KR20000015119U - Resonant circuit capable of resonance by band - Google Patents

Abstract

The present invention is to provide a resonant circuit capable of resonating signals of two frequency bands, one capacitor (C1) and an inductor (L1) is configured in the resonant circuit 10, the resonant circuit 10 Capacitor C2 is connected via diode D1. Accordingly, as the diode D1 is driven, the capacitance in the resonant circuit 10 is changed to the capacitance by the capacitor C1 or the capacitance by the sum of the capacitors C1 and C2, and accordingly the resonance of the resonant circuit 10. The frequency is variable.

Description

Resonant circuit capable of resonance by band

The present invention relates to a resonant circuit, and more particularly to a resonant circuit capable of resonant band by band capable of resonating two or more frequency bands.

An oscillation circuit means a circuit for outputting a signal having a predetermined frequency, which is a reference for processing an electrical signal, and an oscillation frequency is set using a separate resonator.

The resonant circuit refers to a circuit including an inductive element and a capacitance element and continuously outputting a predetermined frequency signal when the reactance component or the susceptance component of the circuit becomes 0 at the frequency at which the absolute value of the reactance thereof is the same.

1 shows a block diagram of an oscillation circuit using such a resonance circuit.

As shown, the resonant circuit 10 is configured by using the inductor L1 as an inductance element and the capacitor C1 as the capacitance element, and in this circuit, the capacitor C1 of the capacitor C1 is extremely low. When the charge is discharged through the inductor L1 or the internal resistance, a vibration current is generated. Even when there is no charge to discharge through the inductor L1, the vibration current is continued and the capacitor C1 is charged in reverse, and then discharged in the reverse direction again. This happens.

The resonant frequency in the resonant circuit 10 is set as in Equation 1 by inductance and capacitance.

Here, L is the inductance of the inductor (L1), C is the capacitance of the capacitor (C1).

As can be seen from Equation 1, in the general resonant circuit 10, only one resonant frequency formed by the inductance component and the capacitance component is formed, and the oscillator circuit 20 oscillates and outputs a signal corresponding to the resonant frequency.

On the other hand, in order to vary the resonant frequency in the above-described resonant circuit 10, a variable capacitor or inductor should be employed to convert capacitance and inductance, but such a variable capacitor or inductor has a problem of being expensive.

The present invention has been devised to solve such a problem, and an object of the present invention is to provide a resonance circuit capable of performing resonance by band.

In order to achieve the above object, the present invention provides a resonant circuit for providing a resonant frequency corresponding to capacitance and inductance of a first capacitor and an inductor; A diode connected to the resonant circuit and selectively driving according to the application of the selection voltage; And a second capacitor connected to the diode, wherein the capacitor and the combined capacitance of the resonant circuit are provided to the resonant circuit when the diode is driven to vary the resonant frequency of the resonant circuit.

1 is a view showing a conventional oscillation circuit using a resonance circuit;

Figure 2 is a view showing a resonance circuit capable of resonance for each band according to the present invention.

<Description of the symbols for the main parts of the drawings>

10 resonant circuit 20 oscillation circuit

C1, C2: Capacitor L1: Inductor

D1: diode

Hereinafter, with reference to the accompanying drawings an embodiment of the present invention will be described in detail.

1 is a circuit diagram of an apparatus according to the present invention, and an oscillation circuit 20 for oscillating a signal according to a resonant frequency of a resonant circuit 10 is configured, and the resonant circuit 10 includes one capacitor C1 and an inductor. It consists of (L1). Thus, the resonant circuit 10 will be set by the resonant frequency of the capacitance and inductance of the capacitor (C1, L1) and inductor (L1).

However, a diode D1 is connected to the resonant circuit 10, and the diode has a configuration in which a predetermined selection voltage is selectively applied through the bias resistor R1. Here, the selection voltage should be at least 0.7V.

On the other hand, the capacitor (C2) is connected in parallel with the resistor (R1), and the capacitor (C2), together with the capacitor (C1) and the inductor (L1) as described later selectively constitute a resonant circuit.

The operation of the present invention configured as described above will be described below.

First, a case in which the selection voltage is not applied through the resistor R1 will be described.

The state in which the selection voltage is not applied means a state in which a voltage of 0.1 V or less is applied to the anode side of the diode D1, and thus the diode D1 is turned off.

Therefore, since the inductor L1 and the capacitor C1 in the resonant circuit 10 constitute a resonant circuit separately from the capacitor C2, a predetermined resonant frequency due to the inductance of the inductor L1 and the capacitance of the capacitor C1 is determined. The oscillation circuit 20 oscillates and outputs a signal having a frequency corresponding to this resonance frequency.

On the other hand, when the selection voltage is applied, it can be seen that the diode D1 is driven by the selection voltage, and thus the capacitors C1 and C2 are connected in parallel. In other words, the capacitance of the resonant circuit 10 is set to the sum of the capacitances of the capacitors C1 and C2. Therefore, the resonance frequency f caused by the capacitors C1 and C2 and the inductor L1 is set as shown in Equation (2).

Here, C ₁ refers to the capacitance of the capacitor (C1), C ₂ refers to the capacitance of the capacitor (C2).

That is, in the present invention, by selectively connecting the capacitor C2 to the resonant circuit by the inductance L1 and the capacitor C1 through the diode D1, the capacitance value of the resonant circuit by the capacitor C2 is varied. The resonant frequency of the resonant circuit is changed.

As such, the present invention has an effect that the resonance frequency of the resonance circuit can be changed by adding a capacitor and a diode to one resonance circuit.

Claims (1)

A resonant circuit providing a resonant frequency corresponding to capacitance and inductance of the first capacitor and the inductor; A diode connected to the resonant circuit and selectively driving according to the application of a selection voltage; A resonance circuit connected to the diode and having a second capacitor configured to provide a capacitor and a synthesized capacitance of the resonant circuit to the resonant circuit when the diode is driven to vary the resonant frequency of the resonant circuit.