Check Out These Tips and Design for the ADP2291 Charger?
ADP2291: Single-cell lithium-ion battery charger with wide input range and integrated safety features.
Having Troubles with ADP2291?
- The battery is not charging: Check the connections properly, and check whether the grounds of the input supply and battery are properly connected to the ground pin of the IC. Also, make sure that the battery is not flat-out dead.
- The charging current is too low: The charging current of ADP2291 is determined by the external resistor that is connected to the CS pin, check the resistor value and ensure the value is in the specified range. Also, Check the temperature of the IC, that is if the generated heat does not dissipate the charging current will be limited by the IC.
- The circuit’s performance is not stable: Use an input supply capacitor (CIN) with a value in the 1 µF to 10 µF range and place it close to the ADP2291. This should provide adequate input bypassing, but the selected capacitor should be checked in the actual application circuit. Check that the input voltage does not drop or overshoot excessively during the start-up transient. Use a battery output capacitor (COUT) with a value of at least 10 µF. This capacitance provides compensation when no battery load is present. In addition, the battery and interconnections appear inductive at high frequencies and must be accounted for when the charger is operated with a battery load. Therefore, a small amount of output capacitance is necessary to compensate for the inductive nature of the battery and connections. Use a minimum output capacitance value of 1 µF for applications where the battery cannot be removed.
Design Choices to be Considered with ADP2291:
How to add reverse polarity protection to the circuit?
To add reverse polarity protection to a circuit using the ADP2291, you can use a diode in series with the input supply. When the input supply is connected with the correct polarity, the diode conducts and allows the voltage to pass through to the ADP2291. If the input supply is connected with reverse polarity, the diode blocks the current, protecting the ADP2291 from damage.
Is a heat sink necessary for the working of ADP2291?
No. For most applications, the ADP2291 can operate without a heat sink within its specified operating conditions.
Is it possible to charge more than one battery with ADP2291?
No, the MAX18903 is designed to charge single-cell lithium-ion/polymer batteries.
What are the design considerations when designing a PCB using ADP2291?
- Keep the output capacitor as close to the BAT and GND pins as possible. Keep the input capacitor as close to the IN and GND pins as possible.
- PC board traces with larger cross-sectional areas remove more heat from the pass transistor. For optimum heat transfer, specify thick copper and use wide traces.
- Use additional copper layers or planes to reduce thermal resistance. When connecting to other layers, use multiple vias if possible.
➡️Applications: Cradle chargers.
➡️Alternatives: MCP7383, TP5000
➡️Manufacturer: Analog Device
