JPS63139407A - Negative feedback type crystal oscillator using complementary metallic oxide film semiconductor - Google Patents

Abstract

PURPOSE:To improve an oscillation frequency fluctuation ratio characteristic to the fluctuation of a power source voltage and the change of an ambient temperature by inserting and connecting a resistance into respective sources of a metallic oxide film semiconductor electric field effect transistor MOS FET, forming the negative feedback circuit of a serial crossflow, inserting the resistance between the gate and the drain of respective stages and forming a parallel negative feedback circuit. CONSTITUTION:In a complementary metallic oxide film semiconductor (CMOS) single stage amplifier, a resistance (R1) is inserted between a metallic oxide semiconductor electric field effect transistor (MOS FET)T 1 source and a ground, a resistance (R2) is inserted between a T2 source and a resistance (R2) and the negative feedback circuit of the serial crossflow is formed. The fluctuation of the parameter of FETT1 and T2 is made smaller, and the bias between the gate and the source is also made stable. Further, a resistance (R3) is inserted from the drain to the gate, the negative feedback of the parallel crossflow is executed and the bias between the gate and the source is made stable. Further, a frequency determining circuit (C, C1 crystal oscillator circuit) is positively fed back from the drain to the gate. At this time, a capacity (C) is made larger as much as possible, determined to the extent of a=C/C1=5-11, a necessary amplification degree is made smaller, and an excess amplification degree is turned to the negative feedback. For this reason, the oscillation frequency fluctuation ratio characteristic is improved.

Description

[Detailed description of the invention] The oscillation frequency of a crystal oscillator for wristwatches, etc. is 3.2768M.
H2 is often used, but the power supply voltage is about 3
The circuit shown in FIG. 1, in which an oscillation frequency fluctuation rate of about 1 ppm is observed for a 0% decrease, has been conventionally used. The value of capacity ffi (C) is relatively small, and a=
The value of C/c1 is about 1 to 4, so the required amplification is large, and there is little margin for negative feedback. Furthermore, series negative feedback is not implemented for each source of T1 and T2. Moreover, the parameter fluctuation rate of each metal oxide semiconductor field effect transistor (MOSFET) of TI and T2 becomes large, and the oscillation frequency fluctuation rate characteristics with respect to fluctuations in power supply voltage and changes in ambient temperature are poor.

Also shown in FIG. 2 is a circuit using a complementary metal oxide semiconductor (CMOS) crystal oscillator actance stabilization method using a compensation crystal. This 1'J property is shown in FIG.

Although there is a difference in power supply voltage, the oscillation frequency fluctuation rate characteristic is about 1 Dpm to 0.5 ppm for a voltage drop of about 30%, which is not very good. This means that the value of ffi (C) is relatively small, and moreover, a=C/C1=1 to 2,
Therefore, the required degree of amplification increases, and the margin for negative feedback is small.Furthermore, since series negative feedback is not applied to the sources of T1 and T2, the metal oxide semiconductor field effect transistors (MOS) of T1 and T2 are This increases the parameter fluctuation rate of the FET (FET), resulting in poor frequency fluctuation characteristics with respect to fluctuations in power supply voltage and changes in ambient temperature. Furthermore, it has the disadvantage that one compensating crystal is used for the remainder i1. In addition, although the reactance stabilization method shows that the transistor parameters do not affect the oscillation frequency, it is difficult to match the required stabilization conditions to the calculated values in the actual circuit, so the oscillation frequency in the actual circuit is difficult. The frequency fluctuation rate is bad. Figure 3 shows this. In other words, we are experimenting with various values of C and 01, but the difficulty in the experimental circuit is that the oscillation frequency fluctuation rate for a 30% drop in power supply voltage changes significantly from IpI)m to 0.5 ppm. It clearly shows that. Furthermore, it has the disadvantage that the gate bias is applied with negative feedback by Rgl and R(+2).

Next, the configuration of the present invention and its effects will be described.

A three-stage complementary metal oxide semiconductor (0M
In the C3> amplifier, (there are no off-the-shelf products (commercial products) on the market, however, it is a circuit that can be easily manufactured considering the current 1.C manufacturing technology.) Metal oxide film semiconductor field effect transistor (MC3FET>T1 , T2.T
3. T4. T5. T6. Each source (Sl, G2
．． G3゜34, 35. G6) and resistors (R1, R2, R
3, R4, R5, R6) to perform series type (current type) cross-current negative feedback, and also insert (D1→G1, D2→G2, D3→G3, D3) between the gate and drain of each stage.
→G1) Resistors (R7゜R8, R9, R10) are inserted to provide parallel type (voltage type) cross-current negative feedback to compensate for fluctuations in various parameters of the metal oxide semiconductor field effect transistor (MC3FET). In addition, a resistor (R11) is connected from the T5 source (G5) to the T1 source (S1).
Also T6 sauce (G6)! : Insert and connect the resistor (R12) to the T2 source (G2), and then connect it to the T6 source (G2).
6) from the T1 source (S1), and from the T5 source (G5) to the T2 source (G2).
14) is inserted to form a negative feedback circuit for cross-current flow between stages, thereby suppressing the fluctuation rate of various parameters of the complementary metal oxide film semiconductor <0MC3> amplifier section to an extremely low level. Furthermore, the capacity of the frequency determining circuit! Make (C) as large as possible, and a
=C/Cl-5 to about 11, the required amplification degree is reduced, and the margin amplification degree is turned to negative feedback to further increase the oscillation frequency stability.

Therefore, as will be described later, the oscillation frequency fluctuation rate characteristics with respect to changes in power supply voltage and ambient temperature are much better than conventional circuit systems. Note that as shown in Figure 4, the gate (G1) is lower than the drain (D3).
) is positively fed back to the oscillation frequency determining circuit consisting of capacitors (C, CI) and a crystal resonator.

Next, as a specific circuit example of the present invention, as shown in FIG.
(MC74HCUO4, MC14069UB, etc.) Insert a resistor (R1) between the T1 source and ground, and also insert a resistor (R2) between the T2 source and the power supply to form a series cross-current negative feedback circuit. , metal oxide semiconductor field effect transistor (MC8FET>TI and T2 (7
) In addition to reducing parameter fluctuations, the bias between the gate and source is also stabilized. Furthermore, a resistor (R3) is inserted from the drain to the gate to provide parallel cross-current negative feedback to stabilize the bias between the gate and source. Furthermore, the frequency determination circuit (C, CI water resonator circuit)
positive feedback from the drain to the gate. At this time, make the comb (C) as large as possible, maybe a=c/
Decide c1=5 to 11 and reduce the required amplification,
Since the margin amplification is turned to negative feedback, the oscillation frequency fluctuation rate characteristics are improved. Therefore, as shown in Figure 6, the Δflf value ±
5.5X 1O-8 = about 0゜055ppm (
(The power supply voltage is doubled compared to the conventional one), and for changes in ambient temperature, Δf/f is ±1.5X10-7=±0. 15 p.
It is about pm. (However, the CC1 crystal was kept constant at room temperature during the experiment. This focused on observing how much the effects of the input/output resistance, phase angle, transfer conductance, etc. of the TI T21 transistor were reduced. ) The power supply voltage characteristics are approximately 1
The 0x Δf/f' characteristic is improved.

Next, in a three-stage complementary metal oxide semiconductor (0MC3) amplifier as shown in FIG. T5.
A resistor (R1) is inserted and connected between the common source (point A) of T2. T4. Ding 6. common source (B
Insert a resistor (R2) between the point) and the power supply to connect the straight type 11 (
Complementarity is achieved by forming a cross-current negative feedback circuit (current type), and inserting a resistor (R3) from the drain (D3) to the gate (G1) to provide parallel type (voltage type) cross-current negative feedback. Metal oxide film semiconductor (0MC3> Variations in various parameters of the amplifier are suppressed to a small level. (Since it is a commercially available product, DI-G
2 and D2-G3 are directly connected. ) Furthermore, capacitance (C) is added from the drain (D3) to the gate (G1).

A frequency determining circuit consisting of CI) and a crystal oscillator is subjected to positive feedback. In this case, the capacitance <c (the capacitance on the side of the drain) is made as large as possible (increasing C makes it difficult to oscillate), and a=c/cL=about 5 to 11, so the required amplification is small. Since the margin amplification can be used for negative feedback, the starting frequency fluctuation rate characteristics are relatively good. Figure 8 shows its characteristics.

Power supply voltage value Vxzn = soil 304 pot 1; village L7Δ
r/f:=±3.5x 1O-8=±o, o3sppm
Although it is only slightly rough, it is about 10 times better than the conventional one.

For changes in ambient temperature, Δf/f or ± for changes in ΔTa = -5 to +55°C.
It is as small as 5.5X 1O-8=±0.055ppm.

Furthermore, although the gist of the present invention has been described qualitatively up to now, it will now be explained quantitatively and theoretically. That is, a complementary metal oxide semiconductor (CMOS>1 device),
In the oscillation frequency determination circuit consisting of a capacitor 1 (C, C1) and a crystal oscillator, and the feedback type crystal oscillation circuit consisting of a complementary metal oxide semiconductor (CMOS), The characteristics of a semiconductor (0MO5) amplifier are analyzed, and the conditional expression for determining the oscillation frequency when a frequency determining circuit is further inserted is derived.This is a fairly long calculation, so only the main points will be described and the details will be omitted.

Here, the conditional expression for determining the oscillation frequency is - generally Aω5-Bω4
It is expressed by a quintic equation: +Cω3-Dω2+Eω-F=o-417, and analysis is generally impossible. However, the actual circuit constants are A, 8. C.

By substituting D, E, and F, ABCDEF becomes a known number, so it can be analyzed by a computer and the unknown number ω(fo) can be found.

(ω = 2πfO) Therefore, ABCDEF at each power supply voltage value is calculated by substituting it into equation (1), and it is plotted on a graph without the theoretical value.On the other hand, the actual value is plotted on the same graph. , the oscillation frequency fluctuation rate characteristics become clear. In other words, it was found that the theoretical value and the measured value fluctuated at the same order of magnitude and showed the same trend curve. In other words, the theoretical value and the measured value showed good agreement. In this way, it has become clear both experimentally and theoretically that the circuit of the present invention has excellent frequency stability due to the Conbuxis Snillion.

The outline of the circuit analysis is described below.

Figure 9 shows the absolute value of the transfer conductance of a complementary metal oxide semiconductor (CMOS>feedback type), its phase angle θ, and the drain resistance GQz. Figure 10 is an equivalent circuit diagram of Figure 9, and the resistance (R3) Apply negative feedback and further resistor (R1)
(R2) forms a negative feedback, and the capacitance (C, CI) and the crystal resonator (LX CX RX ) are subjected to positive feedback. Figure 11
is a complementary metal oxide semiconductor (CMOS) T1 metal oxide semiconductor field effect transistor (MOS FET)
FIG. 3 is an equivalent circuit diagram of a stage. Here, T4=Q -12) V3 ・ Tz RH "NOGOMIZ°'GUKO2...ノη'-11111! F Two Kats! One 2Z
ri2shi1υkahi concubine trout tea a'(=0 i'
28t: 1'l16+b R'(t7>t+?
λ (9) (2u) E r1゛) (+20J Kaorimai's Kisho tU Dokki 1S Bamboo j.

7゛mi 3゜

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a complementary metal oxide semiconductor (CMOS) crystal oscillator. Figure 2 shows a complementary metal oxide semiconductor (C
1 is a circuit diagram showing an example of a MOS (MOS) crystal oscillator. FIG. 3 is a diagram showing the oscillation frequency fluctuation rate characteristics with respect to changes in power supply voltage of the circuit shown in the second diagram. FIG. 4 is a specific circuit diagram showing one embodiment of the present invention. FIG. 5 is a specific circuit diagram showing different embodiments of the present invention. FIG. 6 is a diagram showing the oscillation frequency fluctuation rate characteristics of the circuit shown in FIG. 5 with respect to changes in power supply voltage and ambient temperature. FIG. 7 is a specific circuit diagram showing different embodiments of the present invention. FIG. 8 is a diagram showing the oscillation frequency fluctuation rate characteristics with respect to changes in power supply voltage and ambient temperature of the circuit shown in FIG. 7. FIG. 9 is a diagram showing the principle of an amplifier of a concrete circuit showing different embodiments of the present invention. FIG. 10 is an equivalent circuit diagram of a specific circuit showing different embodiments of the present invention. FIG. 11 shows a specific circuit amplifier metal oxide semiconductor field effect transistor (MO2) showing different embodiments of the present invention.
S FET) 1 amplifier equivalent circuit diagram. FIG. 12 is a block diagram of the present invention. FIG. 13 is a principle diagram of a specific circuit showing different embodiments of the present invention. Patent applicant Sakutomi Chiba. 81δ2 (zoQpJ! 2) jj? ia /
/ /z1, r a −+ L/DO
(V) Issuance of amendment to figure 121 procedure (method) % formula % 1. Indication of case Showa Otsu 1 patent application No. 14. −(S'
No. 17 Hanbakukyu Crystalline Lens T Suishun 3, Relationship with the case of the person making the amendment Patent applicant address (residence)

Claims (3)

[Claims] (1) In a three-stage complementary metal oxide semiconductor (CMOS) amplifier (as shown in Figure 4), metal oxide semiconductor field effect transistors (MOSFETs) T1, T2
, T3, T4, T5, T6,
) (S1, S2, S3, S4, S5, S6,) with resistance (
R1, R2, R3, R4, R5, R6,) are inserted and connected to form a series cross-current negative feedback circuit, and resistors (R7, R8) are connected between the gate and drain of each stage. , R9, R10) (however, R10
is connected from D3 to Gl), a parallel negative feedback circuit is formed, and a resistor (R11) is inserted from the T5 source (S5) to the T1 source (S1), and the T2 source is connected from the T6 source (S6).
Insert a resistor (R12) into the source (S2), and then insert a resistor (R13) from the T6 source (S6) to the T1 source (S1).
and also connect the T2 source (S5) to the T5 source (S5).
A resistor (R14) is inserted into 2) to configure a negative feedback circuit for cross-current flow between stages, and the capacitance (R14) of the frequency determining circuit is also
C) is made as large as possible, and the value of a=C/c1 is set to an appropriate value, so that T is smaller than the drain (D3) of T5 and T6.
1. Negative feedback complementary metal oxide semiconductor (CMOS) characterized by positive feedback of an oscillation frequency determining circuit consisting of capacitors (C, C1) and a crystal resonator to the gate (G1) of T2.
) crystal oscillator. (2) In a single-stage complementary metal oxide semiconductor (CMOS) amplifier (as shown in Figure 5), a resistor (R1) is inserted between the T1 source and the ground, and a resistor (R2) is inserted between the T2 source and the power supply. ) is inserted to form a cross-current series negative feedback circuit, and a resistor (R3) is connected from the drain to the gate to form a cross-current parallel negative feedback circuit. ) as large as possible, a=C/
Negative feedback complementary metal oxide semiconductor (CMOS) crystal characterized by setting c1 to an appropriate value and positively feeding back the oscillation frequency determining circuit consisting of capacitors (C, C1) and a crystal resonator from the drain to the gate. oscillator. (3) In a three-stage complementary metal oxide semiconductor (CMOS) amplifier (as shown in Figure 7, each source is commonly connected and the drain and gate of each stage are directly connected) T1 , T3, T5, a resistor (R1) is inserted between the common source (point A) and ground, and T2, T4, T6
A resistor (R2) is inserted and connected between the common source (point B) of , and the power supply to form a cross-current series negative feedback circuit, and a resistor (R_3) is connected from the drain to the gate (D_3 → G_1
) Form a cross-current parallel negative feedback circuit, further increase the capacitance (C) of the frequency determining circuit as much as possible, set a=C/C1 to an appropriate value, and set the capacitance (C, C
1) A negative feedback complementary metal oxide semiconductor (CMOS) crystal oscillator characterized by positive feedback of an oscillation frequency determining circuit consisting of a crystal resonator from the drain to the gate.