| 摘要 |
An accurate RC oscillator circuit (10) for generating a signal of a predetermined frequency that accurately oscillates between two precise voltage levels, i.e., a low threshold voltage (VL) and a high threshold voltage (VH). The oscillator circuit uses first and second comparators (16, 18) having their outputs respectively coupled to set and reset inputs of a flip flop (20). The output of the flip flop is coupled to a series RC network for controlling the charging and discharging of the voltage across a capacitor (14) of the RC network. The interconnection (12) of the series RC network is coupled to an input of both the first and second comparators. The other input of the first comparator is coupled to a circuit (24) for applying a modified version (V'H) of the high threshold voltage such that the signal generated by the oscillator circuit does not exceed the precise high threshold voltage (VH). Likewise, the other input of the second comparator is coupled to a circuit (25) for applying a modified version (V'L) of the low threshold voltage such that the signal generated by the oscillator circuit does not fall below the precise low threshold voltage (VL).
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