JPH04320366A - Pll module - Google Patents

Abstract

PURPOSE:To avoid a PLL module from increasing in size by providing a voltage regulator and to reduce fabrication cost. CONSTITUTION:A PLL loop is constituted of a voltage controlled oscillator 1, a lowpass filter 2 and a PLL frequency synthesizer IC 3 incorporating a voltage regulator 8. Power is fed from a power supply terminal 6 through the voltage regulator 8 to the voltage controlled oscillator 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PLL module in which a PLL loop is constructed of a voltage controlled oscillator, a low-pass filter, and a PLL frequency synthesizer IC.

0002

2. Description of the Related Art FIG. 3 shows a conventional PLL module, which includes a voltage controlled oscillator 1, a low-pass filter 2, and a PLL module.
The LL frequency synthesizer IC3 constitutes a PLL loop. 4 is a reference oscillator for the PLL frequency synthesizer IC3. This PLL frequency synthesizer IC3 includes at least a phase comparator and a 1/N programmable counter.

[0003] Such a PLL module uses the voltage controlled oscillator 1 as a local oscillation circuit in a wireless communication device such as a cordless telephone, and outputs the output of the local oscillation circuit from an output terminal 5 to a mixing circuit (not shown). It is well known that a PLL frequency synthesizer can be used in a receiving system such as a PLL frequency synthesizer.

By the way, the PL in the PLL module
L frequency synthesizer IC3, voltage controlled oscillator 1,
Power for the reference oscillation circuit 4 is supplied from the power supply terminal 6, but when the same power is directly supplied to the PLL frequency synthesizer IC3 and the voltage controlled oscillator 1, the power is supplied to the PLL frequency synthesizer IC3 via the power supply line.
There is a problem in that the noise enters the voltage controlled oscillator 1 and adversely affects its oscillation operation, resulting in a decrease in the accuracy of the oscillation operation, leading to a decrease in reception function, for example. Therefore, in the conventional PLL module, a noise filter or a voltage regulator 7 is provided.
Even if power is supplied directly to the PLL frequency synthesizer IC 3 and reference oscillation circuit 4 from the power supply terminal 6, power is supplied from the power supply terminal 6 to the voltage controlled oscillator 1 after intervening the voltage regulator 7. This prevents the influence of the noise from reaching the voltage controlled oscillator 1.

[0005]

However, providing the voltage regulator 7 as a separate component within the PLL module as in the past is a major factor in increasing the size of the PLL module, and it is difficult to manufacture the PLL module. There is a problem in that the number of component parts increases and the manufacturing cost increases.

Therefore, an object of the present invention is to avoid increasing the size of the PLL module by not providing the voltage regulator as a separate component within the PLL module, and to reduce the manufacturing cost thereof. It is said that

[0007]

[Means for Solving the Problems] In order to achieve the above object, in the PLL module of the present invention, a PLL loop is configured by a voltage controlled oscillator, a low-pass filter, and a PLL frequency synthesizer IC, and the PLL frequency synthesizer IC is characterized by having a built-in voltage regulator, and supplying power to the PLL frequency synthesizer IC to a voltage controlled oscillator via the voltage regulator.

[0008]

[Operation] Since the voltage regulator is built into the PLL frequency synthesizer IC, the voltage regulator is not a separate component of the PLL module.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a PLL module according to a first embodiment of the present invention, in which parts corresponding to those in FIG. 3 according to the conventional example are given the same reference numerals, and parts related to the same reference numerals are The explanation for this will be omitted.

In FIG. 1, 1 is a voltage controlled oscillator, 2 is a low-pass filter, and 3 is a PLL frequency synthesizer IC.
, 4 is a reference oscillation circuit, 5 is an output terminal, and 6 is a power supply terminal. This configuration is similar to the conventional example.

In the first embodiment, the PLL frequency synthesizer IC 3 has a built-in voltage regulator 8, and the power supply terminal 6
The feature is that the power from the oscillator is supplied to the voltage controlled oscillator 1 via the built-in voltage regulator 8.

As described above, in this embodiment, since the voltage regulator 8 is built into the PLL frequency synthesizer IC 3, unlike the conventional case where the voltage regulator 8 is provided as a separate component, the voltage regulator 8
is integrated with the PLL frequency synthesizer IC3, which avoids increasing the size of the PLL module, and also reduces the manufacturing cost compared to the case where the voltage regulator 8 is mounted as a separate component on the PLL module. Cost can be reduced.

FIG. 2 is a block diagram of a PLL module according to a second embodiment of the present invention, in which parts corresponding to those in FIG. do.

In the PLL module of the second embodiment shown in FIG. 2, the PLL frequency synthesizer IC 3 includes a plurality of voltage regulators 9, 10, two in the embodiment, and one voltage regulator 9 is a reference oscillation circuit. 4, the other voltage regulator 10 is connected to the voltage controlled oscillator 1,
Each can be supplied with power from the power supply terminal 6, and its effects are the same as in the first embodiment.

[0016]

[Effect of the invention] As is clear from the above explanation,
According to the present invention, a voltage regulator is built into a PLL frequency synthesizer IC, and power for the PLL frequency synthesizer IC is supplied to a voltage controlled oscillator via the voltage regulator, so that the voltage regulator is used as a PLL module. Since it is no longer a separate component, compared to the case where the voltage regulator is provided as a separate component, it is possible to avoid increasing the size of the voltage regulator, and the manufacturing cost can also be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a PLL module according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a PLL module according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a PLL module according to a conventional example.

[Explanation of symbols]

1 Voltage controlled oscillator 2 Low pass filter 3 PLL frequency synthesizer IC8~10
voltage regulator

Claims (1)

[Claims] Claim 1: A voltage controlled oscillator (1), a low pass filter (2), and a PLL frequency synthesizer IC (3).
) constitute a PLL loop, and the PLL frequency synthesizer IC (3) has a built-in voltage regulator (8),
The power supply for the PLL frequency synthesizer IC (3) is supplied to the voltage controlled oscillator (
1) A PLL module characterized by supplying.