[sdiy] LM13700 questions

[Magnus Danielson]

On 08/17/2012 09:20 AM, Stewart Pye wrote:
> Is it OK to use the current output of an LM13700 to feed the Iabc pin of
> another LM1300?
> According to the datasheet the maximum output current is in a suitable
> range for the Iabc. The only concern I have is that the Iabc pin is
> referenced to the negative rail.
>
> The application I have in mind is voltage control of modulation amount.
> It seems silly to convert the current to a voltage and back to a current
> again...

You would be a diode away from the negative rail. Also consider that the 
LM13700 output can be bi-polar where as the input only takes one 
polarity. Voltage difference would come in the way.

If you for some reason run into a problem (which I don't think if you 
keep currents low enough) then using another current mirror at a more 
moderate voltage would be a solution.

Cheers,
Magnus