A: the Yellow marked "chip", with overheating, overcurrent, undervoltage protection, when the [B] in short circuit (including the user external power supply chip, harness short) will enter the state of protection, disconnect the output. To effectively protect the charging products, car charge, as well as the vehicle power interface.
B: Pink mark is the "self recovery fuse, over-current, overheating protection and self recovery characteristics, but if power failure or chip protection [A] areas appear short, self recovery fuse will be in a state of long-term protection, if the vehicle ignition again, lighter interface will have transient high pressure, this state may caused by the self recovery fuse smoke or explosion". At this point, will not damage the vehicle, but the resulting pop sound and smoke may cause discomfort.
Taking into account the "situation B" risk, the analysis is as follows:
First of all, A short circuit, there are two main reasons, one is the production process of short circuit, such as chip chip capacitors with residual bad, solder paste, tin slag welding residual artificial plug-in capacitor; another reason is bad devices, such as power chips and other components of potential failure.
Devices with a very low probability of potentially harmful risk, usually in one part of a million, so we need to focus on the production process and plant inspection process.

Countermeasure:
(1) to confirm the specifications of the self recovery fuse within the scope of application (recommended Vmax>25V). (2) the production of the plant needs to be in the SMT furnace, and after the completion of the plug capacitor welding two times, and to clean up residual tin slag.
(3) the products are carried out in all aging test.

Other: the internal circuit design, there will be a fuse fuse, that is to say, even if the cigarette lighter fault, the car would have protection, to avoid damage to the vehicle circuit.