I'm working on a project to drive a CCD array which needs a particular signal with a high of +5V and a low of -4V, changing fairly rapidly. I'm using a PIC18F4620, which as far as I'm aware, looking at the data sheet, cannot produce a negative signal directly.
Above is the design I did a while ago with the components I had available. The inverter is quite slow, so I used a transistor with a switching signal from the PIC. Another signal is output at 0V/5V from the PIC. The two signals alternate so that at any one point, either the negative signal or the positive signal will be sent to the CCD.
Is this the right kind of idea? I tried using a diode to ensure the signals aren't going the wrong way (instead of going to the CCD), but as one is negative and the other is positive, this doesn't work. I feel like there must be a much simpler way to do this. Any help?