A circuit for driving the current for inductive loads such as a electron
beam deflection coil for an x-ray generator system. The circuit includes
two selectable voltage levels which are provided by a high level voltage
source and a low level voltage source or, alternatively, by a low level
voltage source and a boosting converter. A plurality of switches for
selecting the voltage source allow only one voltage source to be
connected to the load at any given time, and for selecting the polarity
of the current through the coil. The high level voltage source is
selected when the load is charging or discharging. The low level voltage
source is selected when the load is operating in a constant current mode,
where a high frequency switching device uses the low level voltage source
to generate a pulse width modulation waveform according to a reference
current duty cycle to control the voltage across the load. A feedback
loop monitors the current through the load so that the duty cycle of the
pulse width modulation waveform may be adjusted to more accurately
control the current through the load.