Controlling turn on FETs of a hot plug device

Patent metadata

Field	Value
Publication number	US-9362901-B2
Application number	US-201514831345-A
Country	US
Kind code	B2
Filing date	Aug 20, 2015
Priority date	Apr 18, 2014
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

A method for controlling the in-rush current to a hot plug device. The method includes providing a series of turn on pulses to the gates of a plurality of turn on FETs on a hot plug device coupled to a direct current power source, wherein each pulse causes the plurality of FETs to pass current from the direct current power source to a subsystem of the hot plug device, and wherein each pulse has a duration that ends before the impedance of the turn on FETs falls below a safe operating region. The method further includes providing a steady turn on signal to the FETs in response to the output voltage from the FETs to a subsystem of the hot plug device exceeding a predetermined voltage threshold.

First claim

What is claimed is:

1. A method, comprising:
providing a series of turn on pulses to the gates of a plurality of turn on FETs on a hot plug device coupled to a direct current power source, wherein each pulse causes the plurality of FETs to pass current from the direct current power source to a subsystem of the hot plug device, and wherein each pulse has a duration that ends before the impedance of the turn on FETs falls below a safe operating region; and
providing a steady turn on signal to the FETs in response to the output voltage from the FETs to a subsystem of the hot plug device exceeding a predetermined voltage threshold.

2. The method of claim 1 , further comprising:
limiting the series of turn on pulses to no more than a predetermined number of turn on pulses.

3. The method of claim 2 , wherein limiting the series of turn on pulses to no more than a predetermined number of turn on pulses prevents damage to the FETs.

4. The method of claim 2 , wherein limiting the series of turn on pulses to no more than a predetermined number of turn on pulses prevents tripping of the power supply.

5. The method of claim 2 , further comprising:
providing no turn on signal to the FETs in response to the output voltage from the FETs to the subsystem of the hot plug device being less than the predetermined voltage threshold after the predetermined number of turn on pulses.

6. The method of claim 2 , further comprising:
providing a low impedance alert in response to the output voltage from the FETs to the subsystem of the hot plug device being less than the predetermined voltage threshold after the predetermined number of turn on pulses.

7. The method of claim 1 , wherein the time between pulses is greater than the duration of the pulses.

8. The method of claim 1 , wherein the predetermined voltage threshold is less than a target operating voltage for the hot plug device.

9. The method of claim 1 , further comprising:
detecting installation of the hot plug device in a host computer, wherein the series of turn on pulses are provided in response to detecting installation of the hot plug device in a host computer.

10. The method of claim 1 , wherein the hot plug device has a 12 Volt rail coupled between outputs of the FETs and the subsystem of the hot plug device.

11. The method of claim 10 , wherein the 12V rail is a capacitor resistor network having a time constant.

12. The method of claim 1 , wherein the output voltage from the FETs to a subsystem of the hot plug device increases after each pulse.

13. The method of claim 1 , wherein providing the series of turn on pulses to the plurality of turn on FETs cause the hot plug device to reach the turn on voltage with less power dissipation in the FETs than by providing a steady turn on signal to the plurality of turn on FETs.

14. The method of claim 1 , further comprising:
monitoring an amount of current through the turn on FETs to a subsystem of the hot plug device.

15. The method of claim 1 , further comprising:
automatically enabling one or more component of the hot plug device in response to the output voltage from the FETs to a subsystem of the hot plug device exceeding a voltage enabling threshold specific to the one or more component.

16. The method of claim 15 , wherein the one or more component includes a fan.

Assignees

• IBM

Inventors

• Barnette Jamaica L
• Celenza Nicholas
• Totten Brian C

Classifications

• H02H7/20

  for electronic equipment (for converters H02H7/10; for electric measuring instruments G01R1/36; for DC voltage or current semiconductor regulators G05F1/569; for amplifiers H03F1/52; for electronic switching circuits H03K17/08) · CPC title

• H03K17/687

  the devices being field-effect transistors · CPC title

• H03K17/08 Primary

  Modifications for protecting switching circuit against overcurrent or overvoltage · CPC title

• H02H9/004

  in connection with live-insertion of plug-in units (involving communication with a central processing unit G06F13/40) · CPC title

• G05F1/569

  for protection · CPC title