| 摘要 |
PURPOSE:To provide a feedback inspecting function for an output current and to simplify constitution by feeding back the output of a counter. CONSTITUTION:The amplitude and frequency of a digital signal from a processor CPU are varied to extract a necessary analog signal by a filter FL1. A comparator CMP compares it with the output signal of an output buffer circuit OBF and sends the result to a counter CNT. The counter CNT varies in counted value by the output based upon the comparison output, and the counted value is supplied to the CPU and also inputted to the 2nd D/A converter D/A2 to vary the amplitude and frequency, so that a necessary analog signal appears at its output. The output buffer circuit OBF controls a transistor to send the output signal to the other input terminal of the comparator CMP. Thus, a digital controller checks the actual analog current output value. |
