KR20130052858A

KR20130052858A - Smart key transmitter and the controlling method of transmitting power

Info

Publication number: KR20130052858A
Application number: KR1020110118165A
Authority: KR
Inventors: 박용희
Original assignee: 현대모비스 주식회사
Priority date: 2011-11-14
Filing date: 2011-11-14
Publication date: 2013-05-23

Abstract

The present invention discloses a smart key transmitter and its transmission output control method. According to an aspect of the present invention, a smart key transmitter includes: a central processing unit for outputting a transmission signal instructing execution of a function and outputting a control signal for adjusting a magnitude of a transmission output; An applied voltage adjusting circuit outputting a voltage corresponding to the control signal; And a varactor diode which is a part of a matching circuit of an antenna, and adjusts a magnitude of the transmission output by changing a matching value of the antenna by a capacitance according to the voltage.

Description

Smart Key Transmitter and the Controlling Method of Transmitting Power}

The present invention relates to a smart key system, and more particularly, to a smart key transmitter and a transmission output control method thereof, the transmission output of which can be adjusted according to an execution function.

In general, RKE (Remote Keyless Entry) transmitter or Fob transmitter transmits the operation instruction such as door lock / unlock / trunk open / start / panic release to the vehicle through a specific frequency. And the receiver of the vehicle, upon receiving the operation instruction, executes the corresponding function.

The conventional RKE / Fob transmitter has a SAW resonator oscillation and transmits an operation instruction of the same transmission output to a vehicle.

Among conventional RKE / Fob transmitters, there has been a RKE / Fob transmitter that can control the transmission power by applying an expensive RF IC that can adjust the transmission power by a program or by additionally applying a circuit for adjusting the transmission power to a low-cost RF IC.

However, the conventional transmission power control type RKE / Fob transmitter has a limitation in the range of output control because it controls the amplification factor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described technical background, and an object thereof is to provide a smart key transmitter and a method of controlling a transmission power thereof, which can adjust a transmission power by changing a matching value of an antenna.

According to an aspect of the present invention, a smart key transmitter includes: a central processing unit for outputting a transmission signal instructing execution of a function and outputting a control signal for adjusting a magnitude of a transmission output; An applied voltage adjusting circuit outputting a voltage corresponding to the control signal; And a varactor diode which is a part of a matching circuit of an antenna, and adjusts a magnitude of the transmission output by changing a matching value of the antenna by a capacitance according to the voltage.

According to another aspect of the present invention, a smart key transmission output control method includes: outputting a transmission signal instructing execution of a function; Outputting a control signal for adjusting a magnitude of a transmission output for transmitting the transmission signal; Applying a voltage corresponding to the control signal to the varactor diode that is part of the matching circuit of the antenna; And changing the matching value according to the capacitance of the varactor diode corresponding to the voltage, and transmitting the transmission signal at a constant magnitude of the transmission output corresponding to the matching value.

According to the present invention, the operating distance of the transmission / reception command can be adjusted by adjusting the transmission output according to the customer's request or each execution function.

In addition, the present invention can control the transmission power in a wider range than the conventional RKE / Fob transmitter that adjusts the transmission distance by adjusting the amplification gain by changing the antenna matching value to adjust the transmission power.

In addition, the present invention can control the transmission output by the SAW resonator, oscillator circuit, switching transistor and varactor diode without using the RF IC, it is possible to reduce the cost.

1 is a circuit diagram showing a smart key transmitter according to an embodiment of the present invention.
2 is a flowchart illustrating a transmission output control method according to an embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, the terms " comprises, " and / or "comprising" refer to the presence or absence of one or more other components, steps, operations, and / Or additions.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 1 is a circuit diagram illustrating a smart key transmitter according to an embodiment of the present invention. Here, the smart key transmitter may be an RKE transmitter or a fob transmitter.

As shown in FIG. 1, the smart key transmitter 10 according to an embodiment of the present invention includes a central processing unit 110, an FSK frequency generating circuit 120, an amplifying circuit 130, a pattern antenna 150, and a first antenna. The matching circuit 140, the applied voltage adjusting circuit 170, and the second matching circuit 160 are included.

The central processing unit 110 outputs a transmission signal instructing the operation of each function to be transmitted to the vehicle, and outputs a control signal for adjusting a transmission output through a general purpose input output (GPIO) to apply an applied voltage regulation circuit 170. To feed.

For example, the central processing unit 110 may output a low signal through the GPIO when executing a specific function, and may output a high signal through the GPIO when executing another function.

Alternatively, the central processing unit 110 may output a signal corresponding thereto through the GPIO when a menu for adjusting the transmission output is operated by the user.

The FSK frequency generating circuit 120 includes a SAW resonator and its peripheral circuits (resistors, inductors, and varactor diodes), and generates a frequency shift keying (FSK) frequency to carry a transmission signal.

The amplifying circuit 130 may be, for example, a Colpitts circuit, and amplifies a transmission signal on an FSK frequency and transmits the amplified signal to the pattern antenna 150.

The pattern antenna 150 is impedance-matched by the first matching circuit 140 and the second matching circuit 160, and transmits a transmission signal carried on the amplified FSK frequency to the vehicle by tuning to the FSK frequency.

The first matching circuit 140 includes an inductor, a capacitor, and the like, and impedance-matches the pattern antenna 150 together with the second matching circuit 160.

The second matching circuit 160 is connected to the varactor diode D1 having a capacitor value changed according to the magnitude of the voltage applied at both ends, and one end thereof to the varactor diode D1, and the other end thereof to the pattern antenna 150. Matching capacitor C1 is included. Here, the matching capacitor C1 is a normal capacitor.

An anode of the varactor diode D1 is connected to the pattern antenna 150 and the applied voltage regulating circuit 170, and a cathode is connected to the ground. Accordingly, the capacitance of the varactor diode D1 varies according to the voltage applied to the anode.

The applied voltage regulating circuit 170 outputs a voltage corresponding to the control signal from the central processing unit 110, and the output voltage of the applied voltage regulating circuit 170 is applied to the anode of the varactor diode D1.

The applied voltage regulating circuit 170 may be an element, a circuit, or a device capable of adjusting the level of the output voltage. However, in the present specification, for convenience of description, the case where the applied voltage regulating circuit 170 is a switching transistor T1 and a load resistor R1 capable of outputting two different voltages will be described as an example.

The switching transistor T1 is a PNP transistor. When the low signal is supplied to the base, the switching transistor T1 is turned on and outputs Vpa 1 close to 3V. Near Vpa 2 is output. In this case, the 3V voltage supplied to the central processing unit 110, the applied voltage adjusting circuit 170, the amplifying circuit 130, and the like may be a battery voltage.

At this time, since the output voltage Vpa of the switching transistor T1 is the voltage between the both ends of the varactor diode D1, the capacitance of the varactor diode D1 is different when Vpa 1 and Vpa 2. Since the capacitance of the varactor diode D1 is inversely proportional to the applied voltage, the capacitance at Vpa 1 is smaller than the capacitance at Vpa 2.

In sum, when the central processing unit 110 outputs a low signal through the GPIO, the applied voltage regulating circuit 170 supplies Vpa 1 close to 3V to the varactor diode D1, and the pattern antenna 150 receives the first signal. Transmit the transmission signal on the FSK frequency with the transmission output of magnitude. When the central processing unit 110 outputs a high signal through the GPIO, the applied voltage adjusting circuit 170 supplies Vpa 2 close to 0V to the varactor diode D1 and the pattern antenna 150 has a second size. The transmission signal on the FSK frequency is transmitted by the transmission output of. At this time, if the pattern antenna 150 is designed based on Vpa 1, when Vpa 1 is applied to the varactor diode D1, the transmission signal loaded on the FSK frequency may be transmitted at the maximum output power.

In this way, the present invention can easily adjust the transmission power by adjusting the matching value of the antenna.

Meanwhile, in FIG. 1, the application voltage adjusting circuit 170 outputs two types of voltages to adjust the transmission output in two stages. However, as described above, the smart key transmitter 10 transmits the transmission output. It can be designed to be adjustable in three or more kinds. In this case, the central processing unit 110 transmits three or more kinds of control signals to the applied voltage regulating circuit 170, and the applied voltage regulating circuit 170 is a circuit element capable of outputting three or more kinds of applied powers, and types of control signals. The voltage corresponding to the voltage across the varactor diode D1 is adjusted by outputting an applied voltage corresponding to the voltage.

Hereinafter, a transmission output control method according to an embodiment of the present invention will be described with reference to FIG. 2. 2 is a flowchart illustrating a transmission output control method according to an embodiment of the present invention. FIG. 2 is implemented by the components of FIG. 1 and adjusts the transmit power in accordance with the function requested by the user, and the pattern antenna 150 is designed to match when the varactor diode D1 is the first value. The case will be described as an example.

2, the central processing unit 110 confirms the transmission output corresponding to the function requested by the user (S210).

The central processing unit 110 outputs a low signal to the GPIO when the transmission output corresponding to the function is the transmission output of the maximum size (S220).

Then, the switching transistor T1 conducts and outputs Vpa 1 close to 3V, and Vpa 1 is applied to the varactor diode D1, so that the capacitance of the varactor diode D1 becomes a first value (S230).

The pattern antenna 150 transmits the transmission signal loaded on the FSK frequency with the transmission output of the maximum magnitude (S240).

The central processing unit 110 outputs a low signal to the GPIO when the size of the transmission output corresponding to the function requested by the user is a specific size less than or equal to the maximum size (S250).

At this time, since the switching transistor T1 is not conductive, Vpa 2 close to 0V is applied to the varactor diode D1, and the capacitance of the varactor diode D1 becomes a second value (S260). At this time, since the capacitance of the varactor diode is inversely proportional to the applied voltage, the second value is larger than the first value.

Then, the pattern antenna 150 transmits the FSK frequency loaded on the FSK frequency to a transmission output of a specific size (S270).

In this manner, the present invention can adjust the operating distance of the transmission and reception command by adjusting the transmission output according to the customer's request or each execution function.

While the present invention has been described in detail with reference to the accompanying drawings, it is to be understood that the invention is not limited to the above-described embodiments. Those skilled in the art will appreciate that various modifications, Of course, this is possible. Accordingly, the scope of protection of the present invention should not be limited to the above-described embodiments, but should be determined by the description of the following claims.

Claims

A central processing unit for outputting a transmission signal instructing execution of a function, and outputting a control signal for adjusting a magnitude of the transmission output;
An applied voltage adjusting circuit outputting a voltage corresponding to the control signal; And
A varactor diode, which is part of a matching circuit of an antenna, adjusts the size of the transmission output by changing the matching value of the antenna by capacitance according to the voltage.
Smart key transmitter comprising a.

The method of claim 1, wherein the central processing unit,
The smart key transmitter according to the type of the function to adjust the size of the transmission output, or to adjust the size of the transmission output in response to a user's request through a user interface.

The method of claim 1, wherein the applied voltage control circuit,
A switching device for outputting different voltages when the control signal is at a low level or a high level; And
A circuit element for outputting a voltage corresponding to the control signal among a plurality of outputable voltages
Smart key transmitter comprising at least one of.

The antenna according to claim 1,
And matching the impedance when the varactor diode has a specific capacitance, and transmitting the transmission signal at the transmission output of maximum magnitude when the varactor diode has the specific capacitance.

The method of claim 1,
A transmitter configured to amplify the transmission signal on a transmission frequency,
And said antenna transmits said transmission signal carried on said transmission frequency and amplified by said matching value by said matching circuit including said varactor diode.

Outputting a transmission signal instructing execution of a function;
Outputting a control signal for adjusting a magnitude of a transmission output for transmitting the transmission signal;
Applying a voltage corresponding to the control signal to the varactor diode that is part of the matching circuit of the antenna; And
The matching value is changed according to the capacitance of the varactor diode corresponding to the voltage, and transmitting the transmission signal at all times with the magnitude of the transmission output corresponding to the matching value.
Smart key transmission output control method comprising a.

The method of claim 6, wherein the outputting the control signal comprises:
Adjusting the size of the transmission output in correspondence with the type of the function; And
Adjusting the size of the transmission power according to a request of a user through a user interface
Smart key transmission output control method comprising at least one of.

The method of claim 6, wherein the transmitting step,
Amplifying the transmission signal on a transmission frequency; And
Transmitting the transmission signal amplified at the transmission frequency to a matching value by the matching circuit including the varactor diode.
Smart key transmission output control method comprising a.