Patent Publication Number: US-2023139517-A1

Title: Reduced power wireless battery management system

Description:
BACKGROUND 
     A battery pack includes multiple battery modules connected in series. A busbar couples adjacent battery modules (e.g., couples a positive terminal of a first battery module to a negative terminal of a second battery module, or vice versa). Such battery packs provide power for electronic devices, such as electric vehicles (EVs) or hybrid EVs (HEVs), among other devices. 
     SUMMARY 
     In an example of this description, a system includes a battery pack having a first battery module, a second battery module, and a busbar that couples the first and second battery modules; a battery management controller having a first wireless transceiver; and a battery monitor coupled to the first battery module and to the busbar. The battery monitor includes monitoring circuitry configured to receive a first indication of a parameter of the first battery module; a second wireless transceiver configured to provide the first indication to the battery management controller via a wireless connection to the first wireless transceiver; and a busbar voltage circuit configured to receive a second indication of a voltage across the busbar, and, responsive to the second indication being greater than a voltage threshold, provide a first signal to the second wireless transceiver to cause the second wireless transceiver to be in a higher-power state. 
     In another example of this description, a method includes receiving, by a battery monitor, a first indication of a voltage across a busbar that couples a first battery module of a battery pack to a second battery module of the battery pack; responsive to the first indication being greater than a voltage threshold, causing a wireless transceiver of the battery monitor to be in a higher-power state; and wirelessly providing, by the battery monitor to a battery management controller, responsive to the wireless transceiver being in the higher-power state, a second indication of a parameter of the first battery module. 
     In yet another example of this description, a device includes monitoring circuitry adapted to be coupled to a first battery module of a battery pack. The monitoring circuitry is configured to receive a first indication of a parameter of the first battery module. The device also includes a busbar voltage circuit adapted to be coupled to a busbar that couples the first battery module to a second battery module of the battery pack. The busbar voltage circuit is configured to receive a second indication of a voltage across the busbar, and, responsive to the second indication being greater than a voltage threshold, provide a first signal to a wireless transceiver to cause the wireless transceiver to be in a higher-power state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a detailed description of various examples, reference will now be made to the accompanying drawings in which: 
         FIG.  1    is a block diagram of a system including a battery management system (BMS) in accordance with an example of this description; 
         FIG.  2    is a block diagram of a battery pack in accordance with an example of this description; 
         FIG.  3    is a circuit diagram of a battery monitor and wireless transceiver of the BMS of  FIG.  1    in accordance with an example of this description; and 
         FIG.  4    is a flow chart of a method for wireless battery management in accordance with an example of this description. 
     
    
    
     DETAILED DESCRIPTION 
     A battery management system (BMS) obtains data related to battery modules of a battery pack, and controls the battery modules of the battery pack. For example, the BMS controls charging of the battery modules, performs balancing between the battery modules, and monitors the operating conditions and/or health of the battery modules. The BMS includes a plurality of battery monitors, and each battery module is coupled to one of the battery monitors. The BMS also includes a battery management controller that is coupled to, and communicates with, each of the battery monitors. Together, the battery monitors and the battery management controller facilitate the monitoring of various parameters of the battery modules, such as voltage, current, temperature, and parameters related to cell balancing within a module, among other functions of the BMS. 
     In some cases, the battery management controller communicates with the battery monitors using wired connections. However, such a wired BMS is both costly and complicated. A wired BMS is also more difficult to repair in cases where the battery pack (or battery modules thereof) are in locations that are difficult to access, such as may be the case in the context of an EV or HEV. 
     Accordingly, in other cases, the battery management controller and the battery monitors each includes a wireless transceiver, which facilitates wireless communication between the battery management controller and the battery monitors. In the event that a battery-powered device is in a power save state or mode (e.g., such as an EV or HEV being parked), it is useful to reduce the power consumption of the BMS, while maintaining the ability of the BMS to begin communication relatively quickly responsive to the device transitioning to an on state (e.g., such as the EV or HEV being driven, or otherwise operated by a user). 
     One way to reduce the BMS power consumption while the device is in the power save mode (e.g., the EV or HEV is parked) is to cause the wireless transceiver of the battery management controller to enter a lower-power state (e.g., to turn off). Other hardware components of the battery management controller, such as a microprocessor, are aware of the state of the device (e.g., whether the vehicle is parked, or a user desires to operate the vehicle), and thus are capable of causing the wireless transceiver of the battery management controller to enter a higher-power state responsive to the device turning on. However, the individual battery monitors are not aware of the device power status. For example, the wireless transceivers of the battery monitors periodically poll or scan to determine whether the wireless transceiver of the battery management controller is in the higher-power state, and/or attempting to communicate with the battery monitors. Accordingly, the wireless transceivers of the battery monitors cannot be turned off while the device is in the power save mode, and thus still consume power to poll or scan for activity from the wireless transceiver of the battery management controller. 
     Examples of this description address the foregoing by providing battery monitors that include a busbar voltage circuit that is configured to sense a voltage across a busbar that couples battery modules of the battery pack. Each of the battery modules can include one or more battery cells in series. For example, a battery module that includes 12 cells in series is sometimes referred to as a 12S module. The voltage across the busbar being greater than a voltage threshold indicates that current is being drawn from the battery pack, which in turn indicates that the device is transitioning out of the power save mode or state (e.g., the EV or HEV is transitioning from parked to being operated). In an example, the threshold to which the sensed voltage across the busbar is compared is system-dependent. In some examples, the threshold is based on resistance characteristics of the busbar being monitored, or an expected current drawn from the battery pack while the device is on (e.g., not in the power save state). 
     The busbar voltage circuit includes an analog-to-digital converter (ADC) that is coupled to the busbar and configured to receive the voltage across the busbar. The ADC provides a digital value responsive to the voltage across the busbar. The busbar voltage circuit also includes a comparator, which compares the digital value indicative of the busbar voltage to the voltage threshold. The comparator provides a wakeup signal to the wireless transceiver of the battery monitor responsive to the digital value being greater than the voltage threshold, which indicates current is being drawn from the battery pack and the device is turning on. 
     The wireless transceiver of the battery monitor is configured to transition to a higher-power state responsive to receiving the wakeup signal, and to begin communicating with the wireless transceiver of the battery management controller. Because the wireless transceiver of the battery monitor transitions to the higher-power state responsive to a physical condition (e.g., a voltage across the busbar) that indicates the device is itself turning on, the battery monitor is able to begin communicating with the battery management controller relatively quickly (e.g., on the order of 50 ms from busbar voltage sensing to network formation, which can be less than a polling or scanning interval) after the device turns on. 
     In some examples, the wireless transceiver of the battery monitor is configured to transition to the lower-power state responsive to the wakeup signal being de-asserted (e.g., the busbar voltage being below the voltage threshold, indicating the device is in the power save mode, or EV/HEV is parked). In other examples, the wireless transceiver of the battery monitor is configured to transition to the lower-power state responsive to an instruction or communication from the battery management controller, which is aware of the device transitioning to the power save mode, or EV/HEV being parked. These and other examples are described below with reference to the accompanying figures. 
       FIG.  1    is a block diagram of a system  100  including a BMS in accordance with an example of this description. The system  100  includes an electronic device  102  (e.g., an EV/HEV  102 ) that is adapted to be coupled to an external power source  104 , which can be an EV charging station  104 . The EV/HEV  102  includes a battery pack  106 , which includes n battery modules  108  connected in series. Each battery module  108  can include one battery cell, or more than one battery cell connected in series. An inverter  110  is coupled to the battery pack  106 , and is configured to receive a direct current (DC) input voltage from the battery pack  106 , and to provide an alternating current (AC) output voltage to a load  112  (e.g., a motor  112  of the EV/HEV  102 ), responsive to the DC input voltage. 
     The EV/HEV  102  also includes an on-board charger  114  that is coupled to the battery pack  106 . The on-board charger  114  is adapted to be coupled to the external power source  104 . The on-board charger  114  is configured to convert an input voltage provided by the external power source  104  (e.g., either an AC voltage or a DC voltage) to an output voltage suitable for charging the battery pack  106  (e.g., a DC voltage). 
     In some examples, the EV/HEV  102  includes a high-voltage (HV) DC-DC power converter  116  that is coupled to the battery pack  106 . The HV DC-DC power converter  116  is configured to convert the DC voltage provided by the battery pack  106  to a DC voltage usable by various other components of the EV/HEV  102  (e.g., a lower DC voltage). The EV/HEV  102  also includes a low-voltage (LV) battery  118 , such as a 12-volt (V) battery, an 18 V battery, a 40 V battery, or the like. In examples in which the EV/HEV  102  includes an LV battery  118 , the EV/HEV  102  also includes an LV DC-DC power converter  120  coupled to the LV battery  118 . The LV DC-DC power converter  120  is configured to convert the DC voltage provided by the LV battery  118  to a DC voltage usable by various other components of the EV/HEV  102  (e.g., a lower DC voltage, such as 5 V). 
     As described, the EV/HEV  102  includes a BMS to obtain data related to the battery modules  108  of the battery pack  106 , and to control the battery modules  108  of the battery pack  106 . For example, the BMS controls charging of the battery modules  108 , performs power balancing between the battery modules  108 , and monitors the operating conditions and/or health of the battery modules  108 . In the example of  FIG.  1   , the BMS is a wireless BMS and includes a battery management controller  130  and a stack of battery monitors  132 . Each of the battery monitors  132  is associated with, and coupled to, one of the battery modules  108 . Accordingly, in the example of  FIG.  1   , there are n battery monitors  132 , each coupled to one of the n battery modules  108 . 
     The battery management controller  130  includes a wireless transceiver  134 , and each of the battery monitors  132  includes an associated wireless transceiver  136 . The wireless transceiver  134  and the wireless transceiver(s)  136  thus enable wireless communication between the battery management controller  130  and the battery monitor(s)  132 . For example, the wireless transceiver  134  of the battery management controller  130  is configured to provide a command and/or a request to the wireless transceiver(s)  136  of the battery monitor(s)  132 . Similarly, the wireless transceiver(s)  136  of the battery monitor(s)  132  are configured to provide a response to the wireless transceiver  134  of the battery management controller  130 . Accordingly, the BMS including the battery management controller  130  and the battery monitors  132  enables monitoring of various parameters of the battery modules  108 , such as voltage, current, temperature, and parameters related to cell balancing within a module, among other functions of the BMS. 
       FIG.  2    is a block diagram of the battery pack  106  of  FIG.  1    in accordance with an example of this description. As described above, the battery pack  106  includes n battery modules  108  connected in series. A busbar  202  couples adjacent battery modules  108 . For example, a busbar  202  couples a positive terminal of Module 1 to a negative terminal of Module 2, and another busbar  202  couples a positive terminal of Module n-1 to a negative terminal of Module n. In the example of  FIG.  2   , a negative terminal of Module 1 is also a negative terminal of the battery pack  106 , while a positive terminal of Module n is also a positive terminal of the battery pack  106 . 
     As described, the battery monitor(s)  132  are configured to sense a voltage across one of the busbars  202 , such as one of the busbars  202  coupled to the battery module  108  that a particular battery monitor  132  monitors. For example, the battery monitor  132  that monitors (or is associated with) Module 1 is configured to sense a voltage across the busbar  202  that couples Module 1 and Module 2 (e.g., the busbar  202  couples first and second battery modules  108 ). Similarly, the battery monitor  132  that monitors (or is associated with) Module n-1 is configured to sense a voltage across the busbar  202  that couples Module n-1 and Module n. In some examples, more than one battery monitor  132  can be configured to sense a voltage across a same busbar  202 . 
       FIG.  3    is a circuit schematic diagram of a battery monitor  132  and wireless transceiver  136  of the BMS of  FIG.  1    in accordance with an example of this description. In some examples, the battery monitor  132  includes the wireless transceiver  136 , while in other examples the battery monitor  132  is adapted to be coupled to the wireless transceiver  136 . For simplicity, in the examples of  FIG.  3   , the battery monitor  132  is described as including the wireless transceiver  136 . 
     The battery monitor  132  is coupled to the battery module  108  and to a busbar  202 , which is coupled to one of the terminals of the battery module  108  as described above. The battery monitor  132  includes monitoring circuitry  302 , which is configured to monitor various parameter(s) of the battery module  108  (e.g., receive indications of the parameter(s)), which can include voltage, current, temperature, and parameters related to cell balancing within the battery module  108 . The monitored parameters, or indications thereof, are provided by the monitoring circuitry  302  to the wireless transceiver  136 , which in turn provides the indications thereof to the battery management controller  130  (e.g., wirelessly to the wireless transceiver  134  coupled to the battery management controller  130 ). 
     The battery monitor  132  (or the monitoring circuitry  302  thereof) also includes a busbar voltage circuit  304 , which is configured to receive an indication of the voltage across the busbar  202 . The busbar voltage circuit  304  is configured to provide a wakeup signal (e.g., a first signal) to the wireless transceiver  136  responsive to an indication that the voltage across the busbar  202  is greater than a first threshold value. The wakeup signal causes the wireless transceiver  136  to be in (e.g., transition to, or remain in) a higher-power state. In an example, the first threshold value to which the sensed voltage across the busbar  202  is compared is system-dependent. For example, the first threshold value is based on resistance characteristics of the busbar  202  being monitored, or an expected current drawn from the battery module  108  while the device  102  is on, or the EV/HEV  102  is operated (e.g., not in the power save state). 
     In some examples, the busbar voltage circuit  304  is also configured to provide a sleep signal (e.g., a second signal) to the wireless transceiver  136  responsive to an indication that the voltage across the busbar  202  is less than a second threshold value. The sleep signal causes the wireless transceiver  136  to be in (e.g., transition to, or remain in) a lower-power state. In some examples, the second threshold value is equal to the first threshold value, while in other examples, the second threshold value is less than the first threshold value (e.g., to provide a hysteretic control response). 
     The busbar voltage circuit  304  includes an analog-to-digital converter (ADC)  312  that is coupled to the busbar  202  and configured to receive the voltage across the busbar  202  (e.g., which is related to a current provided by the battery module  108  and the resistance of the busbar  202 ). The ADC  312  provides a digital value responsive to the voltage across the busbar  202 . The busbar voltage circuit  304  also includes a comparator  314 , which compares the digital value indicative of the busbar voltage to the first threshold value. The comparator  314  provides the wakeup signal to the wireless transceiver  136  of the battery monitor  132  responsive to the digital value from the ADC  312  being greater than the first threshold value, which indicates current is being drawn from the battery module  108 , sufficient to indicate that the device  102  is turning on. 
     In examples in which the busbar voltage circuit  304  is configured to provide the sleep signal, the comparator  314  is also configured to compare the digital value from the ADC  312  to the second threshold value. The comparator  314  provides the sleep signal to the wireless transceiver  136  of the battery monitor  132  responsive to the digital value from the ADC  312  being less than the second threshold value, which indicates that the current drawn from the battery module  108  is sufficiently low to indicate that the device  102  is entering a power save state (e.g., the EV/HEV  102  is parked). In some cases, the sleep signal is analogous to the wakeup signal being de-asserted (e.g., when the first threshold is equal to the second threshold). 
     In some examples, the wireless transceiver  136  includes a radio frequency (RF) core  306  and a digital core  308 . The RF core  306  and the digital core  308  can be implemented as separate processors, or as separate cores of a single processor. Regardless of the particular implementation of the RF core  306  and the digital core  308 , the cores  306 ,  308  are configured to communicate with each other. 
     The digital core  308  is configured to receive and process signals from the monitoring circuitry  302  (e.g., the monitoring circuitry  302  provides TX signals to the digital core  308 ), and to provide control signals and/or commands to the monitoring circuitry  302  (e.g., the monitoring circuitry  302  receives RX signals from the digital core  308 ). The digital core  308  is also configured to interface with the RF core  306 , such as to facilitate wireless communications. 
     The RF core  306  is configured to interface with an antenna  310  of the wireless transceiver  136  to transmit and receive wireless signals, such as to facilitate wireless communication with the wireless transceiver  134  of the battery management controller  130 . 
     In an example, when the wireless transceiver  136  is in the lower-power state, the RF core  306  provides reduced functionality (e.g., does not facilitate wireless communications). When the wireless transceiver  136  is in the higher-power state, the RF core  306  facilitates wireless communications. Accordingly, the RF core  306  consumes more power in the higher-power state of the wireless transceiver  136  than in the lower-power state of the wireless transceiver  136 . Because the wireless transceiver  136  transitions to the higher-power state responsive to a physical condition occurring (e.g., a voltage sensed across the busbar  202  being greater than a threshold), the RF core  306  does not remain active in the lower-power state, such as to poll the battery management controller  130  to determine when to wake up. This enables the RF core  306  to consume less power than in a situation in which polling to wake up is used. 
     In some examples, when the wireless transceiver  136  is in the lower-power state, the digital core  308  is also configured to provide reduced functionality, and thus consume less power. When the wireless transceiver  136  is in the higher-power state, the digital core  308  is configured to provide its normal functionality. 
     In at least some examples, the wireless transceiver  136  does not provide indications of monitored parameters of the battery module  108  to the battery management controller  130  responsive to being in the lower-power state. For example, because the RF core  306  provides reduced functionality in the lower-power state, and thus consumes less power, the RF core  306  does not facilitate wireless communications (including providing indications of a monitored parameter) with the battery management controller  130 . In these examples, the wireless transceiver  136  provides indications of the monitored parameters of the battery module  108  to the battery management controller  130  responsive to being in the higher power state. For example, because the RF core  306  provides normal functionality in the higher-power state, the RF core  306  facilitates wireless communications (including providing indications of a monitored parameter) with the battery management controller  130 . 
     In some examples, the wireless transceiver  136  is configured to receive a power off command from the battery management controller  130 . The power off command can be in addition to, or instead of, the sleep signal provided by the busbar voltage circuit  304 . For example, because the battery management controller  130  is aware of when the EV/HEV  102  is parked, or the device  102  is in a power save mode, the battery management controller  130  is configured to issue the power off command to the wireless transceiver  136  of the battery monitor  132 . The power off command causes the wireless transceiver  136  to be in (e.g., transition to, or remain in) the lower-power state. 
     Accordingly, the wireless transceiver  136  of the battery monitor  132  is configured to transition to a higher-power state responsive to receiving the wakeup signal, and to begin communicating with the wireless transceiver  134  of the battery management controller  130 . Because the wireless transceiver  136  of the battery monitor  132  transitions to the higher-power state responsive to a physical condition (e.g., a voltage across the busbar  202 ) that indicates the device  102  is itself turning on, the battery monitor  132  is able to begin communicating with the battery management controller  130  relatively quickly (e.g., on the order of 50 ms from busbar  202  voltage sensing to network formation, which can be less than a polling or scanning interval) after the device  102  turns on. 
     In some examples, the wireless transceiver  136  of the battery monitor  132  is configured to transition to the lower-power state responsive to the wakeup signal being de-asserted, or a sleep signal being provided (e.g., the busbar  202  voltage being below the voltage threshold, indicating the device  102  is in the power save mode, or EV/HEV  102  is parked). In other examples, the wireless transceiver  136  of the battery monitor  132  is configured to transition to the lower-power state responsive to the power off command from the battery management controller  130 , which is aware of the device  102  transitioning to the power save mode, or EV/HEV  102  being parked. 
     Accordingly, a power consumption of the battery monitor  132  is reduced responsive to the device  102  being in the power save mode (e.g., an EV/HEV  102  being parked). The battery monitor  132  power consumption is also lower than battery monitors that poll the battery management controller  130  to determine when to transition back to the higher-power state. Further, network including battery monitor(s)  132  and the battery management controller  130  is able to form relatively quickly responsive to the device  102  turning on (e.g., the EV/HEV  102  being operated by a user) because the wireless transceiver  136  of the battery monitor  132  transitions to the higher-power state responsive to a physical condition being sensed (e.g., the voltage across the busbar  202 ) that indicates the device  102  is turning on. 
     In some examples, the wireless transceiver  136  is configured to scan and/or listen on one or more RF configuration channels responsive to the wireless transceiver  136  waking up (e.g., transitioning to the higher-power state). Although the wireless transceiver  136  transitions to the higher-power state responsive to a physical condition being sensed (e.g., the voltage across the busbar  202 ) that indicates the device  102  is turning on, a microprocessor of the battery management controller  130  is aware of the state of the device  102  (e.g., whether the vehicle is parked, or a user desires to operate the vehicle). Accordingly, the battery management controller  130  is configured to cause its wireless transceiver  134  to enter a higher-power state responsive to the device  102  turning on. The wireless transceiver  134  is configured to send scan request(s) on the one or more RF configuration channels responsive to the wireless transceiver  134  waking up (e.g., transitioning to the higher-power state). The wireless transceiver  136  of the battery monitor  132  is configured to provide a scan response (e.g., on the one or more RF configuration channels) responsive to receiving scan request(s) from the battery management controller  130 . Subsequently, communication between the battery monitor  132  and the battery management controller  130  (e.g., through their respective wireless transceivers  136 ,  134 ) occurs on an RF data channel. In some examples, a network rejoining process is avoided because data exchanged during such a process (e.g., RF data channels to be used, key values, slot numbers, and the like) are already stored in a memory (e.g., a non-volatile memory) of the battery monitor  132  and/or the battery management controller  130 . 
       FIG.  4    is a flow chart of a method  400  for wireless battery management in accordance with an example of this description. The method  400  begins in block  402  with receiving a first indication of a voltage across a busbar that couples a first battery module of a battery pack to a second battery module of the battery pack. As described above, the battery monitor  132  (or the monitoring circuitry  302  thereof) includes the busbar voltage circuit  304 , which is configured to receive an indication of the voltage across the busbar  202 . For example, the ADC  312  is coupled to the busbar  202  and configured to receive the voltage across the busbar  202  (e.g., which is related to a current provided by the battery module  108  and the resistance of the busbar  202 ). The ADC  312  provides a digital value responsive to the voltage across the busbar  202 . 
     The method  400  continues in block  404  with causing a wireless transceiver of the battery monitor to be in a higher-power state responsive to the first indication being greater than a voltage threshold. As described above, the busbar voltage circuit  304  is configured to provide a wakeup signal (e.g., a first signal) to the wireless transceiver  136  responsive to an indication that the voltage across the busbar  202  is greater than a first threshold value (e.g., the voltage threshold). For example, the busbar voltage circuit  304  includes a comparator  314 , which compares the digital value indicative of the busbar voltage to the first threshold value. The comparator  314  provides the wakeup signal to the wireless transceiver  136  of the battery monitor  132  responsive to the digital value from the ADC  312  being greater than the first threshold value, which indicates current is being drawn from the battery module  108 , sufficient to indicate that the device  102  is turning on. The wakeup signal causes the wireless transceiver  136  to be in (e.g., transition to, or remain in) a higher-power state. In an example, the first threshold value to which the sensed voltage across the busbar  202  is compared is system-dependent. For example, the first threshold value is based on resistance characteristics of the busbar  202  being monitored, or an expected current drawn from the battery module  108  while the device  102  is on, or the EV/HEV  102  is operated (e.g., not in the power save state). 
     The method  400  continues in block  406  with wirelessly providing a second indication of a parameter of the first battery module responsive to the wireless transceiver being in the higher-power state. As described above, the battery monitor  132  includes monitoring circuitry  302 , which is configured to monitor various parameter(s) of the battery module  108  (e.g., receive indications of the parameter(s)), which can include voltage, current, temperature, and parameters related to cell balancing within the battery module  108 . The monitored parameters, or indications thereof, are provided by the monitoring circuitry  302  to the wireless transceiver  136 , which in turn provides the indications thereof to the battery management controller  130  (e.g., wirelessly to the wireless transceiver  134  coupled to the battery management controller  130 ). 
     In at least some examples, the wireless transceiver  136  does not provide indications of monitored parameters of the battery module  108  to the battery management controller  130  responsive to being in a lower-power state. For example, because the RF core  306  provides reduced functionality in the lower-power state, and thus consumes less power, the RF core  306  does not facilitate wireless communications (including providing indications of a monitored parameter) with the battery management controller  130 . In these examples, the wireless transceiver  136  provides indications of the monitored parameters of the battery module  108  to the battery management controller  130  responsive to being in the higher power state. For example, because the RF core  306  provides normal functionality in the higher-power state, the RF core  306  facilitates wireless communications (including providing indications of a monitored parameter) with the battery management controller  130 . 
     The term “couple” is used throughout the specification. The term may cover connections, communications, or signal paths that enable a functional relationship consistent with this description. For example, if device A generates a signal to control device B to perform an action, in a first example device A is coupled to device B, or in a second example device A is coupled to device B through intervening component C if intervening component C does not substantially alter the functional relationship between device A and device B such that device B is controlled by device A via the control signal generated by device A. 
     A device that is “configured to” perform a task or function may be configured (e.g., programmed and/or hardwired) at a time of manufacturing by a manufacturer to perform the function and/or may be configurable (or re-configurable) by a user after manufacturing to perform the function and/or other additional or alternative functions. The configuring may be through firmware and/or software programming of the device, through a construction and/or layout of hardware components and interconnections of the device, or a combination thereof. 
     A circuit or device that is described herein as including certain components may instead be adapted to be coupled to those components to form the described circuitry or device. For example, a structure described as including one or more semiconductor elements (such as transistors), one or more passive elements (such as resistors, capacitors, and/or inductors), and/or one or more sources (such as voltage and/or current sources) may instead include only the semiconductor elements within a single physical device (e.g., a semiconductor die and/or integrated circuit (IC) package) and may be adapted to be coupled to at least some of the passive elements and/or the sources to form the described structure either at a time of manufacture or after a time of manufacture, for example, by an end-user and/or a third-party. 
     While certain components may be described herein as being of a particular process technology, these components may be exchanged for components of other process technologies. Circuits described herein are reconfigurable to include the replaced components to provide functionality at least partially similar to functionality available prior to the component replacement. Components shown as resistors, unless otherwise stated, are generally representative of any one or more elements coupled in series and/or parallel to provide an amount of impedance represented by the shown resistor. For example, a resistor or capacitor shown and described herein as a single component may instead be multiple resistors or capacitors, respectively, coupled in parallel between the same nodes. For example, a resistor or capacitor shown and described herein as a single component may instead be multiple resistors or capacitors, respectively, coupled in series between the same two nodes as the single resistor or capacitor. 
     Uses of the phrase “ground voltage potential” in the foregoing description include a chassis ground, an Earth ground, a floating ground, a virtual ground, a digital ground, a common ground, and/or any other form of ground connection applicable to, or suitable for, the teachings of this description. Unless otherwise stated, “about,” “approximately,” or “substantially” preceding a value means +/- 10 percent of the stated value. Modifications are possible in the described examples, and other examples are possible within the scope of the claims.