As concerns about global environmental pollution continue to grow, the use of clean energy becomes increasingly important. One of the primary causes of air pollution, particularly in major cities, stems from the exhaust gas of a vehicle. In response, the commercial development of electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) has been accelerated.
The electric vehicle and the hybrid vehicle receive electric energy from an external source (e.g., a power plant), charge the electric energy in a battery, and then acquire power, which is mechanical energy, through a motor coupled with a vehicle wheel using the voltage charged in the battery. That is, since the motor is driven with the voltage charged in the battery, the electric vehicle uses a large-capacity chargeable battery and includes a battery charger for charging the large-capacity chargeable battery. Therefore, there is a need to improve battery charging efficiency by accurately sensing a control pilot signal, and the like for charging a battery.