System for supplying multiple voltages to devices on circuit board through a sequencing in a predictable sequence

• US 6,738,915 B1
• Filed: 05/12/2000
• Issued: 05/18/2004
• Est. Priority Date: 05/12/2000
• Status: Expired due to Term

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Mott, James A., Baldwin, William M.
• Primary Examiner(s): Lee, Thomas
• Assistant Examiner(s): DU, THUAN N
• Application Number:
  US09/569,535
• Time in Patent Office: 1,467 Days
• Field of Search: 710/302, 713/300, 713/330, 713/340, 361/1, 361/9, 361/58, 361/111, 361/788
• US Class Current: 713/330
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: H05K 1/0254 High voltage adaptations; Electrical insulation details; Overvoltage or electrostatic discharge protection electrostatic discharge protection for electric apparatus in general H05K9/0067, H05K9/0079; Arrangements for regulating voltages or for using plural voltages

Abstract

An apparatus and method for enabling hot swapped circuit boards to receive multiple power voltages from a backplane and supply the multiple power voltages to devices on the circuit board in a predictable sequence. An apparatus according to the invention would include a circuit board having an electrical connector, a sequencing circuit, and an element. The electrical connector of the circuit board receives the multiple power voltages from another circuit board, such as a backplane or motherboard. The sequencing circuit receives the multiple power voltages from the electrical connector. When a part of the sequencing circuit receives a signal indicating that the sequencing circuit has received a first power voltage, the sequencing circuit provides a second power voltage to the element electrically coupled to the sequencing circuit.

Claims

1. A circuit board adapted to receive at least a first power voltage and a second power voltage and having circuitry for supplying to an element of the circuit board in a predictable sequence the first power voltage and then the second power voltage, comprising:

an electrical connector for receiving the first power voltage and the second power voltage, wherein the first power voltage and the second power voltage are generated externally from the circuit board;

a sequencing circuit electrically coupled to the electrical connector, wherein the electrical connector is adapted to supply the first power voltage and thereafter supply the second power voltage to the sequencing circuit, the sequencing circuit comprising;

a first circuit for receiving the first power voltage and supplying the first power voltage to the element of the circuit board; and

a second circuit electrically coupled to the first circuit, and the second circuit for supplying the second power voltage to the element of the circuit board, responsive to receiving a signal indicating that the sequencing circuit is receiving the first power voltage, wherein the element of the circuit board is electrically coupled to the sequencing circuit and is adapted to receive the first power voltage and the second power voltage in sequence.

2. The circuit board of claim 1, further comprising:

a clamping circuit electrically coupled to the first circuit and the second circuit, wherein the clamping circuit limits a voltage difference between the first power voltage supplied to the element of the circuit board and the second power voltage supplied to the element of the circuit board.

3. The circuit board of claim 2, wherein the clamping circuit includes one or more sequentially coupled diodes.

4. The circuit board of claim 1, further comprising:

current limiting circuitry electrically coupled to the first circuit and the second circuit, the current limiting circuitry for current limiting the first power voltage supplied to the element of the circuit board and the second power voltage supplied to the element of the circuit board.

5. The circuit board of claim 1, further comprising:

a discharge circuit electrically coupling the first circuit and the second circuit for limiting a voltage difference between the first power voltage supplied to the element of the circuit board and the second power voltage supplied to the element of the circuit board when the electrical connector no longer receives at least one of the first power voltage and the second power voltage generated externally from the circuit board.

6. The circuit board of claim 1, wherein the first circuit and the second circuit include power switching circuits.

7. The circuit board of claim 1, wherein the signal received by the second circuit from the first circuit is the first power voltage.

8. The circuit board of claim 1, wherein the first power voltage is supplied to the element of the second circuit board through the first circuit.

9. The circuit board of claim 1, further comprising:

a third circuit electrically coupled to the electrical connector and at least one of the first circuit and the second circuit, and the third circuit for supplying one of the first voltage and the second voltage to the element of the circuit board, responsive to receiving a signal indicating that the sequencing circuit is receiving the first power voltage.

10. The circuit board of claim 1, wherein the electrical connector receives a third power voltage generated externally from the circuit board, the circuit board further comprising:

a third circuit electrically coupled to the electrical connector and at least one of the first circuit and the second circuit, the third circuit for supplying the third voltage to the element of the circuit board, responsive to receiving a signal indicating that the sequencing circuit is receiving at least one of the first power voltage and the second power voltage.

11. The circuit board of claim 1, further comprising:

a clamping circuit electrically coupled to the first circuit and the second circuit; and

a discharge circuit electrically coupled to the first circuit and the second circuit, the discharge circuit limiting a voltage difference between the first power voltage supplied to the element of the circuit board and the second power voltage supplied to the element of the circuit board when the electrical connector no longer receives at least one of the first power voltage and the second power voltage generated externally from the circuit board;

wherein the clamping circuit limits a voltage difference between the first power voltage supplied to the element of the circuit board and the second power voltage supplied to the element of the circuit board; and

wherein the clamping circuit and the discharge circuit are electrically coupled to the first and second circuits in parallel and electrically coupled to each other in sequence.

12. The circuit board of claim 11, wherein the first and second circuits comprise respective first and second microchips;

wherein the first microchip comprises a first input, a second input, a first output, and a second output, the first input receiving a second signal from the electrical connector, the second input receiving the first power voltage from the electrical connector, the first output supplying the first power voltage to the element based on the received second signal, and the second output supplying the signal indicating that the sequencing circuit is receiving the first power voltage; and

wherein the second microchip comprises a third input, a fourth input, a third output, and a fourth output, the third input receiving the signal from the second output, the fourth input receiving the second power voltage from the electrical connector, the third output supplying the second power voltage to the element based on the received signal, and the fourth output supplying a third signal.

13. The circuit board of claim 1, wherein the first and second circuits comprise respective first and second microchips;

wherein the first microchip comprises a first input, a second input, a first output, and a second output, the first input receiving a second signal from the electrical connector, the second input receiving the first power voltage from the electrical connector, the first output supplying the first power voltage to the element based on the received second signal, and the second output supplying the signal indicating that the sequencing circuit is receiving the first power voltage; and

wherein the second microchip comprises a third input, a fourth input, a third output, and a fourth output, the third input receiving the signal from the second output, the fourth input receiving the second power voltage from the electrical connector, the third output supplying the second power voltage to the element based on the received signal, and the fourth output supplying a third signal.

14. The circuit board of claim 13, wherein the third input is connected with the second output via a resistor and a diode;

wherein the resistor and the diode are connected to the third input and the second output in parallel; and

wherein the diode comprises an anode electrically coupled to the third input.

15. The circuit board of claim 1, wherein the first circuit is connected to the second circuit via a resistor and a diode;

wherein the resistor and the diode are connected to the first and the second circuits in parallel; and

wherein the diode comprises an anode electrically coupled to the second circuit.

16. A method for supplying to one or more elements of a circuit board in a predictable sequence at least a first power voltage and then a second power voltage provided from a second circuit board, comprising:

sequentially providing the first power voltage and the second power voltage from the second circuit board to a sequencing circuit of the circuit board;

responsive to the sequencing circuit receiving the first voltage, supplying the first power voltage to an element of the circuit board via a first circuit of the sequencing circuit;

responsive to the sequencing circuit receiving the first voltage, supplying a signal to a second circuit of the sequencing circuit from the first circuit of the sequencing circuit; and

responsive to the second circuit of the sequencing circuit receiving the signal, supplying the second power voltage to the element of the circuit board via the second circuit of the sequencing circuit.

17. The method of claim 16, further comprising:

limiting a voltage difference between the first power voltage supplied to the element of the circuit board and the second power voltage supplied to the element of the circuit board, when the second circuit board no longer provides to the circuit board at least one of the first power voltage and the second power voltage.

18. The method of claim 16, further comprising:

limiting a voltage difference between the first power voltage supplied to the element of the circuit board and the second power voltage supplied to the element of the circuit board, when the second circuit board provides to the circuit board the first power voltage and the second power voltage.

19. The method of claim 16, wherein the first power voltage supplied to the element of the circuit board and the second power voltage supplied to the element of the circuit board are current limited.

20. The method of claim 16, further comprising:

preventing damage to the circuit board when the circuit board is removed from the second circuit board and the removal interrupts in an unpredictable sequence the first power voltage and the second power voltage provided from the second circuit board.

21. The method of claim 16, wherein the first power voltage is higher than the second power voltage.

22. The method of claim 21, wherein the first power voltage is 5 V and the second power voltage is 3.3 V.

23. The method of claim 16, wherein the second power voltage is greater than the first power voltage.

24. The method of claim 16, wherein the predictable sequence follows a hot swapping specification.

25. The method of claim 24, wherein the hot swapping specification is the Compact PCI Hot Swap specification.

26. The method of claim 24, wherein the hot swapping specification is the PCI Hot-Plug specification.

27. A computer system, comprising:

a memory;

a circuit board electrically coupled to the memory, and the circuit board adapted to supply to an element of the circuit board in a predictable sequence at least the first power voltage and the second power voltage, comprising;

an electrical connector for receiving a first power voltage and a second power voltage;

a sequencing circuit electrically coupled to the electrical connector, wherein the electrical connector is adapted to supply the first power voltage before supplying the second power voltage to the sequencing circuit, the sequencing circuit comprising;

a first circuit for receiving the first power voltage and supplying the first power voltage to the element of the circuit board; and

a second circuit electrically coupled to the first circuit, and the second circuit for supplying the second power voltage to the element of the circuit board responsive to the sequencing circuit receiving the first power voltage; and

the element of the circuit board, the element electrically coupled to the sequencing circuit, and the element adapted to receive in the predictable sequence the first power voltage and then the second power voltage; and

a second circuit board electrically coupled to the circuit board, and the second circuit board providing the first power voltage and the second power voltage to the electrical connector of the circuit board.