Card voltage switching and protection

• US 5,613,130 A
• Filed: 11/10/1994
• Issued: 03/18/1997
• Est. Priority Date: 11/10/1994
• Status: Expired due to Term

• Current Assignee: St Clair Intellectual Property Consultants Incorporated
• Original Assignee: Vadem Limited
• Inventors: Bendler, Robert K., Teng, Yen-Chang G.
• Primary Examiner(s): AUVE, GLENN ALLEN
• Application Number:
  US08/337,302
• Time in Patent Office: 859 Days
• Field of Search: 395/282, 395/283, 395/750, 395/284, 395/836, 395/834
• US Class Current: 713/300
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: G06F 13/4068 Electrical coupling

Abstract

A computer system having a power control unit for selection of voltage levels for pluggable cards, such as PCMCIA cards. The computer system includes a primary unit for executing two or more versions of control software (card drivers within the operating system) including a current version of control software. A pluggable PCMCIA card operates with a card voltage and has pins for signalling with a CD signal that the card is plugged into the computer system. The computer includes a power supply for providing at least first and second supply voltages such as 5 V, 3.3 V and x.x V. Power switches select one of the supply voltages as the card voltage. A power control unit controls the power switching unit to select one of the supply voltages. The power control unit includes a voltage select unit operable in response to the current version of the control software for storing a voltage code for specifying the selected one of the supply voltages. The power control unit includes a power enable unit operable to be set in response to the control software for enabling the voltage select unit and operable to be reset in the absence of the CD signal. The power control unit includes a code generating unit that in turn includes a synchronous unit operable in response to the control software for generating the voltage code and including a limit unit for limiting the voltage code to a maximum value and including asynchronous code generating unit operable in response to the CD signal for storing the voltage code in the voltage select unit.

Claims

1. A computer system including,

primary means for executing control software,

a pluggable card operating with a card voltage and having signal means for providing a CD signal for indicating when the pluggable card is plugged into the computer system,

a power supply for providing at least first and second supply voltages,

power switching means for selecting one of said supply voltages as said card voltage,

power control means for controlling said power switching means to select one of said supply voltages, said power control means including,

voltage select means for storing a voltage code for specifying said one of said supply voltages,

power enable means for enabling said voltage select means and operable to be reset in the absence of said CD signal,

code generating means operable for storing said voltage code in said voltage select means.

2. The computer system of claim 1 wherein said code generating means includes asynchronous means that operates independently of said control software.

3. The computer system of claim 2 wherein said pluggable card provides VS signals for indicating a voltage level for said pluggable card and wherein said asynchronous means includes card detect logic for providing a card detect signal in response to said CD signal and includes asynchronous load logic for presetting said voltage code into said voltage select means in response to said VS signal and said card detect signal.

4. The computer system of claim 1 wherein said code generating means includes synchronous means that operates under control of said control software.

5. The computer system of claim 4 wherein said control software provides a software voltage code for specifying a voltage level for said pluggable card, said synchronous means includes a voltage limit register for storing a limit code and includes limit gates for loading said software voltage code into said voltage select means or for loading said limit code into said voltage select means if said limit code specifies a voltage level lower than the voltage level specified by said software voltage code.

6. A computer system including,

primary means for executing control software where the control software has two or more versions including a current version,

a pluggable card operating with a card voltage,

a power supply for providing at least first and second supply voltages,

power switching means for selecting one of said supply voltages as said card voltage,

power control means for controlling said power switching means to select one of said supply voltages, said power control means including,

voltage select means operable only in response to said current version of said control software for storing a voltage code for specifying said one of said supply voltages,

power enable means operable to be set in response to said control software for enabling said voltage select means,

code generating means operable for generating said voltage code.

7. A computer system including,

primary means for executing control software,

a pluggable card operating with a card voltage,

a power supply for providing at least first and second supply voltages,

power switching means for selecting one of said supply voltages as said card voltage,

power control means for controlling said power switching means to select one of said supply voltages, said power control means including,

voltage select means operable in response to said control software for storing a voltage code for specifying said one of said supply voltages,

power enable means operable to be set in response to said control software for enabling said voltage select means,

code generating means operable in response to said control software for generating said voltage code and including limit means for limiting said voltage code to a maximum value.

8. A computer system including,

primary means for executing control software,

a pluggable card operating with a card voltage and having signal means for providing a CD signal for indicating when the pluggable card is plugged into the computer system,

a power supply for providing at least first and second supply voltages,

power switching means for selecting one of said supply voltages as said card voltage,

power control means for controlling said power switching means to select one of said supply voltages, said power control means including,

a voltage select means operable in response to said control software for storing a voltage code for specifying said one of said supply voltages,

power enable means operable to be set in response to said control software for enabling said voltage select means and operable to be reset in the absence of said CD signal,

code generating means for generating said voltage code.

9. A computer system including,

primary means for executing control software,

a pluggable card operating with a card voltage and having signal means for providing a CD signal for indicating when the pluggable card is plugged into the computer system,

a power supply for providing at least first and second supply voltages,

power switching means for selecting one of said supply voltages as said card voltage,

power control means for controlling said power switching means to select one of said supply voltages, said power control means including,

voltage select means for storing a voltage code for specifying said one of said supply voltages,

power enable means for enabling said voltage select means and operable to be reset in the absence of said CD signal,

asynchronous code generating means operable in response to said CD signal for storing said voltage code in said voltage select means.

10. A computer system including,

primary means for executing control software,

a pluggable card operating with a card voltage and having signal means for providing a CD signal for indicating when the pluggable card is plugged,

a power supply for providing at least first, second and third supply voltages,

power switching means for selecting one of said supply voltages as said card voltage,

power control means for controlling said power switching means to select one of said supply voltages, said power control means including,

voltage select means for storing a voltage code for specifying said one of said supply voltages,

power enable means for enabling said voltage select means,

code generating means operable in response to said CD signal for storing said voltage code in said voltage select means.

11. The computer system of claim 10 wherein said control software provides a software voltage code for specifying a voltage level for said pluggable card, said code generating means includes a voltage limit register for storing a limit code and includes limit gates for loading said software voltage code into said voltage select means or for loading said limit code into said voltage select means if said limit code specifies a voltage level lower than the voltage level specified by said software voltage code.

12. A computer system including,

primary means for executing two or more versions of control software wherein one of said two or more versions of control software includes a current version of said control software,

a pluggable card operating with a card voltage and having signal means for providing a CD signal for indicating when the pluggable card is plugged into the computer system,

a power supply for providing at least first and second supply voltages,

power switching means for selecting one of said supply voltages as said card voltage,

power control means for controlling said power switching means to select one of said supply voltages, said power control means including,

a voltage select means operable only in response to said current version of said control software for storing a voltage code for specifying said one of said supply voltages,

power enable means operable to be set in response to said control software for enabling said voltage select means and operable to be reset in the absence of said CD signal,

code generating means including synchronous means operable in response to said control software for generating said voltage code and including limit means for limiting said voltage code to a maximum value and including asynchronous code generating means operable in response to said CD signal for storing said voltage code in said voltage select means.