Relay-welding detection device and detection method

A relay-welding detection device, the device comprising:

• a first analog-to-digital converter (ADC) that measures a voltage of a relay input terminal;
• a second ADC that measures a voltage of a relay output terminal;
• and
• a central processing unit (CPU) that determines whether welding occurs by comparing the voltage of the relay input terminal with the voltage of the relay output terminal,
• wherein, when a charger corresponds to one of a charging state, a charging completion state, or an error state,
• the CPU determines that welding occurs when the voltage of the relay input terminal is the same as the voltage of the relay output terminal, and
• the CPU determines that welding does not occur when the voltage of the relay input terminal is different from the voltage of the relay output terminal;
• a first voltage drop unit that converts the voltage of the relay input terminal to match a specification of the first ADC, wherein the first voltage drop unit comprises:
• a first resistor connected in series to the relay input terminal, and
• a second resistor connected to the relay input terminal and a point to which a reference voltage is applied;
• and
• a second voltage drop unit that converts the voltage of the relay output terminal to match a specification of the second ADC, wherein the second voltage drop unit comprises:
• a third resistor connected in series to the relay output terminal, and
• a fourth resistor connected to the relay output terminal and the point to which the reference voltage is applied.