The MAX1874 charges a single-cell Li+ battery from both USB and AC adapter sources. It also includes battery-to-input power switchover, so the system can be powered directly from the power source rather than from the battery.In its simplest application, the MAX1874 needs no external MOSFET or diodes, and accepts input voltages up to 6.5V; however, DC input overvoltage protection up to 18V can be added with a single SOT PFET.On-chip thermal limiting simplifies printed circuit board (PCB) layout and allows optimum charging rate without the thermal limits imposed by worst-case battery and input voltage. When the MAX1874 thermal limit is reached, the charger does not shut down but simply reduces charging current.Ambient or battery temperature can be monitored with an external thermistor. When the temperature is out of range, charging pauses.Other features include an active-low CHG output to indicate when battery current tapers below a predetermined level. DC power-OK (active-low DCOK), USB power-OK (active-low UOK), and power-on (PON) outputs indicate when valid power is present. These outputs drive logic or power-selection MOSFETs to disconnect the charging sources from the load and to protect the MAX1874 from overvoltage.The MAX1874 contains no logic for communication with the USB host. It must receive instructions from a local microcontroller. The MAX1874 is available in a 16-pin 5mm x 5mm thin QFN package and operates over the -40°C to +85°C temperature range.ApplicationsCell PhonesDigital CamerasPDAsWireless Appliances

The LTC4076 is a standalone linear charger that is capable of charging a single-cell Li-Ion battery from both wall adapter and USB inputs. The charger can detect power at the inputs and automatically select the appropriate power source for charging.No external sense resistor or blocking diode is required for charging due to the internal MOSFET architecture. Internal thermal feedback regulates the battery charge current to maintain a constant die temperature during high power operation or high ambient temperature conditions. The float voltage is fixed at 4.2V and the charge current is programmed with an external resistor. The LTC4076 terminates the charge cycle when the charge current drops below the user programmed termination threshold after the final float voltage is reached. The LTC4076 can be put into shutdown mode reducing the DCIN supply current to 20µA, the USBIN supply current to 10µA, and the battery drain current to less than 2µA even with power applied to both inputs.Other features include automatic recharge, undervoltage lockout, charge status output, power present status output to indicate the presence of wall adapter or USB power and high power/low power mode (C/5) for USB compatible applications.Applications Cellular Telephones Handheld Computers Portable MP3 Players Digital Cameras

The DS2762 high-precision Li+ battery monitor is a data-acquisition, information-storage, and safety-protection device tailored for cost-sensitive battery pack applications. This low-power device integrates precise temperature, voltage, and current measurement, nonvolatile (NV) data storage, and Li+ protection into the small footprint of either a TSSOP package or flip-chip package. The DS2762 is a key component in applications including remaining capacity estimation, safety monitoring, and battery-specific data storage.ApplicationsCell Phones/SmartphonesDigital CamerasPDAs

The MAX846A is a cost-saving multichemistry battery-charger system that comes in a space-saving 16-pin QSOP. This integrated system allows different battery chemistries (Li-Ion, NiMH or NiCd cells) to be charged using one circuit.In its simplest application, the MAX846A is a stand-alone, current-limited float voltage source that charges Li-Ion cells. It can also be paired up with a low-cost microcontroller (µC) to build a universal charger capable of charging Li-Ion, NiMH, and NiCd cells.An internal 0.5%-accurate reference allows safe charging of Li-Ion cells that require tight voltage accuracy. The voltage- and current-regulation loops used to control a low-cost external PNP transistor (or P-channel MOSFET) are independent of each other, allowing more flexibility in the charging algorithms.The MAX846A has a built-in 1%, 3.3V, 20mA linear regulator capable of powering the µC and providing a reference for the µC's analog-to-digital converters. An on-board reset notifies the controller upon any unexpected loss of power. The µC can be inexpensive, since its only functions are to monitor the voltage and current and to change the charging algorithms.ApplicationsCell PhonesDesktop Cradle ChargersHandheld Instruments (PDAs, Palmtops)Li+ Battery PacksLi+-Ion/NiMH/NiCd Multichemistry Battery ChargersNotebook Computers

The MAX745 provides all functions necessary for charging lithium-ion (Li+) battery packs. It provides a regulated charging current of up to 4A without getting hot, and a regulated voltage with only ±0.75% total error at the battery terminals. It uses low-cost, 1% resistors to set the output voltage, and a low-cost N-channel MOSFET as the power switch.The MAX745 regulates the voltage set point and charging current using two loops that work together to transition smoothly between voltage and current regulation. The per-cell battery voltage regulation limit is set between 4V and 4.4V using standard 1% resistors, and then the number of cells is set from 1 to 4 by pin-strapping. Total output voltage error is less than ±0.75%.For a similar device with an SMBus™ microcontroller interface and the ability to charge NiCd and NiMH cells, refer to the MAX1647 and MAX1648. For a low-cost Li+ charger using a linear-regulator control scheme, refer to the MAX846A.ApplicationsCell PhonesDesktop Cradle ChargersHandheld Instruments (PDAs, Palmtops)Li+ Battery PacksNotebook Computers

The MAX20094/MAX20095 ICs combine a configurable constant-current/constant-voltage (CC/CV) battery charger with a high-efficiency synchronous boost controller to supply critical systems in the event the primary power source is lost. In addition, diagnostic features are available to check battery state-of-health (SOH) and IC functionality. Charging thresholds and the boost output voltage are configurable to support popular battery chemistries and a wide range of cell counts. To support system integration, the ICs have an I2C target port through which configuration and status bits can be accessed.Switching frequency of 2.2MHz also helps to reduce system cost by minimizing inductor size. The ICs also include a precision battery SOH check and have built-in functionality to minimize leakage current out of the backup battery (BUB).The MAX20094/MAX20095 are available in a 28-pin (5mm x 5mm) side-wettable TQFN package and are AECQ-100 qualified.ApplicationsAutomotive Telematics Battery BackupSingle or Multicell Battery-Backup Systems

The MAX20094/MAX20095 ICs combine a configurable constant-current/constant-voltage (CC/CV) battery charger with a high-efficiency synchronous boost controller to supply critical systems in the event the primary power source is lost. In addition, diagnostic features are available to check battery state-of-health (SOH) and IC functionality. Charging thresholds and the boost output voltage are configurable to support popular battery chemistries and a wide range of cell counts. To support system integration, the ICs have an I2C target port through which configuration and status bits can be accessed.Switching frequency of 2.2MHz also helps to reduce system cost by minimizing inductor size. The ICs also include a precision battery SOH check and have built-in functionality to minimize leakage current out of the backup battery (BUB).The MAX20094/MAX20095 are available in a 28-pin (5mm x 5mm) side-wettable TQFN package and are AECQ-100 qualified.ApplicationsAutomotive Telematics Battery BackupSingle or Multicell Battery-Backup Systems

The MAX20094/MAX20095 ICs combine a configurable constant-current/constant-voltage (CC/CV) battery charger with a high-efficiency synchronous boost controller to supply critical systems in the event the primary power source is lost. In addition, diagnostic features are available to check battery state-of-health (SOH) and IC functionality. Charging thresholds and the boost output voltage are configurable to support popular battery chemistries and a wide range of cell counts. To support system integration, the ICs have an I2C target port through which configuration and status bits can be accessed.Switching frequency of 2.2MHz also helps to reduce system cost by minimizing inductor size. The ICs also include a precision battery SOH check and have built-in functionality to minimize leakage current out of the backup battery (BUB).The MAX20094/MAX20095 are available in a 28-pin (5mm x 5mm) side-wettable TQFN package and are AECQ-100 qualified.ApplicationsAutomotive Telematics Battery BackupSingle or Multicell Battery-Backup Systems

The LTC4000-1 is a high voltage, high performance controller that converts many externally compensated DC/DC power supplies into full-featured battery chargers with maximum power point control. In contrast to the LTC4000, the LTC4000-1 has an input voltage regulation loop instead of the input current regulation loop.Features of the LTC4000-1’s battery charger include: accurate (±0.25%) programmable float voltage, selectable timer or current termination, temperature qualified charging using an NTC thermistor, automatic recharge, C/10 trickle charge for deeply discharged cells, bad battery detection and status indicator outputs. The battery charger also includes precision current sensing that allows lower sense voltages for high current applications.The LTC4000-1 supports intelligent PowerPath control. An external PFET provides low loss reverse current protection. Another external PFET provides low loss charging or discharging of the battery. This second PFET also facilitates an instant-on feature that provides immediate downstream system power even when connected to a heavily discharged or shorted battery.The LTC4000-1 is available in a low profile 28-lead 4mm × 5mm QFN and SSOP packages.  LTC4000 LTC4000-1 Input Voltage Regulation MPPC No Yes Input Current Monitoring Yes Yes Input Current Regulation Yes No Applications Solar Powered Battery Charger Systems Battery Charger with High Impedance Input Source, e.g., Fuel Cell or Wind Turbine Battery Equipped Industrial or Portable Military Equipments

The MAX14676/MAX14676A are battery-charge-managementsolutions ideal for low-power wearableapplications. These devices include a linear battery-chargerwith a Smart Power Selector™, ModelGauge™fuel gauge, and several power-optimized peripherals.They feature an ultra-low-power buck regulator with aquiescent current of 900nA (typical) and 74% efficiencywith 10μA output.The battery charger features Smart Power Selectoroperation, allowing operation with dead battery. It limitsinput current based on a register setting. If the chargerpower source is unable to supply the entire system load,the smart power control circuit will supplement the systemload with current from the battery.The MAX14676/MAX14676A embed a Maxim proprietaryModelGauge fuel gauge to provide an accurate estimateof the available capacity for rechargeable lithium batteries.The MAX14676/MAX14676A include a synchronous high-efficiencystep-down converter. The device features a fixed-frequencyPWM mode for tighter regulation, and a burstmode for increased efficiency during light-load operation.The MAX14676/MAX14676A have a boost regulator andthree programmable current sinks that can be used todrive a variety of LED configurations. The boost converteris controlled independently from the current sinks, andthey can be also used separately.The MAX14676/MAX14676A feature a power switch controllerthat allows the device to be turned on and off by apushbutton. This controller also provides a delayed resetsignal and voltage sequencing.These devices are available in a 42-bump, 0.5mm pitch,3.497mm x 3.118mm wafer-level package (WLP).ApplicationsFitness MonitorsGPS WatchesPortable Medical DevicesWearable Electronics