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MAX745
Switch-Mode Lithium-Ion Battery-Charger
±0.75% Precision Li+ Charger Delivers 4A Without Heating
MyMaxim SubscriptionsProduct Details
Key Features
Applications/Uses
Parametric specs for Battery Chargers
| Package/Pins | SSOP/20 |
| Budgetary Price (See Notes) | 5.31 |
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Simplified Block Diagram
Technical Docs
| Data Sheet | Switch-Mode Lithium-Ion Battery-Charger | Jul 24, 2019 | |
| App Note | New Developments in Battery Chargers | ||
| Tutorial | How to Design Battery Charger Applications that Require External Microcontrollers and Related System-Level Issues | ||
| Reference Schematic | Portable Devices Need High-Performance Battery Chargers |
How to Use the MAX745 as a Maximum Power Point Tracker Solar Charger
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
Parameters
Parametric specs for Battery Chargers
| Package/Pins | SSOP/20 |
| Budgetary Price (See Notes) | 5.31 |
Key Features
- Charges 1 to 4 Li+ Battery Cells
- ±0.75% Voltage-Regulation Accuracy Using 1% Resistors
- Provides up to 4A without Excessive Heating
- 90% Efficient
- Uses Low-Cost Set Resistors and N-Channel Switch
- Up to 24V Input
- Up to 18V Maximum Battery Voltage
- 300kHz Pulse-Width Modulated (PWM) Operation
- Low-Noise, Small Components
- Stand-Alone OperationNo Microcontroller Needed
Applications/Uses
- Cell Phones
- Desktop Cradle Chargers
- Handheld Instruments (PDAs, Palmtops)
- Li+ Battery Packs
- Notebook Computers
Description
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.
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.
Technical Docs
| Data Sheet | Switch-Mode Lithium-Ion Battery-Charger | Jul 24, 2019 | |
| App Note | New Developments in Battery Chargers | ||
| Tutorial | How to Design Battery Charger Applications that Require External Microcontrollers and Related System-Level Issues | ||
| Reference Schematic | Portable Devices Need High-Performance Battery Chargers |
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
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