Switched Hot Swap Controller

• US 20080253051A1
• Filed: 11/15/2005
• Published: 10/16/2008
• Est. Priority Date: 11/15/2005
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sander, Sverker, Skold, Claes-Goran, Fasth, Kjell-Arne
• Granted Patent: US 8,159,801 B2
• Time in Patent Office: Days
• US Class Current: 361/93.9
• CPC Class Codes: H02H 9/001 limiting speed of change of electric quantities, e.g. soft switching on or off progressive control of electronic switches for eliminating interferences H03K17/16
• CPC Class Codes: H02H 9/004 in connection with live-insertion of plug-in units involving communication with a central processing unit G06F13/40

Abstract

The invention describes an electric circuit (100), a method and a computer program for hot-swapping and electronic board in a telecommunication system, where the increase in current in the electric circuit is controlled by a microcontroller (130) switching a power transistor in a switching circuit (150) so as to gradually increase the capacitor voltage for the electronic board. The current level is measured either in the microcontroller (130) itself or in an external current sense circuit (140) and compared to a maximum current level.

Claims

1. An electric circuit (for hot-swapping of an electronic board, comprising:

circuitry for providing a current charging a capacitive load on said electronic board;

circuitry for controlling the alternation of the current charging said capacitive load on said electronic board;

circuitry for switching the current charging said capacitive load; and

,

a processing unit for controlling the timing of the switching of the current in said electric circuit, characterized in that said processing unit is adapted for continuously switching the current in said electric circuit.

2. The electric circuit according to claim 1, wherein said alternation of the current comprises an increase in said current charging said capacitive load.

3. The electric circuit according to claim 1, wherein the circuitry for switching the current charging said capacitive load includes a discrete transistor.

4. The electric circuit according to claim 3, wherein the circuitry for switching the current charging said capacitive load further includes a driving circuit for said discrete transistor.

5. The electric circuit according to claim 4, wherein the circuitry for switching the current charging said capacitive load further includes a rectifier circuit for freewheeling the current charging said capacitive load.

6. The electric circuit according to claim 4 wherein said driving circuit is a low-ohmic source for the gate charge of said discrete transistor.

7. The electric circuit according to claim 5, wherein said rectifier circuit is a diode circuit or a transistor circuit.

8. The electric circuit according to claim 1, wherein said processing unit for controlling the timing of the switching of the current in said electric circuit is a microcontroller, an ASIC or an FPGA.

9. The electric circuit according to claim 1, wherein said processing unit is a programmable microprocessor.

10. The electric circuit according to claim 1, wherein said processing unit additionally includes circuitry for monitoring the actual level of the supply voltage in the electric circuit.

11. The electric circuit according to claim 1, wherein said circuitry for controlling the increase in said current is adapted to release the energy stored in it during the switching of said current charging the capacitive load in the form of another current additionally charging the capacitive load.

12. The electric circuit according to claim 10, wherein said circuitry includes an inductor.

13. The electric circuit according to claim 1, wherein said electric circuit further includes circuitry for monitoring the current in said circuit.

14. The electric circuit according to claim 12, wherein said circuitry for monitoring the current in said circuit is a shunt resistor circuit, a hall-element or some other circuit performing an equivalent function.

15. The electric circuit according to claim 13, wherein said circuitry for monitoring the current in said circuit further includes an operation amplifier for amplifying a signal indicative of the current in said electric circuit and a comparator for comparing said monitored signal level to a signal level indicative of the maximum allowable current level.

16. The electric circuit according to claim 12, wherein the circuitry for monitoring the current in said circuit is incorporated into said processing unit for controlling the timing of the switching for the current in said electric circuit.

17. A method for providing hot-swapping of electronic boards in an electric circuit, comprising the steps of:

providing a current charging a capacitive load on said electronic board;

controlling an alternation in the current charging said capacitive load on said electronic board;

switching the current charging said capacitive load;

controlling the timing of the switching for the current in said electric circuit using a processing unit; and

,

continuously switching the current in said electric circuit.

18. The method according to claim 17, wherein said switching a current charging said capacitive load includes turning “

on” and

turning “

off”

a discrete transistor.

19. The method according to claim 17, wherein said controlling a current charging said capacitive load comprises controlling an increase in said current charging said capacitive load.

20. The method according to claim 17, wherein said step of switching the current charging said capacitive load includes monitoring a current level in said electric circuit.

21. The method according to claim 20, wherein said step of monitoring the current level in said electric circuit further includes amplifying a signal indicative of the current level monitored and comparing it to a desired signal level indicative of a maximum allowable current level.

22. The method according to claim 21, wherein said step of amplifying the signal indicative of the current level monitored and comparing it to a maximum allowable current level additionally includes limiting the maximum current charging said capacitive load.

23. The method according to claim 21, wherein said step of comparing the signal indicative of the current level monitored in the electric circuit is performed in the analog or digital domain.

24. The method according to claim 22, wherein said step of comparing the signal indicative of the current monitored in the electric circuit is performed in said processing unit or outside of said processing unit.

25. The method according to claim 17, wherein said step of controlling the increase in said current charging said capacitive load further includes controlling the increase in current charging said capacitive load during the time said discrete transistor is turned “

off”

.

26. The method according to claim 19, wherein the step of controlling of the timing of the switching for the current in said electric circuit further includes programming a microcontroller to perform said controlling operation.

27. The method according to claim 17, including the additional step of measuring a signal indicative of the supply voltage level to a signal indicative of the allowable supply voltage range.

28. The method according to claim 17, further including the step of performing a reset of the electric circuit when said supply voltage level is outside of the allowed voltage range.

29-36. -36. (canceled)