connected between the inverting terminal and non inverting terminal of first error amplifier 201 sensing resistor rt is connected to the non inverting terminal of first error amplifier 201 and an electrical ground 111 the output terminal of first error amplifier 201 is electrically coupled to the gate of first nmos transistor 202 first resistor r 1 203 is electrically connected to the inverting terminal of first error amplifier 201 and the drain of first nmos transistor 202 second resistor r 2 204 is electrically coupled between the drain and the source of first nmos transistor 202 continuing with fig2 charging current generator circuit 120 includes a second error amplifier 211 connected in series to a second nmos transistor 212 and current mirror circuit configured by a first pnp bipolar junction transistor 214 and a second pnp bipolar junction transistor 215 more particularly first pnp bipolar junction transistor 215 and second pnp bipolar junction transistor 215 form a current mirror with first pnp bipolar junction transistor 214 first pnp bipolar junction transistor 214 is connected as a diode and its collector connected to the drain of second nmos transistor 212 the collector of second pnp bipolar junction transistor 215 is connected to battery 162 the bases of first pnp bipolar junction transistor 214 and second bipolar junction transistor are connected together and to an input voltage vin 150 the non inverting terminal of second error amplifier 211 is.