Get HIGH voltage with a MCU
01, Driver is critical (dual driver used here)
There are many types of drivers, the dual driver here even has 5 yet implications: 1, 2 pins double the driver's current capacity, thus increasing switching speed; 2-4: By using one of the pin in inverter mode, there are yet 4 more variations for the drivers with buffering transistors to drive the gate/base faster. Here the inverter is used to discharge the gate/base capacity with a nmos, simple yet effective.
2, Mosfet is the key (130v Max with slow NPN; 200v+ with Mosfet)
With mosfet and its superior switching speed, the waveform is more flexible and the output is more controllable. The tested 13003 is too slow, and the test-and-trial-maximum-attainable high voltage is only 130v with the dual driver simple version.
3, Size does matters (the size of an inductor is measured with its pulse storage capacity)
The capacity is NOT just a self-contained parameter, but highly depending on the switching waveform or in other words, the switching speed of the transistor. With slower speed, the inductor value should be bigger or about 470uH-1mH, but with faster speed, 22-100uH range inductor can be used to generate a 170v with merely 5v input. The inductor's charging time depends on the ON time, or the duty cycle of a given PWM signal; The inductor's maximum charging time depends on 2 things: 1,its inductance and its saturation rating. Thus, a smaller 22uH 3A inductor can store more energy than a 1mH 0.1A inductor.
4, Efficiency is gold
Efficiency is measured by output power over input power.
5, Safety is not the last but the priority (A lot of test)
There are 2 main safety concerns: 1, high input current; A simple fuse is enough to avoid catastrophic situation or a more precise current limiting circuit can be used. This is not as important if the driver is coded correctly, but still a feature good to have. 2, high output voltage; The voltage should be stable by a means of decreasing the duty cycle when a preset level has been reached. A comparator can also be used to hard reset the MCU when a higher voltage has been detected.