Power supply architecture with bidirectional battery idealization

A power management system for use in a device comprising a battery and one or more components configured to draw electrical energy from the battery may include a first power converter configured to electrically couple between charging circuity configured to provide electrical energy for charging the battery and the one or more downstream components and a bidirectional power converter configured to electrically couple between the charging circuitry and the battery, wherein the bidirectional power converter is configured to transfer charge from the battery or transfer charge from the battery based on a power requirement of the one or more components and a power available from the first power converter.

FIELD OF DISCLOSURE

The present disclosure relates in general to circuits for electronic devices, including without limitation personal audio devices such as wireless telephones and media players, and more specifically, a power supply architecture with bidirectional battery idealization.

BACKGROUND

Portable electronic devices, including wireless telephones, such as mobile/cellular telephones, tablets, cordless telephones, mp3 players, smart watches, health monitors, and other consumer devices, are in widespread use. Such a portable electronic device may include circuitry for implementing a boost converter for converting a battery voltage (e.g., provided by a lithium-ion battery) into a supply voltage delivered to one or more components of the portable electronic device. The power delivery network may also regulate such supply voltage, and isolate the downstream loads of these one or more devices from fluctuation in an output voltage of the battery over the course of operation.

SUMMARY

In accordance with the teachings of the present disclosure, one or more disadvantages and problems associated with existing approaches to power supply architectures may be reduced or eliminated.

In accordance with embodiments of the present disclosure, a power management system for use in a device comprising a battery and one or more components configured to draw electrical energy from the battery may include a first power converter configured to electrically couple between charging circuity configured to provide electrical energy for charging the battery and the one or more downstream components, and a bidirectional power converter configured to electrically couple between the charging circuitry and the battery, wherein the bidirectional power converter is configured to transfer charge from the battery or transfer charge from the battery based on a power requirement of the one or more components and a power available from the first power converter.

In accordance with these and other embodiments of the present disclosure, a method may include, in a device comprising a battery and one or more components configured to draw electrical energy from the battery receiving electrical energy from charging circuity configured to provide electrical energy for charging the battery at a first power converter configured to electrically couple between the charging circuity and the one or more downstream components. The method may also include transferring charge from the battery or transferring charge from the battery, by a bidirectional power converter configured to electrically couple between the charging circuitry and the battery, based on a power requirement of the one or more components and a power available from the first power converter.

In accordance with these and other embodiments of the present disclosure, a method may include, a device may include a battery, one or more components configured to draw electrical energy from the battery, and a power management system. The power management system may include a first power converter configured to electrically couple between charging circuity configured to provide electrical energy for charging the battery and the one or more downstream components, and a bidirectional power converter configured to electrically couple between the charging circuitry and the battery, wherein the bidirectional power converter is configured to transfer charge from the battery or transfer charge from the battery based on a power requirement of the one or more components and a power available from the first power converter.

DETAILED DESCRIPTION

FIG.1illustrates an example portable electronic device1, in accordance with embodiments of the present disclosure.FIG.1depicts portable electronic device1coupled to a headset3in the form of a pair of earbud speakers8A and8B. Headset3depicted inFIG.1is merely an example, and it is understood that portable electronic device1may be used in connection with a variety of audio transducers, including without limitation, headphones, earbuds, in-ear earphones, and external speakers. A plug4may provide for connection of headset3to an electrical terminal of portable electronic device1. Portable electronic device1may provide a display to a user and receive user input using a touch screen2, or alternatively, a standard liquid crystal display (LCD) may be combined with various buttons, sliders, and/or dials disposed on the face and/or sides of portable electronic device1.

FIG.2illustrates a block diagram of selected components integral to portable electronic device1, in accordance with embodiments of the present disclosure. As shown inFIG.2, portable electronic device1may include a battery charger16, a power converter10, a battery22, a power converter20A, and one or more downstream components18.

Battery charger16may include any system, device, or apparatus configured to charge a battery, for example by delivering electrical energy to a battery in order that such battery converts the electrical energy to chemical energy that is stored in such battery. In some embodiments, battery charger16may include a wired charger configured to draw electrical energy from an electrical power outlet or from a power bank. In other embodiments, battery charger16may include a wireless charger configured to draw electrical energy via inductive coupling from a wireless charging pad or similar device. In some embodiments, a portable electronic device1may include both a wired charger and a wireless charger.

Power converter10may include any system, device, or apparatus configured to receive a charger voltage VCHARGE(e.g., 5 volts, 9 volts, 20 volts) output by battery charger convert such charger voltage VCHARGEinto a supply voltage VSUPPLY(e.g., 5 volts). In some embodiments, power converter10may comprise a buck converter that may convert charger voltage VCHARGEinto supply voltage VSUPPLYequal to or less than charger voltage VCHARGE. In these and other embodiments, power converter10may comprise a capacitive power converter or “charge pump.” In other embodiments, power converter10may comprise an inductor-based power converter.

Battery22may include any system, device, or apparatus configured to convert chemical energy stored within battery22to electrical energy for powering downstream components18of portable electronic device1. Further, battery22may also be configured to recharge, in which it may convert electrical energy received by battery22into chemical energy to be stored for later conversion back into electrical energy. For example, in some embodiments, battery22may comprise a lithium-ion battery.

Power converter20A may include any system, device, or apparatus configured to operate in a boost mode to receive battery voltage VBATgenerated by battery22and convert such battery voltage VBATinto supply voltage VSUPPLYgreater than or equal to battery voltage VBAT. In addition, as described in greater detail below, power converter20A may also operate bidirectionally, including a buck mode in which power converter20A may convert supply voltage VSUPPLYinto battery voltage VBATlesser than or equal to supply voltage VSUPPLYin order to recharge battery22.

Downstream components18of portable electronic device1may include any suitable functional circuits or devices of portable electronic device1, including without limitation processors, audio coder/decoders, amplifiers, display devices, etc. As shown inFIG.2, downstream components18may be powered from supply voltage VSUPPLYgenerated by either or both of power converter10and power converter20A.

FIG.3illustrates a block diagram of selected components of an example power converter20A, in accordance with embodiments of the present disclosure. Power converter20A may be used to implement power converter20A depicted inFIG.2.

As shown inFIG.3, power converter20A may include a plurality of inductive phases24(e.g., phases24A and24B). As shown inFIG.3, each inductive phase24may include a power inductor32, a first switch34, and a second switch36. AlthoughFIG.3depicts only two inductive phases24for the purposes of clarity and exposition, in some embodiments, power converter20A may have a single inductive phase24or may have more than two inductive phases24.

In operation in a boost mode, control circuitry30may periodically commutate first switches34(e.g., during a charging state of an inductive phase24) and second switches36(e.g., during a transfer state of an inductive phase24) of an inductive phase24by generating appropriate control signals P1,P1, P2, andP2, to boost battery voltage VBATto a higher supply voltage VSUPPLYat output capacitor38in order to regulate supply voltage VSUPPLYat a desired voltage level.

In addition, in operation in a buck mode, control circuitry30may periodically commutate second switches36(e.g., during a charging state of an inductive phase24) and first switches34(e.g., during a transfer state of an inductive phase24) of an inductive phase24by generating appropriate control signals P1,P1, P2, andP2, to buck supply voltage VSUPPLYto a lower battery voltage VBATin order to charge a battery (e.g. battery22) regulate supply voltage VSUPPLYat a desired voltage level.

Accordingly, control circuitry30may sense charger voltage VCHARGE, battery voltage VBAT, supply voltage VSUPPLY, and/or another suitable parameter associated with portable electronic device1and based thereon, determine in which mode it is to operate, and then operate in such mode. For example, when power available from battery charger16and power converter10is in excess of a power demanded by downstream components18, control circuitry30may operate power converter20A in the buck mode to deliver such excess power to battery22. As another example, when power available from battery charger16and power converter10is insufficient to supply the power demanded by downstream components18, control circuitry30may operate power converter20A in the boost mode to draw power from battery22.

Using such a power supply architecture such as that described above, in which an output of a charger path (e.g., battery charger16and power converter10) is coupled to supply voltage VSUPPLY, power converter20A may boost to downstream components18during discharge of battery22and buck to battery22during charging of battery22. The flexibility of placing bidirectional power converter20A between the electrical nodes for supply voltage VSUPPLYand battery voltage VBATas described above is that it may provide an ideal fixed voltage of supply voltage VSUPPLYfor both downstream components18and for the charger path (e.g., battery charger16and power converter10), thus presenting an idealized version of battery behavior to both downstream components18and the charger path. Because power converter20A may idealize battery22both during charging and discharge, power converter20A may be able to handle power distribution in complex scenarios such as that which may occur when power demanded by downstream components18exceeds that available from the charger path.

FIG.4illustrates a block diagram of selected components internal to portable electronic device1in an alternate embodiment1B of portable electronic device1, in accordance with embodiments of the present disclosure. In alternate embodiment1B, instead of power converter10directly generating supply voltage VSUPPLY, power converter10may generate intermediate supply voltage VSUPPLY′, which may be received by power converter20B as an input. Also as shown inFIG.4, power converter20B may be used in lieu of power converter20A.

FIG.5illustrates a block diagram of selected components of example power converter20B, in accordance with embodiments of the present disclosure. Power converter20B may be similar in many respects to power converter20A, except that in power converter20B, the node for intermediate supply voltage VSUPPLY′ may be coupled to the boost output of at least one inductive phase24A, the node for supply voltage VSUPPLYmay be coupled to the boost output of at least one inductive phase24B, and a bypass switch40may be interfaced between the nodes for intermediate supply voltage VSUPPLY′ and supply voltage VSUPPLY.

In the embodiments represented byFIGS.4and5, when battery22has insufficient state of charge, it may not be possible to boost from battery22at a high enough voltage to match intermediate supply voltage VSUPPLY′ generated by power converter10. Thus, in the case of portable electronic device1in which the output of power converter10is coupled to the boost output of power converter20A, the resultant difference in voltages generated by power converter10and power converter20A may cause an uncontrolled current to flow from the charger path (e.g., battery charger16and power converter10).

To overcome this problem, control circuitry30may control bypass switch40in either a bypass mode or split mode of power converter20B. In the bypass mode, power converter20B may operate as a single multiphase buck or boost converter (e.g., in either of the boost mode or buck mode as described above with respect to power converter20A). In the split mode, which may be activated when battery22is low on state of charge, power converter20B may be effectively split into two separate converters to allow bucking down from intermediate supply voltage VSUPPLY′ to battery voltage VBAT(in order to charge battery22) and then boosting battery voltage VBATup to at least a minimum voltage level for supply voltage VSUPPLY. Thus, power converter20B may be able to operate in the boost mode in situations in which state of charge of battery22is insufficient to support boosting to higher voltages. Operating supply voltage VSUPPLYat a lower voltage may reduce current demands by downstream components18.