Can anyone help me figure out why this circuit with an MC34063 is not working correctly? I followed the datasheet and also used the design tool to try and boost 12 volts up to 20.
Without a load the voltage slowly creeps up to about 18 and then drops with even a few milliamps applied. My first inductor was a 100uH toroid which I thought was too low so I changed it for a 250uH ferrite core choke. Then I lowered the timing cap from 220pF to 100pF to increase the switching frequency, that also had little effect.
Any ideas as to whats wrong?
Without a load the voltage slowly creeps up to about 18 and then drops with even a few milliamps applied. My first inductor was a 100uH toroid which I thought was too low so I changed it for a 250uH ferrite core choke. Then I lowered the timing cap from 220pF to 100pF to increase the switching frequency, that also had little effect.
Any ideas as to whats wrong?
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