| 摘要 |
PURPOSE:To obtain stability to temperature, and to sense the range of a source voltage accurately and to prevent chattering from occurring by generating a reference voltage by one transistor(TR) and a resistance, and feeding a current which flows through another TR back to further another TR. CONSTITUTION:When the source voltage VCC is low, base potentials of TRs 43 and 44 are low according to the voltage VB of a voltage dividing circuit 35, so the collector current of the TR 43 is larger than the collector current of the TR 44. Then, TRs 36 and 37 turn off and an output voltage V0 falls to 'L'. Then when the voltage VCC rises, the TRs 36 and 37 turn on the moment the collector currents of the TRs 43 and 44 become equal and the output voltage V0 goes up to 'H'. The reference voltage Vth of the source voltage VCC at which the TRs 36 and 37 begin to turn on does not depend upon temperature, so the range of the source voltage VCC is sensed accurately. Further, even when the voltage VCC drops to the voltage Vth, the collector current I14 flows more than the I13, so the TR 37 is still on and when the voltage VCC drops below the Vth, the TR 37 turns off.
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