POWER SUPPLY AND METHOD FOR POWER SUPPLY BY MANAGING PEAK POWER CONSUMPTION

Abstract

Power supply comprising: a first power source (205) configured to supply electrical current to a first current output terminal (215) and to a second current output terminal (220); a second power source (210) with a voltage level lower than that of the first power source (205); and a control circuit (230) configured to: measure a load current supplied to the second current output terminal (220); compare the measured load current with a threshold value; in response to the detection that the measured load current is higher than the threshold value, connect the second power source (210) to the second current output terminal (220) to supply electrical current to it; disconnect the second power source (210) from the second current output terminal (220) in response to the detection that the measured load current is lower than the threshold value.Connecting the second power source (210) to the second power output terminal (220) to supply electrical current to it in response to the receipt of an external control signal indicating an expected peak load current consumption, and preventing the first power source (205) from supplying electrical current to the second power output terminal (220) when the measured load current is higher than the threshold value.

Description

BACKGROUND OF THE INVENTION

[0001] Many communication devices contain battery safety circuits that immediately shut down the devices if the peak current draw exceeds a threshold. For example, in a converged communication device, the combined use of a land-based mobile radio circuit for transmission and an operating system for booting can cause the peak current to exceed the battery pack's rated limits. List of characters

[0002] The accompanying illustrations, in which the same reference numerals refer to identical or functionally similar elements in the individual views, are included in the description together with the following detailed description and form part of it, serving to further illustrate embodiments and concepts that include the claimed invention and explain various principles and advantages of these embodiments. Fig. Figure 1 is a schematic diagram of a communication device, in accordance with some embodiments. Fig. 2 is a diagram of a power supply used in the communication device of Fig. 1 is included, in accordance with some embodiments. Fig. 3 is a schematic of a control circuit used in the power supply of Fig. 2 is included, in accordance with some embodiments. Fig. 4 is a schematic of a current source selector used in the control circuit of Fig. 3 is included, in accordance with some embodiments. Fig. Figure 5 is a schematic of a current source selector used in the control circuit of Fig. 3 is included, in accordance with some embodiments. Fig. Figure 6 is a scheme of a control circuit with an OR gate, in accordance with some embodiments. Fig. Figure 7 is a scheme of a power supply including a trickle charge circuit, in accordance with some embodiments. Fig. Figure 8 is a flowchart of a method for providing power, in accordance with some embodiments.

[0003] Experts will recognize that elements in the figures are illustrated for the sake of simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated compared to other elements to help improve the understanding of embodiments of the present invention.

[0004] Where appropriate, the apparatus and process components have been represented by conventional symbols in the drawings, showing only those specific details essential for understanding the embodiments of the present invention, so as not to obscure the disclosure with details that are readily apparent to those skilled in the art who benefit from this description. DETAILED DESCRIPTION OF THE INVENTION

[0005] A battery pack in a communication device can be damaged if the device's peak current draw exceeds the battery pack's rated limits for an extended period. As mentioned earlier, many communication devices include a battery safety circuit that immediately shuts down the device if the peak current draw exceeds a certain threshold. It is desirable to manage the peak current draw in a communication device without interrupting its operation.

[0006] One approach to better managing peak current draw in a communications device is to improve load efficiency. For example, more power-efficient components can be used to reduce overall peak current draw. However, simply reducing overall peak current draw may still result in peak current draw exceeding the battery pack's rated limits. Furthermore, more power-efficient components may be more expensive and less reliable than less power-efficient components. Additionally, the duration of a peak current event in a communications device is often short (for example, around 10 seconds). Therefore, rather than trying to avoid peak current events in a communications device, it is preferable to manage peak current draw in such a way that the communications device can continue to operate without damaging the battery.

[0007] The embodiments presented here manage, among other things, the peak current consumption in a communication device by adding a secondary power source that supplies electrical current only when the peak current consumption exceeds the nominal limits of the primary power source. With such embodiments, a communication device is able to function during peak current events without damaging the battery and without being switched off.

[0008] An exemplary embodiment provides a power supply. The power supply comprises a first power source, a second power source, and a control circuit. The first power source supplies electrical current to a first power output terminal. The first power source also supplies electrical current to a second power output terminal. The second power source has a voltage level that is lower than that of the first power source. The control circuit is configured to measure a load current supplied to the second power output terminal. The control circuit is also configured to compare the measured load current to a threshold value. Upon detecting that the measured load current is higher than the threshold value, the control circuit is configured to connect the second power source to the second power output terminal to supply electrical current to it.

[0009] Another exemplary embodiment provides a method for supplying power. The method comprises supplying electrical current from a first power source to a first current output terminal and to a second current output terminal. The method also comprises measuring, with a control circuit, a load current supplied to the second current output terminal. The method further comprises comparing, with the control circuit, the measured load current with a threshold value. The method also comprises connecting, with the control circuit, a second power source to the second current output terminal to supply electrical current to it in response to the detection that the measured load current is higher than the threshold value. The second power source has a voltage level that is lower than that of the first power source.

[0010] To simplify the description, some or all of the example systems presented here are illustrated with a single instance of each of their components. Some examples may not describe or illustrate all components of the systems. Other example implementations may contain more or less of each of the depicted components, combine some components, or include additional or alternative components.

[0011] Fig. Figure 1 is a diagram of an example communication device. 100 In the illustrated embodiment, the communication device contains 100 an electronic processor 105 , a storage 110 , an input / output interface 115 , a baseband processor 120 , a transceiver 125 , an antenna 130 , a microphone 135 , a loudspeaker 140 , an advertisement 145 and a power supply 150The components shown are coupled together with other various modules and components by or via one or more electrical connections (for example, control or data buses) that enable communication between them. The use of such connections, including control and data buses, for the connection and exchange of information between the various modules and components would be obvious to a person skilled in the art. In some embodiments, the communication device includes 100 fewer or additional components, in configurations that differ from those in Fig. The two depicted ones differ. For example, the communication device contains 100 In some embodiments, multiple microphones, multiple loudspeakers, or combinations thereof.

[0012] The electronic processor 105 receives and delivers information (for example, from memory). 110and / or the input / output interface 115 ) and processes the information by executing one or more software instructions or modules, which are located, for example, in a Random Access Memory (“RAM”) area of ​​the memory. 110 or a read-only memory ("ROM") of the memory 110 or other non-volatile, computer-readable media (not shown). The software may contain firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. The electronic processor 105 is configured to, among other things, retrieve software related to the control processes and procedures described here from memory 110 retrieves and executes the memory. 110It can contain one or more non-volatile, computer-readable media and comprises a program memory area and a data memory area. The program memory area and the data memory area can comprise combinations of different types of memory, as described herein. In the illustrated embodiment, the memory stores 110 including an operating system 155 In some implementations, the operating system 155 a version or derivative of the Android® mobile operating system (developed by Google, LLC).

[0013] The input / output interface 115 It is configured to receive input and provide system output. The input / output interface 115 Receives information and signals from and delivers information and signals to (for example, via one or more wired and / or wireless connections) devices both internally and externally to the communication device.100 .

[0014] The electronic processor 105 is configured to use the baseband processor 120 and the transceiver 125 It controls the sending and receiving of voice and other data to and from other communication devices. The baseband processor 120 encodes and decodes digital data received from the transceiver 125 sent and received. The transceiver 125 It sends and receives radio signals to and from, for example, a network, using the antenna. 130 The electronic processor 105 , the baseband processor 120 and the transceiver 125They can contain various digital and analog components, which are not described here for the sake of brevity and which can be implemented in hardware, software, or a combination of both. Some embodiments contain separate transmitting and receiving components, for example, a transmitter and a receiver, instead of a combined transceiver. 125 .

[0015] The microphone 135 is a transducer that is able to detect sound, convert the sound into electrical signals, and send the electrical signals to the electronic processor. 105 to transfer. The electronic processor 105 processes the signal from the microphone 135 received electrical signals to generate an audio stream that is transmitted via the transceiver 125 can be transmitted to other devices. The speaker 140is a converter for the audio reproduction of electrical signals (for example, generated from a received audio stream) that are processed by the electronic processor 105 be received. The microphone 135 and the speaker 140 They support both ultrasonic and audible frequencies. In some versions, the microphone has... 135 and the speaker 140 Individual transducers that support both ultrasonic and audible frequencies. Alternatively, some models include a microphone. 135 and the speaker 140 equipped with separate transducers for ultrasonic and audible frequencies. In some embodiments, the microphone can 135 , the loudspeaker 140 or both may be integrated together with the other components in a single housing (for example, in a converged device). In some embodiments, the microphone 135 , the loudspeaker 140or both are provided in an additional device (for example, a remote speaker microphone (RSM)) that connects to the communication device via a wired or wireless connection 100 is connected.

[0016] The display 145 A suitable display is required, for example, a liquid crystal display (LCD) touchscreen or an organic light-emitting diode (OLED) touchscreen. In some embodiments, the communication device implements 100 a graphical user interface (GUI) (for example, generated by the electronic processor) 105 using the operating system 155 , which is in memory 110 is stored, and displays it on the screen. 145 (dar), which allows a user to communicate with the communication device 100 to interact.

[0017] The power supply 150 supplies the communication device 100 with electricity. Fig. 2 shows the power supply150 schematically and in more detail. In the given example, the power supply includes 150 a first power source 205 , a second power source 210 , a first power output connection 215 , a second power output connector 220 , a power or electrical reference connection 225 , a control circuit 230 and a power converter circuit 235 .

[0018] The first power source 205 (For example, a primary power source) includes, for example, a battery cell, one or more batteries, a battery pack (including a multitude of battery cells connected in series, parallel, or both configurations), or a combination thereof. The second power source 210(For example, an auxiliary power source) contains, for example, a battery or accumulator cell, one or more accumulators, a battery pack (including a multitude of accumulator cells connected in series, parallel, or both configurations), a supercapacitor, or a combination thereof. The second power source 210 has a lower voltage level than the first power source 205 For example, the second power source 210 a voltage level between 3 volts and 4.2 volts and the first power source 205 to supply a voltage level between 6 volts and 8.4 volts. As another example, the second power source can 210 a battery pack with one battery cell and the first power source 205 It contains a battery pack with three battery cells. In some embodiments, the voltage level of the first power source is 205 at least twice as high as that of the second power source 210 .

[0019] The first power output connection 215 and the second power output connector 220 Voltage rails can be used to supply components within the communication device. 100 with two different voltages. In some embodiments, the second current output terminal has 220 a rail voltage that is lower than the rail voltage of the first current output terminal 215 For example, the rail voltage of the second current output terminal can 220 between 3 volts and 4.2 volts, and the rail voltage of the first current output terminal 215 The voltage can range between 6 volts and 8.4 volts. The power reference connection 225 includes, for example, a system ground connection.

[0020] The power converter circuit 235 converts the power from the first power source 205supplied voltage converted to a lower voltage for the second current output terminal 220 um. In some embodiments, the power converter circuit includes 235 a step-down regulator.

[0021] In some situations, the peak power consumption of the communication device exceeds the limit. 100 the nominal limits of the first power source 205 For example, the peak power consumption of the communication device 100 the nominal limits of the first power source 205 exceeding the limits when the electronic processor 105 the operating system 155 boots while the transceiver 125 Signals via the antenna 130 transmits. Using the power supply techniques described here, the control circuit detects 230 Peak electricity consumption events and supplies electricity from the second power source 210 , so that the peak power consumption exceeds the nominal limits of the first power source 205does not exceed.

[0022] To detect peak power consumption or the potential for peak power consumption, the control circuit 230 configured to measure the load current supplied by the first power source 205 to the second power output terminal 220 is delivered. As described in more detail below, the control circuit couples 230 the second power source 210 electrically to the second power output terminal 220 , to supply this electrical current when the measured load current is greater than a threshold.

[0023] Fig. 3 is a diagram showing the processing hardware and the operation of the control circuit. 230 illustrated. The control circuit 230 , as in Fig. 3 shown, includes a current detector 305 , a level detector 310 and a power source selector 315To simplify the description, it includes Fig. 3 functions (for example, the level detector) 310 ), which can be implemented in hardware and software, as well as hardware components of the control circuit 230 In some embodiments, all (or some) of the functions of the control circuit described here are 230 by an electronic processor (similar to the electronic processor) 105 ) (for example, using software stored in memory), hardware, or a combination of both.

[0024] The current detector 305 is configured to measure the load current supplied to the second power output terminal 220 is supplied. In some embodiments, the current detector includes 305 a current-sensing resistor and a differential amplifier with two input terminals. The resistor is connected between the current source selector. 315and the second power output connector 220 The resistors are connected in series. The first input terminal of the amplifier is connected to the first electrode of the resistor. The second input terminal of the amplifier is connected to the second electrode of the resistor. The amplifier outputs a signal that corresponds to the load current of the second output terminal. 220 displays.

[0025] The level detector 310 receives the signal from the current detector 305 The measured load current is compared to a threshold value. In some embodiments, the threshold value is set based on the threshold for a current protection circuit, which is present in some embodiments of the communication device. 100 is planned. The threshold value can be, for example, 2 milliamperes. The level detector 310It outputs a signal indicating whether the measured load current is greater than the threshold value. In some embodiments, the level detector outputs 310 It outputs a different signal depending on whether the measured load current is greater than the threshold. For example, the level detector can 310 Output a first voltage signal if the measured load current is greater than the threshold, and a second voltage signal if the measured load current is less than the threshold. In alternative embodiments, the level detector outputs 310 It only outputs a signal if the measured load current is greater than the threshold. In other words, the level detector 310 It does not output a signal if the measured load current is less than or equal to the threshold value.

[0026] The power source selector 315 selectively connects the second power source 210 with the second power output connection 220, based on the level detector 310 output signal. The current source selector 315 connects the second power source 210 with the second power output connection 220 , when the level detector 310 It detects that the measured load current is greater than the threshold value. Furthermore, the current source selector disconnects. 315 the second power source 210 from the second power output terminal 220 , when the level detector 310 determines that the measured load current is less than or equal to the threshold value.

[0027] Fig. Figure 4 is a diagram of an example implementation of the current source selector. 315 The one in Fig. 4 current source selectors shown 315 includes a load switch 405 , a first Schottky diode 410 and a second Schottky diode 415 In some embodiments, the load switch includes 405an electronic relay. The load switch 405 connects the second power source 210 with the second power output connection 220 , when the level detector 310 determines that the measured load current is greater than the threshold value. Furthermore, the load switch disconnects. 405 the second power source 210 from the second power output terminal 220 , when the level detector 310 determines that the measured load current is less than or equal to the threshold value.

[0028] The first and second Schottky diodes 410 and 415 They act together as a power OR logic circuit between the power from the first power source. 205 supplied electric current and that from the second power source 210supplied electrical current. The low forward voltage and fast recovery time of a Schottky diode offer increased efficiency. In some embodiments, the first and second Schottky diodes are 410 and 415 replaced by an ideal diode OR device that uses field-effect transistors to provide very low voltage drops.

[0029] The first and second Schottky diode 410 and 415 are in the power source selector 315 configured so that the second power output connector 220 not simultaneously drawing electric current from the first power source 205 and the second power source 210 receives. When the first power source 205 electric current to the first Schottky diode 410 and the second power source 210 electric current to the second Schottky diode 415delivers, the power OR logic circuit (formed by the first and second Schottky diodes) delivers 410 and 415 ) only electrical current to the second power output terminal 220 , from the power source with the higher supply voltage. For example, the first power source supplies 205 3.6 volts and the second power source 210 4.2 volts, and only the second power source 210 supplies electrical current to the second power output terminal 220 In some designs, the power supply reduces 150 those from the first power source 205 supplied voltage (for example, a first voltage) to a lower voltage (for example, a second voltage) that is lower than that from the second power source 210 supplied voltage (for example, a third voltage). If, for example, the voltage from the second power source 210The supplied voltage is 4.2 volts, the power converter circuit 235 one of the first power source 205 Convert the supplied voltage of 7.2 volts to a voltage of 3.6 volts. In this way, the power supply prevents 150 that the first power source 205 electrical current to the second power output terminal 220 delivers when the second power source 210 electrical current to the second power output terminal 220 delivers. In other words, the power supply 150 prevents the first power source 205 the second power output connection 220 supplied with electrical current when the measured load current is higher than the threshold.

[0030] Fig. Figure 5 is a diagram of another example implementation of the current source selector. 315 The one in Fig. 5 current source selectors shown 315It comprises a negative-channel metal-oxide-semiconductor (NMOS) transistor 505 and a positive-channel metal-oxide-semiconductor (PMOS) transistor 510. The level detector 310 sends a signal to the NMOS and PMOS transistors 505 and 510 , which includes the NMOS and PMOS transistors 505 and 510 caused either the first power source 205 or the second power source 210 with the second power output connection 220 to connect. If the measured load current is greater than the threshold, the level detector sends a signal. 310 a signal (for example, a logic HIGH signal) that activates the NMOS transistor 505 caused the first power source 205 from the second power output terminal 220 to separate, and that the PMOS transistor 510 caused the second power source 210 with the second power output connection 220 to connect. Conversely, the level detector sends310 , if the measured load current is less than the threshold, a signal (for example, a logic LOW signal) is sent to the NMOS transistor 505 caused the first power source 205 with the second power output connection 220 to connect, and that the PMOS transistor 510 caused the second power source 210 from the second power output terminal 220 to separate.

[0031] In some embodiments, the control circuit 230 configured to use the second power source 210 with the second power output connection 220 connects to supply it with electrical current in response to receiving an external control signal. For example, the control circuit can 230 in response to the receipt of an external control signal from the electronic processor 105 is sent, the second power source 210with the second power output connection 220 connect. In some embodiments, the external control signal indicates that there is a peak current draw in the communication device. 100 This is to be expected. The external control signal can be maintained until it is determined that the peak power consumption event has ended. Fig. 6 is an example diagram for the power supply 150 , in which the control circuit 230 additionally an OR gate 605 includes the OR gate. 605 receives a signal from the level detector 310 Additionally, the OR gate receives 605 an external control signal, for example from the electronic processor 105 The OR gate 605 sends a signal that activates the power source selector. 315 caused the second power source 210 with the second power output connection 220 to connect if either the signal from the level detector 310or the external control signal the OR gate 605 caused this.

[0032] In some versions, the power supply includes 150 also a trickle charge circuit 705 , as in Fig. Figure 7 shows the trickle charge circuit. 705 (for example, a low-rate charger) supplies a relatively small amount of electrical current (i.e., charging current) from the first power source. 205 to the second power source 210 , to determine the charge level of the second power source 210 to maintain at (or near) the highest capacity when the second power source 210 is not in use. In some embodiments, the charging current of the trickle charge circuit is 705 partly based on the voltage capacity of the second power source 210 , a predetermined number of high-current events, or both. Generally, the total load current of the second current output terminal should be220 be less than or equal to the charging current over a certain period of time in order to use the second power source 210 to keep it charged. For example, if the communication device 100 The communication device experiences 2-ampere peak values ​​that last 3 seconds and occur every 2 minutes. 100 an average of 50 milliampere-hours (mAh) of the capacity of the second power source per hour 210 In this situation, the charging current of the trickle charge circuit can 705 It must be set to no less than 50 milliamperes. For example, the charging current of the trickle charge circuit can be set to... 705 can be set to 100 milliamperes or 200 milliamperes.

[0033] Fig. Figure 8 illustrates an example procedure 800 for the operation of the power supply 150 for power supply. The procedure 800 will be in relation to the Fig. 2 and Fig. 3 described. The procedure 800is considered to be connected to the power supply 150 and, in particular, with the control circuit 230 The procedure is described below. However, it should be understood that in some embodiments parts of the process are carried out differently. 800 can be performed by other devices, including, for example, another device located in the communication device 100 is included.

[0034] In block 805 the first power source 205 electrical current to the first power output terminal 215 and to the second power output terminal 220 For example, the first power source supplies 205 a first rail voltage to the first current output terminal 215 The first power source 205 It also supplies a second rail voltage to the second power output terminal. 220 , via the power converter circuit 235 .

[0035] In block 810The control circuit measures 230 a load current that is connected to the second current output terminal 220 is delivered. For example, the current detector measures 305 the control circuit 230 the load current that goes to the second current output terminal 220 is delivered, and it sends a signal to the level detector. 310 from which the measured load current is displayed.

[0036] In block 815 compares the control circuit 230 The measured load current is measured against a threshold value. For example, the level detector receives... 310 the signal from the current detector 305 , which displays the measured load current, and it compares the measured load current with a threshold value.

[0037] In block 820 The control circuit detects 230 , if the measured load current is higher than the threshold value. For example, the level detector detects 310based on comparing the measured load current with the threshold value, if the measured load current is higher than the threshold value.

[0038] In response to the detection that the measured load current is higher than the threshold, the control circuit connects 230 , in block 825 , the second power source 210 with the second power output connection 220 , in order to supply this electrical current. In response to the level detector 310 If the level detector determines that the measured load current is higher than the threshold, it sends a signal. 310 for example, a signal to the power source selector 315 , which causes the power source selector 315 the second power source 210 with the second power output connection 220 connects.

[0039] When the load current falls below the threshold again, the control circuit disconnects. 230the second power source 210 from the second power output terminal 220 In some embodiments, the control circuit disconnects 230 the second power source 210 from the second power output terminal 220 immediately after it is detected that the load current has fallen below the threshold again. In alternative embodiments, the control circuit connects 230 the second power source 210 with the second power output connection 220 , in order to supply this continuous electrical current for at least a predetermined period of time after it has been detected that the measured load current is higher than the threshold. For example, the control circuit connects 230 the second power source 210 with the second power output connection 220, to continuously supply it with electrical current for 100 milliseconds after it has been determined that the measured load current is higher than the threshold.

[0040] Embodiments of the invention can be advantageously implemented to solve peak current problems in convergent communication devices. For example, in convergent communication devices combining a land mobile radio (LMR) platform with an Android platform, peak currents caused by both the LMR platform (e.g., during transmission) and the Android platform (e.g., during boot-up) can add up and exceed the nominal limits of the battery pack. This, in turn, can trigger the battery safety circuits, and the convergent communication device is immediately shut down. Embodiments of the invention address this problem by providing a secondary power source for better control of peak currents.

[0041] Specific embodiments have been described in the preceding specification. However, it is clear to those skilled in the field that various modifications and changes can be made without departing from the spirit of the invention, as set out in the claims below. Accordingly, the specification and the figures are to be understood in an illustrative rather than a restrictive sense, and all such modifications are to be included within the scope of protection of the present teachings.

[0042] The benefits, advantages, problem solutions, and any conceivable element that leads to or enhances any benefit, advantage, or solution shall not be construed as critical, necessary, or essential features or elements of any claim or all claims. The invention is defined exclusively by the attached claims, including any amendment made during the pendency of the present application and all equivalents of such claims as published.

[0043] Furthermore, in this document, relational expressions such as first and second, above and below, and the like are to be used solely to distinguish one entity or action from another, without necessarily requiring or implying any actual relationship or order between such entities or actions. The expressions "includes," "comprising," "has," "having," "include," "containing," "containing," or any variation thereof are to cover non-exclusive inclusion, so that a process, procedure, article, or device that includes, has, includes, or contains a list of elements may not only include such elements but may also include other elements not expressly listed or inherent in such processes, procedures, articles, or devices. An element that continues with "includes... a," "has..."The terms "one," "includes... one," or "contains... one" do not, without further stipulations, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprise, have, include, or contain the element. The terms "one" and "a" are defined as one or more unless explicitly stated otherwise herein. The terms "essentially," "essentially," "approximately," "about," or any other version thereof are defined as "being close to" as is clear to those skilled in the art, and in one non-limiting embodiment, the term is defined as being within 20%, in another embodiment within 10%, in another embodiment within 2%, and in yet another embodiment within 1%. The term "coupled," as used herein, is defined as "connected," although not necessarily directly and not necessarily mechanically.A device or structure that is “configured” in a certain way is configured at least in that way, but may also be configured in at least one other way not listed.

[0044] It is desired that some embodiments include one or more generic or specialized processors (or “processing devices”), such as microprocessors, digital signal processors, custom processors and freely programmable field-gate arrays (FPGAs) and unique stored program instructions (comprising both software and firmware) that control the one or more processors to implement, in conjunction with certain non-processor circuitry, some, most or all of the functions of the method and / or device described herein.Alternatively, some or all functions can be implemented by a state machine that has no stored program instructions, or in one or more application-specific integrated circuits (ASICs) where each function, or some combinations of certain functions, are implemented as custom logic. Naturally, a combination of the two approaches can be used.

[0045] Furthermore, an embodiment can be implemented as a computer-readable storage medium containing computer-readable code stored thereon for programming a computer (which, for example, includes a processor) to perform a method described and claimed herein. Examples of such computer-readable storage media include, but are not limited to: a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (read-only memory), a PROM (programmable read memory), an EPROM (erasable programmable read memory), an EEPROM (electrically erasable programmable read memory), and flash memory.Furthermore, it can be expected that a person skilled in the art, regardless of possible considerable effort and a large selection of designs, which is justified, for example, by available time, current technology and economic considerations, guided by the concepts and principles disclosed herein, will be able to produce such software instructions, programs and ICs with minimal experimental effort.

[0046] The summary of the disclosure is provided to allow the reader to quickly grasp the nature of the technical disclosure. It is submitted with the understanding that it is not intended to interpret or limit the spirit or meaning of the claims. Furthermore, it is clear from the preceding detailed description that various features in different embodiments are grouped together to streamline the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly stated in each claim. Rather, as is evident from the following claims, an inventive subject matter is present in fewer than all the features of any single disclosed embodiment.Thus, the following claims are integrated into the detailed description, with each claim standing alone as a separately claimed subject matter.

Claims

[1] Power supply which features: a first power source for supplying electric current to a first power output terminal and to a second power output terminal; a second power source with a voltage level lower than that of the first power source; and a control circuit configured to do the following: Measuring a load current supplied to the second current output terminal, Comparing the measured load current with a threshold value, and in response to the detection that the measured load current is higher than the threshold value, Connect the second power source to the second power output terminal to supply it with electrical current. [2] Power supply according to claim 1, wherein the control circuit is further configured to connect the second power source to the second power output terminal to continuously supply it with electrical current for at least a predetermined period of time after it has been determined that the measured load current is higher than the threshold. [3] Power supply according to claim 1, further comprising a maintenance charging circuit configured to supply electrical current from the first power source to the second power source. [4] Power supply according to claim 3, wherein a charging current of the maintenance charging circuit is determined partly on the basis of a voltage capacity of the second power source and a predetermined number of high current events. [5] Power supply according to claim 1, wherein the control circuit is further configured to connect the second power source to the second power output terminal to supply electrical current to it in response to the reception of an external control signal. [6] Power supply according to claim 1, wherein the voltage level of the first power source is at least twice as high as the voltage level of the second power source. [7] Power supply according to claim 1, wherein the power supply is configured to prevent the first power source from supplying electrical current to the second power output terminal when the measured load current is higher than the threshold. [8] Power supply according to claim 1, wherein the control circuit comprises: a current detector configured to measure the load current supplied to the second current output terminal, a level detector configured to compare the measured load current with the threshold value, and a current source selector configured to selectively connect the second current source to the second current output terminal to supply electrical current to it. [9] Power supply of claim 1, further comprising: a power converter circuit configured to convert a first voltage supplied by the first power source into a second voltage, where the second voltage is less than a third voltage supplied by the second power source. [10] Methods for providing electricity, comprising: Supplying electric current from a first power source to a first power output terminal and to a second power output terminal; Measuring, with a control circuit, a load current that is supplied to the second current output terminal; Compare, with the control circuit, the measured load current with a threshold value; and in response to the detection that the measured load current is higher than the threshold: Connect, with the control circuit, a second power source to the second power output terminal to supply this electric current, the second power source having a lower voltage level than the first power source. [11] The method of claim 10, further comprising: Connect the second power source to the second power output terminal of the control circuit to continuously supply it with electrical current for a predetermined period of time after it has been determined that the measured load current is higher than the threshold. [12] The method of claim 10, further comprising: Supplying electrical current from the first power source to the second power source using a trickle charge circuit. [13] Method according to claim 12, wherein a charging current of the maintenance charging circuit is determined partly on the basis of a voltage capacity of the second current source and a predetermined number of high current events. [14] The method of claim 10, further comprising: Connect, via the control circuit, the second power source to the second power output terminal to supply it with electrical current in response to the receipt of an external control signal. [15] Method according to claim 10, wherein the voltage level of the first current source is at least twice as high as the voltage level of the second current source. [16] The method of claim 10, further comprising: Prevent the first power source from supplying electrical current to the second power output terminal when the measured load current is higher than the threshold. [17] The method of claim 10, further comprising: Converting, using a power converter circuit, a first voltage supplied by the first power source into a second voltage, where the second voltage is less than a third voltage supplied by the second power source.