JPH0638529A - Rectifying circuit - Google Patents

Abstract

PURPOSE:To realize the reduction in number of components and to perform decreases in size and cost of a data carrier by utilizing a diode built in as a protective circuit of an input or output terminal of an IC for controlling the carrier as a rectifying element. CONSTITUTION:A rectifier comprises diodes D1, D3 built in an IC 10 as a protective circuit of an input terminal 11 of the IC 10, diodes D2, D4 built in the IC 10 as a protective circuit of an input terminal 12 of the IC 10, and a capacitor C. Current of the same direction, i.e., a direction directed from a power terminal 13 of the IC 10 to a power terminal 14 of the IC 10 always flows to the capacitor C irrespective of a direction of an AC voltage induced in a coil L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifier circuit, and more particularly to a rectifier circuit suitable for use as an IC operating power source of a data carrier which constitutes a contactless data carrier system.

[0002]

2. Description of the Related Art Conventionally, a data carrier system consisting of an interrogator fixedly arranged at a predetermined location and a responder (data carrier) mounted on a mobile body has been developed. When the data carrier receives the radio wave that is constantly transmitted from the storage device, as a result of transmitting the stored information as a response signal, the interrogator that received the response is configured to send the necessary information to the host computer.
The basic function is automatic remote reading. In this case, when the data carrier is classified according to the power supply method, as a kind thereof, there is a passive type which receives power supply from the outside by magnetic coupling or the like. An apparatus of this type is disclosed in, for example, JP-A-62-1.
The technology (memory package unit) described in Japanese Patent Publication No. 19696 has been proposed.

FIG. 3 shows an example of the structure of a conventional rectifier circuit incorporated in a passive type data carrier.
The anode side of the diode D1 and the cathode side of the diode D3 are connected, and the anode side of the diode D2 and the cathode side of the diode D4 are connected to the other end side of the coil L1 and the cathode sides of the diodes D1 and D2 are connected. A capacitor C is connected in parallel between the anode side of each of the diodes D3 and D4, and both ends of the capacitor C are connected to terminals of an IC (integrated circuit) 1 for controlling a data carrier. Coil L1 accompanying power supply from the outside
When an AC voltage is induced on the IC, bridge rectification is performed by the diodes D1 to D4, converted to a DC voltage, smoothed by the capacitor C, and supplied to the IC1 as an operating power supply.

[0004]

However, in the case of the rectifying circuit incorporated in the conventional data carrier described above,
Since it is necessary to use the diodes D1 to D4 as the rectifying element parts for bridge rectifying the AC voltage induced in the coil L1, the number of parts forming the rectifying circuit increases. Therefore, it is difficult to reduce the size of the data carrier, and there is a problem that the cost is increased.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems.
By using a diode, which is built in the IC as a protection circuit for the input terminal or output terminal of the data carrier control IC, as a rectifying element, the number of parts can be reduced, and the data carrier can be downsized and the price can be reduced. It is an object of the present invention to provide a rectifier circuit that achieves the above.

[0006]

To achieve the above object, the present invention according to claim 1 provides a coil for generating an AC voltage based on an external power supply, and an integrated circuit using an external power supply as an operating power supply. In a rectifier circuit mounted on a device including: a rectified AC voltage generated in the coil, converted into a DC voltage and supplied to the integrated circuit, a protection pre-connected to an input terminal or an output terminal of the integrated circuit. The diode or the parasitic diode is used as a rectifying element. The present invention according to claim 2 is provided with a coil that has both a function of generating an AC voltage based on power supply from the outside and a function of sending a signal to the outside, and an integrated circuit using an externally supplied power as an operating power supply. In a rectifier circuit mounted on a device, which rectifies an AC voltage generated in the coil and converts the AC voltage into a DC voltage and supplies the DC voltage to the integrated circuit, a protection diode or a parasitic diode previously connected to an output terminal of the integrated circuit is used. In addition to being used as a rectifying element, the coil is driven through the output terminal to send a signal.

[0007]

According to the present invention of claim 1, when an AC voltage is induced in the coil due to the external power supply to the device, a current based on the induction of the AC voltage is applied to the input terminal or the output terminal of the integrated circuit. Flows through a rectifying circuit formed by a rectifying element composed of a protection diode or a parasitic diode that is connected in advance. As a result, the AC voltage is rectified by the rectifier circuit and converted into a DC voltage. That is,
As a rectifying element of the rectifier circuit, a protective diode or parasitic diode that is connected in advance to the input terminal or output terminal of the integrated circuit is used, so the number of parts that make up the rectifier circuit can be significantly reduced compared to the past. As a result, it is possible to realize the downsizing and cost reduction of the device incorporating the rectifier circuit. According to the present invention of claim 2, when an AC voltage is induced in the coil due to the external power supply to the device, the current based on the induction of the AC voltage is connected in advance to the input terminal or the output terminal of the integrated circuit. Flows through a rectifying circuit formed by a rectifying element constituted by a protection diode or a parasitic diode that is being protected. As a result, the AC voltage is rectified by the rectifier circuit and converted into a DC voltage. In this case, energization of the coil is blocked. On the other hand, if no AC voltage is induced in the coil,
The coil is energized via the output terminal of the integrated circuit and a signal is transmitted from the coil. That is, as a rectifying element of the rectifying circuit, a protection diode or a parasitic diode that is connected in advance to the output terminal of the integrated circuit is used, and one coil is used for both power generation and transmission. The number of parts constituting the rectifier circuit and the power generation / transmission part can be significantly reduced as compared with the conventional one, and thereby the data carrier incorporating the rectifier circuit can be downsized and the price can be reduced. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First embodiment to which the rectifier circuit of the present invention is applied
An example and a second example will be described with reference to the drawings.

First embodiment. FIG. 1 is a block diagram of a rectifier circuit according to the first embodiment. The rectifier circuit is mounted on a data carrier (responder) that constitutes a data carrier system and supplies operating power to a data carrier control IC. The data carrier control IC 10 is generally composed of diodes D1 to D4 and a capacitor C that are incorporated in advance.

The configuration of the rectifier circuit of the first embodiment will be described in more detail. For example, four diodes D1, diode D2, diode D3, and diode D are provided inside the IC 10.
4 are provided, and the diodes D1 and D3 are IC10.
Of the input terminal (or output terminal) 11 of the IC 10 and the diodes D2 and D4 are incorporated as a protection circuit of the input terminal (or output terminal) 12 of the IC 10. That is, the input terminal 11 of the IC 10 is commonly connected to the anode side of the diode D1 and the cathode side of the diode D3, and the input terminal 12 of the IC 10 is commonly connected to the anode side of the diode D2 and the cathode side of the diode D4. Has been done. In this case, the diodes D1 to D
4 is not limited to the protective diode, but may be a parasitic diode.

Further, the diodes D1 and D inside the IC 10 are
Each cathode side of 2 is the power supply (VDD) terminal 13 of the IC 10.
Diode D inside IC10
The anode sides of 3 and D4 are commonly connected to the power supply (VSS) terminal 14 of the IC 10. The input terminal 11 of the IC 10 is connected to one end side of the coil L for power generation, and the input terminal 12 of the IC 10 is connected to the other end side of the coil L. Further, the power supply terminal 13 of the IC 10
Is connected to one end of a smoothing capacitor C, and the power supply terminal 14 of the IC 10 is connected to the smoothing capacitor C.
The other end side of is connected.

Next, the operation of the rectifying circuit of the first embodiment constructed as described above will be explained.

When an AC voltage is induced in the coil L in the direction of the arrow Y1 due to electromagnetic induction in the coil L based on the external power supply to the data carrier incorporating the rectifying circuit of the first embodiment, , The current based on the induction of the AC voltage is coil L → input terminal 11 of IC10 → diode D1 → power supply terminal 13 of IC10 → capacitor C
→ power supply terminal 14 of IC10 → diode D4 → IC10
Input terminal 12 → coil L. As a result, the AC voltage induced in the coil L is rectified into a DC voltage.

On the other hand, when an AC voltage is induced in the coil L in the direction of arrow Y2, the current resulting from the induction of the AC voltage is coil L → input terminal 12 of IC10 → diode D2 → power supply terminal 13 of IC10 → Capacitor C → IC1
0 power source terminal 14 → diode D3 → IC10 input terminal 11 → coil L. The AC voltage induced in the coil L is rectified into a DC voltage.

In the first embodiment, regardless of the direction of the AC voltage induced in the coil L, the current always flows in the same direction with respect to the capacitor C, that is, from the power supply terminal 13 of the IC 10 to the power supply of the IC 10. Since a current flowing in the direction toward the terminal 14 can flow, the input terminals 11 and 1 of the IC 10
A bridge rectification circuit is configured by the diodes D1 to D4 and the capacitor C as the protection circuit of No. 2.

As described above, according to the first embodiment,
As a protection circuit for the input terminal 11 of the IC 10, the diode D1 and the diode D3 which are incorporated in the IC 10 in advance.
And IC10 as a protection circuit for the input terminal 12 of IC10.
D2 and D already incorporated in the
4 is used to form a rectifying circuit from the diodes D1 to D4 and the capacitor C, the number of components forming the rectifying circuit can be significantly reduced as compared with the related art. As a result, the size and cost of the data carrier incorporating the rectifier circuit can be reduced.

Second embodiment. FIG. 2 is a block diagram of the rectifier circuit of the second embodiment, which is roughly composed of diodes D1 to D4 and a capacitor C which are previously incorporated in the IC 20 for controlling the data carrier. It will be.

The structure of the rectifier circuit of the second embodiment will be described in more detail. For example, four diodes D1, D2, D3 and D are provided inside the IC20.
4 are arranged, and the diodes D1 and D3 are IC20.
Of the output terminal 21 of the IC 20 and the diodes D2 and D4 are incorporated as a protection circuit of the output terminal 12 of the IC 20. That is, the output terminal 2 of the IC 20
1 includes an anode side of the diode D1 and a diode D3.
Is commonly connected to the cathode side of the output terminal 2 of the IC 20.
2 includes an anode side of the diode D2 and a diode D4.
Is commonly connected to the cathode side of.

Further, the diodes D1 and D inside the IC 20 are
Each cathode side of 2 is the power (VDD) terminal 23 of the IC 20.
Diode D inside IC20
The anode sides of 3 and D4 are commonly connected to the power supply (VSS) terminal 14 of the IC 20. Further, the output terminal 21 of the IC 20 is connected to one end side of the coil L that also serves as both power generation and transmission, and the output terminal 22 of the IC 20 is connected to the other end side of the coil L. Furthermore,
The power supply terminal 23 of the IC 20 is connected to one end of the smoothing capacitor C, and the power supply terminal 24 of the IC 20 is connected to the other end of the smoothing capacitor C.

Further, drive circuits 25 and 26 are connected to the output terminals 21 and 22 of the IC 20, respectively, and these drive circuits 25 and 26 are based on the output control signal and the IC 2
The coil L is driven by supplying a transmission signal output from the control unit (not shown) inside 0 to the outside of the data carrier to the coil L via the output terminals 21 and 22.

Next, the operation of the rectifier circuit of the second embodiment constructed as described above will be described.

When an AC voltage is induced in the coil L due to electromagnetic induction in the coil L based on the external power supply to the data carrier incorporating the rectifier circuit of the second embodiment, the drive circuit By applying a predetermined output control signal to the drive circuits 25 and 26,
The output of is disabled. In this case, the current based on the induction of the AC voltage to the coil L flows through the path corresponding to the direction of the induced voltage, as in the first embodiment.
As a result, the AC voltage induced in the coil L is rectified into a DC voltage.

On the other hand, when the AC voltage is not induced in the coil L, a predetermined output control signal is applied to the drive circuits 25 and 26 to activate the drive circuits 25 and 26, and the drive circuits 25 and 26 are activated. A transmission signal is supplied from 26 to the coil L via the output terminals 21 and 22 of the IC 20, the coil L is differentially driven and energized, and the signal is transmitted from the coil L. As a result, the transmission signal is transmitted to the outside of the data carrier.

As described above, according to the second embodiment,
As a protection circuit for the output terminal 21 of the IC 20, the diode D1 and the diode D3 previously incorporated in the IC 20
And the IC20 as a protection circuit for the output terminal 22 of the IC20.
D2 and D already incorporated in the
4 is used to form a rectifier circuit from the diodes D1 to D4 and the capacitor C, and a single coil L
Since it has a configuration for both power generation and transmission, it is possible to significantly reduce the number of parts that make up the rectification circuit and the power generation / transmission part compared to the past. It is possible to reduce the size and cost of the carrier.

[0025]

As described above, according to the present invention,
Since a rectifying circuit is configured by using a protective diode or a parasitic diode previously connected to the input terminal or the output terminal of the integrated circuit that uses the power supplied from the outside as the operating power source, the rectifying circuit is formed. Since a single coil is used for both power generation and transmission, it is possible to significantly reduce the number of parts that configure the rectifier circuit and the power generation / transmission part, as compared with the conventional one. As a result, it is possible to achieve a remarkable effect such as downsizing of a device incorporating the rectification circuit and cost reduction of the device.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a rectifier circuit according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a rectifier circuit according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a rectifier circuit according to a conventional example.

[Explanation of symbols]

 10 IC 11, 12 Input Terminal 13, 14 Power Supply Terminal 20 IC 21, 22 Output Terminal 23, 24 Power Supply Terminal 25, 26 Drive Circuit L Coil C Capacitor

Claims (2)

[Claims] 1. A device equipped with a coil that generates an AC voltage based on an external power supply and an integrated circuit that uses an external power supply as an operating power supply, and rectifies the AC voltage generated in the coil. A rectifier circuit for converting into a DC voltage and supplying the same to the integrated circuit, wherein a protective diode or a parasitic diode previously connected to an input terminal or an output terminal of the integrated circuit is used as a rectifying element. 2. A device equipped with a coil having both a function of generating an AC voltage based on power supply from the outside and a function of sending a signal to the outside, and an integrated circuit using an externally supplied power as an operating power supply. In the rectifier circuit that rectifies the AC voltage generated in the coil and converts the AC voltage into a DC voltage and supplies the DC voltage to the integrated circuit, a protection diode or a parasitic diode previously connected to the output terminal of the integrated circuit is used as a rectifying element. A rectifier circuit which is used and which drives the coil and outputs a signal via the output terminal.