Selection of multiple configuration settings using a single configuration port

Abstract

A device with configurable operating parameters, which features: a configuration port (302); a regulated power source (304); and a detection circuit (306) that is configured to: In response to the regulated current source (304) providing a current to the configuration terminal (302) which is connected in parallel with a resistor (308) and a capacitor (310), monitoring a voltage signal at the configuration terminal (302) to determine a first value and a second value; wherein the first value is determined by a resistance sensing component configured to determine a resistance value associated with the resistor, and wherein the second value is determined by a capacitance sensing component configured to determine a capacitance value associated with the capacitor (310), and Configuring a first operating parameter based on the resistance value and a second operating parameter based on the capacitance value or a combination of the resistance value and the capacitance value.

Description

TECHNICAL AREA

[0001] This application relates to devices having configurable parameters and, more particularly, to configuring parameters of devices using configuration ports. BACKGROUND

[0002] Many configurable devices, such as integrated circuits or other semiconductor devices, provide multiple configuration options that can be set by users. Configurable devices with such configuration options allow semiconductor suppliers to produce programmable devices of a given design that can be used in multiple applications, rather than producing devices with a specific design that are customized for each application. Furthermore, this configuration provides greater design flexibility when using the configurable devices.

[0003] A programmable device can have one or more parameters, such as operating parameters, each of which can be configured for a selected setting. Configuration terminals, such as pins or bumps, can be used to configure the parameters of the programmable device. As described in Fig. As shown in Figure 1, a prior art technique for configuring parameters of a programmable device uses a configuration pin for each parameter. Each configuration pin is connected to a configuration resistor external to the programmable device. A resistance value of each configuration resistor is used to select the desired setting for a corresponding parameter. Fig.Figure 2 shows a prior art mechanism used to determine the resistance values ​​of the configuration resistors to determine the desired setting for each parameter. A regulated current source may be connected to one of the configuration terminals. Since the current from that configuration terminal to ground is known, the resistance value of the configuration resistor connected to that configuration terminal can be determined by measuring the voltage at the configuration terminal and applying Ohm's law. Similarly, by connecting the current source to the other configuration terminal, the resistance value of the other configuration resistor can be determined. There are many examples of parameters that can be configured.For example, as shown in an example configuration Table 1 below, the parameters may include two operating parameters - a thermal protector cut-off temperature and an operating frequency. Table 1 Connection parameter Attitude Resistance 1 Switch-off temperature (thermal protection) 50° C 50K Ohm 60° C 75K Ohm 70° C 100K Ohm 2 Operating frequency 100 MHz 50K Ohm 150 MHz 75K Ohm 200 MHz 100K Ohm

[0004] The desired setting for a parameter can be selected by connecting a resistor with a resistance value associated with the desired setting to the configuration terminal associated with that parameter. Fig. Figure 2 shows an example with two configuration pins, but this mechanism can be used with more configuration pins and configuration resistors.

[0005] Although this technique is simple and reliable, it requires an associated configuration pin for each parameter. This can increase the cost of programmable devices and can also increase the size of programmable devices. For example, control devices used in power control and lighting devices have very few pins due to cost and size constraints.

[0006] Accordingly, there is a need in the art for improved techniques for configuring parameters of programmable devices that enable multiple parameters to be configured using fewer configuration ports.

[0007] US 6 922 071 B2 relates to the field of integrated circuit design and, in particular, to a method for improving cost efficiency by saving integrated circuit terminals.

[0008] DE 10 2013 110 223 A1 relates to a device and a method for the digital configuration of integrated circuits. SUMMARY

[0009] To address the need in the art for improved techniques for configuring parameters using configuration ports, systems, apparatus, and methods are provided for selecting multiple configuration settings using a single configuration port.

[0010] A programmable device (e.g., an integrated circuit or other semiconductor device) includes one or more configuration terminals (e.g., pins, bumps, or other terminals), and at least one of the configuration terminals can be used to select multiple configuration settings. A single configuration terminal of the programmable device is selectively connected in parallel to a configuration resistor and a configuration capacitor. The programmable device configures multiple operating parameters using this configuration terminal based on the configuration resistor and the configuration capacitor.

[0011] The programmable device determines two or more values, which in turn may be determined by the configuration resistor and / or the configuration capacitor. The two or more values ​​may include a resistance value, a capacitor value, a resistor-capacitor (RC) time constant value, and / or other values ​​that depend on the configuration resistor and / or the configuration capacitor. The resistance value may be the resistance of the configuration resistor or a value associated with the resistance. The capacitor value may be the capacitance of the configuration capacitor or a value associated with the capacitance. The RC time constant value may be the RC time constant, which is the product of the resistance value and the capacitance, or a value associated with the RC time constant.

[0012] The programmable device determines the two or more values ​​by monitoring a voltage signal at the configuration terminal. A regulated current source supplies a current to the configuration terminal. A voltage signal at the configuration terminal increases according to the RC time constant based on the resistor value and the capacitor value. When the voltage signal reaches a peak voltage, also known as the DC (direct current) level, the programmable device can determine the peak voltage and determine the resistance value. The programmable device can determine the resistance value using the current from the regulated current source and the peak voltage.

[0013] When the regulated current source is activated, the voltage signal rises according to the RC time constant. When the regulated current source is deactivated, the voltage signal falls according to the RC time constant. Since the resistor value is known based on the peak voltage, the programmable device can determine the capacitor value and / or the RC time constant value by determining a rise time of the voltage signal (e.g., from zero or a predetermined voltage to a threshold voltage) during a rise of the voltage signal and / or a fall time of the voltage signal (e.g., from the peak voltage or a predetermined voltage to a threshold voltage) during a fall of the voltage signal.Alternatively, the programmable device can determine the capacitor value and / or the RC time constant value by measuring two voltages separated by a fixed time during the rise or fall of the voltage signal. The programmable device can determine the capacitor value and / or the RC time constant value using the current of the regulated current source, the peak voltage, the resistance value, and / or at least one of the rise time, the fall time, or the two measured voltages.

[0014] One value, such as the resistance value, can be used to select a configuration setting for one parameter, and another value, such as the capacitor value or the RC time period value, can be used to select a configuration setting for another parameter. Alternatively, a combination of two values ​​can be used to select configuration settings for two or more parameters, such as by assigning each combination to a preset configuration setting for the two or more parameters.

[0015] Accordingly, a single configuration port can be used to configure multiple parameters, such that the number of configuration ports required to configure parameters of programmable devices can be reduced, advantageously reducing the cost and / or size of the programmable devices. These advantageous features will be more readily appreciated by considering the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a diagram of a programmable device using a prior art technique for configuring parameters of the programmable device. Fig.Figure 2 shows a diagram of a programmable device that uses a prior art mechanism for determining values ​​of configuration resistors connected to configuration terminals of the programmable device. Fig. 3 shows a programmable device configuring multiple parameters using a configuration port according to an embodiment of the disclosure. Fig. 4A-B show waveforms at a configuration port used to configure multiple parameters of a programmable device according to an embodiment of the disclosure. Fig. 5 illustrates an operational flow for configuring multiple parameters of a programmable device using a configuration port according to an embodiment of the disclosure.

[0016] Embodiments of the present disclosure and their advantages are best understood by reference to the following detailed description. It should be noted that like reference numerals are used to identify like elements illustrated in one or more of the figures. DETAILED DESCRIPTION

[0017] Systems, apparatus, and methods for configuring multiple parameters using a configuration port are provided.

[0018] Fig.3 shows a programmable device 300, such as an integrated circuit or other semiconductor device, that configures multiple parameters using a configuration terminal 302 according to an embodiment of the disclosure. The programmable device 300 may include at least one configuration terminal 302, a regulated current source 304, and a sense circuit 306. Although only one configuration terminal 302 is shown, the programmable device 300 may include more than one configuration terminal 302 and other types of terminals. The configuration terminal 302 may be a pin, a bump, or another terminal. The regulated current source 304 is configured to selectively provide a regulated current to the configuration terminal 302. The regulated current source 304 may be a programmable regulated current source or another regulated current source.In alternative embodiments, the regulated current source 304 may be part of the detection circuit 306 or may be provided by a circuit or device external to the programmable device 300.

[0019] A resistor, such as configuration resistor 308, and / or a capacitor, such as configuration capacitor 310, are selectively connected to configuration terminal 302 to configure a plurality of parameters. One terminal of resistor 308 may be connected to configuration terminal 302, and the other terminal of resistor 308 may be connected to ground 312. Similarly, one terminal of capacitor 310 may be connected to configuration terminal 302, and the other terminal of capacitor 310 may be connected to ground 312, such that resistor 308 and capacitor 310 are connected in parallel. Resistor 308 and capacitor 310 together may determine a resistor-capacitor (RC) time constant, also referred to as an RC product, which is the product of the resistance of resistor 308 and the capacitance of capacitor 310.

[0020] The sensing circuit 306 may include a voltage sensing component 314 configured to monitor a voltage signal at the configuration terminal 302, such as via the configuration terminal 302 and ground 312. The sensing circuit 306 may also include a resistance sensing component 316 that determines a resistance value to configure a parameter to one of a plurality of configuration settings 318 for a parameter. By determining the resistance value, the sensing circuit 306 may identify or otherwise detect the resistor 308. The sensing circuit 306 may further include a capacitor or RC product (RC time constant) sensing component 320 that determines a capacitor value or an RC time constant value, also referred to as an RC product value, to configure another parameter.By determining the capacitor value or the RC product value, the capacitor / RC product detection component 320 can identify or otherwise detect the capacitor 310.

[0021] The resistance value may be the resistance value of resistor 308 or a value proportional to the resistance value of resistor 308 or otherwise associated therewith. The capacitor value may be the capacitance of capacitor 310 or a value proportional to the capacitance of capacitor 310 or otherwise associated therewith. The RC time constant value may be an RC time constant or a value proportional to the RC time constant or otherwise associated therewith. For example, the resistance value, the capacitor value, and / or the RC time constant value may each be digital values ​​generated in response to the regulated current source 304 providing a current to the configuration terminal 302 and a voltage signal being measured at the configuration terminal.

[0022] In alternative embodiments, the sensing component 316 and / or the sensing component 318 may determine other values ​​that depend on the resistor 308 and / or the capacitor 310. Although two sensing components 316 and 320 are shown, the sensing circuit 306 may include more than two sensing components.

[0023] The sensing component 316 and / or the sensing component 320 may be separate from the voltage sensing component 314 or may be implemented by the voltage sensing component 314. The sensing circuit 306 may include one or more comparators and / or analog-to-digital circuits (ADCs). For example, the voltage sensing component 314, the sensing component 316, and / or the sensing component 320 may each include one or more comparators and / or ADCs.

[0024] When the regulated current source 304 provides a current to the configuration terminal 302 for a period of time, as indicated by a current waveform 400 in the Fig. 4A-B, the detection circuit 306 monitors (e.g., using the voltage detection component 314) a voltage signal at the configuration terminal 302, as represented by a voltage waveform 410 in the Fig.4A-B. When the regulated current source 304 begins providing current (e.g., in response to the sensing circuit 306 enabling the regulated current source 304), the voltage signal rises according to the RC time constant. The voltage signal reaches a peak voltage 412, also referred to as a direct current (DC) voltage or DC level, and remains there until the regulated current source 304 stops providing current (e.g., in response to the sensing circuit 306 disabling the regulated current source 304). When the regulated current source 304 stops providing current, the voltage signal decays according to the RC time constant.

[0025] When the voltage signal reaches peak voltage 412, sensing circuit 306 may determine peak voltage 412 (e.g., using resistance sensing component 316) and determine the resistance value. Sensing circuit 306 may determine the resistance value using the value of the current provided by regulated current source 304 and the value of peak voltage 412.

[0026] The detection circuit 306 may (e.g., using the capacitor / RC product detection component 320) determine another value, such as the capacitor value and / or the RC time constant value, based on another measurement and / or the resistance value. In one embodiment, the detection circuit 306 determines a fall time 414 in response to the regulated current source 304 stopping providing the current. The fall time 414 may be the time it takes for the voltage signal to fall from the peak voltage 412 to zero, as shown in Fig.4A, from the peak voltage 412 to a threshold voltage, from a predetermined voltage to a threshold voltage, or another time period associated with the decay of the voltage signal. The detection circuit 306 may determine the capacitor value based on the decay time 414 and / or the resistance value. Alternatively or additionally, the detection circuit 306 may determine the RC time constant value based on the decay time 414 and / or the resistance value.

[0027] In another embodiment, the detection circuit 306 determines a rise time 416 in response to the regulated current source 304 beginning to provide the current. The rise time may be the time it takes for the voltage signal to rise from zero to the peak voltage 412, as shown in Fig.4B, from a predetermined voltage to the peak voltage 412, from zero to a threshold voltage, from a predetermined voltage to a threshold voltage, or another time period associated with the rise of the voltage signal. The detection circuit 306 may determine the capacitor value based on the rise time 416 and / or the resistance value. Alternatively or additionally, the detection circuit 306 may determine the RC time constant value based on the rise time 416 and / or the resistance value.

[0028] In another embodiment, detection circuit 306 determines the capacitor value and / or the RC time constant value by measuring two voltages separated by a fixed time during the rise or fall of the voltage signal. Detection circuit 306 may determine the capacitor value based on the two voltages and / or the resistance value. Alternatively or additionally, detection circuit 306 may determine the RC time constant value based on the two voltages and / or the resistance value.

[0029] One value, such as the resistor value, can be used to configure one parameter for configuration setting 318. Another value, such as the capacitor value or the RC time period value, can be used to configure another parameter for configuration setting 322. Alternatively, a combination of two values ​​can be used to configure one parameter for configuration setting 318 and another parameter for configuration setting 322, such as by associating each combination with preset configuration settings for the two parameters. Each combination can be associated with one configuration setting for one parameter and another configuration setting for the other parameter. The combinations can be further associated with a configuration setting for a third parameter.In an example, there might be four resistors to choose from and three capacitors to choose from, resulting in an array of twelve resistor and capacitor combinations. The array of twelve combinations can be associated with a set of configuration settings (e.g., a pair of configuration settings if two parameters are present).

[0030] Accordingly, the sensing circuit 306 may determine two or more values ​​(e.g., the resistor value, the capacitor value, the RC time constant value, or another value) by monitoring the voltage signal at the configuration terminal 302 in response to the regulated current source 304 providing a current to the configuration terminal 302. The sensing circuit 306 may then adjust two or more parameters based on the two or more values.

[0031] In one embodiment, an end-product designer may select resistor 308 from a group of resistors and capacitor 310 from a group of capacitors based on the settings for the parameters desired by the end-product designer. Each of the resistors (e.g., by the resistance value of the resistor) in the group of resistors may be associated with a setting (e.g., configuration setting 318) for one parameter. Each of the capacitors (e.g., by the capacitor value of the capacitor) in the group of capacitors may be associated with a setting (e.g., configuration setting 322) for a different parameter.

[0032] In one example, as shown in an example Configuration Table 2 below, the parameters may include two operating parameters, such as a cutoff temperature for thermal protection and an operating frequency, configured based on the selected resistor 308 and the selected capacitor 310. An end-product designer may consult Configuration Table 2 or a datasheet regarding setting configuration parameters. The end-product designer may then select resistor 308 from a group of resistors based on the desired cutoff temperature setting and select capacitor 310 from a group of capacitors based on the desired operating frequency setting. Accordingly, the desired settings for two parameters may be selected by connecting resistor 308 and capacitor 310 into a single configuration terminal 302. Table 2 Connection parameter Attitude Resistance capacitor 1 Switch-off temperature (thermal protection) 50° C 50K Ohm n / a 60° C 75K Ohm n / a 70° C 100K Ohm n / a 1 Operating frequency 50 MHz n / a No capacitor 100 MHz n / a 47 pF 150 MHz n / a 100 pF 200 MHz n / a 220 pF

[0033] In another embodiment, each resistor (e.g., by the resistance value of the resistor) in a group of resistors may be associated with a setting (e.g., configuration setting 318) for one parameter, and each RC product (e.g., by the RC product value) in a group of RC products may be associated with a setting (e.g., configuration setting 322) for a different parameter.

[0034] For example, as shown in an example Configuration Table 3 below, the parameters may include two operating parameters, such as a shutdown temperature and an operating frequency, configured based on the selected resistor 308 and an RC product, in turn dependent on the selected resistor 308 and the selected capacitor 310. An end-product designer may consult Configuration Table 3 or a datasheet regarding the setting of configuration parameters. The end-product designer may then select the resistor 308 from a group of resistors based on the desired shutdown temperature setting, identify an RC product based on the desired operating frequency setting, and select the capacitor 310 based on the identified RC product and the selected resistor 308. Table 3 Operating frequency → 200 MHz 150 MHz 100 MHz 50 MHz Switch-off temperature ↓ RC product 100uSec RC product 33uSec RC product 10uSec RC Product 0 50° C Selection resistor 10K Selection capacitor 10nF Selection capacitor 3.3nF Selection capacitor 1nF Select capacitor 0 60° C Selection resistor 33K Selection capacitor 3.3nF Selection capacitor 1nF Selection capacitor 330pF Select capacitor 0 70° C Selection resistor 100K Selection capacitor 1nF Selection capacitor 330pF Selection capacitor 100pF Select capacitor 0

[0035] In another embodiment, each capacitor (e.g., by the capacitor value) in a group of capacitors may be associated with a setting (e.g., configuration setting 318) for one parameter, and each RC product (e.g., by the RC product) in a group of RC products may be associated with a setting (e.g., configuration setting 322) for a different parameter. In other embodiments, one or more values ​​depending on the resistor 308 and / or the capacitor 310, other than the resistor value, the capacitor value, or the RC product value, may be determined and used to configure one or more corresponding parameters.

[0036] Fig.5 shows an operational flow 500 for configuring several parameters of a programmable device, such as the programmable device 300, using a configuration port, such as the configuration port 302 (in Fig. 3), according to an embodiment of the disclosure.

[0037] At block 502, the programmable device 300 selectively provides a current to the configuration port 302. The programmable device 300 may provide the regulated current source 304 (in Fig. 3) to start and stop providing current to the configuration terminal 302. The configuration terminal 302 is connected to a resistor, such as resistor 308, and a capacitor, such as capacitor 310 (in Fig.3), connected in parallel or in series. Resistor 308 and capacitor 310 may be selected and connected by an end-product designer based on configuration settings desired by the end-product designer.

[0038] At block 504, the programmable device 300 monitors a voltage signal at the configuration terminal 302. The programmable device 300 may include the detection circuit 306 (in Fig. 3) to sense, measure, detect, compare, or otherwise monitor the voltage signal in response to the regulated current source 304 providing a current.

[0039] At block 506, the programmable device 300 determines a value based on monitoring the voltage signal. While the voltage signal is at peak voltage 412 (in the Fig.4A-B), the programmable device 300 may determine the peak voltage 412 and determine the resistance value based on the peak voltage 412.

[0040] At block 508, the programmable device 300 configures a parameter to a configuration setting. The programmable device 300 may configure an operating parameter based on the resistance value determined in block 506.

[0041] At block 510, the programmable device 300 determines another value based on monitoring the voltage signal. When the resistance value is determined at block 506, another value, such as the capacitor value or the RC time constant value, may be determined using the rise or fall of the voltage signal, for example, by measuring a rate of change of the voltage signal or a time period associated with the rise or fall of the voltage signal.

[0042] The capacitor value or the RC time constant value can be determined by monitoring the voltage signal as it drops according to the RC time constant when the regulated current source 304 stops providing current. During a drop in the voltage signal, the programmable device 300 can determine a fall time of the voltage signal from the peak voltage 412 or a predetermined voltage to a threshold voltage or two voltages measured a fixed time apart.

[0043] Alternatively, the capacitor value or the RC time constant value can be determined by monitoring the voltage signal as it rises according to the RC time constant when the regulated current source 304 begins to provide the current. During a rise in the voltage signal, the programmable device 300 can determine a rise time of the voltage signal to a threshold voltage or measure two voltages measured a fixed time apart.

[0044] At block 512, the programmable device 300 configures another parameter to a different configuration setting. The programmable device 300 may configure the other operating parameter based on the capacitor value or the RC time constant value determined in block 510.

[0045] A single configuration port, such as configuration port 302, can thus be used to configure multiple parameters. If an end-product designer selects resistor 308 and capacitor 310 and connects them in parallel to configuration port 302, programmable device 300 can capture two values, such as the resistance value of resistor 308 and the capacitor value of capacitor 310. Programmable device 300 can configure a parameter to a desired setting based on one of the two values ​​or a combination of the two values. Further, programmable device 300 can configure another parameter to a desired setting based on the other of the two values ​​or the combination of the two values.In further embodiments, one or more additional values ​​may be determined based on the voltage signal, and one or more additional parameters may be set to a desired setting based on the additional values.

[0046] As will now be apparent to those skilled in the art, and depending on the particular application at hand, many modifications, substitutions, and variations may be made in and to the materials, apparatus, configurations, and methods of using the devices of the present disclosure without departing from its spirit and scope. In view of this, the scope of the present disclosure is not intended to be limited to the specific embodiments illustrated and described herein, which serve merely as examples, but rather to be fully consistent with the claims provided hereinafter and their functional equivalents.

Claims

[1] A device with configurable operating parameters, comprising: a configuration port (302); a regulated current source (304); and a detection circuit (306) configured to: in response to the regulated current source (304) providing a current to the configuration terminal (302) connected in parallel to a resistor (308) and a capacitor (310), monitoring a voltage signal at the configuration terminal (302) to determine a first value and a second value; wherein the first value is determined by a resistance sensing component configured to determine a resistance value associated with the resistor, wherein the second value is determined by a capacitance sensing component configured to determine a capacitance value associated with the capacitor (310), and Configuring a first operating parameter based on the resistance value and a second operating parameter based on the capacitance value or a combination of the resistance value and the capacitance value. [2] The device of claim 1, wherein the combination of the resistance value and the capacitance value is a resistance-capacitance (RC) time constant associated with the resistor (308) and the capacitor (310), the RC time constant being a product of the resistance value and a capacitance value of the capacitor (310). [3] The apparatus of claim 1, wherein the detection circuit (306) is configured to monitor the voltage signal to determine a peak voltage, the first value being based on the peak voltage. [4] The apparatus of claim 1, wherein the detection circuit (306) is configured to monitor the voltage signal to determine a fall time from a peak voltage or a predetermined voltage to a threshold voltage during a fall of the voltage signal, the second value being based on the fall time. [5] The apparatus of claim 1, wherein the detection circuit (306) is configured to monitor the voltage signal to determine a rise time to a threshold voltage during a rise of the voltage signal, the second value being based on the rise time. [6] The apparatus of claim 1, wherein the detection circuit (306) is configured to monitor the voltage signal to measure two voltages at a fixed time interval during a rise or fall of the voltage signal, the second value being based on the two voltages. [7] The apparatus of claim 1, wherein the detection circuit (306) is configured to: Configuring the first operating parameter to a first setting associated with a combination of the first value and the second value; and Configuring the second operating parameter to a second setting associated with the first value, the second value, or the combination. [8] The apparatus of claim 1, wherein the detection circuit (306) comprises an analog-to-digital circuit (ADC) or a comparator configured to monitor the voltage signal. [9] A method for configuring operating parameters of a device, comprising: Providing a current to a configuration terminal (302) connected in parallel to a resistor (308) and a capacitor (310); Monitoring a voltage signal at the configuration terminal (302); Determining a first value and a second value based on the monitoring; wherein the first value is determined by a resistance sensing component for determining a resistance value associated with the resistor (308), wherein the second value is determined by a capacitance sensing component for determining a capacitance value associated with the capacitor (310), and Configuring a first operating parameter based on the resistance value and a second operating parameter based on the capacitance value or a combination of the resistance value and the capacitance value. [10] The method of claim 9, wherein the combination of the resistance value and the capacitance value is a resistor-capacitor (RC) time constant associated with the resistor (308) and the capacitor (310), the RC time constant being a product of the resistance value and a capacitance value of the capacitor (310). [11] The method of claim 9, wherein monitoring comprises determining a peak voltage, wherein determining the first value is based on the peak voltage. [12] The method of claim 9, wherein monitoring comprises determining a fall time from a peak voltage or a predetermined voltage to a threshold voltage during a fall of the voltage signal, and wherein determining the second value is based on the fall time. [13] The method of claim 9, wherein monitoring comprises determining a rise time to a threshold voltage during a rise of the voltage signal, wherein determining the second value is based on the rise time. [14] The method of claim 9, wherein monitoring comprises measuring two voltages at a fixed time interval during a rise or fall of the voltage signal, and wherein determining the second value is based on the two voltages. [15] The method of claim 9, wherein configuring comprises: Configuring the first operating parameter to a first setting associated with a combination of the first value and the second value; and Configuring the second operating parameter to a second setting associated with the first value, the second value, or the combination. [16] The method of claim 9, wherein the monitoring is performed using an analog-to-digital circuit (ADC) or a comparator.

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