Overview:

QW2886 is a special chip for emergency detection and control. The chip adopts patented high-voltage isolation and detection technology, which directly monitors the state of the AC input signal without any external components, and directly or indirectly drives the LED light string. Also supports full voltage 85-265Vac input.

QW2886 integrates high-precision single-cell lithium battery management and MOSFET. It has the functions of overcharge protection, overdischarge protection, overcurrent protection and short circuit protection.

QW2886 has built-in reverse battery protection function. When the battery is reversely connected, it will automatically protect the battery and cut off the internal current path, so that the battery will not be damaged by overcurrent.

The QW2886 EN side supports up to 2A drive capability. A current limiting resistor can be directly connected in series to directly drive a single string of LEDs, and an external boost circuit is also supported to drive multiple strings of LEDs. The QW2886 is packaged in a ROHS SP-8 package and has an operating temperature range of -40°C to 105°C.

characteristic

? Minimalist application circuit

? Accurate AC input impedance detection

? 85-265Vac full voltage input

? EN up to 2A direct drive capability

? Perfect battery protection and management

? Built-in reverse battery protection

application

? All and all bright LED emergency lights

? Full string semi-bright LED emergency light

? LED emergency light with boost circuit

? Fire emergency lights

2. Battery management QW2886 integrates a complete single-cell lithium battery protection and management module. The battery protection management includes: overcharge protection, overdischarge protection, overcurrent protection, battery short circuit protection and charger detection circuit. Since the voltage detected by the battery charge and discharge management is the battery voltage, when designing the PCB layout, the BATP (PIN6) and BATN (PIN5) of the QW2886 chip should be as close to the battery terminals as possible. Adding high-frequency filter capacitors close to these two pins will also help to suppress the interference of AC/DC switching on battery voltage sampling. It is recommended to use a 1uF chip capacitor, and try to place the capacitor as close to the pins of the chip as possible. The QW2886 integrates reverse battery protection internally. When it is detected that the battery is reversely connected, the current path inside the chip is closed to cut off the battery discharge path. So that the battery will not be damaged by overcurrent.

3. The EN PIN of the output current QW2886 has a built-in switch of 200 milliohms. When EN outputs a high level, a current limiting resistor can be connected between the EN PIN and the LED output to supply power to the LED load.

4. Precautions for PCB layout Reasonable PCB layout is very important to ensure system stability and low noise to the greatest extent. Using a multi-layer PCB board is a very effective way to avoid noise interference. In order to effectively reduce the noise of the current loop, the input bypass capacitor should be grounded separately. Connect the high-current ground return, the ground lead of the input bypass capacitor, and the ground lead of the output filter to the same point (star ground connection) to minimize ground noise.