The present invention is directed to a remotely controlled power supply
system that can change output polarity at a high slew rate without using
switching devices. The system comprises a control circuit and two
individual high voltage DC-DC converter power supply sections, one
positive and one negative, connected in series. By nature of the control
circuitry, either a positive or negative controllable current is produced
depending upon a programmed voltage input. The two individual power
supply sections are each self-oscillating single transistor circuits. The
self-oscillating circuits contain an RC network tuned to provide
attenuation at the second harmonic of the natural oscillating frequency
of the circuit. This reduces and/or eliminates the tendency of this
circuit to begin oscillation at the wrong harmonic of the natural
frequency. A power-on delay circuit is used to suppress the outputs of
the two power supply sections no matter the command of the input control
programming signal. An enable signal input allows for suppression of the
power supply system output at any other time.