Apparatus and methods for adapting power supply voltage

Abstract

A method (800) for adapting the power supply voltage of a device includes: configuring (810) a change in the operating state of the device; measuring (820) the temperature of the device; determining (830) the power supply voltage level required for the device to operate in the configured operating state; and adapting (840) the power supply voltage of the device based at least on the measured temperature and the power supply voltage level required for the device to operate in the configured operating state.

Description

Technical Field

[0001] This technical field generally relates to an apparatus having digital control circuitry and a method for adapting the power supply voltage of said apparatus. This technical field is applicable to, but not limited to, radio frequency identification (RFID) devices or circuits and methods for adapting power supply voltages according to temperature and operating conditions (or conditions, such as operating frequency). Background Technology

[0002] Radio Frequency Identification (RFID) has extremely wide applications, ranging from public transportation to animal identification and product tracking. In industrial environments, RFID tags are used to track parts or assets, which is very useful for automation and / or logistics purposes. RFID devices / tags are generally known to be categorized into three frequency groups: Low Frequency (LF) tags, High Frequency (HF) tags, and Ultra High Frequency (UHF) tags. Each frequency group of RFID devices / tags is dedicated to its typical application due to the inherent advantages of the RFID device / tag itself, typically based on the RFID's 'read distance' (which is based on the operating frequency). Low Frequency RFID (typically in the 30 to 300 kHz frequency range) has the shortest read distance, usually around 10 cm between the reader and the tag. Read times are also slower; however, low frequencies have the least amount of radio interference. Therefore, LF RFID is commonly used for applications such as animal tracking and access control. High Frequency RFID (typically in the 3 to 30 MHz frequency range) offers read distances typically around 10 cm to 1 m. Most HF RFID devices operate at a frequency of 13.56 MHz, are moderately sensitive to radio interference, and typically involve near-field communication (NFC), which focuses on data transmission between two devices. This is common in smart payment cards and other proximity-activated devices. HF RFID devices / tags can accommodate read-only, write-only, and rewritable RFID tags, with memory capacities ranging from 64 bytes to 8 KB. UHF RFID tags offer the fastest read speeds and the longest read range.

[0003] Another known method for classifying RFID devices / tags is by their power supply method: active, semi-active (or battery-assisted passive (BAP)), and passive. Active devices / tags are those that continuously transmit radio signals to be picked up by a reader. These devices / tags are equipped with a battery or another continuous power source, and an antenna for transmitting and receiving radio frequency signals. Semi-active or BAP devices / tags use a battery to power the tag's integrated circuits without transmitting signals; the signal power comes directly from the RFID reader. Active and semi-active RFID tags have a longer operating range than passive tags. Passive devices / tags are powered solely by the magnetic field emitted by the reader, which induces a current in the passive tag's antenna. The examples of RFID described in this article pertain only to active and semi-active (or BAP) powered devices.

[0004] In semiconductor circuits, especially in RFID devices / tags / circuits, power consumption plays a crucial role in performance. In RFID circuits, read distance can be equated with 'power consumption' because power is supplied by the reader device via the air interface. Therefore, minimizing power consumption is a primary concern and design factor in RFID circuit design. It is also typically necessary to monitor power supply voltage conditions and trigger a device reset when the power supply voltage is too low. It is well known that defined voltage levels are needed to characterize logic units to achieve proper digital timing closure, where known timing closure is the process of determining whether the speed of the integrated circuit / chip meets timing constraints and ensuring that all signals arrive at the correct logic device or circuit at the correct time for smoother chip operation.

[0005] It is known that a stable power supply voltage for RFID can aid in timing convergence and that logic gate states can be easily monitored via power sensors (using a fixed bandgap reference). However, since the turn-on threshold of both PMOS and NMOS transistors depends on temperature, higher temperatures will result in higher operating and leakage currents if the power supply voltage remains constant. Each type of transistor (PMOS and NMOS) has a threshold voltage at which it begins to conduct. The higher the threshold, the greater the voltage required to 'start' the device, and the slower the device operates (because as the threshold increases, the overdrive of the device decreases, and the current conducted also decreases, resulting in a slower transition time from 'high' to 'low', and vice versa). Typically, it is assumed that the power supply generally provides a constant voltage independent of temperature. However, the inventors have recognized and understood that the threshold voltage depends on temperature and varies by approximately '-2 mV / K', which has a significant impact on low-power devices, particularly battery-powered devices or wireless devices such as RFID devices / tags.

[0006] Therefore, the inventors have recognized and understand that in order to ensure the proper functioning of low-power devices (e.g., battery-powered devices or wireless devices such as RFID devices / tags / circuits, etc.) under all conditions, optimization for worst-case conditions (e.g., minimum operating temperature) is necessary. However, if the same supply voltage is used, this results in additional current consumption at higher temperatures because the threshold is lower at these temperatures, while a higher threshold is observed at lower temperatures. To mitigate this effect, it is known that the supply voltage can be reduced based on temperature. However, the inventors also recognize and understand that these known techniques continuously track temperature (e.g., by using a diode as a reference). In this way, these continuously adjusting techniques provide optimal power, but are difficult to verify under all conditions and difficult to monitor with voltage sensors.

[0007] US7095288B2, entitled 'Logic system with adaptive supply voltage control', describes a mechanism that uses an oscillator to determine the delay of digital logic and continuously adapts the supply voltage to match the oscillator speed (see Figure 7(a)). Therefore, there is a need for an improved apparatus and method for adapting the supply voltage according to variable conditions. Summary of the Invention

[0008] The examples described herein provide an apparatus, such as an RFID device, tag, or circuit, and a method for adapting to a power supply voltage, as set forth in the appended claims. Specific examples are set forth in the dependent claims. These and other aspects will become apparent and will be clarified with reference to the examples described below. Attached Figure Description

[0009] Additional details, aspects, and examples will be described by way of example only with reference to the accompanying drawings. In the drawings, the same reference numerals are used to identify elements that are the same or similar in function. Elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale.

[0010] Figure 1 The diagram illustrates, based on several examples, the changes in power supply voltage after temperature evaluation and depending on whether the operation is low-frequency or high-frequency.

[0011] Figure 2 A block diagram of a device adapted according to some examples is shown.

[0012] Figure 3 An example timing diagram is shown, illustrating how the power supply voltage depends on the switching frequency.

[0013] Figure 4An example flowchart of a digital control circuit (based on a state machine or central processing unit (CPU)) is shown, based on an example, when switching from a low frequency to a high frequency.

[0014] Figure 5 An example flowchart of a digital control circuit (based on a state machine or CPU) is shown, based on an example, when switching from a high frequency to a low frequency.

[0015] Figure 6 An example of a timing diagram related to a sequence of changes in working state is shown, based on an example example.

[0016] Figure 7 Another example of a flowchart of a digital control circuit (based on a state machine or CPU) is shown, illustrating the transition from the first operating state 'A' to the second operating state 'B', based on the example.

[0017] Figure 8 An example overview of flowcharts for methods of adapting the power supply voltage of a device is shown, based on some examples. Detailed Implementation

[0018] The inventors have recognized and understand that, particularly for Radio Frequency Identifier (RFID) device chips, maintaining a reliable operating power supply is crucial for achieving good performance. To overcome previous identification problems, the examples described herein propose configuring an operating state (e.g., receive mode, transmit mode, encryption operation, etc.) and then measuring the temperature of the device or integrated circuit equipped with a voltage source. Subsequently, the examples propose adapting a threshold voltage based on the measured temperature and the configured operating state to optimize power consumption according to the configured operating state.

[0019] In some cases, a change in the configured operating state may involve a change in the operating frequency. In such cases, after temperature evaluation, the example adapts the threshold voltage in response to the change in operating frequency to optimize power consumption based on the operating frequency of the configured operating state. Similarly, in some cases, such as when the coprocessor operates at the same frequency, a change in the configured operating state may involve a change in power. Therefore, changes in operating frequency and changes in power can be considered subsets of changes between the configured operating states.

[0020] In some examples, an improved apparatus and method are described for determining an appropriate power supply voltage based on a measured temperature in discrete steps. Subsequently, the improved apparatus and method propose configuring operating states (e.g., receive operating mode, transmit operating mode, encryption operating mode, etc.) to optimize the device's power supply voltage (in some examples, encompassing the device's power or 'power consumption') based on the measured temperature and the operating state or a change in operating state. The inventors have recognized that the device's power consumption and / or operating frequency may also change when adopting or changing to some operating states (e.g., switching to a higher or lower operating frequency), while in some operating states the device's power consumption and / or operating frequency may not change.

[0021] In some cases, a finite number of power supply voltage levels can be applied and used, where each power supply voltage remains constant, such as... Figure 1 As shown. Therefore, in some cases and when operating within a specific temperature range, the supply voltage can be easily monitored, and timing convergence can be performed at the boundaries of a given operating condition (e.g., at minimum and maximum temperatures at the same supply voltage level. In some cases, this can be performed for all different supply voltage levels).

[0022] It is well known that the threshold power supply voltage of a semiconductor transistor is temperature-dependent, as higher temperatures decrease the threshold voltage. Therefore, for power-saving purposes, the inventors have recognized the need to adjust the power supply voltage after a temperature measurement of the device, circuit, or tag, and subsequently based on the operating state of the RFID device, circuit, or tag. For a more comprehensive understanding, the examples described herein are intended to be applicable to any device or circuit, such as an RFID device, RFID tag, or RFID circuit, which are encompassed herein and are referred to 'device' below. In some examples described herein, a step-wise adjustment of the power supply voltage is implemented based on a specific temperature threshold. In some examples described herein, the power supply voltage is adjusted only under specific operating states / conditions, for which the power supply voltage can be adjusted based on a configurable value.

[0023] Now for reference Figure 1Two graphical examples of power supply voltage changes following device temperature measurements, adapted according to some example embodiments, are shown, where the first graph 100 shows low-frequency operation and the second graph 150 shows high-frequency operation. The first graph 100 and the second graph 150 show the relationship between power supply voltage 110 and temperature 115, where in these examples, temperature 115 particularly highlights a lower first lower temperature threshold 120 and a second higher temperature threshold 125. Therefore, some examples employ a step-by-step approach for adjustable power supply voltages following corresponding temperature measurements of the device. According to some examples, it is conceivable to adjust the temperature thresholds based on the device's operating state and, in some examples, based on the device's operating frequency, such that the power supply voltage adaptation is arranged to occur only at specific points in time (e.g., when the RFID device transitions from one operating state to another, or when the operating state (e.g., operating frequency) changes).

[0024] Here, in some examples and in response to the working state itself (e.g., transitioning from one working state to another), it is conceivable that a change in working state occurs in a state machine design, transitioning from working state 'A' to working state 'B' and then to working state 'C', or in a central processing unit (CPU)-based design, enabling a coprocessor or executing a subroutine, where various working states can be idle, processing, etc. Similarly, it is conceivable that in some examples, if, for example, the coprocessor is activated, more power may be required (e.g., consumed) even if the operating frequency may not change.

[0025] According to some examples, an RFID device may include a temperature sensor arranged to measure the operating temperature of an integrated circuit (IC). Temperature measurement is initiated when a new operating state is configured. The digital control circuitry of the RFID device adjusts the power supply voltage in response to the measured operating temperature. In some examples, this may be in response to a change in temperature that may exceed a certain temperature threshold, such as a lower temperature threshold (T1) 120 and / or a higher temperature threshold (T2) 125. According to some examples, the temperature thresholds may be configurable and controlled by the digital control circuitry or a processor, wherein the configurable thresholds are stored in memory along with the power supply voltage information. In these examples, the power supply voltages 145 and 195 remain stable between the temperature thresholds, such that a constant voltage source condition exists between the lower temperature threshold (T1) 120 and / or the higher temperature threshold (T2) 125. This enables timing convergence between two temperature thresholds (e.g., Tmin with a lower temperature threshold (T1) 120; a lower temperature threshold (T1) 120 with a higher temperature threshold (T2) 125; or a higher temperature threshold (T2) 125 with Tmax) and easy monitoring of the power supply. As shown in the first graph 100 and the second graph 150, different power supply voltages are provided for different operating frequencies, thus the edge-to-edge timing is higher à T = 1 / f if the frequency is lower.

[0026] According to some examples, the RFID device may also include a configurable low-dropout (LDO) regulator with a voltage range of 130, 180 or a voltage sensor (sensor voltage range 135, 185), wherein the LDO regulator is a DC linear regulator circuit that operates even when the supply voltage is very close to the output voltage. According to some examples, the LDO regulator or voltage sensor can be adapted once a temperature threshold is exceeded (e.g., a lower temperature threshold (T1) of 120 or a higher temperature threshold (T2) of 125). Therefore, in some examples, if a temperature change occurs, the 'sensor' can be modified (e.g., reconfigured) because, in some examples, the voltage sensor should follow the LDO regulator. If the LDO output voltage drops by a certain amount (e.g., 50 mV) and the voltage sensor detects the same voltage level, it is conceivable that the voltage sensor will trigger and cause a reset. To avoid this, the voltage sensor should be configured to follow changes in the LDO. In some examples, this tracking may also include upward tracking because, in some examples, too low a supply voltage may cause a logic fault (which will be detected by the voltage sensor). According to some examples, RFID devices may also include digital circuitry that evaluates the output (i.e., the current temperature of the measuring device or IC) under specific conditions (e.g., changes in operating state and / or clock frequency). In some envisioned examples, there are two methods for measuring temperature: continuous measurement, or measurement only at a specific point in time (e.g., when a temperature sensor might be disabled to further save power if it is not needed). In some examples described herein, temperature measurement may be performed before a change in operating state (which may include a change in operating frequency and / or power consumption). In the case of continuous temperature measurement, a simple evaluation of the currently measured temperature can be made. However, in the case of temperature measurement at a specific point in time, it may be important to ensure that the temperature measurement begins and is evaluated before or after a change in operating state (e.g., operating frequency or power consumption).

[0027] In some examples, such as after a change in operating frequency, it is conceivable that a device or IC might require different minimum supply voltages (140, 190) for specific measured temperatures and operating states because the settling time between clock edges may change (e.g., for lower frequencies, the timing between two edges is longer, thus allowing for more delay time in the digital unit). Therefore, as Figure 1 As shown, different power supply voltage steps can be used for each operating frequency.

[0028] In some cases, such as after a change in operating conditions, it may be necessary to determine whether the power supply voltage can be adapted based on the currently measured temperature (e.g., if the temperature changes and exceeds a temperature threshold, for example...). Figure 1(T1 120 or T2 125 in the code will be adapted to the power supply voltage accordingly). Furthermore, it is conceivable that the voltage source step size could be adjustable for each different operating state.

[0029] Based on some examples, it is conceivable that RFID devices may also include more than two configurable temperature thresholds and / or more than two configurable power supply voltage thresholds.

[0030] In some examples described herein, a power-saving mechanism is provided that measures the temperature of a device or an IC within a device, compares the measured temperature to one or more temperature thresholds, and subsequently adapts the supply voltage according to the device's operating state (which, in some examples, may involve changes in the operating frequency). In some examples, it is conceivable to use specific temperature steps based on temperature thresholds, where the supply voltage remains at a constant voltage level over the entire temperature range between (at least) two temperature thresholds. In this way, this approach can help sensors monitoring the supply voltage (e.g., LDO regulators or voltage sensors) to ensure that the supply voltage is always maintained within a specific supply voltage range. In this way, this approach can also help with digital timing convergence. In this context, it is known that digital logic cells have inherent delays (e.g., the time it takes for a signal to transition from a 'low' logic state to a 'high' logic state, or vice versa). This delay typically depends on one or more of the following: temperature, voltage, load, process, etc. Therefore, timing convergence ensures that digital cells have sufficiently high drive strength to meet timing requirements, thereby ensuring that the logic circuit / cell can function properly. In some scenarios, this can be referred to as Static Timing Analysis (STA) checkout, which ensures that certain digital design logic cell setup and hold requirements are met across all given process variations, voltage variations, and temperature variations (sometimes referred to as PVT operating angles).

[0031] In some of the examples described herein, it is conceivable that power supply voltage adaptation could be based additionally on operating conditions (e.g., operation using a faster clock might require a higher power supply voltage than operation with a lower clock speed). Therefore, when a slower clock is provided, the risk of not operating at the correct power supply voltage due to general ambient temperature variations is less, as temperature, operating voltage, and load conditions affect the inherent latency of the digital unit. If the RFID device operates at a lower frequency, a longer inherent latency can be tolerated because the time between operating edges increases by ΔT = 1 / f. Thus, the examples described herein can provide two scenarios requiring power supply voltage adaptation: changes in temperature and / or changes in operating frequency at a specific measured temperature. In this way, maintaining a constant voltage source at temperature would result in increased power consumption at higher temperatures, which in turn would lead to degraded performance (e.g., earlier system resets, shorter read distances, etc.).

[0032] As an example of a chart Figure 1 Table 1 describes an example method of adapting a voltage source after the measurement of the operating temperature of a device or IC is identified as falling into one of the following three ranges: Tmin to T1; T1 to T2; and T2 to Tmax. At a given discrete operating state, the temperature is measured and the power supply voltage (through the LDO) is adjusted to a new value based on the 'current supply voltage' and the'measured temperature' as described in the table below (refer only to the first chart 100, but also applicable to the second chart 150).

[0033] Table 1:

[0034] In Table 1 (and referring to Figure 1 ), 'Measured temperature < T1' means 'Tmin to T1'; 'T1 < measured temperature < T2' means 'T1 to T2'; and 'Measured temperature > T2' means 'T2 to Tmax'.

[0035]

[0036] For a discrete operating state, the operating frequency is checked and the power supply voltage (through the LDO regulator) is adjusted to a new power supply voltage level based on the 'current supply voltage' and the 'operating frequency' mentioned in Table 2, while the measured temperature remains unchanged. Table 2 (below) shows an example scenario where the temperature also changes, in which case the methods / changes proposed in both Example Table 1 and Example Table 2 can be applied.

[0037] Table 2:

[0038]

[0039] Now referring to Figure 2 , a block diagram of device 200 is shown. In this example, device 200 is a radio frequency identification (RFID) device and thus includes an antenna 252 for receiving RFID transmissions, the antenna 252 being coupled to an antenna switch or filter 254 that provides isolation between the receive chain and the transmit chain within device 200. As is known in the art, the receive chain includes a receiver front-end circuit 256 and optionally filtering and baseband frequency conversion. The receiver front-end circuit 256 is coupled to a signal processor 258 (commonly implemented by a digital signal processor (DSP)). Those skilled in the art will understand that in some cases, the degree of integration of the receiver circuits or components can depend on the implementation.

[0040] Digital control circuit 264 maintains overall operational control of device 200 and specifically monitors the operating status of device 200. Digital control circuit 264 is also coupled to receiver front-end circuitry 256 and signal processor 258. In some examples, digital control circuit 264 is also coupled to frequency generation circuitry 267 and memory 266, which selectively stores temperature ranges and thresholds, voltage source information and thresholds, etc. Timer 268, for example configured to monitor settling time, is operatively coupled to digital control circuit 264 to control the operating timing within device 200 (e.g., transmission or reception of time-dependent signals).

[0041] Regarding the transmit chain, this essentially comprises transmitter circuitry 272 and RF amplifier 274 coupled to antenna 252. Transmitter circuitry 272 and RF amplifier 274 are operationally responsive to digital control circuitry 264. Clearly, the various components within device 200 can be implemented as discrete or integrated components, thus the final structure is application-specific or a design choice.

[0042] According to the example described herein, the device includes a temperature sensor 269 connected to a digital control circuit 264 and arranged to measure the temperature of one or more of the ICs in the device 200, which are powered by a voltage source 270. According to the example described herein, the digital control circuit 264 is connected to a voltage sensor 278 and an LDO regulator 276 and controls / monitors the voltage sensor 278 and the LDO regulator 276. The LDO regulator 276 generates a stable power supply voltage for the digital circuitry in the device 200. Reconfiguration of the LDO regulator 276 provides different power supply voltage levels (e.g., ...). Figure 1 (As described in [the text]). Voltage sensor 278 is arranged to monitor the level of the supply voltage and, for example, indicate whether the supply voltage level is too low. Therefore, voltage sensor 278 needs to track LDO regulator 276, ideally with a certain offset. In some examples, it is conceivable that in some applications with a known reliable supply voltage, it may not be necessary to monitor the supply voltage via voltage sensor 278. In some examples, for example... Figure 2 For safety reasons, the example could include a voltage sensor 278.

[0043] In some examples, digital control circuit 264 sets the operating frequency of frequency generation circuit 267 and uses this information, along with the temperature measured by temperature sensor 269 and information stored in memory 266, to set the power supply voltage provided by voltage source 270. In some examples, digital control circuit 264 is configured to control the operating frequency and operating state of device 200 and determine whether a threshold has been exceeded / triggered, then, for example, change the power supply voltage 270 in a stepwise manner. Specifically, if digital control circuit 264 wants to perform an operation, it initiates a change in operating frequency or operating state so that it knows exactly what is going to happen. Therefore, digital control circuit 264 is able to initiate temperature measurement before the change in operating state (e.g., a change in power and / or frequency) and also pre-adapt the power supply voltage, as referenced. Figure 4 , 5 As described in 7.

[0044] In some examples, digital control circuitry 264 refers to an example digital design implementation that may implement a finite state machine (FSM) or processor-based functionality to regulate the digital power supply voltage by updating the trim value of the analog LDO regulator 276. Analog measurements and sensors, along with control circuitry, can be envisioned in other examples. In some examples, digital control circuitry 264 can control and adapt step sizes when the configurable voltage amplitude changes after temperature measurement and according to the operating state of device 200.

[0045] Based on some examples, an example sequence for changing the operating frequency follows these steps. If there is no temperature change, the change in the settings of the LDO regulator 276 and voltage sensor 278 may simply be due to the higher frequency required at that particular temperature. If a temperature change also occurs, as monitored by temperature sensor 269, then in some cases, a corresponding supply voltage change must be added on top of any other supply voltage adjustment (e.g., if the temperature drops below T1, an additional offset between T1 and Tmin needs to be added, while if the temperature increases above T2, assuming the temperature range initially is between T1 and T2, the offset between T2 and Tmax needs to be subtracted).

[0046] Now for reference Figure 3 This illustrates an example of a timing waveform diagram 300 according to some example embodiments, relating to a sequence for changing the power supply voltage based on the switching frequency. In the example timing diagram, the temperature of the device or device IC has been measured, but temperature changes (as opposed to...) are not considered. Figure 6 (The timing diagrams are different), as shown in 350. If a temperature change occurs, additional offsets need to be added, such as... Figure 6The timing diagram is shown below. Power supply voltage waveform 310 at 312 shows the power supply voltage transition from the median power supply voltage 311 for low-frequency operating mode when the device temperature is between the lower temperature threshold (T1) and the higher temperature threshold (T2) to the higher power supply voltage 314 for high-frequency operating mode when the device temperature is maintained between the lower temperature threshold (T1) and the higher temperature threshold (T2). Power supply voltage waveform 310 also shows the power supply voltage transition at 316 from the higher power supply voltage 314 again for low-frequency operating mode when the device temperature is maintained between the lower temperature threshold (T1) and the higher temperature threshold (T2).

[0047] The second timing diagram 320 illustrates the transition timing between various operating frequencies (e.g., operating states), namely, a low-frequency operating state 322, a high-frequency operating state 324, and a subsequent low-frequency operating state 326, which can be repeated in this manner. The third timing diagram 330 illustrates the device operation / function that triggers the power supply voltage waveform 310 and the transition timing in the second timing diagram 320. The third timing diagram 330 is also triggered by the action in the fourth timing diagram 340. The fourth timing diagram effectively initiates the change in device operation / function in the third timing diagram 330, for example, if the FSM wants to change its operating frequency to a higher frequency (e.g., after sending a command requesting a specific operation). The fifth timing diagram 350 illustrates the temperature at different operating frequencies. Figure 3 In the example, the temperature remains unchanged; only the operating frequency changes (i.e., the fifth timing diagram 350 shows a flat line). Therefore, the adaptation of the power supply voltage only needs to consider the requirements due to the frequency change. This corresponds to the adaptation from V3 to V4 described in row 2 of Table 2.

[0048] As shown in the figure, the device changes from a lower frequency to a higher frequency at 342, which is initiated in the third timing diagram 330 by measuring the device temperature at 332 and changing the trim value at 333, followed by changing the supply voltage at 312. In this case, the trim value can be an interface signal between the digital and analog interfaces, for example, where a certain number of trim bits (e.g., 5 bits) implement multiple (e.g., 32) different settings (2^5=32) during decoding. In some examples, it is conceivable that if a standard setting of, for example, 16 is used, the increased voltage setting can be configured to add an offset of '4', which can be configurable in some examples, resulting in a new setting of 16+4=20. If the step size '1' equals 12.5 mV, then when 4 steps can be used, the LDO output voltage will increase by up to 50 mV. In analog (at the LDO), simply select the different reference voltage to which the regulation loop will be adjusted (the standard implementation of the LDO loop). The same applies to voltage sensors.

[0049] A settling time for the voltage sensor and / or LDO regulator is implemented at 334 to ensure that the outputs of the LDO regulator and voltage sensor are stable before switching to higher frequency operation. The new frequency can then be applied to digital operation at 324. Waiting for a specific settling time allows RFID to achieve its full power-saving potential.

[0050] As also shown in the figure, the device changes from a higher frequency to a lower frequency at 328, which is initiated in the third timing diagram 330. The device temperature is measured at 336 and the trim value is changed at 336, followed by a change in the supply voltage at 316. Settlement time for the voltage sensor and / or LDO regulator is achieved at 338, after which low power consumption is implemented at 348. For example, power consumption is frequency-dependent; the operating frequency has already decreased at 328, and note that the voltage level decreases at 316, but stabilizes at the lowest voltage level at 348. From that moment on, power consumption is at its minimum.

[0051] Now for reference Figure 4 The diagram shows an example flowchart 400 of a digital control circuit 420 (which may be a state machine-based implementation or a CPU-based implementation, wherein a state machine-based implementation is described) when switching from low-frequency operation 442 to high-frequency operation 448, according to some examples. In the main state machine 440, a frequency transition event is triggered at 444, followed by the initiation of a subroutine 450 at 452 to adapt to the power supply voltage level.

[0052] It should be noted that, in order to switch to a higher frequency, some example implementations may first adapt the supply voltage (e.g., simultaneous low voltage and high frequency may not be allowed, as this could lead to timing violations). If a switch to a lower frequency is performed, the frequency may need to be reduced first, and then the supply voltage reduced (again, simultaneous low voltage and high frequency are not allowed).

[0053] In this example flowchart 400, it may be necessary to disable and enable voltage sensor reset to avoid unnecessary resets. As a starting point, input temperature sensor 410 measures the temperature of an integrated circuit, such as that of an RFID device. Digital control circuitry 420 provides output power supply voltage control signals 430 to an analog LDO regulator and / or an analog voltage sensor. In this example, when switching from high-frequency operation 448 to low-frequency operation 442, the validity of the temperature provided by the digital control circuitry 420 to the input temperature sensor 410 can be determined at 446 in the main state machine 440. This example is only necessary if the temperature measurement takes some time. The result is invalid as long as the temperature measurement is in progress. Once the temperature measurement is complete, a valid result is obtained.

[0054] In subroutine 450, voltage sensor reset can be disabled at 454, and digital reset can be disabled at 472. At 456, subroutine 450 waits until the temperature sensor provides valid sensor input after the confirmation at 446. Once valid sensor input is received at 446 and 456, voltage trimming can be changed at 458 based on the defined configuration. After changing voltage trimming at 458, the main state machine 440 creates a control signal at 474 and outputs it at 430, which is configured to change the analog interface signal of the LDO and / or voltage sensor. After changing voltage trimming at 458, subroutine 450 also waits for the LDO and voltage sensor to stabilize at 460 and enables voltage sensor reset at 462. Then, the main state machine 440 enables digital reset at 476, and the subroutine terminates at 464.

[0055] Now for reference Figure 5 A further example flowchart 500 is shown, illustrating the digital control circuitry 520 (which may be a state machine-based implementation or a CPU-based implementation, with the state machine-based implementation described) when switching from high-frequency operation 542 to low-frequency operation 548, according to an example. In the main state machine 540, a frequency transition event is triggered at 544, and a switch to low-frequency operation is executed at 545, followed by the initiation of a subroutine 550 at 552 to adapt to the power supply voltage level. In this example flowchart 500, it may be necessary to disable and enable voltage sensor reset to avoid unnecessary resets. An input temperature sensor 510 measures the temperature of the digital control circuitry 520, such as an RFID device, which provides an output power supply voltage control signal 530 to an analog LDO regulator and / or an analog voltage sensor. In this example, when switching from high-frequency operation 542 to low-frequency operation 548, at 546, it is determined in the main state machine 540 whether the temperature of the digital control circuitry 520 provided by the input temperature sensor 510 is valid.

[0056] In subroutine 550, voltage sensor reset can be disabled at 554, and digital reset can be disabled at 572. At 556, subroutine 550 waits until the temperature sensor provides valid sensor input after the confirmation at 546. Once valid temperature sensor input is received at 546 and 556, voltage trimming can be changed at 558 based on the defined configuration. After changing voltage trimming at 558, the main state machine 540 creates a control signal at 574 and outputs a control signal at 530, which is arranged to change the analog interface signal of the LDO and / or voltage sensor. After changing voltage trimming at 558, subroutine 550 also waits for the LDO and voltage sensor to stabilize at 560 and enables voltage sensor reset at 562. Then, the main state machine 540 enables digital reset at 576, and the subroutine terminates at 564.

[0057] Now for reference Figure 6 An example of a timing waveform diagram 600 according to some examples is shown, relating to a change in the operating state of the device. The power supply voltage waveform 610 at 612 shows a power supply voltage transition from a median power supply voltage 611 when the device temperature is between a lower temperature threshold (T1) and a higher temperature threshold (T2) to a higher power supply voltage 614 when the device temperature is below the lower temperature threshold (T1). The power supply voltage waveform 610 also shows a power supply voltage transition at 616 from a higher power supply voltage 614 when the device temperature is below the lower temperature threshold (T1) to a lower power supply voltage 618 when the device temperature is above the higher temperature threshold (T2).

[0058] The second timing diagram 620 illustrates the timing of transitions between various operating states (i.e., state 'A' 622, state 'B' 624, state 'C' 626, etc.). The third timing diagram 630 illustrates the device operation / function triggered by the actions in the fourth timing diagram 640. According to... Figure 3 The fourth timing diagram 640 initiates a state change, and the fifth timing diagram 650 only shows a temperature change, but has no effect on 640. According to... Figure 3 The fourth timing diagram 640 triggers the device operation / function in the third timing diagram 630, which evaluates the temperature shown in the fifth timing diagram 650. If the temperature changes, adjustment values ​​are applied at 633 and 637.

[0059] As shown in the figure, the device temperature starts between a lower temperature threshold (T1) and a higher temperature threshold (T2), and transitions at 652 to a temperature below the lower temperature threshold (T1) at 654. This transition at 652 is caused by a temperature change in the RFID device (e.g., by changing the ambient temperature, such as by moving the RFID to a cooler environment). The temperature is measured at 654 after, for example, the FSM initiates a change from state 'A' to state 'B' at 642. Since this temperature differs from 650, the LDO and voltage sensor outputs are adapted. In the third timing diagram 630, the device temperature is measured at 632, and a trim value is changed at 633, followed by a change in the power supply voltage at 612. The voltage sensor and / or LDO regulator stabilize at 634, followed by a state transition at 624 at 644.

[0060] As also shown in the figure, the device temperature transitions at 657 to a temperature higher than the higher temperature threshold (T2) 658. This transition at 652 is caused by a temperature change in the RFID device (e.g., by a change in ambient temperature). Since the temperature at 658 differs from the temperature at 654 (the last measurement), the LDO and voltage sensor outputs need to be adapted. In the third timing diagram 630, the device temperature is measured at 636, and the trimmed value is changed at 637, followed by a change in the power supply voltage at 616. Settlement time for the voltage sensor and / or LDO regulator is achieved at 638, followed by a state transition at 648 at 628.

[0061] Therefore, as shown in the figure, switching from any state to another state (e.g., from state 'A' 622 to state 'B' 624) involves the following operations: (i) measuring the temperature; (ii) determining whether the temperature is above or below a threshold (e.g., a lower temperature threshold (T1) 654 or a higher temperature threshold (T2) 658), and then applying trimmed values ​​from the LDO and / or voltage sensor; (iv) then waiting for a specific settling time to ensure that the output of the LDO and the voltage sensor are stable before switching to the new operating state.

[0062] Now for reference Figure 7The diagram illustrates yet another example flowchart 700 of the digital control circuit 720 (which could be a state machine-based implementation or a CPU-based implementation, with the state machine-based implementation described herein) when switching from operating state 'A' 742 to operating state 'B' 748, according to the example. In the main state machine 740, at 744, a state transition event is triggered, followed by the initiation of a subroutine 750 at 752 for adapting to the power supply voltage level, and the main state machine 740 records the input temperature. In this example flowchart 700, it may be necessary to disable and enable voltage sensor reset to avoid unnecessary resets. An input temperature sensor 710 measures the temperature of, for example, the digital control circuit 720 of an RFID device, which provides an output power supply voltage control signal 730 to an analog LDO regulator and / or an analog voltage sensor. In this example, when switching from operating state 'A' 742 to operating state 'B' 748, at 746 the main state machine 740 determines whether the temperature provided by the digital control circuit 720, based on the input temperature sensor 710, is valid, for example, whether the temperature measurement has been completed. If the temperature measurement has not been completed, the operation waits until the result is available, thus indicating that the temperature measurement is valid.

[0063] In subroutine 750, voltage sensor reset can be disabled at 754, and digital reset can be disabled at 772. At 756, subroutine 750 waits until the temperature sensor provides valid sensor input after the determination at 746. Once valid sensor input is received at 746 and 756, voltage trimming can be changed at 758 based on the defined configuration. After changing voltage trimming at 758, the main state machine 740 creates and outputs a control signal at 774 and 730, which is configured to change the analog interface signal of the LDO and / or voltage sensor. After changing voltage trimming at 758, subroutine 750 also waits for the LDO and voltage sensor to stabilize at 760 and enables voltage sensor reset at 762. Then, the main state machine 740 enables digital reset at 776.

[0064] In replaceable examples, it is conceivable that it may not be necessary. Figure 4 , Figure 5 and Figure 7 Some steps in flowcharts 400, 500, and 700 are incorrect because the method can be implemented by sequentially changing the LDO and voltage sensor settings, for example, waiting until one of the LDO and voltage sensor stabilizes before switching to the other. In this alternative example, disabling the reset is not required, but the subroutine will still be executed. In another alternative example, it is conceivable to use the option of disabling the voltage sensor and then waiting until the temperature sensor input is determined to be valid.

[0065] Now for reference Figure 8 The diagram illustrates an example overview of a flowchart 800 for adapting the power supply voltage of a device, based on several examples. Flowchart 800 includes configuring a change in the device's operating state at 810, such as a change in the device's operating frequency or, for example, a change in the power consumed by a coprocessor. In one example, the FSM knows it wants to change from state 'A' to state 'B' or enable a function that requires operation at a higher frequency. At 820, flowchart 800 includes measuring the device's temperature, such as the IC temperature, and, for example, whether the temperature has exceeded a (configurable) temperature threshold. At 830, flowchart 800 includes determining the power supply voltage level required for the device to operate in the configured operating state. At 840, flowchart 800 includes adapting the device's power supply voltage (and, in some examples, sensor levels) based at least on the measured temperature and the power supply voltage level of the configured operating state (e.g., operating frequency and / or power (consumption)).

[0066] It is conceivable that the concepts described herein can be used in a variety of applications, not just RFID devices, such as where power / leakage may be a concern and / or continuous monitoring of the power domain should be monitored by voltage sensors (e.g., as seen in low-power ICs).

[0067] It should also be understood that, for clarity, embodiments described with reference to different functional units and processors may be modified or reconfigured, wherein any suitable distribution of functions among the different functional units or processors is possible without departing from the concepts described herein. For example, functions shown to be performed by a separate processor or controller may be performed by the same processor or controller. Therefore, references to specific functional units are to be regarded only as references to suitable means for providing the described functions, and not as indications of strict logical or physical structure or organization.

[0068] In the foregoing specification, examples have been described with reference to specific examples of possible implementations or applications. However, it will be apparent that various modifications and changes can be made thereto without departing from the scope set forth in the appended claims, and the claims are not limited to the specific examples described above.

[0069] The connections discussed herein can be of any type suitable for transmitting signals from or to a corresponding node, device, or circuit, for example, via an intermediate means. Therefore, unless otherwise implied or stated, a connection can be, for example, a direct connection or an indirect connection. Connections can be shown or described as a single connection, multiple connections, unidirectional connections, or bidirectional connections. However, different embodiments can vary the implementation of the connection. For example, a single unidirectional connection can be used instead of a bidirectional connection, and vice versa. Furthermore, multiple connections can be replaced by a single connection that transmits multiple signals in a continuous or time-multiplexed manner. Similarly, a single connection carrying multiple signals can be divided into various different connections carrying subsets of those signals. Therefore, many options exist for transmitting signals. Those skilled in the art will recognize that the architectures depicted herein are merely exemplary, and in practice, many other architectures can be implemented to achieve the same functionality.

[0070] Any arrangement of components that perform the same function is effectively 'associated' to achieve the desired functionality. Therefore, any two components combined in this paper to achieve a specific function can be considered 'associated' with each other to achieve the desired functionality, regardless of the architecture or intermediate components. Similarly, any two such associated components can also be considered 'operably connected' or 'operably coupled' with each other to achieve the desired functionality.

[0071] Furthermore, those skilled in the art will recognize that the boundaries between the above operations are merely illustrative. Multiple operations can be combined into a single operation, a single operation can be distributed among additional operations, and the execution of operations can at least partially overlap in time. Moreover, alternative embodiments may include multiple instances of a particular operation, and the order of operations can be varied in various other embodiments. Furthermore, for example, in one embodiment, the illustrated example can be implemented as circuitry located on a single integrated circuit or within the same device.

[0072] In some examples, the various components within an RFID tag can be implemented as discrete or integrated components, thus the final structure is application-specific or a design choice. Since the illustrated embodiments can be implemented extensively using electronic components and circuitry known to those skilled in the art, details will not be explained to a greater extent than deemed necessary below in order to understand and grasp the basic concepts described herein and to avoid confusion or deviation from the teachings described. Those skilled in the art will appreciate that, in some cases, the degree of integration of the processor and memory circuitry within the RFID tag can depend on the implementation method.

[0073] Furthermore, examples or portions thereof may be implemented as physical circuits or as a software or code representation of a logical representation that can be converted into physical circuits, for example, using any suitable type of hardware description language. Moreover, the described examples are not limited to physical devices or units implemented in non-programmable hardware, but can also be applied to programmable devices or units by operation according to suitable program code, such as minicomputers, personal computers, laptops, personal digital assistants, automotive and other embedded systems, mobile phones and various other wireless devices, generally referred to as 'devices' in this application. Of course, other modifications, variations, and substitutions are also possible. Therefore, the specification and drawings should be considered illustrative rather than restrictive.

[0074] In the claims, any reference numerals placed between parentheses should not be construed as limiting the claims. The word 'including' does not exclude the presence of elements or steps other than those listed in the claims. Furthermore, the terms 'a' or 'an' as used herein are defined as one or more. Moreover, the use of introductory phrases such as 'at least one' and 'one or more' in the claims should not be construed as implying that introducing another claim element by the indefinite article 'a' or 'an' limits any particular claim containing such an introduced claim element to an invention containing only one such element, even when the same claim includes the introductory phrase 'one or more' or 'at least one' and the indefinite article such as 'a' or 'an'. The same applies to the use of definite articles. Unless otherwise stated, terms such as 'first' and 'second' are used to arbitrarily distinguish the elements described by these terms. Therefore, these terms are not necessarily intended to indicate the time or other priority of these elements. The fact that certain measures are recited in claims that differ from each other does not imply that combinations of these measures cannot be used to gain an advantage.

Claims

1. A method (800) for adapting the power supply voltage of a device, characterized in that, include: Configuration (810) to change the operating state of the device; Measure the temperature of the device described in (820); Determine (830) the power supply voltage level required for the device to operate in its configured operating state; The power supply voltage of the device is adapted (840) at least according to the measured temperature and the power supply voltage level required for the device to operate in the configured operating state.

2. The method (800) according to claim 1, characterized in that, The changes to the operating state of the device include: Change at least one of the following: the power consumption of the device, the operating frequency of the device; And among them The power supply voltage of the device (840) is adapted to at least the power supply voltage level required for the device to operate at a changed operating frequency or power consumption, based on the measured temperature.

3. The method (800) according to claim 1 or claim 2, characterized in that, Measuring the temperature of the device includes determining that the temperature of the device has exceeded a temperature threshold, and adapting the power supply voltage of the device includes adapting the power supply voltage of the device at least based on the measured temperature exceeding the temperature threshold and the power supply voltage level required for the device to operate in the configured operating state.

4. The method (800) according to claim 3, characterized in that, The device employs multiple temperature thresholds.

5. The method (800) according to claim 3 or claim 4, characterized in that, The device employs a configurable temperature threshold.

6. The method (800) according to any one of the preceding claims, characterized in that, Adapting the power supply voltage of the device based on the measured temperature and the configured operating state includes: adapting the power supply voltage of the device in a stepwise manner, wherein the corresponding voltage step provides a constant power supply voltage over the entire temperature range.

7. The method (800) according to claim 6, characterized in that, The corresponding voltage step size for providing a constant supply voltage can be configured according to one of the following: The operating state of the device and the measured temperature of the device; The operating frequency of the device and the measured temperature of the device.

8. The method (800) according to any one of the preceding claims, characterized in that, Adapting the power supply voltage of the device to the measured temperature and the configured operating state further includes: adapting the sensing range of the voltage sensor or low-dropout regulator output in response to the measured temperature of the device.

9. The method (800) according to claim 8, characterized in that, Additionally, it includes the ability to perform the sensing range of the voltage sensor or low-dropout regulator output independently of the power supply voltage adapted to the device, in response to the temperature measured by the device.

10. An apparatus, characterized in that, include: A voltage source configured to supply voltage to a plurality of circuits of the device; A temperature sensor configured to measure the temperature of the device; A digital control circuit, operably coupled to the voltage source and the temperature sensor, and arranged as follows: Configure changes to the operating state of the device; Determine the power supply voltage level required for the device to operate in its configured working state; as well as The power supply voltage supplied to the plurality of circuits is adapted at least according to the measured temperature and the power supply voltage level required for the device to operate in the configured operating state.

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