| 摘要 |
PURPOSE:To stabilize a substrate bias preventing oscillating frequency from fluctuating by a method wherein the substrate bias is generated by a pumping circuit making use of an oscillator where odd number of CMOS inverters are longitudinally and circularly connected to one another. CONSTITUTION:A circular OSC circuit is made of three sets of inverters comprising N channel FET Q1-Q3 on P type substrate and P channel Q4-Q6 in N type well inserting P channel Q7, Q8 and MOS capacities C1, C2 as resistors into specified positions and providing N channel Q13 as common rated current power supply on ground side to supply gate with voltage Vcc. An oscillating output is supplied for a pumping circuit through inverters (AMP) P channel Q10, N channel Q9 provided between Vcc and ground. In case of high output, diode Q11 is turned ON charging capacitor C3 while in case of low output, Q11 is turned OFF and Q12 is turned ON dispersing charge into parasitic capacity Cp supplying the substrate with -VBB conforming to oscillating frequency. Through these constitution, the rise speed (gm) of OSC inverter is rated regardless of the fluctuation of -VBB stabilizing the oscillating frequency and -VBB in consequence. |
