# Design Support

Energy Harvesting

## AP447x Power Simulator - Environmental Power Generation Elements

The simulator can calculate the output power of AKM's step-up DC-DC converter, enabling the checking of the time required for harvesting the required environmental energy. This simulator is useful at consideration of a system.

＊From here on, you will be redirected to sites other than akm.com site. ### How to operate #1 Enter a type and output characteristics of the environmental power generation element

#2 Next, enter a type of the step-up DC-DC converter and press the Run button.

### Information available from the simulation

#1  Does the step-up circuit start up?

By checking the presence or absence of an intersection between the output characteristics of the generation element (blue line) and the input (black line) characteristics of the step-up DC-DC converter in the graph, it is possible to confirm whether the output characteristics of the input generator element will activate the step-up circuit of the step-up DC-DC converter. #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.