EVHR1204-S-00A

The EVHR1204-S-00A is a 21V/18A 400W Battery charger for power tools.

This reference design is a complete battery charger design for cordless power tool, which is widely used in drilling, grinding, cutting, polishing, and various garden tools. The design can be used in Li-ion and Li-poly chemistry battery with a voltage range from 10V to 21V. The maximum current can support up to 18A. The charger provides constant voltage and constant current control with programmable voltage and current.

The HR1204 integrates a digital PFC controller and a half-bridge resonant controller into a single chip. It uses very low power at no load or ultra-light load.

The PFC of the HR1204 employs a patented average current control scheme, which can operate in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) according to the instantaneous condition of the input voltage and output load.

The half-bridge LLC converter achieves high efficiency with zero-voltage switching (ZVS). The HR1204 implements an adaptive dead-time adjustment (ADTA) function so the LLC converter can easily achieve ZVS from heavy load to light load. Additionally, the HR1204 can prevent the LLC converter from operating in capacitive mode, making it more robust and easier to design.

The EVHR1204-S-00A has excellent efficiency and a high power factor for the entire load range. Full protection features include overload protection; short-circuit protection (SCP), over-voltage protection (OVP), and anti-capacitive mode protection. The EVHR1204-S-00A also meets the Class C standard of IEC61000-3-2 and EN55022 standard.