OPA Alice Circuit

[Fenton Bresler]

Thanks, 1mA makes more sense, I expected the current to be less than 100 smaller.

 

[Cqwet Dbdfte]

Sim says 780uA. Oscillates at 3.18MHz. Sim takes long time.
Better put this baby under a shield. Shielded inductor too.
BC547 is not a top choice in this circuit, ZTX857 will draw less current and produce higher output voltage in the same conditions.
With ZTX857 (or FZT857Q) this circuit makes -88V at 120uA from input.

 

[jp8]

Sim says 780uA. Oscillates at 3.18MHz. Sim takes long time.
Better put this baby under a shield. Shielded inductor too.
BC547 is not a top choice in this circuit, ZTX857 will draw less current and produce higher output voltage in the same conditions.
With ZTX857 (or FZT857Q) this circuit makes -88V at 120uA from input.
View attachment 139799

Sim is right. My bad, I must have measured the current including the zener current. But OTOH, it is fair to include a zener current in the total current consumption if the oscillator has its own shunt regulator, which is often the case. On my MXL770 PCBA, the oscillator draws 545uA, without zener current.

Attached picture shows the supply current of a CMOS oscillator with voltage tripler. Oscillator consists of two TC4S584F,LF gates. This is my standard circuit. It is powered from the same shunt regulator as the preamp, so no extra powerloss from an additional zener. Relaxation oscillator: simple and always works and has consistant output voltage. This is not always the case with Hartley oscillators, to my experience.

Jan