WO2006038549A1

WO2006038549A1 - Power supply control circuit

Info

Publication number: WO2006038549A1
Application number: PCT/JP2005/018092
Authority: WO
Inventors: Ryouichi Sugita
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2004-10-01
Filing date: 2005-09-30
Publication date: 2006-04-13
Also published as: JP2008005564A

Abstract

A power supply control circuit comprises a voltage detecting circuit (12) for detecting a first power supply voltage (16) to be applied to a contact terminal (11); a rectifying circuit (14) for rectifying an induced electromotive force occurring in an antenna (13) to output a second power supply voltage (17); a power supply separating circuit (19) for separating the first power supply voltage (16) from the second power supply voltage (17); and a status control circuit (18) for controlling, based on a detection result of the voltage detecting circuit (12) and a rectifying operation detecting circuit (15), the power supply separating circuit (19) such that during operation of the rectifying circuit (14), the power supply separating circuit (19) separates the first power supply voltage (16) from the second power supply voltage (17) when the first power supply voltage (16) falls below a given level. This can prevent the collision between any voltage and the second power supply voltage (17) when that voltage is applied to the contact terminal (11).

Description

Specification

Power control circuit

Technical field

The present invention relates to a power supply control circuit that supplies a stable power supply to an internal circuit having a plurality of power supplies.

Background art

[0002] In a mobile phone or the like, an inserted memory card performs contact-type communication (hereinafter referred to as contact communication) in which the conductive metal terminals are in physical contact with an external host, and simultaneously with another external host and electromagnetic waves. When implementing non-contact communication (hereinafter referred to as non-contact communication) using multiple interfaces, there are multiple power supply systems to the memory card controller when simultaneous communication using multiple interfaces is realized.

FIG. 12 shows a power supply circuit configuration of a conventional memory card controller, which includes a contact terminal 11, an antenna 13, a rectifier circuit 14, and an internal circuit 20. The contact terminal 11 is a terminal to which a power supply voltage is applied during contact communication. The antenna 13 generates an induced electromotive force by an electromagnetic wave generated by a host that supports non-contact communication. The rectifier circuit 14 is a circuit that rectifies the induced electromotive force generated as described above. The internal circuit 20 is a memory arithmetic circuit that processes data as a memory card controller, and it is necessary to supply a stable power supply voltage to the internal circuit 20 regardless of the communication state.

An outline of the operation of the power supply circuit configured as described above will be described. At the time of contact communication, the voltage applied to the contact terminal 11 is supplied to the internal circuit 20 as the power supply voltage 21.

[0005] During non-contact communication, the induced electromotive force generated by the antenna 13 is rectified by the rectifier circuit 14. FIG. 13 shows a specific configuration example of the antenna 13 and the rectifier circuit 14. The induced electromotive force (alternating voltage) generated in the antenna 13 is converted into a positive component voltage by the diode 131 a in FIG. 13 and flattened by the smoothing capacitor 132. The flattened voltage is clamped to a constant voltage by the shunt regulator 133, output as the power supply voltage 21, and supplied to the internal circuit 20. [0006] At this time, if contact communication is stopped in a state where contactless communication is started, contactless communication is started, and then contactless communication is performed. . The power supply voltage 21 supplied to the internal circuit 20 in the communication state described above is supplied from both the contact terminal 11 and the rectifier circuit 14 simultaneously with the start of non-contact communication from the state supplied from the contact terminal 11. Further, when the contact communication is stopped, the power supply voltage is supplied only from the rectifier circuit 14.

[0007] In the communication state in which the non-contact communication is being performed and the contact communication is stopped, the voltage applied to the contact terminal 11 is an arbitrary voltage equal to or lower than the voltage level necessary for the operation of the internal circuit 20. This is because, for example, when contact communication is performed with a mobile phone, it is assumed that the contact communication is stopped due to battery exhaustion.

Patent Document 1: Japanese Unexamined Patent Publication No. 2000-123140

Disclosure of the invention

Problems to be solved by the invention

[0008] In the above conventional configuration, when contact communication is stopped at the time of non-contact communication, and a power supply voltage (for example, a ground level) lower than the voltage level required for the operation of the internal circuit 20 is applied to the contact terminal 11, The power supply voltage supplied from the rectifier circuit 14 and the power supply voltage of the contact terminal 11 collide, and there is a problem that a stable power supply voltage cannot be supplied to the internal circuit 20.

Means for solving the problem

In order to solve the above-described problem, the power supply control circuit according to the first aspect of the present invention includes a contact terminal to which a voltage is applied from the outside, and a first power supply voltage having the same potential as the contact terminal. A detection circuit; an antenna that generates an induced electromotive force by electromagnetic waves; a rectifier circuit that rectifies the induced electromotive force; a rectification operation detection circuit that detects an operating state of the rectifier circuit; the first power supply voltage and the rectifier. A power supply separation circuit that separates a second power supply voltage generated from the circuit, and a state control circuit that controls the state of the power supply separation circuit from the output of the voltage detection circuit and the output of the rectification operation detection circuit. It is characterized by that.

[0010] A power supply control circuit according to a second aspect of the present invention is characterized in that, in the first aspect, a resistor for connecting the first power supply voltage and a ground level is provided. [0011] The power supply control circuit of the invention according to claim 3 includes a contact terminal to which a voltage is also applied to an external force, a voltage detection circuit that detects a first power supply voltage having the same potential as the contact terminal, and the first A regulator that steps down the power supply voltage of 1 and outputs a third power supply voltage; an antenna that generates induced electromotive force by electromagnetic waves; a rectifier circuit that rectifies the induced electromotive force; and an operating state of the rectifier circuit is detected. A rectifying operation detection circuit that performs the operation, a power supply separation circuit that separates the third power supply voltage and the second power supply voltage generated from the rectification circuit, an output of the voltage detection circuit, and an output of the rectification operation detection circuit And a state control circuit for controlling the state of the separation circuit.

[0012] The power supply control circuit of the invention according to claim 4 is characterized in that, in claim 3, a resistor for connecting the first power supply voltage and a ground level is provided.

[0013] Further, the power supply control means of the invention according to claim 5 is characterized in that, in claim 3, the power supply control means includes a resistor for connecting the third power supply voltage and a ground level.

[0014] Further, the power supply control circuit of the invention according to claim 6 includes a contact terminal to which a voltage is also applied to an external force, an antenna that generates an induced electromotive force by electromagnetic waves, and a fifth power supply that rectifies the induced electromotive force. A rectifier circuit that outputs a voltage, and a diode that connects a fourth power supply voltage and a fifth power supply voltage that have the same potential as the contact terminal are provided.

[0015] Further, the power supply control circuit of the invention according to claim 7 includes a contact terminal to which a voltage is also applied to an external force, a clock terminal for inputting a clock signal from the outside, a plurality of capacitors and transistors, The power supply voltage and the clock signal are input, and the charge pump for boosting the power supply voltage of 6 using the charge / discharge of the capacitor to generate the seventh power supply voltage, and the induced electromotive force is generated by electromagnetic waves. An antenna and a rectifier circuit that rectifies the induced electromotive force and outputs the seventh power supply voltage.

[0016] A power supply control circuit stage according to an eighth aspect of the invention is characterized in that, in the seventh aspect, a resistor for connecting the sixth power supply voltage and a ground level is provided.

The invention's effect

[0017] According to the power supply control circuit of the present invention, when contact communication is stopped and contactless communication is being performed, a voltage at the ground level or a level close thereto is applied to the contact communication power supply terminal. In addition, a stable power supply voltage can be supplied to the internal circuit. Brief Description of Drawings

[0018] FIG. 1 is a diagram showing a power supply control circuit according to a first embodiment of the present invention.

FIG. 2 is an internal circuit diagram of the state control circuit 18 in the first embodiment.

FIG. 3 is an internal circuit diagram of the power supply separation circuit 19 in the first embodiment.

FIG. 4 is a diagram showing a power supply control circuit according to Modification 1 of Embodiment 1 of the present invention.

FIG. 5 is a diagram showing a power supply control circuit according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a power supply control circuit according to Modification 1 of Embodiment 2 of the present invention.

FIG. 7 is a diagram showing a power supply control circuit according to a second modification of the second embodiment of the present invention.

FIG. 8 shows a power supply control circuit according to Embodiment 3 of the present invention.

FIG. 9 shows a power supply control circuit according to Embodiment 4 of the present invention.

[FIG. 10] FIG. 10 is an internal circuit diagram of charge pump 114 in the fourth embodiment of FIG.

FIG. 11 is a diagram showing a power supply control circuit according to Modification 1 of Embodiment 4 of the present invention.

[FIG. 12] FIG. 12 shows a conventional power supply control circuit.

FIG. 13 is an internal circuit diagram of rectifier circuit 14 in the first embodiment.

[0019] 11 Contact terminal

12 Voltage detection circuit

13 Antenna

14 Rectifier circuit

15 Rectification operation detection circuit

16 First supply voltage

17 Second supply voltage

18 State control circuit

19 Power supply separation circuit

20 Internal circuit

1A voltage detection signal

1B Rectification operation detection signal

1C Power supply separation circuit control signal 21, 22, 23, 24 Logic gate

31 PMOS transistor

32, 33, 34 logic gate

35 Gate control signal

41 Resistance

51 Regulator

61 resistance

71 resistance

81 diode

82 Fourth power supply voltage

83 Fifth power supply voltage

91 Clock input terminal

92 clock lines

93 6th power supply voltage

94 Charge pump

95 7th power supply voltage

102 logic gate

111 resistance

131a diode

132 Smoothing capacitor

133 Chantreguirator

105 NMOS transistor

BEST MODE FOR CARRYING OUT THE INVENTION

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

[0021] (Embodiment 1)

FIG. 1 is a configuration diagram showing a power supply control circuit according to the first embodiment of the present invention.

In FIG. 1, a contact terminal 11 is a terminal to which a voltage is applied from the outside, and the applied voltage supplies a power supply voltage to the power supply separation circuit 19 via the first power supply voltage 16. Voltage The detection circuit 12 is a detection circuit that detects that the voltage of the first power supply voltage 16 has reached a certain level or more. On the other hand, the antenna 13 generates an induced electromotive force by an electromagnetic wave generated from a host that supports non-contact communication. The rectifier circuit 14 rectifies the induced electromotive force generated as described above, and supplies a power supply voltage to the internal circuit 20 via the second power supply voltage 17. The rectification operation detection circuit 15 is a circuit that detects that the above-described rectification circuit 14 is performing the rectification operation. The state control circuit 18 is a circuit that controls the power supply separation circuit 19 using the voltage detection signal 1A generated from the voltage detection circuit 12 and the rectification operation detection signal 1B generated from the rectification operation detection circuit 15. The power supply separation circuit 19 is a circuit that receives the power supply separation circuit control signal 1C from the state control circuit 18 and separates and conducts the first power supply voltage 16 and the second power supply voltage 17.

The operation of the power supply control circuit according to the first embodiment having the above configuration will be described below.

First, an operation will be described for a state in which contact communication to which a power supply voltage is applied from the contact terminal 11 is performed and non-contact communication is stopped.

[0025] At the start of contact communication, a power supply voltage is applied to the contact terminal 11 from an external contact communication compatible host (not shown), and the power supply voltage described above is applied to the first power supply voltage 16 via the contact terminal 11. Propagated and applied to the power supply separation circuit 19. On the other hand, since non-contact communication is not performed, no electromagnetic wave is generated with respect to the antenna 13, and no induced electromotive force is generated. As a result, the diode 131a shown in FIG. 13 stops backflow to the antenna 13, and the output from the rectifier circuit 14 to the second power supply voltage 17 becomes high impedance.

The operation of the power supply separation circuit 19 in such a state will be described. FIG. 3 shows the inside of the power supply separation circuit 19. The power supply separation circuit 19 includes a PMOS transistor 31 having a first power supply voltage 16 and a second power supply voltage 17 as a source and a drain and a substrate voltage as a second power supply voltage 17 and a first power supply. It is composed of a NAND logic gate 34 that inputs a signal whose voltage 16 is waveform-shaped by NOT logic gates 32 and 33 and a power supply separation circuit control signal 1C, and inputs the output to the gate of the PMOS transistor 31 described above. Yes. The first power supply voltage 16 in FIG. 3 gradually increases, and when the voltage rises above the PN junction threshold between the source and the substrate of the PMOS transistor 31, the first power supply voltage 16 It propagates to the second power supply voltage 17 through the source 'substrate of the transistor 31. As a result, as the first power supply voltage 16 increases, the arithmetic element operating with the second power supply voltage 17 starts to operate normally.

At this time, the voltage detection circuit 12 of FIG. 1 outputs “H” as the voltage detection signal 1A from the time when the first power supply voltage 16 becomes equal to or higher than a certain level. When it is below a certain level, "L" is output. The above-mentioned constant level is the power supply voltage level at which the internal circuit 20 can operate normally.

[0028] On the other hand, since non-contact communication is not performed, no electromagnetic waves are generated with respect to the antenna 13, and no induced electromotive force is generated. Accordingly, the rectification operation detection circuit 15 outputs “L” as the rectification operation detection signal 1B to the state control circuit 18 in response to the fact that the rectification circuit 14 is not operating.

[0029] The state control circuit 18 receives the voltage detection signal 1A and the rectification operation detection signal IB, performs an operation, and outputs a signal to the power supply separation circuit 19 as the power supply separation circuit control signal 1C. FIG. 2 shows a specific circuit example of the state control circuit 18. From the above situation, in FIG. 2, the rectification operation detection signal 1B is “L”, the voltage detection signal 1A is “H”, the first power supply voltage 16 is “H”, and the second power supply Since the voltage 17 reaches the voltage at which the arithmetic element operates, the power supply separation circuit control signal 1C is fixed to “H”.

In response to the power supply separation circuit control signal 1C, the gate control signal 35 in FIG. 3 becomes “H”, and the source and drain of the PMOS transistor 31 become conductive. As a result, the first power supply voltage 16 becomes completely conductive with the second power supply voltage 17, and the voltage applied to the contact terminal 11 in FIG. 1 can be stably supplied to the internal circuit 20. It becomes possible.

[0031] Next, the operation of the power supply control circuit in a state in which contactless communication is started while contact communication is continued will be described.

An induced electromotive force is generated in the antenna 13 by electromagnetic waves transmitted from a host corresponding to non-contact communication (not shown), and the voltage is supplied to the second power supply voltage 17 via the rectifier circuit 14. Is done. Since the operations of the antenna 13 and the rectifier circuit 14 are as described in the prior art, they are not described here. In response to the operation of the rectifier circuit 14, the rectifier operation detection circuit 15 receives “H” as the rectifier operation detection signal 1 B as the state control circuit 18. Is input. On the other hand, since the contact communication is continuously performed, the voltage detection signal 1A that does not change in the voltage detection circuit 12 remains “H”. In the state control circuit 18 shown in FIG. 4, since the voltage detection signal 1A force S "H", the power supply separation circuit control signal 1C output to the power supply separation circuit 19 remains "H". In the power supply separation circuit 19, the first power supply voltage 16 and the second power supply voltage 17 remain conductive.

[0033] Next, the operation of the power supply control circuit in a situation where the contact communication is stopped and only the non-contact communication is continued from the state where the contact communication and the non-contact communication are performed will be described.

[0034] When the contact communication is stopped, the power supply from the external host corresponding to the contact communication (not shown) is stopped, and the power supply voltage applied to the contact terminal 11 in FIG. It becomes a level soon.

In the conventional technique, when a ground level power supply voltage is applied to the contact terminal 11, the power supply voltage 21 supplied from the antenna 13 and the rectifier circuit 14 and the ground level applied to the contact terminal 11 are A collision occurs and it becomes impossible to supply a stable power to the internal circuit 20.

On the other hand, in the first embodiment, the above-described problems can be avoided by performing the following operations.

[0037] When the power supply voltage applied to the contact terminal 11 decreases, the first power supply voltage 16 also decreases accordingly. The voltage detection circuit 12 detects this drop in the power supply voltage and changes the voltage detection signal 1A to “L”. At this time, the voltage level detected by the voltage detection circuit 12 is set to a voltage level at which the internal circuit 20 can operate.

On the other hand, since the non-contact communication continues, the rectification operation detection signal 1B remains “H”. Since the voltage detection signal 1A is “L” and the rectification operation detection signal IB is “Η”, the power supply separation circuit control signal 1C is changed to “L” in the state control circuit 18 shown in FIG. As the power supply separation circuit control signal 1C changes to “L”, the gate control signal 35 in the power supply separation circuit 19 shown in FIG. 3 becomes “Η”, and the PMOS transistor 31 causes the first power supply voltage 16 to be The second power supply voltage 17 is separated.

[0039] As described above, the first power supply voltage 16 and the second power supply voltage 17 are separated, so that the contact Even when the voltage applied to the terminal 11 is at the ground level, the internal circuit supplies a stable power supply voltage from the rectifier circuit 14 in which the first power supply voltage 16 and the second power supply voltage 17 do not collide. Can be supplied to 20.

[0040] Next, the operation of the power supply control circuit in a state in which contactless communication and contact communication are stopped and power supply voltage is not supplied to start contactless communication will be described.

An induced electromotive force is generated in the antenna 13 by an electromagnetic wave transmitted from a host corresponding to non-contact communication (not shown), and the voltage is supplied to the second power supply voltage 17 via the rectifier circuit 14. Is done.

[0042] The operations of the antenna 13 and the rectifier circuit 14 are as described in the prior art, and are not described here.

At this time, the first power supply voltage 16 is at or near the ground level because contact communication has not started. In this state, the second power supply voltage 17 rises.1S In the PMOS transistor 31 of FIG. 3, the base and the drain that are the second power supply voltage 17 are Not conducting. As a result, the second power supply voltage 17 rises until the arithmetic circuit driven thereby operates normally. When the second power supply voltage 17 rises to a level at which the arithmetic circuit can operate normally, the first power supply voltage 16 is near the ground level, so that the gate control signal 35 becomes the “H” level and P In the MOS transistor 31, the first power supply voltage 16 and the second power supply voltage 17 are separated.

By the operation as described above, the second power supply voltage 17 can supply a stable power supply voltage to the internal circuit 20 that does not collide with the first power supply voltage 16.

[0045] In the first embodiment, preferably, a resistor 41 is provided between the first power supply voltage 16 and the ground level as shown in the first modification of the first embodiment in FIG. To do. The resistor 41 is a resistor that flows a current that allows the internal circuit 20 to operate normally. As a result, even when contact communication is performed, even if the contact terminal 11 is in a high impedance state, the first power supply voltage 16 can be reliably set to the ground level, and the power supply can be separated. A malfunction of the circuit 19 can be prevented. [0046] According to the power supply control circuit according to the first embodiment and the modification 1 as described above, the contact terminal to which a voltage is applied from the outside, and the first power supply voltage having the same potential as the contact terminal are provided. A voltage detection circuit to detect; an antenna that generates an induced electromotive force by electromagnetic waves; a rectification circuit that rectifies the induced electromotive force; a rectification operation detection circuit that detects an operating state of the rectification circuit; and the first A power supply separation circuit that separates the power supply voltage and the second power supply voltage generated, and a state control circuit that controls the state of the power supply separation circuit from the output of the voltage detection circuit and the output of the rectification operation detection circuit Therefore, when contact communication is stopped and contactless communication is being performed, even if a ground level voltage is applied to the contact communication power supply terminal, the internal circuit is stable. Supply power supply voltage Effect that can be obtained.

[0047] (Embodiment 2)

As shown in FIG. 5, the power supply control circuit according to the second embodiment of the present invention is different from the power supply control circuit according to the first embodiment in that the power supply voltage on the contact terminal 11 side and the power supply voltage on the rectifier circuit 14 side (second Power supply voltage 17) is to be separated by the power supply separation circuit 19, and is the power supply voltage on the contact terminal 11 side that is a signal directly input to the power supply separation circuit 19 (the first The regulator 51 is inserted between the power supply voltage 52) of FIG. 3 and the first power supply voltage 16 which is the voltage at the contact terminal 11. Furthermore, the voltage detected by the voltage detection circuit 12 is the voltage at the contact terminal 11 and the internal circuit 20 operates normally with the first power supply voltage 16 applied to the contact terminal 11. The first power supply voltage 16 is stepped down by the regulator 51, input to one input of the power supply separation circuit 19, and controlled by the state control circuit 18 to obtain the first power supply voltage 16 The power supply is separated or connected between the antenna 13 and the second power supply voltage 17 on the rectifier circuit 14 side.

Here, the voltage level detected by the voltage detection circuit 12 is set to the first power supply voltage 16 or less and the second power supply voltage 17 or more. For example, when the first power supply voltage 16 is 3.3V and the second power supply voltage 17 is 1.8V, the detection level of the voltage detection circuit 12 is set to 2V.

In such a configuration, at the moment when contact communication stops, the first power supply voltage 16 is Although the voltage starts to decrease, the second power supply voltage 17 that applies the voltage to the internal circuit 20 has not yet decreased. At this stage, the voltage detection circuit 12 detects that the contact communication is stopped, and the power supply separation circuit 19 separates the second power supply voltage 17 and the first power supply voltage 16, so that the internal circuit 20 It is possible to prevent a decrease in voltage supplied to.

At this time, as shown in the power supply control circuit according to the first modification of the second embodiment in FIG. 6, a resistor 61 is provided between the first power supply voltage 16 and the ground level. The resistor 61 is a resistor that allows a current to flow so that the internal circuit 20 operates normally. In this way, even if contact communication is performed, even if the contact terminal 11 is in a high impedance state, the first power supply voltage 16 can be reliably set to the ground level. The malfunction of the regulator 51 can be prevented.

Furthermore, as shown in the power supply control circuit according to the second modification of the second embodiment in FIG. 7, a resistor 71 is provided between the third power supply voltage 52 and the ground level. Resistor 71 is a resistor that allows current to flow to the extent that internal circuit 20 operates normally. In this way, the _third power supply voltage 52 is reliably set to the ground level even when the regulator 51 is stopped in a state where contact communication is not performed and the output becomes high impedance due to the circuit configuration. Thus, malfunction of the power supply separation circuit 19 and the state control circuit 18 can be prevented.

[0052] According to such a power supply control circuit according to the second embodiment, a contact terminal to which a voltage is applied from the outside, a voltage detection circuit that detects a first power supply voltage having the same potential as the contact terminal, An antenna that generates an induced electromotive force by electromagnetic waves, a rectifier circuit that rectifies the induced electromotive force, a rectifier operation detection circuit that detects an operating state of the rectifier circuit, and the first power supply voltage and the rectifier circuit A power supply separation circuit that separates the second power supply voltage; and a state control circuit that controls the state of the power supply separation circuit from the output of the voltage detection circuit and the output of the rectification operation detection circuit. In the circuit of the first embodiment, when contact communication is stopped in a state where non-contact communication is performed, the first power supply voltage falls below a certain level after the first power supply voltage starts to decrease. The voltage detection times There was detected, until the first power supply line and the power separation circuit and the second power supply line are separated, the power supply voltage becomes below a certain level is propagated to the second power supply line, subjected to an internal circuit However, in the second embodiment, the contact communication is stopped after the contact communication stops and the first power supply voltage level starts to gradually decrease. There is an effect that a stable power supply voltage can be supplied to the internal circuit until the voltage detection circuit detects it.

Further, as in Modification 1 of Embodiment 2, a resistance is applied between the first power supply voltage and the ground level, and this resistance is such that the internal circuit operates normally. If the contact current is set to a resistance, the first power supply voltage must be set to the ground level reliably even when contact communication is not performed and the contact terminal is in a high-impedance state. And can prevent malfunction of the regulator, and as in Modification 2 of Embodiment 2, a resistor is added between the third power supply voltage and the ground level. In addition, if this resistor is a resistor that allows a current that allows the internal circuit to operate normally, the regulator stops when contact communication is not performed, and the output of the circuit is high impedance depending on the circuit configuration. Even if it becomes third The power supply voltage can be reliably set to the ground level, and malfunctions of the power supply separation circuit and the state control circuit can be prevented.

[Embodiment 3]

FIG. 8 is a configuration diagram of a power supply control circuit according to the third embodiment of the present invention.

In FIG. 8, a contact terminal 11 is a terminal to which a voltage is applied from the outside, and is connected to a diode 81 via a fourth power supply voltage 82. The output of the diode 81 is connected to the internal circuit 20 as the fifth power supply voltage 83. The configurations of the antenna 13 and the rectifier circuit 14 are the same as in the conventional example, and their outputs are connected to the fifth power supply voltage 83.

[0056] In such a configuration, the conventional technology cannot supply a stable power supply voltage to the internal circuit 20, but the contact communication is stopped and the non-contact communication is continued! I will explain.

In the third embodiment, when the contact communication is stopped, the power supply voltage applied to the contact terminal 11 is in the ground level or the no-impedance state. As a result, the fourth power supply voltage 82 input to the diode 81 is at or near the ground level. On the other hand, since non-contact communication is carried out, the antenna 13 and the rectifier circuit 14 The fifth power supply voltage 83 is supplied with a power supply voltage at which the internal circuit 20 can operate.

At this time, the power supply voltage applied to the fifth power supply voltage 83 by the diode 81 does not flow into the fourth power supply voltage 82. Thereby, a stable power supply voltage can be supplied to the internal circuit 20.

[0059] According to such a power supply control circuit according to the third embodiment of the present invention, a contact terminal to which a voltage is applied from the outside, an antenna that generates an induced electromotive force by electromagnetic waves, and the induced electromotive force Since the rectifier circuit that rectifies and outputs the fifth power supply voltage and the diode that connects the fourth power supply voltage and the fifth power supply voltage, which have the same potential as the contact terminal, are provided, non-contact communication is possible. When contact communication is stopped in the current state, any voltage at the level near or near the ground level applied to the contact terminal is the fourth power supply voltage. This prevents the collision with the fifth power supply voltage supplied to the internal circuit, and provides an effect of supplying a stable power supply voltage to the internal circuit.

[0060] (Embodiment 4)

FIG. 9 is a configuration diagram of a power supply control circuit according to the fourth embodiment of the present invention.

In FIG. 9, a clock input terminal 91 indicates an external host (not shown) or a terminal to which an internally generated clock waveform signal is input. The clock waveform signal input to the clock input terminal 91 is input to the charge pump 94 via the clock line 92. The contact terminal 11 is a terminal to which a power supply voltage is applied from an external host (not shown) as in the prior art, and the applied power supply voltage is propagated to the sixth power supply voltage 93. The sixth power supply voltage 93 is input to the charge pump 94. The charge pump 94 to which the clock waveform signal and the sixth power supply voltage 93 are input connects the output to the internal circuit 20 as the seventh power supply voltage 95. The configurations of the antenna 13 and the rectifier circuit 14 are the same as in the conventional example, and their outputs are connected to the seventh power supply voltage 95.

The operation of the power supply control circuit according to the fourth embodiment having such a configuration will be described below.

When contact communication is started, a power supply voltage is applied to the contact terminal 11 in FIG. 9 from an external host (not shown). This applied power supply voltage is applied to the charge pump 94 as the sixth power supply voltage 93. On the other hand, the clock input from the clock input terminal 91 The waveform signal is input to the charge pump 94 via the clock line 92.

FIG. 10 shows a circuit example of the charge pump 94, and the voltage that has risen from the sixth power supply voltage 93 by the clock waveform signal supplied from the clock line 92 is changed to the seventh power supply voltage 95. Applied. The applied seventh power supply voltage 95 is supplied to the internal circuit 20 of FIG. In FIG. 10, reference numeral 102 denotes a NOT logic gate.

Hereinafter, details of the charge pump 94 will be described with reference to FIG. When the sixth power supply voltage 93 is applied to the line A and the charge pump 94 is in the state of the clock waveform signal power 'H', the line A and the line B are turned on, and the sixth power supply voltage is applied to the line B. If the clock waveform signal is set to “L” in this state, the capacitors connected to line B and line B will be in series, so the capacitor will discharge and the voltage on line B will become the sixth power supply voltage. 9 Doubled from 3. Because of this, the NMOS transistor between line A and line B is closed, and the voltage of line B does not propagate to line A. In this state, line C and line B The NMOS transistor between the two is open and the voltage of line B propagates to line C. Here, if the clock waveform signal is set to “H”, the capacitors connected to line C and line C are Since it is in series, the voltage on line B The total of the power supply voltage 93 of 6 becomes the voltage of line C. At this time, the voltage of line C becomes larger than the voltage of line B, so the NMOS transistor between line B and the line is closed. The voltage of line C does not propagate to line B. As described above, the charge pump 94 has a plurality of stages of NMOS transistors and capacitors, and the voltage input using the discharge of the capacitor (the sixth power supply voltage). ), And the NMOS transistor 105 connected to the seventh power supply voltage 95 causes a collision between the sixth power supply voltage 93 and the seventh power supply voltage 95. prevent.

On the other hand, when non-contact communication is started, the induced electromotive force is generated at antenna 13 in FIG. 11 by electromagnetic waves transmitted from a host corresponding to non-contact communication shown in FIG. The voltage is supplied to the seventh power supply voltage 95 via the rectifier circuit 14. Since the operations of the antenna 13 and the rectifier circuit 14 are as described in the prior art, they are not described here. The supplied seventh power supply voltage 95 supplies a power supply voltage to the internal circuit 20.

[0067] When the non-contact communication is being performed and the contact communication is stopped, the contact terminal 11 is at or near the ground level, and in the conventional technology, the sixth power supply voltage 93 and the seventh power supply voltage 95, which are at the same potential as the contact terminal 11, cause a voltage level collision and The circuit 20 was unable to supply a stable power supply voltage.

In contrast, in the fourth embodiment, the charge pump 94 is inserted between the sixth power supply voltage 93 and the seventh power supply voltage 95, and the seventh power supply in FIG. The NMOS transistor 105 to which the voltage 95 is connected can avoid a voltage level collision, and a stable power supply voltage can be supplied to the internal circuit 20.

Preferably, as shown in Modification 1 of Embodiment 4 in FIG. 11, resistor 111 is connected between sixth power supply voltage 93 and the ground level. The resistor 111 is a resistor that allows a current to flow so that the internal circuit 20 operates normally. As a result, even when contact communication is not being performed and the contact terminal 11 is in a high impedance state, the sixth power supply voltage 93 can be reliably set to the ground level, and the malfunction of the charge pump 94 can be prevented. It is possible to prevent this.

[0070] According to such a power supply control circuit according to the fourth embodiment, the seventh power supply is configured by changing the contact terminal to which a voltage is applied from the outside and the sixth power supply voltage having the same potential as the contact terminal. A power supply voltage adjusting circuit (charge pump) that outputs a voltage; an antenna that generates an induced electromotive force by electromagnetic waves; and a rectifier circuit that rectifies the induced electromotive force and outputs the seventh power supply voltage. Therefore, when contact communication is stopped when this non-contact communication is being carried out, the contact terminal is at or near the ground level, and in the prior art, the sixth power source that is at the same potential as the contact terminal. Although the voltage level and the seventh power supply voltage collided with each other and the power supply voltage could not be stably supplied to the internal circuit, in this fourth embodiment, the charge pump is 6th power supply voltage When the contact communication is stopped while this non-contact communication is being performed, the contact terminal is connected to the ground level or any voltage at or near the ground level. Even if it is applied, it is possible to prevent collision between an arbitrary voltage and the power supply voltage supplied from the rectifier circuit to the internal circuit by the charge pump, and the power supply voltage can be stably supplied to the internal circuit.

[0071] That is, the voltage level is reduced by the NMOS transistor to which the seventh power supply voltage is connected. Thus, a stable power supply voltage can be supplied to the internal circuit.

[0072] Further, if a resistor is connected between the sixth power supply voltage and the ground level, and this resistor is a resistor that flows a current that allows the internal circuit to operate normally, contact communication is performed. Even if the contact terminal is in a high-impedance state in V, N, etc., the sixth power supply voltage can be reliably set to the ground level, and malfunction of the charge pump can be prevented.

Industrial applicability

[0073] The power supply control circuit of the present invention is effective for an IC card or the like having a plurality of communication interfaces.

Claims

The scope of the claims

[1] A contact terminal to which voltage is applied from the outside,

A voltage detection circuit for detecting a first power supply voltage having the same potential as that of the contact terminal; an antenna for generating an induced electromotive force by electromagnetic waves;

A rectifier circuit for rectifying the induced electromotive force;

A rectification operation detection circuit for detecting an operation state of the rectification circuit;

A power supply separation circuit for separating the first power supply voltage and the second power supply voltage generated by the rectifier circuit;

A state control circuit for controlling the state of the power supply separation circuit from the output of the voltage detection circuit and the output of the rectification operation detection circuit;

A power supply control circuit comprising:

[2] In the power supply control circuit according to claim 1,

A resistor connecting the first power supply voltage and the ground level;

A power supply control circuit comprising:

[3] a contact terminal to which voltage is applied from the outside;

A voltage detection circuit for detecting a first power supply voltage having the same potential as the contact terminal; a regulator for stepping down the first power supply voltage and outputting a third power supply voltage; and an antenna for generating an induced electromotive force by electromagnetic waves When,

A rectifier circuit for rectifying the induced electromotive force;

A power supply separation circuit that separates the third power supply voltage and the second power supply voltage generated by the rectifier circuit;

A power supply control circuit comprising:

[4] In the power supply control circuit according to claim 3,

A resistor connecting the first power supply voltage and the ground level;

A power supply control circuit comprising:

[5] The power supply control circuit according to claim 3,

A resistor connecting the third power supply voltage and the ground level;

A power supply control circuit comprising:

[6] a contact terminal to which voltage is applied from the outside;

An antenna that generates an induced electromotive force by electromagnetic waves;

A rectifier circuit that rectifies the induced electromotive force and outputs a fifth power supply voltage;

A diode for connecting a fourth power supply voltage and a fifth power supply voltage that have the same potential as the contact terminal;

A power supply control circuit comprising:

[7] a contact terminal to which voltage is applied from the outside;

Clock terminal for inputting external power clock signal,

A charge having a plurality of capacitors and transistors, inputting the sixth power supply voltage and the clock signal, and boosting the power supply voltage of 6 using the charge / discharge of the capacitor to generate a seventh power supply voltage A pump,

A rectifier circuit that rectifies the induced electromotive force and outputs the seventh power supply voltage.

[8] In the power supply control circuit according to claim 7,

A resistor connecting the sixth power supply voltage and the ground level;

A power supply control circuit comprising: