Power fault detection in transceivers
A host voltage monitor is provided for a transceiver. The host voltage monitor may include a comparator, which compares two voltages, one representative of the present host voltage, and the other representative of a threshold voltage level for the host voltage, that may indicate an imminent loss of power. Once the threshold is crossed, an alarm and/or a fault warning data packet may be automatically generated before the power fault causes the transceiver to shut down.
1. A transceiver for being hosted by a network communications device, the transceiver comprising:
a transmitter for transmitting first data packets,
a receiver for receiving second data packets,
a packet processor coupled to the transmitter and the receiver for processing the first and second data packets;
a connector coupled to the packet processor for transmitting and receiving the first and second data packets in electrical domain to and from a host device, and for providing a host voltage from the host device; and
a host voltage monitor for providing a fault trigger signal for the packet processor to generate a fault data packet when the host voltage becomes equal to or drops below a predetermined threshold voltage,
wherein the host voltage monitor comprises a comparator for comparing a reference voltage, corresponding to the predetermined threshold voltage, to a variable voltage based on the host voltage, and for providing the fault trigger signal to the packet processor when the variable voltage becomes equal to or drops below the reference voltage.
2. The transceiver of claim 1 , wherein the packet processor comprises a fault packet generator responsive to the fault trigger signal, for generating the fault data packet upon receiving the fault trigger signal.
3. The transceiver of claim 1 , wherein the host voltage monitor further comprises a DC-DC voltage converter for generating the reference voltage from the host voltage.
4. The transceiver of claim 3 , wherein the host voltage monitor further comprises a voltage divider for generating the variable voltage as a pre-determined portion of the host voltage.
5. The transceiver of claim 4 , wherein the pre-determined portion is between 0.2 and 0.6.
6. The transceiver of claim 1 , wherein the host voltage monitor further comprises a DC-DC voltage converter for generating a substantially constant operating voltage from the host voltage.
7. The transceiver of claim 6 , wherein the host voltage monitor further comprises a reference generator coupled to the DC-DC voltage converter for generating the reference voltage from the operating voltage.
8. The transceiver of claim 7 , wherein a ratio of the reference voltage to the operating voltage is between 0.4 and 0.6.
9. The transceiver of claim 6 , wherein the comparator is coupled to the DC-DC voltage converter, enabling the comparator to be powered by the operating voltage.
10. The transceiver of claim 9 , wherein the packet processor comprises a DSP or FPGA powered by the operating voltage.
11. The transceiver of claim 10 , wherein in operation, the DSP or FPGA have a processing speed enabling the generation of the fault data packet within 25 microseconds of receiving the fault trigger signal from the comparator.
12. The transceiver of claim 10 , further comprising a SFP package, wherein the transmitter, the receiver, the packet processor, the connector, and the host voltage monitor are disposed within, or supported by, the SFP package.
13. The transceiver of claim 10 , wherein the transmitter comprises electrical and optical transmitter portions each coupled to the packet processor,
wherein the receiver comprises electrical and optical receiver portions each coupled to the packet processor, and
wherein the electrical portions of the transmitter and the receiver are coupled to the connector for transmitting and receiving the first and second data packets in the electrical domain.
14. A method of reporting a host voltage loss by a transceiver hosted by a network communications device, the method comprising:
(a) generating a variable voltage based on the host voltage;
(b) generating a reference voltage corresponding to a threshold voltage, wherein a reduction of the host voltage to a level equal to or below the threshold voltage indicates an imminent host voltage loss;
(c) comparing the variable voltage to the reference voltage; and
(d) upon determining in step (c) that the variable voltage is at a level equal to or below the reference voltage, generating and transmitting a fault data packet before the host voltage becomes equal to or falls below the reference voltage.
15. The method of claim 14 , wherein in step (b), the reference voltage is generated at a substantially constant level from the host voltage.
16. The method of claim 15 , wherein a ratio of the reference voltage to the host voltage is 0.2 to 0.5.
17. The method of claim 14 , wherein in step (c), a comparator is used to compare the variable voltage to the reference voltage, the method further comprising generating a substantially constant operating voltage from the host voltage, and powering the comparator with the operating voltage.
18. The method of claim 17 , wherein step (a) comprises generating the variable voltage as a pre-defined portion of the host voltage.
19. The method of claim 18 , wherein the pre-defined portion is between 0.2 and 0.6.
20. The method of claim 17 , further comprising powering the transceiver with the operating voltage.
21. The method of claim 17 , wherein step (b) comprises generating the reference voltage from the operating voltage.
22. The method of claim 14 , wherein step (d) is completed during a time interval of 25 microseconds or less after determining in step (c) that the variable voltage is at a level equal to or below the reference voltage.