Originally posted by padova
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His says this.
I just ordered the new HV version PCB's from China. Hopefully this new design will work. The LV PCB's work great but are designed for a smaller motor running between 18 and 36 VDC. This new version will require an additional power supply upto 160VDC. This new design is based on the data sheet for the MC33033 fig 24 and 29 are added to the original schematic. Fig 29 shows the implementation of the Boost circuitry which allows the TOP FET's to switch do to the Boost voltage being added to the HV 160 VDC power supply. To get the FET to fire you need a difference of potential between the gate and source that is around 10vdc. The boost circuit does this by using the HV vdc as the reference voltage, Their is a DC blocking cap in the boost circuit which prevent the HV DC from burning up the Osc IC.
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