JPH0884030A - High frequency power amplifier - Google Patents

Abstract

PURPOSE: To provide a small-sized high frequency power amplifier by using the parallel resonance circuit, which consists of a pattern inductor or a chip inductor resonating to a desired frequency and a capacitor, as the transistor choke circuit of the high frequency power amplifier. CONSTITUTION: Choke circuits 8 and 9 are loads of transistors TRs Q1 and Q2, and LC resonance circuits are used as them. Each of choke circuits 8 and 9 is set to a desired resonance frequency by the parallel resonance circuit consisting of a pattern inductor L3 and a chip capacitor C6 . It is set to a desired resonance frequency by the parallel resonance circuit consisting of a chip inductor L4 and a chip capacitor C7 . The high frequency power amplifier having choke circuits 8 and 9 set in this manner amplifies the high frequency signal of a desired frequency band determined by choke circuits 8 and 9. Since LC resonance circuits are used as choke circuits 8 and 9, the inductance is low, and circuit parts are considerably miniaturized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact high frequency power amplifier.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a circuit configuration of a conventional high frequency power amplifier. In the figure, 1 is an input terminal, 2, 3 and 4 are matching circuits, C ₁ , C ₂ , C ₃ , C ₄ and C ₅ are capacitors, Q ₁ and Q ₂ are transistors, G is a gate, and Vcc ₁ is a first 1 power supply, Vcc ₂ is the second power supply, 5 and 6 are transistors Q ₁ ,
A choke circuit serving as a load of Q ₂ (hereinafter, a choke circuit serving as a transistor load is referred to as a transistor choke circuit), and 7 are output terminals, which are connected as illustrated. The operation of this circuit is similar to that of a normal high frequency amplifier, and amplifies a high frequency signal in a desired frequency band determined by the choke circuits 5 and 6.

As the choke circuits 5 and 6, the pattern inductor L ₁ as shown in FIG.
A chip inductor L ₂ as shown in (b) is used.

[0004]

In order to provide the choke circuits 5 and 6 with a high choke property in such a circuit structure, the inductance of the pattern inductor L ₁ or the chip inductor L ₂ must be increased. However, this inevitably leads to an increase in size and an increase in DC loss.

The present invention solves such a conventional problem and provides a small-sized high frequency power amplifier which does not increase the inductance and the DC loss.

[0006]

In order to solve the above problems, the present invention uses, as a transistor choke circuit in a high frequency power amplifier, a pattern inductor that resonates at a desired frequency or a parallel resonant circuit including a chip inductor and a capacitor. Is.

[0007]

With the above construction, the circuit inductance becomes smaller than that of the conventional one, so that the transistor choke circuit becomes smaller and the DC loss thereof becomes smaller.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the same parts as those of the above-mentioned conventional one are denoted by the same reference numerals. FIG. 1 is a circuit configuration diagram showing an embodiment of a high frequency power amplifier of the present invention. In the figure, 1 is an input terminal, 2, 3 and 4 are matching circuits, C ₁ , C ₂ , C ₃ , C ₄ and C ₅ are capacitors, and Q ₁ and Q ₂ are capacitors.
Is a transistor, G is a gate, Vcc ₁ is the first power supply, and Vcc ₂
Is a second power source, 8 and 9 are choke circuits that serve as loads on the transistors Q ₁ and Q ₂ , and 7 is an output terminal, which are connected as shown in the drawing.

The contents of the choke circuits 8 and 9 are the gist of the present invention, and an LC resonance circuit as shown in FIGS. 2 (a) and 2 (b) is used. What is shown in Fig. 2 (a) is
A parallel resonance circuit composed of the pattern inductor L ₃ and the chip capacitor C ₆ is set to a desired resonance frequency, and the one shown in FIG. 2B is a parallel resonance circuit composed of the chip inductor L ₄ and the chip capacitor C _7. The desired resonant frequency is set as in the resonant circuit of FIG.

The choke circuits 8 and 9 set in this way
The operation of the high frequency power amplifier having the above is to amplify a high frequency signal in a desired frequency band determined by the choke circuits 8 and 9 as in the conventional one. Is used,
Its inductance is small, compared to the conventional one,
The circuit components are significantly downsized.

[0011]

As is apparent from the above embodiments, the present invention uses the LC resonance circuit as the transistor choke circuit of the high frequency power amplifier, so that its inductance is small and therefore the circuit parts of the transistor choke circuit are The size is greatly reduced, which leads to size reduction of the high frequency power amplifier itself. Moreover, since the DC loss of the entire transistor choke circuit is also reduced, the power efficiency of the amplifier can be improved.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a high frequency power amplifier of the present invention.

FIG. 2 is a schematic diagram showing each example of a choke circuit used in an embodiment of the present invention.

FIG. 3 is a circuit configuration diagram showing an example of a conventional high frequency power amplifier.

FIG. 4 is a schematic diagram showing each example of a choke circuit used in a conventional example.

[Explanation of symbols]

1 ... input terminal, 2, 3, 4 ... matching circuit,
_{C 1, C 2, C 3} , C 4, C 5 ... capacitor, Q _1, Q ₂ ...
Transistor, G ... Gate, Vcc ₁ ... First power supply, Vc
c ₂ ... Second power supply, 5, 6, 8, 9 ... Choke circuit, 7
… Output terminals, L ₁ , L ₃ … Pattern inductors,
L _2, L ₄ ... chip inductor, C _6, C ₇ ... chip capacitors.

Claims (2)

[Claims] 1. A high frequency power amplifier, wherein a parallel resonance circuit of a pattern inductor and a capacitor which resonates at a desired frequency is used as a transistor choke circuit in the high frequency power amplifier. 2. A high frequency power amplifier characterized in that a parallel resonance circuit of a chip inductor and a capacitor which resonates at a desired frequency is used as a transistor choke circuit in the high frequency power amplifier.