I have a small circuit board I pulled from a device that does something really neat and unusual.
It is a DC inverter doubler. It takes a positive voltage, inverts it, and doubles it. For example, If I connect a 9 volt battery to the input, the output of the board is -18 volts. Really cool. I inspected the board and took pictures. I am about 90% sure of the components. I got models for them but I can’t get it too work in simulation. I was hoping someone out there could take a look at the schematic and help me figure this out.
Here are some pictures and datasheets.
D1 & D2 - are BAV99 dual diodes. Here is datasheet BAV99
D3 - is a 20 volt zener diode in a SOT23 package. I believe it is BZX84-C20. Here is datasheet Voltage regulator diodes pin 3 is not used
Q1 - I “think” is a BC850C NPN BJT. I pulled it off board and did a diode test with multimeter, and I have confirmed that it is an NPN BJT. What makes me think it’s a BC850C is because it has the marking (2G) on it. The only reference from google I found was the BC850C.
Here is the schematic file (The markings in red are what the actual board shows) As you will see I am way off from those values. Everything is fine up until the Q1. On the board, the gate should operate in negative voltage ranges.
Rework2.qsch (17.8 KB)
I am perplexed by this little circuit. Any help would go a long ways, thanks.
