Hi everyone, I build a boost circuit using MC34063 as control IC,
The schematic I build is like this,
The datasheet can be found here: MC34063 datasheet
At first, I want to build a boost converter to drive the nixie tube clock I made, so I measure the current consumption of the project is about 81.9mA, when using 12v/2A AC-DC power adapter.
And then, I design the peripheral component of the MC34063 circuit as this website (Other website had the same result)
So I choose the component value in the schematic above.
The circuit works fine when I attaching small load such as EL-wire which only need 35mA of current,
but when I connect the nixie tube clock, the output of boost converter is suddenly dropped to 5 volts, and the current increase to 173mA.
As you can see in the picture, the output voltage hooked up to the oscilloscope's RMS value is 5.65 volt, and the meter shows the current is 175mA.
I'm wondering is the nixie clock needs a lot of current at startup to charge the input capacitance of the clock or something needs a high impulse current to drive?
So I use a 1-ohm resistor, connect it in series to the 12v/2A AC-DC adapter and the nixie clock, then hook CH1 to the adapter output, CH2 to the clock input, like the picture below, so I can measure the current by the voltage drop of the 1-ohm resistor.
The oscilloscope shows the result like this, the yellow is Ch1, which is the adapter voltage, the blue one is the nixie clock input voltage and the red one is CH1-CH2 the differential of two voltage, aka the resistor voltage.
As you can see, there is a very high voltage when the nixie clock attaches to the power source, convert the voltage into current, It's about 6A when I want to start the nixie clock.
The question is how can I solve this issue? Does something like "soft start" can apply in this situation?
or I need an external NPN transistor or MOSFET to make the circuit can handle more switching current?
Thanks for reading!! Hope you have a nice day
More information about the nixie tube clock circuit is at The project site
The schematic I build is like this,
The datasheet can be found here: MC34063 datasheet
At first, I want to build a boost converter to drive the nixie tube clock I made, so I measure the current consumption of the project is about 81.9mA, when using 12v/2A AC-DC power adapter.
And then, I design the peripheral component of the MC34063 circuit as this website (Other website had the same result)
So I choose the component value in the schematic above.
The circuit works fine when I attaching small load such as EL-wire which only need 35mA of current,
but when I connect the nixie tube clock, the output of boost converter is suddenly dropped to 5 volts, and the current increase to 173mA.
As you can see in the picture, the output voltage hooked up to the oscilloscope's RMS value is 5.65 volt, and the meter shows the current is 175mA.
I'm wondering is the nixie clock needs a lot of current at startup to charge the input capacitance of the clock or something needs a high impulse current to drive?
So I use a 1-ohm resistor, connect it in series to the 12v/2A AC-DC adapter and the nixie clock, then hook CH1 to the adapter output, CH2 to the clock input, like the picture below, so I can measure the current by the voltage drop of the 1-ohm resistor.
The oscilloscope shows the result like this, the yellow is Ch1, which is the adapter voltage, the blue one is the nixie clock input voltage and the red one is CH1-CH2 the differential of two voltage, aka the resistor voltage.
As you can see, there is a very high voltage when the nixie clock attaches to the power source, convert the voltage into current, It's about 6A when I want to start the nixie clock.
The question is how can I solve this issue? Does something like "soft start" can apply in this situation?
or I need an external NPN transistor or MOSFET to make the circuit can handle more switching current?
Thanks for reading!! Hope you have a nice day
More information about the nixie tube clock circuit is at The project site