| 摘要 |
<p>PURPOSE:To stabilize a circuit operation and to stabilize an oscillation frequency by providing a constant voltage generation circuit, which generates two reference voltages with different potentials by splitting a resistance, two voltage comparators, an output selection circuit to invert the logical level of an output signal, and a CR time constant circuit. CONSTITUTION:The terminal voltage Vc of a capacitor C ascends like an exponential function according to the time constant of the CR time constant circuit, consisting of the capacitor C and a resistor R. In the process of this ascent, at first, the terminal voltage Vc of the capacitor C exceeds a reference voltage V2, and the output node 5 of the second voltage comparator 4 is inverted from a high level into a low level. Next, the terminal voltage Vc of the capacitor C exceeds the reference voltage V1, and the output node 3 of the first voltage comparator 2 is inverted from the high level into the low level. By repeating above-mentioned operations, an oscillation operation is performed. In this case, the two reference voltages V1, V2 are generated by splitting the resistance, and because the value of Schmidt voltage width/ power source voltage is kept constant extending over the wide range of the power source voltage, the circuit operation is stabilized, and the oscillation frequency is stabilized as well.</p> |
