Hi All,
I'm pretty new to switching power supplies, but what I want is a switching DC-DC converter that inverts its input supply.
The specs I am aiming for are as follows:
*Vin Max = 24V
*Iout Max ~= >0.8A
*Vout = -(Vin)
*Should work down to a few volts, but this is not critical
*Continuous short circuit capable (and generally robust)
*Efficiency and size is not of particular interest
I have successfully used several DC-DC converter ICs (LMZ14201, TL2575-ADJ and MC34063A) in inverting mode and each of these devices can satisfy my requirements above, however they are all regulated, so whilst I may adjust the output voltage with no issues, I cannot think of a way for the device to "track" or mirror whatever the input voltage is.
For comparison purposes, the MAX7660(S) is unregulated and would be great, but it's limited to 13V max and about 100mA.
I have noticed that the datasheets show the feedback pin being compared to a voltage reference. I have experimented with varying voltages on the feedback pins of several devices but since the comparator will be outputting either "voltage too high" or "voltage too low", I can't think of how I might be able to achieve a circuit where Vout is just -(Vin).
If anyone has any suggestions, I would be most grateful.
For your reference (devices I have right now):
TL2575-ADJ,
LMZ14201,
MC34063A.
PS: I've searched some manufacturers to see if a part is available, but nothing that meets my desired specs (namely output current) seems to be available. If anyone knows of a part (preferably Ti / Intersil / Microchip / Linear) I would also love to hear it.
Thank you!