Design Support

#2-1 . When there is an intersection

Power generation is possible when there is an intersection between the blue line and the black line. The input voltage and current of the step-up DC-DC converter and the output power and current are also displayed in the table. In addition, this output power can be used to predict the following.

I [mA] : Average current of the system to be operated

T [msec] : System operating time

POUT [uW] : Output power of AP447x calculated by the simulator

Charge time [sec] ＝3V × I × T ÷ POUT

* Assuming that the average voltage supplied by AP447x is 3[V]

For example, the average current I = approx. 0.76[mA] and the operating time T = 31[msec] for the evaluation kit with wireless function provided by AKM, so the charging time is approx. 5[sec] when output power POUT = 14[μW].

#2-2  When there is no intersection

If there is no intersection between the blue line and the black line, the input power to the step-up DC-DC converter is insufficient and the step-up circuit will not start.

In addition, the input voltage/current and output power/current of the step-up DC-DC converter are all displayed as 0.

For example, if the result shown on the left side is obtained, increase the short-circuit current of the generator elements in order to boost the voltage (= create an intersection). For example, you can connect several generating elements in parallel.