Power supply charging circuit of ultra-low-power wireless mesh network node

The utility model discloses a power supply charging circuit of an ultra-low-power wireless mesh network node, comprising an LM3420-4.2 including an operational amplifier, a band gap reference PNP output transistor, and a voltage dividing resistor setting the output constant voltage. The power supply charging circuit is a specially designed shunt regulator which is determined by a resistive voltage divider between an output pin IN and a grounding pin GND. If the voltage of an input pin is lower than the regulated voltage of the LM3420, the output pin outputs no current. When the voltage of the output pin reaches the regulated voltage, the output pin starts outputting current. The current driving feedback device or the power device of a linear regulator or a switching regulator is stable in output.