the first receiver configured to provide a first received signal;

a second receiver circuit having a second receiver circuit input coupled to the second microstrip differential trace second end, the second receiver configured to provide a second received signal; and

a processor configured to receive the first received signal and the second received signal and to perform digital signal processing on the first received signal and the second received signal, to detect a coolant leak, and to provide an alert upon detection of the coolant leak.

2. The apparatus of claim 1 further comprising:

a low-pass filter having a low-pass filter input and a low-pass filter output, the transmitter output coupled to the low-pass filter input, the low-pass filter output coupled to the first resistor first end and to the second resistor first end.

3. The apparatus of claim 1 , wherein the first microstrip differential trace and the second microstrip differential trace are disposed on a coplanar surface of a circuit board.

4. The apparatus of claim 1 , wherein the circuit board defines an aperture configured for the acceptance of a heat exchanger therein.

5. The apparatus of claim 1 , wherein the first microstrip differential trace and the second microstrip differential trace are disposed over a plurality of regions of the circuit board, wherein a raised barrier selected from a group consisting of solder mask material and silk screen material separates a first region of the plurality of regions from a second region of the plurality of regions.

6. The apparatus of claim 1 , wherein the transmitted waveform is periodic at a frequency of between 0.1 Hertz and 10 kiloHertz.

7. The apparatus of claim 1 , wherein the transmitted waveform is periodic at a frequency of between 1 Hertz and 1000 Hertz.

8. A method comprising:

driving a first microstrip differential trace with an alternating-current (AC) waveform;

providing a first received signal obtained from the first microstrip differential trace;

driving a second microstrip differential trace with the alternating-current (AC) waveform;

providing a second received signal obtained from the second microstrip differential trace;

performing digital signal processing (DSP) to obtain a first magnitude representative of a first moisture level at the first microstrip differential trace and a second magnitude representative of a second moisture level at the second microstrip differential trace; and

providing an alert when a comparison of the first magnitude and the second magnitude indicates a presence of a coolant leak.

9. The method of claim 8 , wherein the performing the DSP further comprises:

calculating a discrete Fourier transform (DFT) to obtain the first magnitude for the first microstrip differential trace and the second magnitude for the second microstrip differential trace.

10. The method of claim 8 , wherein the providing the alert when the comparison of the first magnitude and the second magnitude indicate the presence of the coolant leak comprises:

providing the alert when the first magnitude and the second magnitude are substantially different.

11. The method of claim 8 , wherein the providing the alert when the comparison of the first magnitude and the second magnitude indicate the presence of the coolant leak comprises:

providing the alert when the first magnitude and the second magnitude have abruptly changed from previous magnitudes.

12. The method of claim 8 , wherein the providing the alert when the comparison of the first magnitude and the second magnitude indicate the presence of the coolant leak comprises:

providing the alert when at least one of the first magnitude and the second magnitude has changed, respectively, from a previous first magnitude and a previous second magnitude.

13. The method of claim 8 , wherein the first magnitude is a first bin-1 magnitude and the second magnitude is a second bin-1 magnitude.

14. The method of claim 8 further comprising:

calibrating the first magnitude and the second magnitude with respect to a humidity measurement of a humidity sensor.

15. An apparatus comprising:

a transmitter circuit configured to provide a transmitted waveform at a transmitter output;

a first voltage divider circuit;

a second voltage divider circuit;

a first receiver circuit;

a second receiver circuit; and

a processor,

wherein the first voltage divider circuit includes:

a first microstrip differential trace extending from a first microstrip differential trace first end to a first microstrip differential trace second end; and

a first impedance device having a first impedance device first end coupled to the transmitter output and a first impedance device second end coupled to the first microstrip differential trace first end;

wherein the second voltage divider circuit includes:

a second microstrip differential trace extending from a second microstrip differential trace first end to a second microstrip differential trace second end; and

a second impedance device having a second impedance device first end coupled to the transmitter output and a second impedance device second end coupled to the second microstrip differential trace first end,

wherein the first receiver circuit has a first receiver circuit input coupled to the first microstrip differential trace second end, the first receiver configured to provide a first received signal,

wherein the second receiver circuit has a second receiver circuit input coupled to the second microstrip differential trace second end, the second receiver configured to provide a second received signal; and

wherein the processor is configured to receive the first received signal and the second received signal and to perform digital signal processing on the first received signal and the second received signal, to detect a coolant leak, and to provide an alert upon detection of the coolant leak.

16. The apparatus of claim 15 , further comprising:

a low-pass filter having a low-pass filter input and a low-pass filter output, the transmitter output coupled to the low-pass filter input, the low-pass filter output coupled to the first impedance device first end and to the second impedance device first end.

17. The apparatus of claim 15 , wherein the first microstrip differential trace and the second microstrip differential trace are disposed on a coplanar surface of a circuit board.

18. The apparatus of claim 15 , wherein the circuit board defines an aperture configured for the acceptance of a heat exchanger therein.

19. The apparatus of claim 15 , wherein the transmitted waveform is periodic at a frequency of between 0.1 Hertz and 10 kiloHertz.

20. The apparatus of claim 15 , wherein the transmitted waveform is periodic at a frequency of between 1 Hertz and 1000 Hertz.