| 摘要 |
A digital drive system for a pulse width modulated power control utilizes an output transformer driving a load device with the transformer primary winding being connected to a pair of power output devices such as field effect transistors. Each of the output devices is switched on and off from a flip-flop whose "on" and "off" time is controlled by means of digital counters and gate devices, the times of "off" and "on" cycles being controlled by a digital counter connected to a clock and receiving amplitude information from a digital register which is programmable to vary the count of the amplitude counter with a desired variation in amplitude. By programming the gate devices to switch from one flip-flop to the other with an identical clock count, the two half cycles of the output signal supplied to the transformer are maintained identical and ensure that the transformer core is not saturated. Where desired, a digital phase counter may be used to modify the counter output relative to the clock to shift the phase output relative to the clock without danger of unbalancing the output waveform.
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