DC power tool with a safety detection device
A DC power tool having an interiorly provided lithium battery element and a charging switch includes a safety protection module to eliminate the risk of circuitry burn-out and other dangers resulting from connecting the power tool to a power supply with unmatched rated voltage and rated current when charging the power tool via use of an adapter.
1. A DC power tool comprising:
an interiorly provided lithium battery element; and
a charging switch electrically coupled to an exterior power supply and the battery element;
a safety protection module electrically coupled to at least one of the battery element or the charging switch and comprising an over-current and over-voltage protection module, wherein the over-current and over-voltage protection module comprises a locking device.
2. The DC power tool of claim 1 , wherein the safety protection module further comprises an overheating protection module.
3. A DC power tool comprising:
a charging circuit comprising:
an interiorly provided battery element;
a charging switch for controlling a charging process; and
an outer adapter electrically coupled to the charging switch and connectable to a power supply for supplying power for the charging process; and
a safety protection module electrically connected to the charging circuit for providing safety protection, the safety protection module comprising:
a current sampling circuit connected to the battery element to detect a current provided to the charging circuit,
a current reference circuit to provide a predetermined current value;
a voltage reference circuit to provide a predetermined voltage value and to generate an over-voltage signal to turn off the charging switch when a voltage value provided to the charging circuit larger than the predetermined voltage value is detected;
a current reference circuit to generate an over-current signal when the charge provided to the charging circuit is detected as being larger than the predetermined value to turn off charging switch,
wherein the over-current signal and over-voltage signal are transferred to turn off the charging switch via an OR-gate; and
a locking device to lock an output of the OR-gate.
4. The DC power tool of claim 3 , wherein the safety protection module further includes an overheating protection module for generating an overheating signal when a temperature value in the charging circuit higher than a predetermined temperature value is detected to turn off the charging switch.