Antenna driving apparatus

• US 10,152,839 B2
• Filed: 04/18/2016
• Issued: 12/11/2018
• Est. Priority Date: 07/30/2015
• Status: Active Grant

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Koizumi, Takaaki, Tabata, Takehiro
• Primary Examiner(s): Pendleton, Dionne H
• Application Number:
  US15/131,057
• Publication Number:
  US 20170032603A1
• Time in Patent Office: 967 Days
• CPC Class Codes: B60C 23/0452 Antenna structure, control or arrangement vehicle tyre mounted antennas H01Q1/2241
• CPC Class Codes: B60R 25/2036 by using the door logic and door and engine unlock means
• CPC Class Codes: B60R 25/246 characterised by the challenge triggering
• CPC Class Codes: B60R 25/406 Power supply in the remote key
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: G01R 19/0092 measuring current only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G07C 2009/0019 the keyless data carrier having only one limited data transmission rangs
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/65 using means for sensing the user's hand
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/00714 with passive electrical components, e.g. resistor, capacitor, inductor
• CPC Class Codes: H01Q 1/3241 particular used in keyless entry systems
• CPC Class Codes: H01Q 1/3283 side-mounted antennas, e.g. bumper-mounted, door-mounted mounted on windscreens H01Q1/1271
• CPC Class Codes: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H

Abstract

An antenna driving apparatus includes: a direct current power source supplying direct current power to a human detecting IC detecting contact to a human detecting area by a user, the power source outputting a power source voltage to a first connecting line connected to a power source terminal of the IC and outputting a reference potential to a second connecting line connected to a GND terminal of the IC; an antenna driving circuit driving an antenna transmitting a signal to a portable device, the antenna driving circuit outputting a first antenna drive signal to the first connecting line and outputting an antenna drive signal; and a control unit performing switching control of the power source voltage and the antenna drive signal to be output to the first and second connecting lines and switching control of the antenna driving circuit.

Claims

1. An antenna driving apparatus comprising:

a direct current power source configured to supply direct current power to a human detecting integrated circuit (IC) configured to detect contact to a human detecting area of a vehicle by a user of the vehicle, the direct current power source outputting a direct current power source voltage to a first connecting line electrically connected to a power source terminal of the human detecting IC and outputting a reference potential to a second connecting line electrically connected to a GND terminal of the human detecting IC;

an antenna driving circuit configured to drive an antenna that transmits a signal to a portable device carried by the user, the antenna driving circuit;

outputting an antenna drive signal generated by switching between a first state in which the direct current power source voltage is output to the first connecting line electrically connected to one end of the antenna and the reference potential is output to the second connection line electrically connected to the other end of the antenna and a second state in which the direct current power source voltage is output to the second connecting line and the reference potential is output to the first connecting line; and

a control unit configured to;

perform switching between a state in which the direct current power source voltage is supplied to the human detecting IC by outputting the direct power source voltage to the first connecting line and outputting the reference potential to the second connecting line and a state in in which the antenna drive signal is output to the antenna, and

perform switching control of the antenna driving circuit.

2. The antenna driving apparatus according to claim 1, further comprising:

a step-up/step-down circuit configured to step up and step down the direct current power source voltage and output a stepped-up and stepped-down voltage,

wherein the second state of the antenna driving circuit is a state in which the stepped-up and stepped-down voltage is output to the second connecting line and the reference potential is output to the first connecting line.

3. The antenna driving apparatus according to claim 1, further comprising:

a current measuring circuit configured to measure an antenna current flowing in the antenna; and

an antenna voltage variable circuit configured to;

vary the direct current power source voltage or a stepped-up/stepped-down voltage so that a measured value of the antenna current becomes equal to a current value required by the antenna, and

output a varied voltage,

wherein the second state of the antenna driving circuit is a state in which the varied voltage is output to the second connecting line and the reference potential is output to the first connecting line.

4. The antenna driving apparatus according to claim 3, wherein

the current measuring circuit is connected to the first connecting line or the second connecting line in series, and

a damping resistance for regulating impedance of the antenna connected to the first connecting line or to the second connecting line in series is concurrently used as a resistance for measuring the antenna current.

5. The antenna driving apparatus according to claim 1, wherein the direct current power source voltage and the antenna drive signal are output to the human detecting IC configured to continue an operation by using the antenna drive signal as a power source when the direct current power source voltage is not supplied.

6. The antenna driving apparatus according to claim 2, wherein the stepped-up and stepped-down voltage is only output to the second connecting line.