| 摘要 |
A bidirectional constant current driving circuit is connected between the positive and negative terminals of a power supply. This drive circuit has an input terminal and an output terminal with a load coupled to the output terminal, and with the current supplied thereto being controlled to vary in either a positive or a negative electrical direction. The inventive driving circuit has four transistors . A first and second of these transistors have a first electrode connected to the first power supply terminal. The second transistor has second and third electrodes connected to a second electrode of the first transistor. A third and fourth of these transistors have a first electrode connected to the second power supply terminal. The fourth of these transistors has second and third electrodes connected to a second electrode of the third transistor. First and second resistors are serially connected between the third electrodes of the second and fourth transistors. The junction of the first and second resistors are connected to the input terminal. The third electrodes of the first and third transistors are coupled to the output terminal.
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