DELAY CIRCUIT AND OSCILLATION CIRCUIT USING THE DELAY CIRCUIT

摘要

PROBLEM TO BE SOLVED: To avoid the delay circuit from being affected by the parasitic capacitance of the MOS transistors(TRs) used in the circuit. SOLUTION: A P-MOS TR 3 acts like a charging current source that is controlled by a charging current control circuit 1 when a level of an input signal is a power supply level, and is turned off when the input signal is at a ground GND level. An N-MOS TR 4 is turned off when the level of the input signal is the power supply level, and the TR 4 acts like a discharge current source that is controlled by a discharge current control circuit 2 when the input signal is at a ground GND level. The charging current control circuit 1 controls the P-MOS TR 3 so that a charging current proportional to a delayed control current 7 flows through a capacitor 5 via the P-MOS TR 3, and the discharge current control circuit 2 controls the N-MOS TR 4 so that a discharge current proportional to a delayed control current 8 flows through the capacitor 5 via the N-MOS TR 4. According to above, charging/discharge of the capacitor 5 is controlled to control the charging current and the discharge current and to control a gradient of an input via a circuit to an identification circuit 6 thereby controlling the delay time.