GB2615651A

GB2615651A - Method of controlling an operating state of a computer system and corresponding computer system

Info

Publication number: GB2615651A
Application number: GB2300799.0A
Authority: GB
Inventors: Kraus Dominik; Baltos Apostolos
Original assignee: Fujitsu Client Computing Ltd
Current assignee: Fujitsu Client Computing Ltd
Priority date: 2022-01-24
Filing date: 2023-01-19
Publication date: 2023-08-16
Also published as: FR3132152A1; JP2023107757A; DE102022101557B3; GB202300799D0

Abstract

Controlling an operating state of a computer system (1, fig.2) includes triggering a command instructing the system to transition from a main operating state to a standby state defining an operation of the system (1, fig.2) with a lowest power consumption compared to the main operating state. A power consumption of the system (1, fig.2) is measured and a main supply mode of a power supply unit (2, fig.2) of the system (1, fig.2) is maintained as long as a threshold value of the measured power consumption of the system (1, fig.2) is exceeded. Transition of the system (1, fig.2) from the main operating state to a power-saving state is initiated as soon as the threshold value of the measured power consumption of the system (1, fig.2) falls below the threshold. The power-saving state corresponds to a state with reduced power consumption compared to the main operating state, wherein the power supply unit (2, fig.2) of the system (1, fig.2) is switched in the power-saving state to an auxiliary supply mode with a reduced power output compared to the main supply mode. The power-saving state may correspond to the standby state.

Description

Method of controlling an operating state of a computer system and corresponding computer system The invention relates to a method for controlling an operating state of a computer system. Furthermore, the invention relates to a corresponding computer system.

Driven by the trend in the computer industry to improve the power consumption of computer systems, such as notebooks and desktop PCs, more advanced standby states have been implemented to replace or extend traditional computer system states, such as the SO (working) and 33 (standby) states according to the so-called Advanced Configuration and Power Interface (AC2I). In particular, manufacturers of processors and operating systems have started to push the implementation of a new system state called "Modern Standby". This system state aims to transfer standby states, as known from mobile computing (smartphones, tablets, etc.), to traditional x86 systems.

A key difference of the "Modern Standby" system state from the traditional S3 standby state is permanent network connectivity, the ability to perform background tasks (if required), fast system "wake-up", and improved security implementations. To reduce power consumption to levels similar to or even lower than those achieved in the traditional 53 standby state, the mainboard and all connected components and devices in the computer system (including the CPU) switch to power-saving modes. In addition, the power supply unit (PSU) in desktop PCs is switched to a light load mode. The disadvantage here, however, is that not all power lines can be operated with an improved light-load efficiency.

For the "Modern Standby" system state to be reliably adopted and executed, all connected components and devices in the computer system (including the CPU) must support this system state. For example, PCIe devices (PCIe = Peripheral Component Interconnect express) must support a low power mode, as a result of which a disconnection of the main power supply can take place. Furthermore, the support of operating system drivers is necessary. If individual devices or components do not meet all the requirements of the "Modern Standby" system state or otherwise block the transition to power-saving modes, the computer system will remain energetically stuck in the SO state (working) so that the power supply cannot transition to a standby state or light load operation.

Another problem is that frequent transitions and changes between a main operation and a standby mode of the power supply unit may occur if a device or component of the computer system requires constant updating from the network or background tasks. Depending on an implementation of the power supply unit, this can lead to audible switching noise or reduce the lifetime of the power supply unit.

Previous implementations of computer systems using the "modern standby" system state are mainly limited to battery-powered devices, such as notebooks, that do not use internal power supply units (e.g., ATX power supply units) that need to switch between a main supply mode and a standby mode. In the context of desktop PCs, only reference designs are proposed so far that use ATX power supply units with multiple supply lines and switch them constantly, e.g. every second, between a main supply mode and a standby mode. For power supplies with only one supply line, for example, a blocking time window of two seconds is implemented in the power supply unit so that the power supply unit does not switch on for two seconds even if an activation signal is specified that blocks switching between a main supply mode and a standby mode.

It is therefore a task of the present invention to improve existing solutions for power-saving states on x86 systems.

This task is solved according to a first aspect by a method according to claim 1. Supplementary or improved implementations are given in the dependent claims.

The method is implemented for controlling an operational state of a computer system and comprises the following steps: - triggering a command that directs a transition of the computer system from a main operating state to a standby state, the standby state defining an operation of the computer system with a lowest power consumption relative to the main operating state, - measuring a power consumption of the computer system, - maintaining a main supply mode of a power supply of the computer system as long as a threshold value of the measured power consumption of the computer system is exceeded, - initiating a transition of the computer system from the main operating state to a power-saving state as soon as the measured power consumption of the computer system -4 -falls below the threshold value, wherein the power-saving state corresponds to a system state with reduced power consumption compared to the main operating state, and wherein the power supply unit of the computer system is switched in the power-saving state to an auxiliary supply mode with a reduced power output compared to the main supply mode.

Such a method improves existing solutions for standby states on x86 systems by implementing a power (consumption) dependent (load dependent) power-saving state. In this power-saving state, individual components of the computer system are throttled in their power consumption or completely shut down depending on their power consumption. The power-saving state is, subject to a power consumption of the computer system, a power-dependent state, which energetically applies between the main operating state and the standby state requested by the triggering of the command. The power -saving state therefore takes effect energetically even before the lowest power consumption, which is defined by the standby state. In the power -saving state, the power supply unit is switched to an auxiliary supply mode in order to save electrical energy. The auxiliary supply mode of the power supply unit is, for example, a standby mode or light load mode.

This allows improved reduction of the power consumption of computer systems, especially desktop PCs. The method controls the transition from the main operating state to the power -saving state as soon as the threshold value of the measured power consumption of the computer system is undershot and the command to enter the standby state has been triggered. -5 -

The method thus has the effect and advantage over conventional solutions that a power -saving state can be entered even if individual components and devices in the computer system (including the CPU) do not support the requested standby state or block it in some other way. In this way, power consumption can still be reduced and the computer system does not remain energetically stuck in the main operating state.

The standby state is an operating state of the computer system, in which the computer system is still in operation, i.e. not switched off. The standby state corresponds, for example, to a sleep state (sleep) with a lowest power consumption. The standby state is configured, for example, in an operating system of the computer system. For example, the standby state is a "modern standby" system state. In this system state, the computer system is in the lowest power consumption state. This system state is defined, for example, in such a way that individual or several components and devices of the computer system behave under the condition of operational standby in a manner analogous to S0 operation in accordance with the ACPI standard, but are energetically in the lowest consumption state. This allows the power consumption to be reduced to a very low level, while the computer system can still be reactivated very quickly back to the main operating state.

An effect and advantage of measuring the power consumption of the computer system is that the main supply mode of the power supply of the computer system is maintained as long as a threshold value of the measured power consumption of the computer system is exceeded. This ensures that the computer system is running stably and that the power supply does not, in any case, switch to an auxiliary supply mode, in which the power requirements of the computer system cannot be served.

Another effect and advantage of measuring the power consumption of the computer system is that the power -saving state can be set load dependent. This means that the power-saving state can be dimensioned more or less moderately depending on the required remaining power. If the computer system still requires significant remaining power, e.g. because background tasks or updates from the network have to he completed, the power-saving state is dimensioned more moderately than in the case only a few processes or components have to run.

In various implementations of the method, the power-saving state corresponds to the standby state when the computer system can be operated in the power-saving state with the lowest power consumption. For example, in such a case, the power-saving state corresponds to the "modern standby" system state.

In various implementations of the method, the power consumption of the computer system is repeatedly measured in several measurement processes as long as the threshold value of the measured power consumption of the computer system is exceeded. A timer is started after each measurement process. A new measurement process is performed as soon as the timer has expired. This has the effect and advantage that running tasks or processes that have an influence on the power consumption can be terminated first before the power consumption of the computer system is measured again. In supplementary implementations of the method, the timer is incremented after each measurement process. This has the -7 -advantage that different running tasks or processes with different completion durations can be accommodated.

In various implementations of the method, an error signal is 5 generated if a certain number of measurement operations is reached and the threshold value of the measured power consumption of the computer system is still exceeded. This has the advantage that an internal controller in the computer system or a user can be signaled that the power-saving state 10 cannot be assumed (despite a requested command). This increases the system security of the computer system.

In various implementations, the procedure has the further steps: - measuring the power consumption of the computer system in power-saving state, - attempting to further reduce the power consumption of the computer system as soon as the threshold value of the measured power consumption of the computer system in the power-saving state is exceeded.

These steps have the effect and advantage of allowing a controller within the computer system to respond to a change in power consumption. In order to keep the computer system in the power-saving state despite an increase in power consumption above the threshold value, a further reduction in the power consumption of the computer system is aimed for.

For example, the CPU is (further) throttled or other components or devices that are not required are switched off.

In various implementations, the process has the further step: - initiating a transition of the computer system from the power-saving state back to the main operating state if the threshold value of the measured power consumption of the computer system in the power-saving state continues to be exceeded after a (pre-)determined period of time, switching the power supply of the computer system back to the main operating state.

This measure has the effect and advantage of preventing an unintentional shutdown of the computer system due to overload in the power-saving state.

According to a second aspect, the above task is solved by a 15 computer system according to claim 7. Supplementary or improved embodiments are provided in the dependent claims.

The computer system has a power supply unit and components that are supplied with electrical power via the power supply 20 unit. The computer system is configured to: - trigger a command for transitioning the computer system from a main operating state to a standby state, the standby state defining an operation of the computer system with a lowest power consumption relative to the main operating state, - measure a power consumption of the computer system and maintain a main supply mode of the power supply unit of the computer system as long as a threshold value of the measured power consumption of the computer system is exceeded, -initiate a transition of the computer system from the main operating state to a power-saving state as soon as the measured power consumption of the computer system falls below the threshold value, wherein the power-saving state is adjustable as a function of a load and corresponds to a system state with reduced power consumption compared with the main operating state, and wherein the power supply unit of the computer system is switchable in the power-saving state to an auxiliary supply mode with a reduced power output compared with the main supply mode.

Such a computer system also achieves the effects and advantages explained above in the context of the method according to the first aspect.

In various embodiments of the computer system, a measurement circuit is set up to measure the power consumption of the computer system, which generates a control signal. This indicates whether or not the threshold value of the measured power consumption of the computer system has been exceeded. This has the effect and advantage that a simple determination of the power consumption of the computer system can be made. The measuring circuit is constructed, for example, as an analog circuit with a shunt and a measuring amplifier, whereby a detection of a temporal change in the current consumption within the computer system takes place. This can be, for example, a first mathematical derivative of the current di/dt. For example, the current signal is averaged over a certain period of time and the control signal is generated when the averaged current signal exceeds the threshold value.

-10 -In various embodiments, the computer system is further arranged to provide the control signal generated by the measurement circuit to a controller and to control, by means of the controller, the transition of the computer system between the main operating state and the power-saving state. This has the effect and advantage that the various states can be controlled automatically and reliably. The controller is, for example, an embedded controller on the main board of the computer system.

In various embodiments, the computer system is adapted to perform a procedure of the type explained above.

The invention exemplary is explained in more detail below by means of embodiment with the aid of several drawings.

Figure 1 shows a schematic flow diagram of an implementation of a method for controlling an operating status of a computer system.

Figure 2 shows a schematic representation of components of a computer system according to an exemplary embodiment.

Figure 3 shows a circuit arrangement of a measuring circuit according to an exemplary embodiment.

Figure 4 shows a schematic representation of a comparison of an implementation of a standby state with and without a power-saving state.

Figure 1 shows a schematic flowchart of an implementation of a method for controlling an operating state of a computer system. Here, on the left side of the dashed separation line (under the heading "system state") various method steps 51 to 57 concerning system states of a computer system are shown. On the right side of the dashed separation line (under the heading "PSU state"), a respective state of a power supply unit of the computer system is shown.

The procedure starts in step Si, in which the computer system is in a main operating state. In this state, the computer system is powered on and all devices and components of the computer system are active. The power supply unit of the computer system is on (ON state) in this system state and is in a main supply mode to supply electrical power to the computer system. For example, the main operating state of the computer system corresponds to an SO state according to the ACPI standard. In step Si, a command is triggered to instruct a transition of the computer system from the main operating state to a standby state. This command is triggered, for example, by an operating system of the computer system. This is done, for example, by a user of the computer system pressing a power button on the computer system or a software button in the operating system of the computer system.

Then, in step S2, a power consumption of the computer system is measured. For this purpose, for example, a current consumption of components of the computer system from the power supply unit of the computer system is measured at a specified supply voltage and compared with a predefined threshold value. A measurement method and a measurement circuit for this are explained in more detail below. In step 52, the power supply unit of the computer system is still in the main supply mode (ON state).

-12 -If the measured power consumption is above the threshold value, it means that the power consumption of the computer system is higher than an output power that the power supply can provide in an auxiliary supply mode. In this case, the main supply mode of the power supply unit of the computer system is maintained as long as the threshold value of the measured power consumption of the computer system is exceeded. In this case, the method changes to step 53.

A timer is started in step 53. After the timer has expired, the power consumption is measured again according to step 52. If the measured power consumption is still above the limit, the system switches to step 53 again and a new timer is started. With each such iteration between steps 52 and S3, a time duration of the timer is increased as long as the power consumption is above the threshold value. For example, in the implementation example according to Figure 1, an iterative increase of the timer from 500 ms to 10 s delay is performed. For example, different timers are set with the values 500 ms, 1 s, 5 s and 10 s. Such an approach allows running tasks or processes that have an impact on the power consumption of the computer system to be terminated first before the power consumption of the computer system is measured again. The more often it is switched between steps 52 and S3, the longer the timers are set accordingly to enable longer running tasks or background processes and their termination.

Steps S2 and S3 are repeated, for example, until a predetermined number of iterations (for example, five iterations) has been completed or the power consumption of the computer system has fallen below the threshold value. If, after the predetermined number of iterations has expired, the power consumption of the computer system is still above the -13 -threshold value, an error signal is generated. This indicates that entering a power-saving state has failed. This is signaled, for example, to a user of the computer system via an alarm signal or a message, e.g. via the operating system.

However, if the power consumption has fallen below the threshold value before the maximum number of iterations is reached, the procedure changes from step S2 to step S4. In step 34, an optional preconfiguration of a power-saving state or an entry into this power-saving state takes place. Preconfiguring specifies, for example, settings in devices, components, or in software (e.g., operating system) of the computer system. This includes, for example, specific commands or command sets for controlled transition of the devices and components into the power-saving state. For example, the preconfiguring occurs once when the power-saving state is first entered. If preconfiguring is performed in step 54 and this is completed, the computer system enters the power-saving state. Alternatively, preconfiguration may be performed separately to step 54, for example in advance of a procedure explained herein.

The power-saving state is a system state with reduced power consumption compared to the main operating state. In particular, the power-saving state is an intermediate energy state of the computer system between the main operating state and the standby state that has been instructed via the command in step Sl. For example, the standby state defines an operation of the computer system with the lowest power consumption compared to the main operating state. For example, the standby state is a "modern standby" system state.

-14 -In the power-saving state according to step 54 and depending on the power consumption, the power consumption of individual components of the computer system is reduced or they are completely switched off. For example, fans in the computer system are regulated down or switched off completely and the processor (CPU) is throttled in its clock speed. The power supply of the computer system can then be switched to the auxiliary supply mode. The auxiliary supply mode of the power supply unit is, for example, a standby mode or a light load mode. The computer system is then in the power-saving state, which is explained in more detail below in comparison with the standby state.

In the power-saving state, the power consumption of the computer system is measured continuously in step 55. If the power consumption exceeds the explained threshold value in the power-saving state, a power warning or a system interrupt is issued and the procedure changes to step S6. In this step Sc, a further power reduction of the computer system is initiated. For this purpose, an attempt is made to further reduce the system power, for example by further throttling the CPU. For example, the CPU is throttled to its minimum clock speed in this case. Also, the power reduction of other devices and components in the computer system can take place at this stage.

If, as a result of the actions in step S6, the power consumption drops below the threshold value again within a specified period of time, the procedure switches back to step 55, with the computer system remaining in the power-saving state. In the exemplary implementation, the specified time period is 5 ms. If, on the other hand, the actions in step 56 do not lead to a reduction of the power consumption below the -15 -threshold value in the period of 5 ms, the procedure switches to step S7. Thereby, the power-saving state is left and, if necessary, an overload event is logged, which led to the power increase. The actions of step S7 thus transition the computer system from the power-saving state back to the main operating state. In this case, the power supply of the computer system is switched back to the main operating state (ON state). According to the implementation example of Figure 1, the procedure is thus again in step S1.

Figure 2 shows a schematic representation of components of a computer system 1 according to an embodiment. A method as explained above for Figure 1 is used, for example, in the computer system 1 according to Figure 2. The computer system 1 according to Figure 2 has a power supply unit 2 for supplying components 4a, 4b (or other components not shown) of the computer system 1. The power supply unit 2 is for example a so-called single-rail power supply unit. This means that the power supply unit outputs only one supply voltage.

The power supply unit is configured, for example, to output the same supply voltage in the auxiliary supply mode as in the main supply mode, but at a lower output power than in main supply mode. This has the advantage that the supply voltage is also available in the auxiliary supply mode, which is used to supply important components 4a, 4b. In the embodiment example shown in Figure 2, the power supply unit 2 has an output, to which a 12 V supply voltage is applied. This supply voltage is used, for example, to supply PCI Express (PCIe) components 4a on a main board of the computer system 1. Various other board voltages can be generated via several voltage regulators 3a to 3d. For example, a voltage regulator 3a is provided to provide a supply voltage for the CPU core of the computer system 1, which can be used to -16 -supply the CPU (component 4b). Further voltage regulators 3b to 3d generate further board voltages of 5 V, 3.3 V and 1.8 V, as shown by way of example in Figure 2.

Furthermore, the computer system 1 has a measuring circuit 5 which is connected between an output of the power supply unit 2 and the voltage regulators 3a to 3d. In the exemplary embodiment according to Figure 2, the measuring circuit 5 has a shunt, which is connected to a circuit for detection of a change in current over time (di/dt). The latter detects a temporal change of the electric current drawn from the power supply unit. The shunt comprises, for example, a measuring resistor for measuring the electric current. In the exemplary embodiment according to Figure 2, the measurement of the electrical power consumption by means of the measuring circuit 5 comprises only a supply path towards the components 4b of the computer system 1, without any consideration of the components 4a. However, in alternative embodiments, the latter may also be included in a measurement of a power consumption.

The measuring circuit 5 thus takes over the task of measuring the power consumption of the computer system 1, as explained for steps S2 and S5 in the procedure of Figure 1. If the power consumption of the computer system 1 exceeds the threshold value, the measuring circuit 5 generates a control signal 8 and forwards this as a power warning or system interrupt to a controller 6 of the computer system 1. In the exemplary embodiment according to Figure 2, the controller 6 is an embedded controller. The controller 6 controls the operating state of the computer system 1 depending on the control signal 8. For example, if the control signal 8 indicates a continuous exceeding of the threshold value for -17 -the power consumption of the computer system 1 (via a defined first signal level of the control signal 8) and if the predefined number of iterations of measurement operations is exceeded, as explained in Figure 1 for steps 52 and S3 above, the controller 6 generates an error signal 13. This indicates that the entering of a power-saving state of the computer system 1 has failed. The error signal 13 is transmitted to a chipset 7, which processes it accordingly, takes appropriate action and, if necessary, issues a signal to a user of the computer system 1. The chipset 7 is, for example, a so-called system on a chip (SoC).

If, on the other hand, the control signal 8 indicates (via a defined second signal level of the control signal 8) that the power consumption falls below the threshold value during the iterative measurement processes, the controller 6 generates a trigger signal 14, as a result of which the power supply unit 2 is switched to the auxiliary supply mode. As a result, the computer system 1 assumes the power-saving state, whereby components 4a and 4b, respectively, are throttled or restricted in their power consumption. See also the explanation of step S5 according to Figure 1 above. The controller 6 as shown in Figure 2 also uses the measuring circuit 5 to continuously monitor the power consumption of the computer system 1 in the entered power-saving state and, if necessary, initiates the actions as explained in steps 36 and 57 above with respect to Figure 1.

Signaling between the controller 6 and the power supply unit 30 2 or the chipset 7 is performed, for example, via pin signaling in accordance with the so-called general purpose input/output standard (GFI0).

-18 -The detection of a change in current over time di/dt in the measuring circuit 5 comprises, for example, a current measuring amplifier in which the current is averaged over a predetermined short period of time, for example 8 ms, and which detects whether the predefined threshold value of the power consumption is exceeded after this period of time. The measuring circuit 5 is configured, for example, to transmit the control signal 8 as a digital output signal to the controller 6.

An alternative or supplementary embodiment of a measuring circuit 5 is shown in Figure 3. The measuring circuit 5 according to Figure 3 comprises a measuring resistor R20 which serves as a shunt for detecting an electric current of the computer system. On the left side, the measuring resistor R20 is connected to a signal input 1 (IN(+)) of a current measuring amplifier 9. On the right side, the measuring resistor R20 is connected to a signal input 10 (IN(-)) of the current sensing amplifier 9. Thus, a supply signal on the power supply side is present at the input 1 of the current measuring amplifier 9, while a supply signal on the load side (towards the computer system 1) is present at the input 10 of the current measuring amplifier 9. Furthermore, a capacitor C4 is connected in parallel with the measuring resistor R20 and serves as a filter capacitor.

The current measurement amplifier 9 determines a differential signal from the input signals 1 and 10 and compares this with a reference signal at input 7 (CMPREF) of the current measurement amplifier. The reference signal is formed via a voltage divider R26, R28 from a standby supply power of the power supply unit (P3V3P_STSY). This also serves as a voltage supply (VS+) at input 2 of the current measuring amplifier 9.

-19 -An output signal (ALERT#) at an output 3 of the current measuring amplifier 9 is used to signal a behavior of the differential signal of the inputs 1 and 10 of the current measuring amplifier 9 with respect to the reference signal at input V of the current measuring amplifier 9. In normal operation (differential signal falls below reference signal), the output signal (ALERT#) is at the signal level HIGH. As a result, transistor Q5, which is also supplied with current via the standby supply power (P3V3P_STBY), is conducting. The capacitor 06 is discharged. In this state, the further transistor Ql blocks and generates, also supplied from the standby supply (P3V3P_STBY), a signal level HIGH at its collector terminal 3, which serves as control signal 8.

If the differential signal of the inputs 1 and 10 of the current measuring amplifier 9 exceeds the reference signal at the input 7 of the current measuring amplifier 9, the current measuring amplifier 9 generates a signal level LOW of the output signal (ALERT#) at its output 3. This causes transistor Q5 to turn off. This causes capacitor 06 from the standby supply (P3V3P_STBY) to charge via resistors R23 and R25.

The capacitor 06 acts as a delay element. As soon as capacitor 06 has reached a certain state of charge (and the voltage drop across 06 exceeds a certain value), the further transistor Ql is switched via diode D3 to a conducting state and pulls the signal level at its collector terminal 3 to a signal level LOW, which in turn serves as a control signal 8.

The capacitor 06, for example, is dimensioned in such a way that a charging constant with a time delay of 8 ms is set.

-20 -In this way, the measuring circuit 5 determines a current consumption of the computer system according to Figure 3, which is recognized as a change in the current over time di/dt and averaged over the period of 8 ms. If the current consumption after the 8 ms is still above the reference level (input 7 of the current measuring amplifier 9), the signal level of control signal 8 is set to LOW by measuring circuit 5. The control signal 8 thus indicates that the power consumption of the computer system is above the specified limit. On the other hand, if the power consumption of the computer system decreases again within 8 ms, the transistor Ql remains in the off state (no conductive state of the diode D3), which keeps the control signal 8 at a signal level HIGH. In this case, the control signal 8 indicates that the current consumption does not exceed the critical limit.

The control signal 8 according to Figure 3 serves, for example, as an output signal of the measuring circuit 5 according to Figure 2 for corresponding signaling to the controller 6, as explained above, if, in an exemplary embodiment, the measuring circuit 5 according to Figure 3 is used in the implementation according to Figure 2. The computer system may be configured such that the signal output 8 is ignored if no transition to or operation in the power-saving state is requested.

Figure 4 shows a schematic representation of a comparison of an implementation of a standby state of the computer system of the type explained above with and without the power-saving state explained above. In the upper part of Figure 4, a standby state of the computer system without a power-saving state of the type explained above is shown. Here, the computer system can switch between the main operating state -21 -and the standby state 11. The standby state 11 corresponds here, for example, to the "modern standby" system state. In the upper case according to Figure 4, the computer system is in the main operating state 10 as long as at least some system activity is present. The main operating state 10 is assumed when the system is completely switched on and all devices are active (see system state 10a). However, the main operating state 10 is also active when the system is in standby and there is little or limited system activity (see system state 10b). In this case, the computer system enters the standby state 11 only when the system is in standby and no system activity is recorded. Only in this case of low power consumption is the power supply switched to standby (auxiliary power supply mode). In all other cases, the power supply unit is active in the main supply mode and supplies the computer system with electrical energy.

Thus, the upper case according to Figure 4 illustrates that, without an explained power-saving state, the electrical power consumption in the power supply unit 2 of the computer system can only be reduced if the standby state 11 can be assumed. However, if some or all of the components or devices of the computer system block the transition to the standby state 11 or are in a state of low system activity, the computer system remains in the main operating state 10.

In contrast, the lower case of Figure 4 illustrates a standby state with an explained power-saving state. In this case, the computer system is in the main operating state 10 only when the system is fully powered on and all devices are active. In this case of higher power consumption, the power supply is active and is in the main operating state (see step S1 according to Figure 1). However, in the lower case according -22 -to Figure 4, the computer system assumes a power-saving state 12, which can be assumed depending on the power consumption. This means that the power-saving state 12 is already assumed when the system is switched on but some devices are in standby (system state 12a). Already then the power supply unit is switched to standby (auxiliary supply mode), which results in a lower power consumption. The less system activity is recorded, the deeper the computer system goes into a standby state (system state 12b). Thus, the power-saving state 12 can further limit the power consumption. As soon as the computer system is completely in standby and no system activity is recorded, the power-saving state 12 in the lower case of Figure 4 corresponds to the standby state 11. In the power-saving state 12 corresponding to the lower case of Figure 4, all components and devices of the computer system can be addressed, for example, analogously to a state SO according to the ACPI standard. This has the advantage that no further software implementations, or device or driver support are necessary.

The overview according to Figure 4 illustrates that a reduced consumption can already be set via the control of the computer system in the explained power-saving state (see in particular explanations to Figure 1) if the system is still active but some devices are already switched to standby (from system state 12a onwards). So even if, according to the lower scenario in Figure 4, individual components or devices of the computer system would not allow a standby state 11, the power consumption of the computer system can still be reduced according to the invention.

All the designs and implementations shown are merely selected as examples.

-23 -List of reference signs 1 Computer system 2 Power supply unit 3a-3d Voltage regulator 4a, 4b Components Measuring circuit 6 Controller 7 Chipset 8 Control signal 9 Current measuring amplifier Main operating state 10a, 10b System states in the main operating state 11 Standby state 12 Power-saving state 12a, 12b System states in power-saving mode 13 Error signal 14 Trigger signal 31-37 Method steps

Claims

-24 -Claims 1. A method of controlling an operational state of a computer system (1), comprising the following steps: -triggering a command instructing a transition of the computer system (1) from a main operating state (10) to a standby state (11), wherein the standby state (11) defines an operation of the computer system (1) with a lowest power consumption compared to the main operating state (10), - measuring a power consumption of the computer system (1), - maintaining a main supply mode of a power supply unit (2) of the computer system (1) as long as a threshold value of the measured power consumption of the computer system (1) is exceeded, - initiating a transition of the computer system (1) from the main operating state (10) to a power-saving state (12) as soon as the measured power consumption of the computer system (1) falls below the threshold value, wherein the power-saving state (12) corresponds to a system state with reduced power consumption compared with the main operating state (10), and wherein the power supply unit (2) of the computer system (1) is switched in the power-saving state (12) to an auxiliary supply mode with a reduced power output compared with the main supply mode.
2. The method according to claim 1, wherein the power-saving state (12) corresponds to the standby state (11) if the computer system (1) can be operated in the power-saving state 30 with the lowest power consumption.
3. The method according to claim 1 or 2, wherein the power consumption of the computer system (1) is repeatedly measured -25 -in several measuring operations as long as the threshold value of the measured power consumption of the computer system (1) is exceeded, wherein a timer is started after each measuring operation and a new measuring operation is performed as soon as the timer has expired.
4. The method according to claim 3, wherein an error signal (13) is generated if a certain number of measuring operations is reached and the threshold value of the measured power 10 consumption of the computer system (1) is still exceeded.
5. The method according to any one of claims 1 to 4, comprising the further steps: - measuring the power consumption of the computer system (1) in the power-saving state (12), - attempting to further reduce the power consumption of the computer system (1) as soon as the threshold value of the measured power consumption of the computer system (1) in the power-saving state (12) is exceeded.
6. The method according to claim 5, comprising the further step: - initiating a transition of the computer system (1) from the power-saving state (12) back to the main operating state (10) if the threshold value of the measured power consumption of the computer system (1) in the power-saving state (12) continues to be exceeded after a determined period of time, wherein the power supply (2) of the computer system (1) is switched back to the main supply mode.
-26 - 7. A computer system (1) with a power supply unit (2) and with components (4a, 4b), which are supplied with electrical power via the power supply unit (2), wherein the computer system (1) is configured to: -trigger a command instructing a transition of the computer system (1) from a main operating state (10) to a standby state (11), wherein the standby state (11) defines an operation of the computer system (1) with a lowest power consumption compared to the main operating state (10), -measure a power consumption of the computer system (1) and maintain a main supply mode of the power supply unit (2) of the computer system (1) as long as a threshold value of the measured power consumption of the computer system (1) is exceeded, initiate a transition of the computer system (1) from the main operating state (10) to a power-saving state (12) as soon as the measured power consumption of the computer system (1) falls below the threshold value, wherein the power-saving state (12) corresponds to a system state with reduced power consumption compared with the main operating state (10), and wherein the power supply unit (2) of the computer system (1) is switchable in the power-saving state (12) to an auxiliary supply mode with a reduced power output compared with the main supply mode.
8. The computer system (1) according to claim 7, wherein a measuring circuit (5) is configured for measuring the power consumption of the computer system (1), which generates a control signal (8) indicating whether the threshold value of the measured power consumption of the computer system (1) is exceeded or not.
-27 - 9. The computer system (1) according to claim 8, which is further configured to transfer the control signal (8) generated by the measuring circuit (5) to a controller (6) and to control, by means of the controller (6), the transition of the computer system (1) between the main operating state (10) and the power-saving state (12).
10. The computer system (1) according to any one of claims 7 to 9, wherein the computer system (1) is configured to 10 perform a method according to any one of claims 1 to 6.