Maxim Integrated Products has introduced the MAX17435/MAX17535 highly-integrated SMBus multichemistry battery chargers. The MAX17435/MAX17535 provide SMBus™-programmable charge current, charge voltage, input current limit, relearn voltage, and digital readback of the IINP voltage. The MAX17435/MAX17535 utilize a charge pump to control the adapter selection n-channel MOSFETs when the adapter is present. When the adapter is absent, the charge pump is shut down and a p-channel MOSFET selects the battery.
The MAX17435/MAX17535 provide up to 7A of charge current to 2, 3, or 4 lithium-ion (Li+) cells in series. The charge current, and input current-limit sense amplifiers have low offset errors and can use 10mΩ sense resistors. The MAX17435/MAX17535 fixed-inductor ripple architecture significantly reduces component size and circuit cost.
The MAX17435/MAX17535 provide a digital output that indicates the presence of the adapter, an analog output that indicates the adapter or battery current, depending upon the presence or absence of the adapter, and a digital output that indicates when the adapter current exceeds a user-defined threshold.
The MAX17435 switches at 850kHz, and the MAX17535 switches at 500kHz.
The MAX17435/MAX17535 are available in a small, 4mm x 4mm x 0.75mm 24-pin, lead-free QFN package. An evaluation kit is available.
An evaluation kit is available: MAX17435EVKIT MAX17535EVKIT
Key Features
- Low-Cost SMBus Charger
- High Switching Frequency (0.85MHz, 0.5MHz)
- Internal Boost Switches
- SMBus-Programmable Charge Voltage, Input Current Limit, Charge Current, Relearn Voltage, and Digital IINP Readback
- Single-Point Compensation
- Automatic Selection of System Power Source
- Adapter n-channel MOSFETs Driven by an Internal Dedicated Charge Pump
- Adapter Soft-Start
- ±0.4% Accurate Charge Voltage
- ±2.5% Accurate Input Current Limiting
- ±3% Accurate Charge Current
- Monitor Outputs for
- AC Adapter Current (±2% Accuracy)
- Battery Discharge Current (±2% Accuracy)
- AC Adapter Presence
- AC Adapter Overvoltage Protection
- 11-Bit Battery Voltage Setting
- 6-Bit, Charge-Current Setting/Input Current Setting
- Improved IINP Accuracy at Low Input Current
Applications/Uses
- 2- to 4-Li+ Cell Battery-Powered Devices
- Notebook Computers
- PDAs and Mobile Communicators
Standard MAX17435 / MAX17535 application circuit
