Introduction to bq24780S, commonly used for laptop battery management

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Introduction to bq24780S, commonly used for laptop battery management [Copy link]

 

The bq24780S is a 1- to 4-cell hybrid boost mode battery charge controller from Texas Instruments that supports power monitoring and processor thermal monitoring. It is currently used in a wide range of applications, mainly in notebooks, ultrabooks, detachable tablets, and regular tablets.

Many notebooks now use the bq24780S. Why is this chip so popular with notebook manufacturers? The main reason is that the chip has the following main features:

1. The bq24780S device is a high-efficiency synchronous battery charger with a small number of components, suitable for space-constrained multi-chemical battery charging applications. The bq24780S device supports hybrid boost mode (formerly known as "turbo boost mode"). When the system power demand suddenly exceeds the maximum power level of the adapter, this mode can be used to discharge the system. In this way, the adapter will not be damaged.

2. The bq24780S device uses two charge pumps to drive N-channel MOSFETs (ACFET, RBFET, and BATFET) respectively to automatically select the system power supply. The system power management microcontroller can program the input current, charge current, discharge current, and charge voltage DACs with high regulation accuracy through the SMBus.

3. The bq24780S device can monitor the adapter current (IADP), battery discharge current (IDCHG), and system power (PMON) so that the host can control the CPU speed to fall back or reduce the system power supply as needed.

4. The bq24780S device can charge 1, 2, 3, or 4 series lithium-ion batteries.

Well, with the above understanding, let's take a look at the official application schematic diagram in the design as follows:

The design schematic diagram provided by TI is quite comprehensive, including: the detection unit of the AC adapter, the design circuit of the charging parameters, the charging current and AC current regulation (DPM) part, the boost module and the selection of the power path, etc. Since TI officially provides a comprehensive reference design for this chip, I will not introduce it here. If you are interested, you can take a look at the TIDA-00657 reference design on TI's official website, which will be of great help to friends who are doing laptop battery management.