Suitable for portable devices applications Linear lithium battery charging management chip

The article describes CN3052A/CN3052B/CN3056 linear high-performance lithium battery charge management chip. These devices are integrated inside the power tube requires minimal external components, without the need for an external current sense resistor and blocking diode, and

And in accordance with the technical specifications of the USB bus, through the USB port for rechargeable lithium batteries, so it is suitable for all kinds of chargers and MP4 players, Bluetooth headsets, digital cameras and other portable products. Figure 1 is a typical application circuit diagram.

    Figure 2 is CN3052A/CN3052B/CN3056 internal functional block diagram of the pin functions of the chip as shown in Table 1. Thermal modulation circuit chip temperature control device power operation or high ambient temperature in a safe range

To facilitate the customer's system design. The modulation output voltage of 4.2V, and an accuracy of 1%; adjustment of charging current through an external resistor. Automatically enter a low-power sleep mode when the input voltage is too low or power down, CN3052A/CN3052B/CN3056

, The battery drain current to less than 3uA.

    CN3052A/CN3052B/CN3056 workflow

    Figure 3 is a CN3052A/CN3052B/CN3056 charging process diagram. When the input voltage is greater than the power low voltage detection threshold and the chip can input is high, CN3052A/CN3052B/CN3056 start charging the battery, CHRG pin input

A low, indicating that charging is in progress. If the battery voltage is less than 3V, the pre-charging the battery charger with a small current. Constant current mode when the battery voltage exceeds 3V, the charger to charge the battery, the charging current by ISET pin and GND

Resistance RISET <OK. When the battery voltage is close to the battery terminal modulation voltage of 4.2V, the charging current gradually decreases, CN3052A/CN3052B/CN3056 into the constant voltage charging mode.

    When the charge current drops to charge termination threshold, CHRG a high impedance state, said the end of the charge cycle, charge termination threshold is 10% of the current constant current charging. If you want to start a new charge cycle, as long as the input voltage power off, then on

Electricity can, or CE pin voltage temporarily pulled to 0V, and then return to the high level. Automatically start the charging cycle when the battery voltage falls below the recharge threshold below. When the input voltage is lower than the battery voltage, the charger enters a low power

Sleep mode, the current drain on the battery is less than 3uA, thus increasing standby time. If the enable input CE pin to GND, the charger is turned off.

    CN3052A/CN3052B/CN3056 main Features

    Power low-voltage detection (UVLO) CN3052A/CN3052B/CN3056 internal power supply voltage detection circuit, when the supply voltage drops below the power supply voltage is too low threshold (typ. 4.03V), the chip is in the off state, the charge is also prohibited.

    The the sleep comparator the sleep mode CN3052A/CN3052B/CN3056 internal, when VIN falls below +40 mV when the battery terminal voltage, the charger is in sleep mode; Only when VIN rises to the battery terminal voltage 90mV
Mobile power pack, battery pack for iphone, Mobile Power Station, extra iPhone charger

Sleep mode, the charger can be left to enter the normal operating state.

    The precharge state at the beginning of the charge cycle if the battery voltage is lower than 3V, the charger is in precharge state, charger constant current charging mode charging current 10% of the battery charge.

    Set the charging current CN3052A/CN3052B/CN3056 the constant current mode charging current can be set by the ISET pin resistor.

    The thermal modulation circuit, the inside of the thermal modulation function CN3052A/CN3052B/CN3056 integrated When the chip temperature rises to a certain temperature (115 ℃), the thermal modulation circuit starts its operation, the temperature of the chip is maintained at 115 ° C, at a constant temperature.

This feature is very important for the linear charger circuit can even be said to be indispensable. With this feature, users in the design of the maximum charging current considerations usually can be, without the need to consider the worst working conditions. If

No thermal modulation function, the user must be fully considered in the design of the maximum charging current, worst case, otherwise the slightest mistake, the chip will be burned because the temperature is too high.