JPH0440005A - oscillation circuit - Google Patents

Abstract

PURPOSE:To more exactly control symmetricity between the upper and lower waveforms of an oscillation waveform in an output by finely adjusting the ratio of amplification capability between the p-ch transistor and the N-ch transistor of a transistor amplifying an oscillation signal. CONSTITUTION:In the oscillation circuit composed of complementary MOS transistors 9 and 10 and equipped with an amplification part, a detecting means 5 is provided to detect the symmetricity between the upper and lower waveforms of the oscillation waveforms to an input voltage level in the initial state of the transistors in the amplification part. Then, the output of this detecting means 5 controls the amplification capability of the p-ch transistor 9 in the amplification part, the amplification ability of the N-ch transistor 10 or the amplification ability of the both transistors 9 and 10. Thus, the symmetricity can be corrected between the upper and lower waveforms of the oscillation output waveforms.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a complementary MO9 (hereinafter referred to as 0M08) [Prior Art] As shown in FIG.
CMO3 oscillation circuits in which transistor sizes are fixed for both h transistors and N-ch transistors have been known.

[Problem to be solved by the invention]

However, the conventional C! In MO3 oscillation circuits, the vertical symmetry of the oscillation waveform is disrupted due to manufacturing variations, changes in operating temperature, etc., so when used as a clock in a digital circuit, the pulse width changes, causing problems in circuit operation. Therefore, in order to solve the above problem, the present invention has developed an oscillation circuit that can always obtain an oscillation waveform with good waveform symmetry regardless of manufacturing variations or changes in operating temperature. The purpose is to provide.

[Means to solve the problem]

In order to solve the above problems, the oscillation circuit according to the present invention includes a P = ch transistor and an N -ch transistor.
An oscillation circuit having an amplification section configured of complementary MO8 transistors, including a detection means for detecting vertical waveform symmetry of the oscillation waveform with respect to an input voltage level in an initial state of the transistor of the amplification section. , P-cl of the amplification section is detected by the output of the detection means.
Amplification ability of l transistor, or amplification ability of N-ch transistor, or P-ch, N-c
h The feature is that the amplification capacity of both transistors is controlled.

[Effect]

In the oscillation circuit configured as described in 5 above, the oscillation waveform is converted into a DC voltage according to the waveform symmetry using an integrating circuit, and compared with the potential of a reference voltage source set in advance using a comparator. By changing the amplification capability ratio of the P-ch transistor and the N-ch transistor, which are the transistors that amplify the oscillation signal, it is possible to correct the vertical symmetry of the oscillation output waveform.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. FIG. 1 shows an embodiment according to the present invention, in which 1 is an oscillation transistor, 2 is an oscillator, 5 is an oscillation capacitor, and 4 is an oscillation transistor.
5 is a feedback resistor, 5 is a transistor for the waveform symmetry detection circuit of the oscillation waveform, 6 is an integrator for converting the oscillation signal into a DC voltage according to its waveform symmetry, 7 is a reference voltage source, and 8 is the integrator 6. The output is compared with the potential of the reference voltage source 7, and the vertical symmetry of the oscillation waveform with respect to the potential of the reference voltage source 7 changes, and the output potential of the integrator is higher than the potential of the reference voltage source 7 (
This is a comparator that outputs a signal when the Also, by controlling the reference voltage source 7 using the output of the comparator 8,
A hysteresis characteristic is provided between the output change of the integrator 6 and the output change of the comparator 8 to prevent the output of the comparator 8 from becoming unstable when the comparator 8 receives an input at the judgment boundary level. . 9 is a P-ch transistor, 10 is an N
-ch is a transistor, and 11 is an output terminal for an oscillation signal. Here, the waveform symmetry between the upper and lower sides of the oscillation waveform collapses, and the upper waveform becomes larger than the lower one, causing the output of the integrator B to rise and become higher than the potential of the reference voltage source 7. When this happens, the output of the comparator 8 goes low. From level to high level. As a result, the transistor on the power supply side of the P-ch transistors connected in series in the amplifier section becomes conductive, and the other P-ch transistor connected in series becomes in an operating state. Therefore, in addition to the amplification capacity of transistors that are constantly operating, P
-ch By increasing the amplification capacity on the h side, the upper waveform of the output waveform of the amplification section is made thicker (amplified) than the lower waveform, and the vertical waveform symmetry can be restored.

5 shows signal waveforms in the embodiment shown in FIG. 1, 12 is the output waveform of the oscillation transistor 1, 16 is the output terminal 110 waveform when the output of the comparator 8 is at high level, and 14 is the same. This is the waveform of the output terminal 110 at low level.

Also, instead of the integrator 6 and comparator 8 in FIG.
Using a converter, the P-c of the amplification transistor
By providing a plurality of transistors controlled by the output of the AII) core inverter on the h side and N-ch side, the amplification transistor's p-ch side and N-Q , h side amplification ability can be finely adjusted, and the vertical waveform symmetry of the oscillation waveform applied to the output can be controlled more accurately.

〔Effect of the invention〕

With the oscillation circuit of the present invention, it is possible to correct the collapse of the vertical waveform symmetry of the oscillation waveform caused by manufacturing variations in semiconductor devices and changes in operating temperature, and it is possible to always maintain the desired vertical waveform symmetry. An oscillation waveform can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of an oscillation circuit according to the present invention, FIG. 2 is a diagram showing an oscillation circuit according to a conventional example, and FIG. 3 is a diagram showing signal waveforms in the embodiment of FIG. i ・---・−・Oscillation transistor 2・−・・Vibrator 5−−・・・Oscillation capacitor 4・・・・・・・・・・Feedback resistor 5−− ・−・, −・Detection circuit transistor 6--・
・--Integrator 7-, ---Reference voltage source 8-- ・--Comparator 9--P-ch transistor 10...
-----・N -ch Transistor 11-...
・・・−・Output terminal

Claims (1)

[Claims] In an oscillation circuit with an amplification section configured by complementary MOS transistors consisting of a P-ch transistor and an N-ch transistor, the vertical symmetry of the oscillation waveform with respect to the input voltage level in the initial state of the transistor in the amplification section. The output of the detection means detects the amplification ability of the P-ch transistor, the amplification ability of the N-ch transistor, or the P-c
An oscillation circuit characterized by controlling the amplification capabilities of both h- and N-ch transistors.