GB2611614A

GB2611614A - System component, electronic device and method for providing a control signal

Info

Publication number: GB2611614A
Application number: GB2211305.4A
Authority: GB
Inventors: Kraus Dominik; Noor Daniyal
Original assignee: Fujitsu Client Computing Ltd
Current assignee: Fujitsu Client Computing Ltd
Priority date: 2021-08-31
Filing date: 2022-08-03
Publication date: 2023-04-12
Also published as: JP2023035997A; JP7385154B2; GB202211305D0; DE102021122493B3

Abstract

The invention relates to a system component (20 Fig 2), in particular to a motherboard of a mini PC, having a voltage monitoring circuit (30) which comprises a voltage regulator (32) for providing at least two output voltages (VOUT1, VOUT2), and a control signal output (PWROK) for providing a first control signal (PWROK_VR) which indicates whether the voltage regulator is providing the at least two output voltages , a monitoring circuit (34) having a second control signal output (VOUT) for providing a second control signal (PWROK_CH1), which indicates whether the voltage regulator (32) is providing the first output voltage (VOUT1), and a combiner circuit (36), which is connected to the voltage regulator (32) and to the monitoring circuit (34), and has a third control signal output (OUT) for providing a third control signal (SYSTEM_PWROK), which indicates, depending on a present operating state of the system component (20), whether the voltage regulator (32) is providing all the output voltages required for the operating state. The invention also relates to an electronic device (10) and to a method for providing a control signal (SYSTEM_PWROK) for said system component (20).

Description

System component, electronic device and method for providing a control signal The invention relates to a system component, in particular to a motherboard of a mini PC, having a voltage monitoring circuit. The invention also relates to an electronic device comprising said system component, and to a method for providing a control signal for said system component.

System components having voltage monitoring circuits are known from the prior art. In particular, integrated voltage regulators often have an internal monitoring circuit, which outputs a "Power Good" or "Power OK" signal as soon as all the output voltages provided by the voltage regulator have reached a predetermined voltage level and, if applicable, are stable. One of the problems with the known monitoring circuits is that they do not allow selective monitoring of individual provided voltages. This means that said Power Good signals produced by integrated voltage regulators are in some cases not evaluated by further circuits of associated system components in individual operating states.

The object of the present invention is to define a system component having an improved monitoring circuit that allows reliable monitoring of operating voltages in further operating states of the system component.

According to a first aspect, a system component, in particular a motherboard of a mini PC, having a voltage monitoring circuit is disclosed. The voltage monitoring circuit comprises a voltage regulator having at least two -2 -voltage outputs for providing at least two output voltages, and a first control signal output for providing a first control signal, which indicates whether the voltage regulator is providing both output voltages. The voltage monitoring circuit additionally comprises a monitoring circuit having a first voltage input, which is connected to the first voltage output of the voltage regulator, and a second control signal output for providing a second control signal, which indicates whether the voltage regulator is providing the first output voltage. The voltage monitoring circuit additionally comprises a combiner circuit having a first control signal input, which is connected to the first control signal output of the voltage regulator, a second control signal input, which is connected to the second control signal output of the monitoring circuit, and a third control signal output for providing a third control signal, which indicates, depending on a present operating state of the system component, whether the voltage regulator is providing all the output voltages required for the operating state.

The voltage monitoring circuit according to the first aspect produces a further control signal for the system component, the third control signal, which can be monitored in all the operating states regardless of which voltage outputs of the voltage regulator are active. The combined third control signal is produced by combining a first control signal, produced internally by a voltage regulator, with a second control signal, produced externally by a monitoring circuit, and indicates reliably for different operating states of the system component whether the voltage regulator is providing all the output voltages required for a present operating state. -3 -

For example, on the basis of a further control signal for selectively activating a second output voltage, it can be selected whether the first control signal, produced by the voltage regulator, or the second control signal, produced by the monitoring circuit, is meant to be selected as the voltage source for the combined third control signal.

According to different embodiments, the combiner circuit can comprise a multiplexer, in particular an integrated multiplexer IC, or a discrete circuit for combining the various control signals.

According to a second aspect, an electronic device, in particular a mini PC, having a system component according to 15 the first aspect is described.

Mini PCs of particularly compact design can typically assume different operating states, in particular power-saving operating states. They can thus use the described voltage monitoring circuit to monitor reliably in each of their operating states the presence of required operating voltages, and, if applicable, implement necessary measures, for instance restarting the electronic mini PC, if an operating voltage required for a present operating mode is not being provided reliably.

According to a third aspect of the disclosure, a method is described for providing a control signal for a system component, in particular a combined Power Good signal for a 30 motherboard of a mini PC.

The method comprises the steps: -4 - -requesting at least one operating voltage of a plurality of possible operating voltages from a multichannel voltage regulator; -if all the operating voltages are requested from the multichannel voltage regulator, providing via a control signal line of the system component a common control signal provided by the multichannel voltage regulator; and -if only one predetermined operating voltage is requested from the multichannel voltage regulator, monitoring a voltage output of the multichannel voltage regulator, which voltage output corresponds to the predetermined operating voltage, by means of a monitoring circuit that is separate from the multichannel voltage regulator, and providing via the control signal line of the system component a control signal produced by the monitoring circuit.

Said method combines the advantages of monitoring a control signal produced directly by a multichannel voltage regulator in the time intervals in which this signal has validity, with the facility of monitoring separately at least one predetermined operating voltage in time intervals in which the control signal produced internally by the voltage regulator has no validity.

The invention is described in detail below using exemplary 30 embodiments with reference to the accompanying figures, in which: Figure 1 is a schematic diagram of an electronic device; -5 -Figure 2 is a schematic diagram of a voltage monitoring circuit; Figure 3 is a circuit diagram of a combined monitoring and combiner circuit in a discrete design; and Figure 4 is a flow diagram of a method for providing a control signal.

Figure 1 shows schematically the design of an electronic device 10 in the form of a mini PC. The electronic device 10 comprises a system component 20 in the form of a motherboard, which can be supplied with a required operating power selectively from an internal power supply unit 12 or from an external power supply unit 14. For this purpose, a voltage regulator 22 arranged on the system component 20 makes different operating voltages available for the correct operation of power consumers of the system component 20. In the exemplary embodiment, the system component 20 comprises a processor 24, for example, which in a normal operating state of the electronic device 10, for instance the ACPI SO state, is supplied with a normal operating voltage. The system component 20 additionally comprises a control circuit 26. The control circuit 26 is responsible for, inter alia, selecting a present operating state of the electronic device 10. It controls both the voltage regulator 22 and the processor 24 by means of suitable control signals, and monitors the operation of same by means of control signals that they provide.

For example, the control circuit 26 monitors whether in the normal operating state, the voltage regulator 22 is providing a "Power Good" signal, which indicates that all the supply -6 -voltages that can be produced by the voltage regulator 22 are being provided. The control circuit 26 does not start up the processor 24, for instance in order to run an operating system, until the control circuit 26 has detected this control signal. For this purpose, the control circuit 26 can comprise, for example, what is known as a power sequencing chip or parts of a chip set.

However, in particular when multichannel voltage regulators 22 are employed that selectively make available individual supply voltages of a plurality of possible supply voltages, this is not sufficient in all situations to ensure correct operation of the electronic device 10.

For example, mini PCs usually have one or more power-saving or standby states in which the voltage regulator 22 does not provide all the possible operating voltages. In a standby state, for instance, just a standby voltage is provided, which is used, inter alia, to supply the control circuit. It is also typical during an initialization state of the device, for instance during the sequenced activation of different circuits of the system component by a power sequencing chip, that not all the operating voltages are provided yet. In these cases, the Power Good signal from the voltage regulator 22 has no validity and also is not usually evaluated by the control circuit 26. If, in one such operating state, an interruption occurs in a supply voltage provided by the voltage regulator 22, for instance in the standby voltage, this may possibly not be detected by the control circuit 26.

This can in turn lead to impairments in the operation or the start-up of the electronic device 10. -7 -

In order to avoid such problems when a voltage regulator 22 is providing only individual operating voltages of a plurality of possible operating voltages, the system component 20 has, according to an exemplary embodiment of the invention, an improved voltage monitoring circuit, which monitors the operating voltage required for one such operating state independently of the voltage regulator 22.

Figure 2 shows a voltage monitoring circuit 30 according to an exemplary embodiment of the present disclosure. The voltage monitoring circuit 30 shown in Figure 2 comprises a multichannel voltage regulator 32, for instance the voltage regulator 22 of the electronic device 10 shown in Figure 1, and also a monitoring circuit 34 and a combiner circuit 36.

In the exemplary embodiment, the multichannel voltage regulator 32 has two control inputs EN CH1 and EN CH2 for providing corresponding control signals EN 1 and EN2. In addition, the multichannel voltage regulator 32 has two voltage outputs VcLIT CHI and \Jou:, rH2 and a control signal output PWROK. If a request is made via the control signals EN1 and EN2 respectively to provide a first operating voltage Vac, for instance a standby voltage, or a second operating voltage Vap72, for instance a normal operating voltage, or both, the multichannel voltage regulator 32 provides these at the respective voltage outputs Vcuj_chl and VouLL012. In addition, the voltage regulator 32 provides at the control signal output PWROK a positive control signal if both the first requested operating voltage V0LIT1 and the second requested operating voltage V0LIT2 are provided at the two voltage outputs VoulLcHl and Vou1_oi2. Otherwise, a negative control signal is provided via the control signal output PWROK, which -8 -indicates that the multichannel voltage regulator 32 is not providing all the possible output voltages Voun and VOUI2.

Hence the control signal PWROK VR provided by the multichannel voltage regulator 32 has validity only in those operating states in which the two control signals EN1 and EN2 are requesting the corresponding output voltages VoLLi and VOU'22 * In order to be able to provide also in at least one further operating state a valid Power Good signal for a system component 20, the monitoring circuit 34 monitors the first operating voltage VcuiL provided by the multichannel voltage regulator 32. The monitoring circuit 34 has, for example, a comparator, which compares the voltage VOUTIL provided at a first voltage input VIN of the monitoring circuit 34 with a reference voltage VTN, which is provided via a second voltage input V1 of the monitoring circuit 34. If the voltage provided at the first voltage input VIN exceeds the reference voltage V7N provided via the second voltage input VREFf the monitoring circuit 34 produces a second control signal PWROK CH1 at a control signal output VOUT.

Hence, depending on the operating state, two different possible Power Good signals are available, namely the first control signal RWROK_VR, which is produced internally by the multichannel voltage regulator 32, and the PWROK_CH1 produced by the external monitoring circuit 34. In order to select the currently relevant control signal, the combiner circuit 34 selects on the basis of the control signal EN2 either the first control signal PWROK_VR or the second control signal PWROK CH1, and makes this available to further components of the system component 20 as a combined third control signal -9 -SYSTEM PWROK via a further control signal output OUT. In particular, the first control signal PWROK VR is selected if the control signal EN2 is activated, and the second control signal PWROK CH1 is selected if the control signal EN2 is deactivated. For this purpose, the combiner circuit 36 can comprise, for instance, an integrated multiplexer IC, which, on the basis of one or more input control signals, selects one of two or more signal sources in order to provide a corresponding Power Good signal.

Although Figure 2 shows only a circuit having two possible operating voltages VOUT1 and V011T2 and two operating states corresponding thereto, in which both or only one of the two operating voltages Vomi and V0ur2 are selectively provided, obviously the described concept can also be extended to system components 20 having a plurality of operating voltages required in, and corresponding to, different operating states. In this case, if applicable, further monitoring circuits and a multichannel multiplexer for the combiner circuit 36 are required, which monitor further operating voltages and control signals for selecting the relevant operating voltages of the multichannel voltage regulator.

Figure 3 shows a combined monitoring and combiner circuit 40 25 in a discrete design. The circuit 40 thus replaces the components 34 and 36 shown in Figure 2.

For reasons of clarity, the actual voltage regulator is not shown in Figure 3. The circuit 40 again covers two possible operating states. In a first, normal operating state, both channels of a two-channel voltage regulator are active. In a further, limited operating mode, the first channel of the -10 -two-channel voltage regulator is active, and the second channel is inactive.

The circuit portion shown at the top in Figure 3 is used to produce a further control signal PWROK CH1 R H. For this purpose, the combined monitoring and combiner circuit 40 comprises a comparator 42, which compares an operating voltage VR VOUT1 provided by a multichannel voltage regulator 32 with a threshold value in the form of a reference voltage VREF. If the operating voltage VR_VOUT1 provided by the voltage regulator 32 exceeds the reference voltage VREF, a logically positive control signal PWROK CH1 H is provided at an output of the comparator 42. Otherwise, a logically negative control signal is provided at the output of the comparator 42.

The control signal PWROK CH1 H thus produced by the comparator 42 does not have validity in all the operating states of an electronic device, however. In order to prevent the positive control signal PWROK CH1 H being issued unintentionally, the circuit 40 therefore has a suppression circuit 44 containing two transistors Q1A and Q1B, via which a signal line for providing the control signal PWROK_CHLR_E produced by the top circuit portion can be pulled selectively to a low voltage potential, in particular to a ground potential GND.

The first transistor Q1A is in the form of a MOSFE1 transistor, which is connected at its control output to a control signal EN2 CH2 H for selecting the second operating voltage V0u12. The control signal EN_CH2_E is activated if the voltage regulator 32 is also meant to provide the second operating voltage. In this case, the control signal PWROK CH1 H produced by the comparator 42 has no validity and is suppressed by switching on the first transistor Q1A. For this purpose, a source terminal of the first transistor Q1A is connected to the ground potential GND, and a drain terminal of the first transistor Q1A is connected to an internal node 46 for providing the control signal PWROK CH1 R H. In order to protect the comparator 42, the

_

internal node 46 is decoupled from the output thereof by a resistor R1.

In order to optimize the circuit, a further, second transistor Q1B is provided, which selectively connects the internal node 46 of the circuit 40 to the ground potential ONE) if the multichannel voltage regulator 32 is already indicating via a control signal PWROK VR OUT H that all the possible supply voltages are being provided. Monitoring by the comparator 42 is no longer required in this case, and may lead to problems in the coupling-in, described below, of the two possible control signals PWROK VR OUT H and PWROK CH1 R H. The bottom part of Figure 3 shows the combining of the first control signal PWROK_VR_OUT_H from the multichannel voltage regulator 32 with the second control signal PWROK CH1 R H from the circuit 40. The two control signals are coupled in at a common node 48 via respective diodes D1 and D2, effectively being combined by a logical OR. In particular, a combined control signal SYSTEM_PWROK_R assumes a logically high level if at least one of the two control signals PWROK VR OUT H or PWROK CH1 R H has a logically high level.

In the described exemplary embodiment, the first control signal "PWROK VR OUT H" from the voltage regulator 32 is an -12 -output signal of type "open drain". Therefore the associated signal line is connected via a pull-up resistor R2 to a voltage potential F3V3R_ALW in order to avoid an undefined state of the first control signal "PWROK VR OUT H".

The combined control signal SYSTEM PWROK R thus provided at the common node 48 is then filtered via a low-pass filter 50 in order to avoid any interference pulses during switchover of the signal sources. For this purpose, the common node 48 is connected to the ground potential GND via a further resistor R3 and a capacitor Cl. The actual output control signal SYSTEM PWROK is taken off at a node between the resistor R3 and the capacitor Cl and provided to further circuits of the system component, for instance to the control circuit 26 of the electronic device 10 shown in Figure 1.

It is evident that the discrete monitoring and combiner circuit 40 has a relatively simple design and requires for its implementation merely three active components in the form of the comparator 42 and the two transistors Q1A and Q1B. In addition, a relatively small number of passive components are provided in the form of two Schottky diodes D1 and D3, three resistors R1 to R3 and a capacitor Cl. Such a circuit can hence be implemented in a very small space and, if applicable, as part of a control circuit 26 that is already present.

Figure 4 shows schematically a flow diagram of a method for providing a combined control signal SYSTEM PWROK.

In a first step Si, an operating state of a system component of an electronic device 10 is selected. For example, a selection can be made between a normal ACPI-SO operating -13 -state, an ACPI-55 standby state, or an initialization state or transition state between different operating states.

If it is an operating state in which all the operating voltages that can be produced by a voltage regulator are being provided, a control signal PWROK VR produced internally by the voltage regulator can be output directly as the control signal SYSTEM PWROK for all the system components in a step 32.

If, however, in other operating states, a voltage regulator is providing only one, or a subset, of a plurality of possible operating voltages, the provided operating voltages are separately monitored by corresponding external monitoring circuits. For example, in step S3, a first voltage VOU71 provided by a voltage regulator 22 at an output VOUTICHI of the voltage regulator 22 is monitored.

In addition, if applicable, further voltages required for the 20 operation of the electronic device in a present operating state can be monitored in optional further steps 54.

If all the voltages are provided as required, a corresponding combined control signal SYSTEM PWROK is provided in a step 35, which indicates that all the required operating voltages are being provided for the operating state selected in step Si.

If, on the other hand, one of the requested voltages is not 30 being provided as required, a control signal SYSTEM PWROK is provided in an alternative step S6, which indicates that not all the required operating voltages are being provided.

-14 -List of references 14 30 42 Si to 56 electronic device internal power supply unit external power supply unit system component voltage regulator processor control circuit voltage monitoring circuit multichannel voltage regulator monitoring circuit combiner circuit monitoring and combiner circuit comparator suppression circuit internal node common node low-pass filter method steps

Claims

-15 -Claims 1. System component (20), in particular a motherboard of a mini PC, having a voltage monitoring circuit (30), wherein the voltage monitoring circuit (30) comprises the following: - a voltage regulator (32) having at least two voltage outputs (VIJUIJHU VDUn{2) for providing at least two output voltages (Vcur, Vour2), and a first control signal output (PWROK) for providing a first control signal (PWROK VR), which indicates whether the voltage regulator (32) is providing both output voltages (Vou7L, V0=2); - a monitoring circuit (34) having a first voltage input (ViN), which is connected to the first voltage output (V,411_64_) of the voltage regulator (32), and a second control signal output (VOUT) for providing a second control signal (PWROK CH1), which indicates whether the voltage regulator (32) is providing the first output voltage (V44n1); - a combiner circuit (36) having a first control signal input, which is connected to the first control signal output (PWROK) of the voltage regulator (32), a second control signal input, which is connected to the second control signal output (VOUT) of the monitoring circuit (34), and a third control signal output (OUT) for providing a third control signal (SYSTEM PWROK), which indicates, depending on a present operating state of the system component (20), whether the voltage regulator is providing all the output voltages required for the operating state.
2. System component (20) according to Claim 1, wherein - the voltage regulator (32) additionally has a third control signal input (EN CH2) for selectively activating -16 -the second output voltage (Voun) at the second voltage output (V0u701-12); - the combiner circuit (36) additionally has a fourth control signal input, via which selectively the first or the second control signal input can be selected as the source for the third control signal output; and - the third control signal input and the fourth control signal input are coupled together in order to supply a common control signal (EN2), wherein the common control signal (EN2) indicates whether or not the second output voltage (V0u12) is meant to be provided in the present operating state.
3. System component (20) according to Claim 1 or 2, 15 wherein the monitoring circuit (34) comprises a comparator (42) for comparing the first output voltage (Vou71) with a predetermined reference voltage (Vm).
4. System component (20) according to any of Claims 1 to 3, wherein the combiner circuit (36) comprises a multiplexer for selecting the first control signal (PWROK VR) or the second control signal (PWROK CH1) depending on the present operating state.
5. System component (20) according to any of Claims 1 to 3, wherein the voltage monitoring circuit (30) has two diodes (D1, D2) for coupling in the first control signal (PWROK_VR) or the second control signal (PWROK_CH1), and a transistor (Q1A) for selectively suppressing the second control signal (PWROK CH1) if the second output voltage (Vour2) is meant to be provided in the present operating state.
-17 - 6. Electronic device (10), in particular mini PC, having a system component (20) according to any of Claims 1 to 5.
7. Electronic device (10) according to Claim 6, wherein the electronic device (10) - has a normal operating state, in which the first and the second output voltages (VoLbl, Voyr2) are meant to be provided by the voltage regulator (32); and - has at least one limited operating state, in particular a standby, initialization or transition state, in which only the first output voltage (Vobri) is meant to be provided by the voltage regulator (32).
8. Electronic device (10) according to Claim 6 or 7, wherein the system component (20) additionally comprises a control component (26), in particular a power sequencing chip and/or a chip set, which is configured to shift the electronic device (10) into a predetermined operating state if the third control signal (SYSTEM PWROK) indicates that the voltage regulator (32) is not providing all the output voltages required for the present operating state.
9. Method for providing a control signal (SYSTEM_PWROK) for a system component, in particular a combined Power Good 25 signal for a motherboard of a mini PC, having the steps: - requesting at least one operating voltage of a plurality of possible operating voltages ()Van, Vorb.2) from a multichannel voltage regulator (32); - if all the operating voltages are requested from the multichannel voltage regulator (32), providing via a control signal line of the system component (20) a common control signal (PWROK VR) provided by the multichannel voltage regulator (32); and -18 - -if only one predetermined operating voltage (Voryn) is requested from the multichannel voltage regulator (32), monitoring a voltage output (VoLuj of the multichannel voltage regulator (32), which voltage output corresponds to the predetermined operating voltage (Vh,r1), by means of a monitoring circuit (34) that is separate from the multichannel voltage regulator (32), and providing via the control signal line of the system component (20) a control signal (PWROK CH1) produced by the monitoring circuit (34).
10. Method according to Claim 9, having the step: if a predetermined subset of the possible operating voltages is requested from the multichannel voltage regulator (32), monitoring all the voltage outputs of the multichannel voltage regulator (32) that correspond to the requested operating voltages by means of at least one monitoring circuit (34) that is separate from the multichannel voltage regulator (32), and, only when all the requested operating voltages are being provided, providing via the control signal line of the system component (20) a control signal produced by the at least one monitoring circuit (34).