Clamping circuit for use in computer system

A method of operating a computer system, comprising:

• providing a voltage rail to a plurality of components in the computer system, wherein the voltage rail is provided by a linear regulator, and wherein the plurality of components comprise a switching regulator;
• providing a termination voltage, separate from the supply voltage, to system memory, wherein the termination voltage is provided by the switching regulator;
• detecting when the voltage rail exceeds a first voltage level;
• and
• clamping the voltage rail in response to said detecting so that the voltage rail does not exceed a maximum voltage level, wherein the maximum voltage level is a voltage level that causes erroneous behavior in a first portion of the components provided with the voltage rail.

A clamping circuit configured to clamp a voltage rail in a computer system, comprising:

• a voltage divider coupled to the voltage rail and to a shunt regulator, wherein the voltage divider is configured to apply an input voltage to the shunt regulator, wherein the voltage divider is configured so that the input voltage is greater than or equal to a reference voltage level of the shunt regulator when a voltage on the voltage rail is greater than or equal to a first voltage level, and wherein the voltage divider is configured so that the input voltage is less than the reference voltage level when the voltage on the voltage rail is less than the first voltage level;
• the shunt regulator coupled to the voltage divider, wherein the shunt regulator is configured to turn on when the input voltage is greater than or equal to the reference voltage level and turn off when the input voltage is less than the reference voltage level;
• and
• a transistor coupled to the voltage rail and to the shunt regulator, wherein the transistor is configured to turn on in response to the shunt regulator turning on, wherein the transistor is configured to sink current from the voltage rail when the transistor is on to decrease the voltage on the voltage rail below first voltage level while the voltage rail is being supplied by a power supply, and wherein the transistor is further configured to turn off when the shunt regulator is off.