JPS6180905A - Oscillating circuit - Google Patents

Abstract

PURPOSE:To obtain a good oscillation frequency stability in the whole area of an oscillation frequency by a simple constitution, by using a constitution for changing only an impressed voltage to a collector with respect to at ambient temperature. CONSTITUTION:A temperature variation of an inter-electrode voltage of a Zener diode 13 is utilized by placing the Zener diode 13 through a resistance 12 in a collector voltage impressed terminal of an oscillating circuit. In case when a Zener diode of 11V inter-electrode voltage has been used, a temperature coefficient of the inter-electrode voltage is 6mV/ deg.C, and with respect to an ambient temperature variation of + or -40 deg.C, the inter-electrode voltage is varied by + or -0.24V, an oscillation frequency is changed by + or -0.72MHz, and the oscillation frequency is compensated. In a collector ground oscillating circuit, and also in an emitter ground oscillating circuit, the internal capacity of between the collector and the base is an element for determining the oscillation frequency, therefore, a temperature compensating effect is obtained by the same constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an oscillation circuit using transistors.

[Background of the invention]

In the oscillation circuit of a cheese or humperter, one of the three terminals of the oscillation transistor is grounded at a high frequency, as shown in FIG. A configuration is used in which a feedback capacitor is connected between the other two terminals, a resonant circuit is placed to one of the above two terminals via a coupling capacitor, and a variable capacitance diode is used in the resonant circuit to make the frequency variable. . In this oscillation circuit, the capacitance value of the variable capacitance diode changes due to temperature changes, and the oscillation frequency fluctuates. Generally, a temperature compensation capacitor whose capacitance changes with temperature is used for the feedback capacitor and the coupling capacitor shown in the figure to reduce changes in the oscillation frequency due to changes in the capacitance of the variable capacitance diode. This conventional #l generation oscillator circuit is characterized by the fact that the capacitance temperature change of the variable capacitance diode differs depending on the capacitance value, the temperature coefficient of the compensation capacitor has a limit on its absolute value, and the compensation of the coupling capacitor is limited to the oscillation frequency. Since it is effective only on the low frequency side, it has been difficult to obtain an oscillation frequency that is stable over temperature over the entire oscillation frequency range.

In addition, in the above conventional configuration, it is easy to think of making the voltage applied to the variable capacitance diode change with temperature or placing a temperature compensation capacitor in parallel with the variable capacitance diode to reduce the capacitance change of the variable capacitance diode. However, in the former case, the oscillation frequency change due to the variable capacitance is large, so it is difficult to optimally design the temperature change of the applied voltage circuit, and in the latter case, the variable range of the oscillation frequency is narrower, and the oscillation frequency changes in the high range. It had the disadvantage that only the compensation effect appeared.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an oscillation circuit configuration that has a simple I-structure and whose oscillation frequency changes little with temperature.

[Summary of the invention]

In the present invention, by using a configuration in which only the voltage applied to the collector is changed according to the ambient temperature without changing the base and emitter voltages of the oscillation transistor, it is possible to achieve good oscillation frequency stability over the entire oscillation frequency range with a simple configuration. Get a degree.

[Embodiments of the invention]

FIG. 1 shows a conventional oscillation circuit with a grounded base.

The base of the oscillation transistor 10 is grounded impedance at high frequency with a large capacity capacitor 2, and a feedback capacitor 3 is connected between the collector and emitter. -)-6 is arranged, and the power supply voltage is supplied to terminals 10 and 11.・It is determined by the resonant layer wave number of the circuit consisting of the internal capacitance 8 between the bases, the emitter 7, and the internal capacitance 9 between the bases.If any one of these capacitances becomes smaller, the oscillation frequency increases. However, as the capacitance increases, the oscillation frequency decreases. In this oscillation circuit, a voltage Z is applied to the variable capacitance diode through the resistor 7, and as the applied voltage increases, the capacitance of the variable capacitance diode decreases and the oscillation frequency increases.
In the IGHz band oscillation circuit with this circuit configuration, s o o I'
It is possible to vary the frequency over a wider range than ilz. Since the capacitance value of the variable capacitance diode 6 increases as the ambient temperature rises, the oscillation frequency has a negative slope that decreases as the temperature rises.

Here, when voltage application terminals 10 and 11 to the collector and base of the oscillation transistor 1 are separated and the voltage applied to each is changed, the fluctuation in the oscillation frequency is as follows: MIJz/V, the application terminal 11 to the base is -2.5MHz/V at the total oscillation frequency
When the voltages applied to terminals 10 and 11 were changed simultaneously, the total oscillation frequency was 0.5 MHz/V. This is because when the voltage between the collector and base increases, the capacitance 8 between the collector and base decreases and the oscillation frequency increases.The increase in base voltage causes the collector voltage to decrease due to the increase in current, and the collector pace increases. The intervening capacitance 8 increases and the oscillation frequency decreases.

From this, a stable oscillation frequency can be obtained with a simple configuration by increasing the voltage applied from the terminal 10 in response to the rise in ambient temperature and compensating for oscillation frequency fluctuations due to changes in capacitance temperature of the variable capacitance diode.

FIG. 2 shows an embodiment of the present invention. A Zener diode 13 is arranged via a resistor 12 to the collector voltage application terminal of the oscillation circuit shown in FIG. now,
When using a Zener diode with an interelectrode voltage of 11V, the temperature coefficient of the interelectrode voltage is 6mV/''C, which is ±40
When the ambient temperature changes by .degree. C., the voltage between the electrodes changes by .+-.0.24 V, and the oscillation frequency changes by t.+-.072.times.Z. That is, the oscillator with this configuration has an oscillation frequency stability of +0.72 2 for all oscillation frequencies against a temperature rise of ±40°C.

Embodiment 7 of the present invention is shown in FIG. This is a configuration that greatly compensates the temperature of the oscillation frequency, and a resistor 14 is connected between the power supply terminal and the collector tlE pressure application terminal 10 of the oscillation transistor 1, and the collector of a PNP transistor 15 is connected to the terminal 10. The emitter of the PNP transistor 15 is connected to the i source terminal via a resistor 16, and a fixed voltage is applied to the base of the PNP transistor 15 through resistors 17 and 18.

Now, the current of oscillation transistor 1 is 1. The resistor 16 is set to R8, the resistor 14 is set to R8, and the pace voltage of the PNP transistor 15 is set to V.
B, base emitter l'J'? [When the voltage is VBE, the voltage V at the collector voltage application terminal 1o of the oscillation transistor 1 is given by the following formula: B - Va - VBE V "" B - Rt (I R,) Here, consider voltage changes due to temperature. To one ■ - knee”! , dvBE dT R,dT . Generally, the temperature change in the base-emitter voltage is -
2m V/'C, R8 and horse *5aa and 500 respectively
If you choose g, the collector will be applied t IE V C ±4o''C
The circumferential M temperature changes by ±α8V, and the oscillation frequency is compensated by 2°4 Mh. It is clear that any temperature compensation can be obtained by selecting R2 and R2.

Furthermore, as shown in FIG. 4, a diode 19 is connected to the emitter of the PNP transistor 15.
By arranging , the temperature compensation sensitivity is further improved. It is also effective to use a heat-sensitive semiconductor device in the pace voltage supply circuit formed by resistors 17 and 18, or to use a heat-sensitive resistance element whose resistance value changes with the ambient temperature M in either of resistors 16, 17 and 18. It is clear that

FIG. 5 is a diagram showing a modification Y of the present invention, in which an NPN transistor 20 is used to transfer two currents, the current flowing through the oscillation transistor 1 and the current flowing through the transistor 20, to the resistor 14.
By changing the current flowing through the transistor 20 in response to the mW temperature, the voltage applied to the collector of the transistor 1 is changed.
Place 23 energized diodes with zero base voltage,
Temperature compensation can be performed for all oscillation frequencies by arranging a heat-sensitive resistance element or the like on the resistor 21 or 22 to reduce the current flowing through the transistor 20 as the temperature rises.

Although the present invention has been described with respect to a pace grounding oscillation circuit, it is not limited to this circuit, and the present invention is not limited to this circuit.
In the common emitter oscillator circuit as well as the common emitter oscillator circuit as shown in Figure 4 of Publication No. 7900,
Since the internal capacitance between the collector and the pace is a factor in determining the oscillation frequency, the present invention provides a temperature compensation effect.

FIG. 6 shows a circuit array when the present invention is applied to the conventional collector oscillation circuit described above. In an oscillation circuit in which the collector of the oscillation transistor 24 is grounded at high frequency, by arranging the circuit of the present invention consisting of the resistor 14 and the PNP transistor 15 to the voltage terminal 25 applied to the collector, the temperature rise will cause The flowing current increases, the voltage at the terminal 25 rises, the internal capacitance 26 between the collector and the pace decreases, and the oscillation frequency absorbs the positive slope compensation with respect to temperature, resulting in stable characteristics at all oscillation frequencies. It will be done.

The present invention changes the collector voltage without changing the current of the oscillation transistor, and compensates for the temperature by changing the internal capacitance between the collector and the pace. Therefore, stable oscillation operation and stable oscillation frequency can be achieved in the entire oscillation band. It will be done. Furthermore, since a compensation capacitor in parallel to the variable capacitance diode is not used, a wide variable width can be obtained.

In addition, although the present invention has been explained using a variable frequency oscillation circuit, the present invention is not limited to this, and the effects of the present invention are obvious also in a fixed frequency oscillation circuit in which a variable capacitance diode is replaced with a fixed capacitance capacitor or the like.

〔Effect of the invention〕

By using the configuration of the present invention that changes only the voltage applied to the collector in accordance with the ambient temperature without changing the current of the oscillation transistor, good oscillation layer wavenumber stability can be achieved over a wide range of variable frequencies with a simple configuration. degree can be obtained.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a conventional example of a common base oscillator circuit, Fig. 2 is a circuit diagram showing an embodiment of the present invention, and Figs. FIG. 3 is a circuit diagram showing another example. 1.24...Oscillation transistor, 3...Feedback capacitor, 4...Coupling capacitor, 5
... Inductance, 6... Variable capacitance diode, 8... Collector/base H1llfE capacity iL, 15
...PNP transistor, 20...NPN transistor, 14...resistor, 13.23...Zener diode. Tsumugi 1 Kuchi 2 Ward Otsu 2

Claims (1)

[Claims] 1) A first resistor is connected between a collector voltage application terminal of the oscillation transistor and a power supply voltage supply terminal, a collector of a voltage control PNP transistor is connected to the collector voltage application terminal, and the PNP transistor is connected to the collector voltage application terminal of the oscillation transistor. An oscillation circuit characterized in that an emitter of the transistor is connected to the power supply voltage supply terminal via a second resistor, and a fixed voltage is applied to the base of the PNP transistor. 2) In the first claim of the patent, PNP for voltage control
An oscillation circuit characterized in that a heat-sensitive semiconductor or a heat-sensitive resistor is used in the circuit for supplying voltage to the base of a transistor or the emitter circuit.