Charging device and control method thereof

A charging device, used to charge an electronic device, comprising:

• an adapter providing an adapter current;
• an energy storage unit receiving a first charging current and providing a second charging current;
• and
• a charging module connected to the adapter, the energy storage unit and the electronic device receiving the adapter current and the second charging current, providing the first charging current to the energy storage unit and an output current to the electronic device, wherein the charging module includes:
• a detecting unit, including:
• a first current sense amplifier having a first sense input terminal connected to a node between the adapter and a first terminal of a first transistor, and a second sense input terminal connected to a second terminal of the first transistor;
• a first error amplifier having a first error input terminal connected to a first reference voltage source, and a second error input terminal connected to an output terminal of the first current sense amplifier and a first current source;
• a first comparator having a first comparator input terminal connected to an output terminal of the first error amplifier, and a second comparator input terminal connected to a first ramp generator;
• a second current sense amplifier having a third sense input terminal connected to a node between the energy storage unit and a first terminal of a second transistor, and a fourth sense input terminal connected to a second terminal of the second transistor;
• a second error amplifier having a third error input terminal connected to a second reference voltage source, a fourth error input terminal connected to the output terminal of the first current sense amplifier and the first current source, and a fifth error input terminal connected to an output terminal of the second current sense amplifier and a second current source;
• a second comparator having a third comparator input terminal connected to an output terminal of the second error amplifier, and a fourth comparator input terminal connected to a second ramp generator;
• a third current sense amplifier having a fifth sense input terminal connected to the second terminal of the second transistor, and a sixth sense input terminal connected to the node between the energy storage unit and the first terminal of the second transistor;
• a third comparator having a fifth comparator input terminal connected to the output terminal of the first current sense amplifier and the first current source, and a sixth comparator input terminal connected to an output terminal of the third current sense amplifier and a third current source;
• an upper bridge switch having an upper control terminal connected to an output terminal of the first comparator, a first upper input terminal connected to the second terminal of the first transistor and the electronic device, and a second upper input terminal connected to the second terminal of the second transistor;
• and
• a lower bridge switch having a lower control terminal connected to an output terminal of the second comparator, a first lower input terminal connected to the second upper input terminal of the upper bridge switch and the second terminal of the second transistor, and a second lower input terminal is grounded.