Quiescent power supply

A quiescent power supply including an AC/DC converter, a switch, an energy storage device, and a controller is disclosed. The switch is electrically coupled to the AC/DC converter to electrically disconnect the AC/DC converter from an AC supply line. The controller is operably coupled to the switch to actuate the switch. In particular, the controller can actuate the switch to disconnect the switch during when the AC/DC converter is idle.

TECHNICAL FIELD

Examples described herein are generally related to power supplies and power controllers.

BACKGROUND

In general, all electrical devices draw an amount of current when plugged into an AC outlet. This is true even when the electrical device is not being used. For example, when a television is turned off it continues to consume power due to the electronics within the televisions power supply. This is often referred to as the “trigger current” or the current consumed by the transformer and/or electronics within the power supply. As another example, AC charger adapters have a small quiescent current when plugged into an AC outlet, even when no load is plugged into the AC charger.

DETAILED DESCRIPTION

The present disclosure provides a quiescent power supply to reduce, and in some examples eliminate, current drawn from an AC power source during periods of inactivity. Said differently, the quiescent power supply can disconnect itself from the AC power source when either no load is connected to the quiescent power supply or when a load is in an idle state.

Accordingly, the present disclosure provides a quiescent power supply to disconnect from an AC power source to increase an efficiency of energy usage, reduce an amount of energy consumed, and/or reduce a cost to operate the electronic device to which the quiescent power supply is attached.

A quiescent power supply according to the present disclosure can be implemented as a standalone AC power adapter or in an electronic device. For example, an electronic device (e.g., television, monitor, stereo equipment, printer, refrigerator, computer power supply, battery charger power supply, or the like) can be implemented with a quiescent power supply according to the present disclosure. It is noted, that no attempt is made to provide an exhaustive list of all electronic devices that can be implemented with a quiescent power supply according to the present disclosure. As such, the claims are not to be limited in this context.

FIG. 1illustrates an example quiescent power supply100. The quiescent power supply100includes an AC to DC converter110(“AC/DC converter”), an AC input line120, and a DC output line130. The quiescent power supply100also includes a quiescent controller140including a switch142, an energy storage device144, and logic146. The switch142is electrically coupled between the input line120and the AC/DC converter110.

The AC/DC converter110can be any converter to receive AC current from the AC input line120and output DC current on the DC output line130. The AC/DC converter110can be a switched-mode power supply, a rectifier, a mains power supply unit, or the like.

During operation, the switch142can electrically disconnect the AC/DC converter110from the AC input line120. Accordingly, the switch142can stop the flow of current from an AC power source (e.g., the power grid, an AC generator, or the like) into the AC/DC converter110. As such, current drawn by the quiescent power supply100in an idle mode can be reduced and/or eliminated.

The switch142can be any of a variety of switching devices to electrically couple and/or decouple the AC/DC converter110from the AC input line120. For example, the switch142can be a relay (e.g., a normally open relay, a normally closed relay, or the like), a semiconductor switch, a triode for alternating current (TRIAC), or the like.

In some examples, the energy storage device144is configured to provide power to the logic146and to actuate the switch142. Additionally, in some examples, the energy storage device144can provide trigger current to a load operably coupled to the quiescent power supply100. The energy storage device144can be any of a variety of device to store energy, such as, for example, a battery, a capacitor, a super capacitor, a fuel cell, or the like. In some examples, the energy storage device144can be a battery such as, for example, a rechargeable battery. The battery can be implemented with any of a variety of types of materials, such as, for example, lead-acid, nickel cadmium (NiCad), nickel metal hydride (NiMH), lithium ion (Li-ion), and lithium ion polymer (Li-ion polymer). Examples are not limited in this context. The energy storage device144can sized (e.g., physically, voltage capacity, current capacity, or the like) based on the application of the quiescent power supply.

The logic146is configured to control actuation of the switch142. In particular, the logic146can actuate the switch142to electrically disconnect the AC/DC converter110from the AC input line120. For example, the logic146can actuate the switch142to electrically disconnect the AC/DC converter110from the AC input line120when the quiescent power supply100is idle (e.g., refer toFIG. 6). The logic146can actuate the switch142to electrically connect the AC/DC converter110to the AC input line120. For example, the logic146can actuate the switch142to electrically connect the AC/DC converter110to the AC input line120when the quiescent power supply100is operational (e.g., refer toFIG. 7).

In some examples, the logic146can be configured to monitor the DC output line130to determine whether the quiescent power supply100is idle or is operational (e.g., refer toFIGS. 2-3). In some examples, the logic146can be triggered by an interrupt to determine whether the quiescent power supply100is idle or operational (e.g., refer toFIG. 4). For example, the logic146can receive a control signal (e.g., from a processing component, from a device operably coupled to the quiescent power supply100, or the like), the control signal to include an indication that the current on DC output line130is below a threshold current and/or that the quiescent power supply100is idle.

FIG. 2illustrates a block diagram of a quiescent power supply200. The quiescent power supply200includes the AC/DC converter110, the AC input line120, and the DC output line130. The quiescent power supply200also includes a quiescent controller240including the switch142, the energy storage device144, and logic246. The switch142is electrically coupled between the input line120and the AC/DC converter110. Additionally, the energy storage device144can be electrically coupled to the DC output line130. In particular, the DC output line130includes a converter supply line132and an energy storage device supply line134. The logic246is coupled to the DC output line130and the switch142and is operable to actuate the switch142to electrically couple and decouple the AC/DC converter110from the AC input line120. In particular, the logic246is configured to determine whether the quiescent power supply200is idle based on the converter supply line132and the energy storage device supply line134.

The logic246can determine that the quiescent power supply200is idle based on a determination that power consumption on the DC output line130has dropped below a threshold amount. Said differently, the logic246can determine whether the quiescent power supply200is idle based on a determination that power consumption of the target device, or the load on the quiescent power supply200, has dropped below a threshold amount.

The logic246can actuate the switch142to electrically decouple the AC/DC converter110from the AC input line120based on a determination that power consumption on the DC output line130has dropped below a threshold value. Additionally, the logic246can actuate the switch142to electrically couple the AC/DC converter110to the AC input line120based on a determination that power consumption on the DC output line130has risen above a threshold value. In some examples, the threshold values at which the AC/DC converter100is decoupled and coupled from the AC input line120may be the same. In some examples, the threshold values at which the AC/DC converter110is decoupled and coupled from the AC input line120may be the different. In some examples, the threshold at which the AC/DC converter110is decoupled from the AC input line120may be lower than the threshold at which the AC/DC converter110is coupled to the AC input line120.

It is noted, that the threshold value may be based on the load to which the quiescent power supply200is to be attached. However, to provide a clear disclosure only and not to be limiting, the threshold value may in some examples be between 0.1 milliamps and 250 milliamps.

Turning more particularly toFIG. 3, a portion of the quiescent power supply200is depicted in greater detail. In particular, the logic246and the connection between the logic246and the DC output line130is depicted in greater detail. As depicted, the quiescent power supply200can include a shut-off resistor252disposed in series between the AC/DC converter110(e.g., refer toFIG. 2) and the DC output line130. Said differently, the converter supply line132can include the shut-off resistor252. The quiescent power supply200can also include a turn-on resistor254disposed in series between the energy storage device144and the DC output line130. Said differently, the energy storage device supply line134can include the turn-on resistor254.

The logic246may be operably coupled to the shut-off resistor252and the turn-on resistor254to determine whether power consumption on the DC output line130has fallen below or risen above the threshold level(s). For example, the logic246can determine whether a voltage drop across the shut-off resistor252is below a threshold level to determine whether power consumption on the DC output line130has fallen below a threshold level. The logic246can determine whether a voltage drop across the turn-on resistor254is above a threshold level to determine whether power consumption on the DC output line130has risen above a threshold level.

In some examples, the logic246can include discrete and/or digital logic to actuate the switch142based on the voltage drops across the shut-off resistor252and turn-on resistor254. In some examples, the logic246can include a microcontroller to monitor the voltage drops (e.g., across resistors252/254), compare the voltage drops to a preset (or selectable) threshold, and actuate the switch142based on the comparison.

FIG. 4illustrates a block diagram of a quiescent power supply300. The quiescent power supply300includes the AC/DC converter110, the AC input line120, and the DC output line130. The quiescent power supply300also includes a quiescent controller340including the switch142, the energy storage device144, and logic346. The switch142is electrically coupled between the input line120and the AC/DC converter110. The logic346is coupled to the switch142and is operable to actuate the switch142to electrically couple and decouple the AC/DC converter110from the AC input line120.

The logic346additionally includes a control signal line360(e.g., an interrupt pin, or the like) to receive a control signal to include an indication of whether the quiescent power supply300is idle or not. In particular, the logic346can receive a control signal to include an indication that a load (not shown) coupled to the quiescent power supply300is idle. The logic346can receive a control signal346from a processor and/or logic within the load, or device to which the quiescent power supply300is coupled. For example, the quiescent power supply300can be implemented in a television. The television (e.g., a media device operably coupled to the television, or a remote control, or the like) may provide a control signal to the quiescent power supply300(e.g., applied to the control signal line360, or the like) during shutdown to include an indication that the quiescent power supply300is idle. The logic346may decouple the AC input line120from the AC/DC converter110to reduce and/or eliminate current drawn from the AC input line120. During the idle period (e.g., while the AC/DC converter110is decoupled from the AC input line120) the energy storage device144can provide trigger current to the television.

When the television is powered back on, the television may provide a control signal to the quiescent power supply300(e.g., applied to the control signal line360, or the like) during power up to include an indication that the quiescent power supply300is not idle. The logic346may couple the AC input line120to the AC/DC converter110to provide sufficient operating current to be drawn from the AC input line120for operation of the television.

It is worthy to note, that the television example given above is provided for clarity of presentation only and not to be limiting. The quiescent power supplies described herein can be implemented in any of a variety of electronic devices. Additionally, the control signal can be provided over any of a variety of interfaces. For example, the logic could receive the control signal via a USB Type-C interface.

FIG. 5illustrates a block diagram of an example logic500. The logic500can be implemented as the logic146, the logic246, and/or the logic346of the quiescent controllers100,200, and/or300. The logic500, at least a portion of which can be implemented in hardware, may include circuitry, discrete logic, digital logic, specially programmed processors, non-transient memory storing instructions to be executed by the specially programmed processors, or the like. The logic500includes a current measurement module510, an idle determination module520, and a switching module530. It is noted, that the logic500may optionally include the current measurement module. For example, as described above, in some examples, the logic may receive a control signal (e.g., interrupt, or the like) including an indication that the quiescent power supply is idle. Accordingly, in such an example, the logic500may not necessarily include the current measurement module510.

The current measurement module510can determine a current flowing through the DC output line130. In particular, the current measurement module510can determine a current flowing through the converter supply line132and/or the energy storage device supply line134. For example, the current measurement module510can determine a voltage drop across the shut-off resistor252to determine an amount of current flowing through the converter supply line132. The current measurement module510can determine a voltage drop across the turn-on resistor254to determine an amount of current flowing through the energy storage device supply line134.

It is worthy to note, the with some examples, the current measurement module510may optionally be implemented. More specifically, some examples (e.g., televisions, media players, or the like) can include circuitry to implement an idle and/or sleep control signal (e.g., main power button circuitry, or the like) to provide an indication that the device is idle.

The idle determination module520can determine whether the current (e.g., as measured by the current measurement module510, or the like) is less or greater than a threshold current to determine whether the quiescent power supply is in an idle mode or in an active mode (e.g., not in idle).

The switching module530can actuate the switch142to electrically decouple the AC/DC converter110from the AC input line120during while the quiescent power supply is idle or the electrically couple the AC/DC converter110to the AC input line120while the quiescent power supply is active (e.g., not idle).

FIG. 6illustrates an example logic flow600. The logic flow600can be implemented by the quiescent power supply, or the quiescent controller (e.g., the quiescent controller140, the quiescent controller240, the quiescent controller340, or the like) to decouple the AC/DC converter110from the AC input line120. It is noted, the logic flow600is described with reference to the quiescent power supply100ofFIG. 1. However, this is done for convenience and clarity only and not to be limiting.

The logic flow600may begin at block610. At block610“measure current on the DC output line” the controller140can determine the current on the DC output line130. Continuing to decision block620“is the current below a threshold value?” the controller140can determine whether the current on the DC output line130is below a threshold value. From decision block620, the logic flow600can continue to block630or return to block610. In particular, the logic flow600can continue from decision block620to block610based on a determination that the current on the DC output line130is not below the threshold value. Conversely, the logic flow600can continue from decision block620to block630based on a determination that the current on the DC output line130is below the threshold value.

At block630“disconnect the AC/DC converter from the AC input line,” the controller140can actuate the switch142to disconnect the AC/DC converter110from the AC input line120. Thus, the controller140can prevent current from being drawn from the AC supply line120during a period where the power supply is idle.

FIG. 7illustrates an example logic flow700. The logic flow700can be implemented by the quiescent power supply, or the quiescent controller (e.g., the quiescent controller140, the quiescent controller240, the quiescent controller340, or the like) to couple the AC/DC converter110to the AC input line120. It is noted, the logic flow700is described with reference to the quiescent power supply100ofFIG. 1. However, this is done for convenience and clarity only and not to be limiting.

The logic flow700may begin at block710. At block710“measure current on the DC output line” the controller140can determine the current on the DC output line130. Continuing to decision block720“is the current above a threshold value?” the controller140can determine whether the current on the DC output line130is above a threshold value. From decision block720, the logic flow700can continue to block730or return to block710. In particular, the logic flow700can continue from decision block720to block710based on a determination that the current on the DC output line130is not above the threshold value. Conversely, the logic flow700can continue from decision block720to block730based on a determination that the current on the DC output line130is above the threshold value.

At block730“connect the AC/DC converter from the AC input line,” the controller140can actuate the switch142to connect the AC/DC converter110from the AC input line120.

FIG. 8illustrates an example logic flow800. The logic flow800can be implemented by the quiescent power supply, or the quiescent controller (e.g., the quiescent controller140, the quiescent controller240, the quiescent controller340, or the like) to decouple and/or couple the AC/DC converter110to the AC input line120. It is noted, the logic flow800is described with reference to the quiescent power supply200ofFIGS. 2-3. However, this is done for convenience and clarity only and not to be limiting.

The logic flow800may begin at block810. At block810“measure current on the converter supply line” the logic246can determine the current on the converter supply line132. Continuing to decision block820“is the current below a threshold value?” the logic246can determine whether the current on the converter supply line132is below a threshold value. From decision block820, the logic flow800can continue to block830or return to block810. In particular, the logic flow800can continue from decision block820to block810based on a determination that the current on the converter supply line132is not below the threshold value. Conversely, the logic flow800can continue from decision block820to block830based on a determination that the current on the converter supply line132is below the threshold value.

At block830“disconnect the AC/DC converter from the AC input line,” the logic246can actuate the switch142to disconnect the AC/DC converter110from the AC input line120. Thus, the logic246can prevent current from being drawn from the AC supply line120during a period where the power supply is idle.

Continuing to block840“measure current on an energy storage device supply line” the logic246can determine the current on the energy storage device supply line134. Continuing to decision block850“is the current above a threshold value?” the logic246can determine whether the current on the energy storage device supply line134is above a threshold value. From decision block850, the logic flow800can continue to block860or return to block840. In particular, the logic flow800can continue from decision block850to block840based on a determination that the current on the DC output line130is not above the threshold value. Conversely, the logic flow800can continue from decision block850to block860based on a determination that the current on the energy storage device supply line134is above the threshold value.

At block860“connect the AC/DC converter from the AC input line,” the logic246can actuate the switch142to connect the AC/DC converter110from the AC input line120.

FIG. 9illustrates an example logic flow900. The logic flow900can be implemented by the quiescent power supply, or the quiescent controller (e.g., the quiescent controller140, the quiescent controller240, the quiescent controller340, or the like) to decouple and/or couple the AC/DC converter110to the AC input line120. It is noted, the logic flow900is described with reference to the quiescent power supply300ofFIG. 4. However, this is done for convenience and clarity only and not to be limiting.

The logic flow900may begin at block910. At block910“receive a control signal to include an indication that the quiescent power supply is idle” the logic346can receive a control signal (e.g., interrupt, or the like) on control signal line360, the control signal to include an indication that the quiescent power supply300is idle. Continuing to block920“disconnect the AC/DC converter from the AC input line,” the logic346can actuate the switch142to disconnect the AC/DC converter110from the AC input line120. Thus, the logic346can prevent current from being drawn from the AC supply line120during a period where the power supply is idle.

Continuing to block930“receive a control signal to include an indication that the quiescent power supply is not idle” the logic346can receive a control signal (e.g., interrupt, or the like) on control signal line360, the control signal to include an indication that the quiescent power supply300is not idle. Continuing to block940“connect the AC/DC converter from the AC input line,” the logic346can actuate the switch142to connect the AC/DC converter110from the AC input line120.

FIG. 10illustrates an example storage medium1000. As shown inFIG. 10, the storage medium includes a storage medium1000. The storage medium1000may comprise an article of manufacture. In some examples, storage medium1000may include any non-transitory computer readable medium or machine readable medium, such as an optical, magnetic or semiconductor storage. Storage medium1000may store various types of computer executable instructions, such as instructions to implement logic flow600, logic flow700, logic flow800, or logic flow900. Examples of a computer readable or machine readable storage medium may include any tangible media capable of storing electronic data, including volatile memory or non-volatile memory, removable or non-removable memory, erasable or non-erasable memory, writeable or re-writeable memory, and so forth. Examples of computer executable instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, object-oriented code, visual code, and the like. The examples are not limited in this context.

FIG. 11illustrates an example device1100. In some examples, as shown inFIG. 11, computing platform1100may include a processing component1140, storage medium1150, platform components1180, a communications interface1190and a quiescent power supply (e.g., the quiescent power supply100, the quiescent power supply200, the quiescent power supply300, or the like). Device1100may any of a variety of computing devices, such as, for example, a standalone power supply, a mobile device (e.g., smart phone, laptop, tablet, a wireless router, a docking station, a wireless charging station, or the like) a computing device (e.g., a display, desktop computer, a workstation computer, a server, or the like), an entertainment device (e.g., a television, a radio, a media player, powered speakers, or the like), an appliance (e.g., a range, a refrigerator, a washer, a dryer, a dishwasher, or the like), a tool (e.g., power tool, rechargeable tool, or the like).

In some examples, communications interface1090may include logic and/or features to support a communication interface. For these examples, communications interface1090may include one or more communication interfaces that operate according to various communication protocols or standards to communicate over direct or network communication links. Direct communications may occur via use of communication protocols or standards described in one or more industry standards (including progenies and variants) such as those associated with the PCIe specification. Network communications may occur via use of communication protocols or standards such those described in one or more Ethernet standards promulgated by IEEE. For example, one such Ethernet standard may include IEEE 802.3. Network communication may also occur according to one or more OpenFlow specifications such as the OpenFlow Hardware Abstraction API Specification. Network communications may also occur according to the Infiniband Architecture specification or the TCP/IP protocol.

A quiescent power supply comprising: a converter to convert an alternating current (AC) from an AC input line to a direct current (DC) and to provide DC current on a DC output line; a switch disposed in series between the AC input line and the converter; an energy storage device to provide power to actuate the switch; and a controller operably coupled to the switch and the DC output line, the controller to actuate the switch to electrically disconnect the converter from the AC input line.

The quiescent power supply of example 1, the controller to: determine whether power is needed on the DC output line; and actuate the switch to electrically disconnect the converter from the AC input line based on a determination that power is not needed on the DC output line.

The quiescent power supply of example 1, the controller to: determine whether power is needed on the DC output line; and actuate the switch to electrically connect the converter to the AC input line based on a determination that power is needed on the DC output line.

The quiescent power supply of example 1, the controller to: determine whether a current on the DC output line is less than a threshold value; and actuate the switch to electrically disconnect the converter from the AC input line based on a determination that the current on the DC output line is less than the threshold value.

The quiescent power supply of example 3, the controller to actuate the switch to electrically connect the converter to the AC input line.

The quiescent power supply of example 5, the controller to: determine whether a current on the DC output line is greater than the threshold value; and actuate the switch to electrically connect the converter to the AC input line based on a determination that the current on the DC output line is greater than the threshold value.

The quiescent power supply of example 6, the DC output line comprising: a converter supply line to electrically couple the converter to the DC output line; and a energy storage device supply line to electrically couple to the energy storage device to the DC output line.

The quiescent power supply of example 7, the converter supply line comprising a shut-off resistor disposed in series between the converter and the DC output line, the controller to: determine a voltage drop across the shut-off resistor; and determine whether a current on the DC output line is less than the threshold value based on the voltage drop across the shut-off resistor.

The quiescent power supply of example 7, the energy storage device supply line comprising a turn-on resistor disposed in series between the energy storage device and the DC output line, the controller to: determine a voltage drop across the turn-on resistor; and determine whether a current on the DC output line is above the threshold value based on the voltage drop across the turn-on resistor.

The quiescent power supply of example 1, the switch comprising a triode for AC (TRIAC), a normally open relay, or a normally closed relay.

The quiescent power supply of example 1, the energy storage device comprising a rechargeable battery, a capacitor, a super capacitor, or a fuel cell.

A system comprising: a platform component; and a quiescent power supply operably coupled to the platform component, the quiescent power supply comprising: a converter to convert an alternating current (AC) from an AC input line to a direct current (DC) and to provide DC current to the platform component via a DC output line; a switch disposed in series between the AC input line and the converter; an energy storage device to provide power to actuate the switch; and a controller operably coupled to the switch, the controller to actuate the switch to electrically disconnect the converter from the AC input line.

The system of example 12, the controller to: determine whether current is needed on the DC output line; and actuate the switch to electrically disconnect the converter from the AC input line based on a determination that current is not needed on the DC output line.

The system of example 12, the controller to: determine whether a current on the DC output line is less than a threshold value; and actuate the switch to electrically disconnect the converter from the AC input line based on a determination that the current on the DC output line is less than the threshold value.

The system of example 14, the controller to actuate the switch to electrically connect the converter to the AC input line.

The system of example 15, the controller to: determine whether a current on the DC output line is greater than the threshold value; and actuate the switch to electrically connect the converter to the AC input line based on a determination that the current on the DC output line is greater than the threshold value.

The system of example 16, the DC output line comprising: a converter supply line to electrically couple the converter to the DC output line; and a energy storage supply line to electrically couple to the energy storage device to the DC output line.

The system of example 17, the converter supply line comprising a shut-off resistor disposed in series between the converter and the DC output line, the controller to: determine a voltage drop across the shut-off resistor; and determine whether a current on the DC output line is less than the threshold value based on the voltage drop across the shut-off resistor.

The system of example 17, the energy storage device supply line comprising a turn-on resistor disposed in series between the energy storage device and the DC output line, the controller to: determine a voltage drop across the turn-on resistor; and determine whether a current on the DC output line is above the threshold value based on the voltage drop across the turn-on resistor.

The system of example 12, the switch comprising a triode for AC (TRIAC), a normally open relay, or a normally closed relay.

The system of example 12, the energy storage device comprising a rechargeable battery, a capacitor, a super capacitor, or a fuel cell.

The system of example 12, the platform component comprising one or more of a processing component, a graphics processing unit, a display, a speaker, or a light emitting diode.

A method comprising: determining whether a current on a direct current (DC) output line of a converter is less than a threshold value, the converter to convert an alternating current (AC) from an AC input line to DC and to provide DC current on the DC output line; actuating a switch to electrically disconnect the converter from the AC input line based on a determination that the current on the DC output line is less than the threshold value, the switch disposed in series between the AC input line and the converter; and providing trigger current to the DC output line from an energy storage device during a period when the AC input line is electrically disconnected from the converter.

The method of example 23, comprising: determining whether a current on the DC output line is greater than the threshold value; and actuating the switch to electrically connect the converter to the AC input line based on a determination that the current on the DC output line is greater than the threshold value.

The method of example 24, comprising: determining a voltage drop across a shut-off resistor, the shut-off resistor disposed in series between the converter and the DC output line; and determining whether a current on the DC output line is less than the threshold value based on the voltage drop across the shut-off resistor.

The method of example 24, comprising: determining a voltage drop across a turn-on resistor, the turn-on resistor disposed in series between the energy storage device and the DC output line; and determining whether a current on the DC output line is above the threshold value based on the voltage drop across the turn-on resistor.

The method of example 23, the switch comprising a triode for AC (TRIAC), a normally open relay, or a normally closed relay.

The method of example 23, the energy storage device comprising a rechargeable battery, a capacitor, a super capacitor, or a fuel cell.

An apparatus comprising a converter, a switch, an energy storage device, and a controller to perform the method of any one of examples 23 to 28.

At least one machine-readable storage medium comprising instructions that when executed by a controller, cause the controller to: determine whether a current on a direct current (DC) output line of a converter is less than a threshold value, the converter to convert an alternating current (AC) from an AC input line to DC and to provide DC current on the DC output line; actuate a switch to electrically disconnect the converter from the AC input line based on a determination that the current on the DC output line is less than the threshold value, the switch disposed in series between the AC input line and the converter; and provide trigger current to the DC output line from an energy storage device during a period when the AC input line is electrically disconnected from the converter.

The at least one machine-readable storage medium of example 30, comprising instructions that cause the controller to: determine whether a current on the DC output line is greater than the threshold value; and actuate the switch to electrically connect the converter to the AC input line based on a determination that the current on the DC output line is greater than the threshold value.

The at least one machine-readable storage medium of example 30, comprising instructions that cause the controller to: determining a voltage drop across a shut-off resistor, the shut-off resistor disposed in series between the converter and the DC output line; and determining whether a current on the DC output line is less than the threshold value based on the voltage drop across the shut-off resistor.

The at least one machine-readable storage medium of example 30, comprising instructions that cause the controller to: determining a voltage drop across a turn-on resistor, the turn-on resistor disposed in series between the energy storage device and the DC output line; and determining whether a current on the DC output line is above the threshold value based on the voltage drop across the turn-on resistor.

The at least one machine-readable storage medium of example 30, the switch comprising a triode for AC (TRIAC), a normally open relay, or a normally closed relay.

The at least one machine-readable storage medium of example 30, the energy storage device comprising a rechargeable battery, a capacitor, a super capacitor, or a fuel cell.