| 摘要 |
PROBLEM TO BE SOLVED: To provide a pulse width conversion circuit which can obtain a signal having highly stable pulse width even if it is made into IC by realizing a stable constant current source circuit against a temperature change. SOLUTION: A constant current circuit is provided with a current mirror-type constant current circuit having a terminal to which an external reference resistance deciding the current value of the constant current circuit is connected and a voltage feedback circuit which voltage-feeds back the current mirror-type constant current circuit so that the voltage of the terminal becomes equal to reference voltage. Another feature of the circuit resides in a ramp waveform generation circuit 10 formed of the consent current circuit, a capacitor and a switch element and in a pulse width conversion circuit which is provided with a comparator 11 and which incorporates IC. The current circuit can obtain stable current against a temperature change and the operation of the pule width conversion circuit is stabilized.
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