Protection circuit and method thereof

The invention relates to a protection circuit and a method thereof. The protection circuit is applied to the lithium battery provided with a charging and discharging circuit, the protection circuit comprises a first pre-discharging circuit and an adjusting circuit, the adjusting circuit is connected with a discharging control switch of the charging and discharging circuit in parallel, and the adjusting circuit comprises a second switch element and a capacitor assembly which are connected in series. The first pre-discharge circuit is connected with the discharge control switch in parallel or connected with the capacitor assembly in parallel. The first pre-discharge circuit comprises a first switch element and a first resistor assembly which are connected in series. A controller of the charging and discharging circuit controls the first switch element and/or the second switch element to be switched on or switched off so as to charge the capacitor assembly or discharge energy through the first resistor assembly.