TWI663806B - Supplying-end module of induction type power supply system and signal detection method using the same - Google Patents

Abstract

A power supply module is used in an inductive power supply system. The power supply module includes a power supply coil, a first drive device, a second drive device, and a signal detection module. The first driving device is coupled to the power supply coil for driving the power supply coil to transmit power. The second driving device is coupled to the power supply coil and is used to control the power supply coil to output a detection signal. The signal detection module is coupled to the power supply coil for detecting a reflection signal corresponding to the detection signal.

Description

Power supply module of inductive power supply system and signal detection method thereof

The invention relates to a power supply module of an inductive power supply system and a signal detection method thereof, and particularly to a method for detecting a smart card that can be used for a power supply module of an inductive power supply system.

In an inductive power supply, the power supply end drives the power supply coil to resonate through a drive circuit, and then emits radio frequency electromagnetic waves. The electromagnetic power is then converted through the power receiving coil to generate a DC power supply to the power receiving device. If the electromagnetic energy sent by the power supply coil is applied to a metal body, it will have a heating effect, and the accumulated heat may cause the metal body to burn and cause harm. In the prior art, the inductive power supply has included technology that can be used to detect metal objects, which can effectively detect metal objects that may be affected by electromagnetic energy and generate heat, and interrupt the energy transmission for protection when metal objects are found .

Smart cards are widely used in daily life, using Near Field Communication (Near Field Communication) Communication (NFC), Radio Frequency Identification (RFID) or other similar technologies for communication. It can capture the small electromagnetic energy and start the internal chip for data feedback transmission. This technology only needs to receive the small electromagnetic energy to start, and vice versa , The excessive electromagnetic energy received by the smart card will damage the internal chip, and the inductive power supply may cause damage to this type of device. When great harm.

In other words, the electromagnetic energy sent by the inductive power supply is too powerful for the smart card, and it is often burned directly after being received by the smart card. However, the electromagnetic energy that smart cards can receive is very subtle and cannot be identified by the detection technology of traditional inductive power supplies. At present, the only reliable method is to set a corresponding card reading device on the transmitting coil of the inductive power supply, and the card reading device determines whether a smart card exists before transmitting power. However, setting up additional card reading devices requires additional costs, and smart cards corresponding to multiple specifications require multiple different card reading devices. In addition to increasing costs, the card reading coil also greatly increases the size of the device. In view of this, it is necessary to improve the conventional technology.

Therefore, the main object of the present invention is to provide a smart card detection method that can be used in a power supply module of an inductive power supply system, which can output a detection signal for a smart card through a power supply coil of the inductive power supply system To achieve smart card detection and improve the above problems.

The invention discloses a power supply module for an inductive power supply system. The power supply module includes a power supply coil, a first driving device, a second driving device, and a signal detection module. The first driving device is coupled to the power supply coil for driving the power supply coil to transmit power. The second driving device is coupled to the power supply coil and is used to control the power supply coil to output a detection signal. The signal detection module is coupled to the power supply coil for detecting a reflection signal corresponding to the detection signal.

The present invention also discloses a signal detection method for a power supply module of an inductive power supply system. The power supply module includes a power supply coil. The signal detection method includes stopping driving through a first driving device to control the power supply coil to suspend output of power; and to suspend output at the power supply coil. During the power period, the power supply coil is driven to resonate through a second driving device; a coil signal of the power supply coil is detected to obtain a peak voltage level of the coil signal; a reference voltage is set at the peak voltage level Subtract a preset voltage; the second driving device stops driving the power supply coil and restarts driving the power supply coil a specific number of times to output a detection signal; and after outputting the detection signal, compares the reference voltage with The coil signal is used to determine whether a reflection signal corresponding to the detection signal is received.

100, 400, 500‧‧‧‧ Inductive power supply system

1‧‧‧power supply module

10‧‧‧ Power Supply

11‧‧‧ processor

12‧‧‧ Clock Generation Module

121, 421‧‧‧ clock generator

13‧‧‧Power supply drive

43‧‧‧high frequency drive

14,141,451,452‧‧‧Resonant capacitors

15‧‧‧Power supply coil

16‧‧‧Signal Detection Module

17‧‧‧ Comparator

18‧‧‧ Digital Analog Converter

160‧‧‧Divided voltage circuit

161, 162‧‧‧ divided voltage resistors

19‧‧‧ reminder device

44‧‧‧Switch Module

441, 442, 443‧‧‧ switches

152‧‧‧Inductance

Vc‧‧‧coil signal

2‧‧‧ Power receiving module

21‧‧‧load unit

22‧‧‧ Power receiving coil

3‧‧‧Smart Card

31‧‧‧coil

32‧‧‧Integrated Circuit

20‧‧‧Signal detection process

200 ~ 214‧‧‧step

V1‧‧‧ peak voltage level

V2‧‧‧Reference voltage

Sdet ‧‧‧ detection signal

Sref‧‧‧Reflected signal

R1‧‧‧ resistance

FIG. 1 is a schematic diagram of an inductive power supply system according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a signal detection process according to an embodiment of the present invention.

FIG. 3 is a waveform diagram of sending a detection signal and detecting a corresponding reflection signal according to an embodiment of the present invention.

4 and 5 are schematic diagrams of another inductive power supply system according to an embodiment of the present invention.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of an inductive power supply system 100 according to an embodiment of the present invention. As shown in FIG. 1, the inductive power supply system 100 includes a power supply module 1 and a power receiving module 2. The power supply module 1 can receive power from a power supply 10. The power supply module 1 includes a processor 11, a clock generation module 12, a power supply driving device 13, resonance capacitors 14 and 451, a high-frequency driving device 43, a switch module 44, a power supply coil 15, and a signal detection device. The test module 16, a prompting device 19 and a voltage dividing circuit 160. The power supply coil 15 can be used to send electromagnetic energy to the power receiving module 2 for power supply. The resonance capacitor 14 is coupled to the power supply coil 15 and can be used to resonate with the power supply coil 14 during power supply. The power supply driving device 13 is coupled to the resonance capacitor 14 and the power supply coil 15. The power supply driving device 13 can be controlled by the processor 11 and is used to send a driving signal to drive the power supply coil 15 to send power. The power supply driving device 13 may adopt a full-bridge or half-bridge method. The driving mode is not limited by the present invention. In addition, in the power supply module 1, a magnetic conductor made of a magnetic material may be selectively used to improve the electromagnetic induction capability of the power supply coil 15 while avoiding electromagnetic energy affecting objects in the direction of the non-inductive surface of the coil.

In the embodiment of the present invention, in addition to being used for transmitting power, the power supply coil 15 can also be used for smart card detection. In detail, the high-frequency driving device 43 is coupled to the power supply coil 15 through the resonance capacitor 451, and can be used to control the power supply coil 15 to output a detection signal. The detection signal can be used to detect the presence of the smart card. The switch module 44 includes a switch 441, which is coupled between the high-frequency driving device 43 and the resonance capacitor 451 and can be used to control the operation of the high-frequency driving device 43. When the power supply coil 15 wants to output power, the control switch 441 can be turned off; when the power supply coil 15 wants to output a detection signal, the control switch 441 can be turned on, so that the high-frequency driving device 43 can drive the power supply coil 15 to operate. In addition, the power supply driving device 13 may also be provided with a switch (not shown), which starts the power supply driving device 13 when outputting power, and turns off the power supply driving device 13 when outputting a detection signal, and controls the power supply coil 15 to not receive the high-frequency driving device. One end of the driving signal of 43 is coupled to the ground terminal.

After the power supply coil 15 outputs a detection signal, the signal detection module 16 can detect a reflection signal corresponding to one of the detection signals. In one embodiment, the signal detection module 16 may be composed of a comparator 17 and a digital to analog converter (DAC) 18, which may be used to track the peak value of the coil signal Vc of one of the power supply coils 15 and Based on this, a reflected signal is detected. The voltage dividing circuit 160 includes voltage dividing resistors 161 and 162, which can attenuate the coil signal Vc on the power supply coil 15 and output it to the signal detection module 16. In some embodiments, if the circuits such as the processor 11 and the signal detection module 16 have sufficient withstand voltage, the voltage detection circuit 160 may be used instead, and the signal detection module 16 may directly receive the coil signal on the power supply coil 15 Vc.

In addition, the processor 11 can be used to receive the detection result of the signal detection module 16 to determine whether a smart card exists, and then control the operation of the power supply driving device 13 and the power supply coil 15 such as controlling whether to output power. The processor 11 may be any type of processing device, such as a central processing unit (CPU), a microprocessor (microprocessor), a microcontroller (microcontroller unit, MCU), and the like. The clock generation module 12 includes clock generators 121 and 421, which are respectively used to output clock signals to the power supply driving device 13 and the high-frequency driving device 43. The clock generating module 12 may be implemented by a pulse width modulation generator (PWM generator) or other types of clock generators. The prompting device 19 may be selectively disposed on the power supply module 1, and when the processor 11 determines that the smart card exists, a prompt signal is generated to notify the user of the inductive power supply system 100 to remove the smart card. The prompting device 19 can notify the user in any manner, such as displaying a light, a buzzer, a speaker, or displaying on a screen. As for other possible constituent elements or modules, such as a power supply unit, a display unit, etc., they may be increased or decreased according to the system requirements, so they are not shown without affecting the description of this embodiment.

Please continue to refer to Figure 1. The power receiving module 2 includes a load unit 21 and a power receiving coil 22. The power receiving coil 22 can be used to receive power from the power supply coil 15. The load unit 21 generally refers to various internal components or modules of the power receiving coil 22, such as voltage stabilization circuits, resonant capacitors, rectifier circuits, signal feedback circuits, power receiving end processors, etc. The above components or modules can be increased or decreased according to the needs of the system , And should not be a limitation of the present invention. In addition, a smart card 3 is not included in the inductive power supply system 100 but is shown in FIG. 1. The smart card 3 may be, for example, a smart card conforming to Near Field Communication (NFC) specifications, which includes a coil. 31 and an integrated circuit (IC) 32.

Please refer to FIG. 2. FIG. 2 is a schematic diagram of a signal detection process 20 according to an embodiment of the present invention. The signal detection process 20 can be used for a power supply module of an inductive power supply system (such as the power supply module 1 of the inductive power supply system 100 in FIG. 1), which includes the following steps: Step 200: Start.

Step 202: Stop driving through the power supply driving device 13 to control the power supply coil 15 to suspend output of power.

Step 203: Engage the switch 441.

Step 204: During the period when the power supply coil 15 suspends outputting power, the high-frequency driving device 43 drives the power supply coil 15 to resonate.

Step 206: Detect the coil signal Vc of the power supply coil 15 to obtain a peak voltage level V1 of the coil signal Vc.

Step 208: Set a reference voltage V2 to the peak voltage level V1 minus a preset voltage.

Step 210: The high-frequency driving device 43 stops driving the power supply coil 15 and restarts driving the power supply coil 15 a specific number of times to output a detection signal Sdet.

Step 212: After outputting the detection signal Sdet, compare the reference voltage V2 with the coil signal Vc to determine whether a reflection signal Sref corresponding to one of the detection signals Sdet is received.

Step 213: Turn off the switch 441.

Step 214: End.

According to the signal detection process 20, the detection signal Sdet may be transmitted during the period when the power supply coil 15 suspends outputting power. Since the same power supply coil 15 is used for power transmission and detection signal output, the operation of power transmission and detection signal output needs to be performed in a time-sharing manner. In this example, the power supply driving device 13 may stop driving to control the power supply coil 15 to suspend output of power, and the high frequency driving device 43 drives the power supply coil 15 to resonate. Generally, the energy output by the power supply coil 15 depends on factors such as the amplitude of the driving signal output by the driving device, the capacitance value of the resonance capacitor, the inductance value of the power supply coil 15 and the operating frequency. When the power supply driving device 13 drives the power supply coil 15 to output power, its output energy is large. The moving device 13 needs to output a larger signal amplitude, and at the same time uses a resonant capacitor 14 with a larger capacitance value, so that the power supply coil 15 operates at a lower frequency. When the high-frequency driving device 43 drives the power supply coil 15 to resonate, in the case of using the same power supply coil 15 (having the same inductance value), the capacitance value of its resonance capacitor 451 is small (usually much smaller than the resonance capacitor 14), making power The coil 15 operates at a higher frequency while having a lower output signal amplitude that can be received by the smart card. In an embodiment, the driving capability of the high-frequency driving device 43 may be reduced, or a resistor may be provided between the high-frequency driving device 43 and the power supply coil 15 to reduce the output signal amplitude of the high-frequency driving device 43 driving the power supply coil 15.

According to the specifications of a general short-range communication interface (such as Near Field Communication (NFC)), the communication device is divided into a master end and a slave end. The master end may be, for example, a card reader, and the slave end may be, for example, a smart card. The slave usually adopts a powerless mechanism, that is, it does not need to receive power when it is in standby. The host can send signals intermittently. This signal has electromagnetic energy and has a specific frequency. When the slave is close to the host, if the received signal meets its identifiable frequency, it can be activated by the received signal energy. Operation. After the slave is activated, the signal / data can be reflected on the coil carrier through load modulation technology. In other words, the host device can send a signal by polling, and after the slave terminal receives the polling signal, it can feedback the identification code to the host at a specific point in time. If the slave does not receive the polling signal, no action is performed.

In an embodiment, in order to detect a near field communication standard smart card so that the power supply coil 15 can output a detection signal corresponding to the near field communication standard, the high-frequency driving device 43 needs to drive the power supply coil 15 to operate at a frequency of 13.56 MHz. . In comparison, when the power supply driving device 13 drives the power supply coil 15 to output power, its operating frequency is approximately 100 kHz. In this case, the capacitance of the resonance capacitor 14 should be greater than the capacitance of the resonance capacitor 451 to control the power supply coil 15 to operate at a suitable frequency.

In this example, the step of the high-frequency driving device 43 driving the power supply coil 15 to output the detection signal may be performed while the power supply driving device 13 controls the power supply coil 15 to suspend the output of power. In another embodiment, the step of outputting the detection signal may be performed before the power supply coil 15 starts to output power, so as to determine whether a smart card exists before outputting power.

Then, the power supply coil 15 can send a detection signal similar to the polling signal. Please refer to FIG. 3. FIG. 3 is a waveform diagram of a detection signal Sdet and a corresponding reflection signal Sref according to an embodiment of the present invention. FIG. 3 shows the waveform of the coil signal Vc of the power supply coil 15 (that is, the voltage signal between the power supply coil 15 and the resonance capacitor 14). The driving of the high-frequency driving device 43 causes the coil signal Vc on the power supply coil 15 to oscillate. Then, the high-frequency driving device 43 may intermittently stop driving the power supply coil 15 several times, that is, stop driving the power supply coil 15 and restart driving the power supply coil 15 for a specific number of times to control the power supply coil 15 to output a detection signal Sdet. This specific number of times is specified by the smart card related specifications, but should not be limited to this number. At this time, if a smart card 3 exists near the power supply coil 15, the coil 31 of the smart card 3 can detect the detection signal Sdet and return a reflected signal Sref after a predetermined time, and the reflected signal Sref will be at the coil signal Vc Modulation is generated on the amplitude, so that the amplitude decrease section appears on the coil signal Vc, as shown in FIG. 3.

In order to detect the change in the amplitude of the coil signal Vc to determine the reflected signal Sref, the signal detection module 16 can obtain and track the peak voltage level V1 of the coil signal Vc before receiving the reflected signal Sref. The tracking method of bit V1 is recorded in the Republic of China Patent No. I577108, and will not be repeated here. Then, the processor 11 may set the reference voltage V2 to the peak voltage level V1 minus a preset voltage level, and the preset voltage may be determined according to the specifications of the smart card and the type of the reflection signal Sref. In an embodiment, if the smart card complies with the near field communication specifications, it uses a 10% amplitude modulation method to feed back the reflected signal Sref, that is, the amplitude of the reflected signal Sref reducing the peak voltage on the coil signal Vc is approximately 10% of the amplitude. In this case, the magnitude of the preset voltage can be set close to but not more than one tenth of the amplitude when the high-frequency driving device 43 drives the power supply coil 15 to resonate, that is, the height of the control reference voltage V2 is slightly higher than 90% of the resonance amplitude. %, As shown in Figure 3. In this case, the processor 11 can control the digital analog converter 18 to output the reference voltage V2 to one input terminal of the comparator 17, and the other input terminal of the comparator 17 receives the coil signal Vc to control the coil signal Vc and the reference voltage. V2 performs a comparison to determine whether a reflection signal Sref is received.

It can be known from the above that the signal detection module of the present invention can adopt the same structure as the comparator module for detecting metal foreign objects in the Republic of China Patent No. I577108. In other words, the same circuit structure can be used for metal foreign object detection and smart card detection. Testing can reduce additional circuit costs.

Further, when the reflected signal Sref appears, the comparator 17 of the signal detection module 16 can detect that a peak voltage lower than the reference voltage V2 appears on the coil signal Vc, and can determine that the reflected signal Sref is received and related information is received. Transfer to processor 11. The processor 11 further determines that the smart card 3 exists in the power supply range of the power supply coil 15. It should be noted that according to the near field communication specifications, the smart card 3 needs to respond to the reflected signal Sref 86 microseconds (μs) after receiving the detection signal Sdet. Therefore, the reference voltage V2 can be set to output the detection signal Sdet It is then completed within 86 microseconds to detect the reflected signal Sref.

In this case, if the detection of the smart card is performed while the power supply coil 15 suspends outputting power, when the smart card 3 is detected, the processor 11 may control the power supply coil 15 to stop transmitting power completely. If the detection of the smart card is performed before the power supply coil 15 has started to output power, when the smart card 3 is detected, the processor 11 may control the power supply coil 15 not to start transmitting power. In an embodiment, the processor 11 may control the prompting device 19 to generate a prompting signal to a user of the inductive power supply system 100 to communicate with Know that the user has removed the smart card, and then the power supply module 1 re-performs the above steps of detecting whether the smart card 3 exists, and then starts to transmit power after determining that the smart card 3 is removed.

In addition, if the reflected signal Sref is not detected within a period of detection, it means that there is no smart card 3 in the power supply range of the power supply coil 15. In this case, the processor 11 may control the power supply coil 15 to continue to transmit power through the power supply driving device 13, and may temporarily suspend power supply after outputting power for a period of time to perform the step of detecting whether the smart card 3 exists. Alternatively, after confirming that the smart card does not exist, the power supply module 1 may further perform other detections, such as metal foreign object detection, before transmitting power.

It is worth noting that the purpose of the present invention is to detect whether the smart card exists near the coil or within the power supply range of the coil through the coil of the inductive power supply, so as to prevent the smart card from being burned by the electromagnetic energy output by the coil. Therefore, taking the power supply module 1 in FIG. 1 as an example, when the processor 11 determines that the reflected signal Sref is received, it can control the power supply coil 15 to stop the power output without performing subsequent decoding of the reflected signal Sref. In other words, unlike traditional card readers, which need to decode the smart card to receive detailed information after receiving the data from the smart card, the present invention only needs to determine whether the smart card exists, without the need to obtain the smart card number, content, or Other relevant information.

In addition, the power supply module and signal detection method of the present invention can be used not only for smart card detection that conforms to near field communication specifications, but also for other types of smart cards. Please refer to FIG. 4, which is a schematic diagram of another inductive power supply system 400 according to an embodiment of the present invention. The structure of the inductive power supply system 400 is similar to that of the inductive power supply system 100, so signals or components having the same function are represented by the same symbols. The main difference between the inductive power supply system 400 and the inductive power supply system 100 is that the power supply module 1 of the inductive power supply system 400 further includes a resonance capacitor 452, which is coupled between the power supply coil 15 and the high-frequency driving device 43. , And is controlled by another switch 442 in the switch module 44. In addition, in In the inductive power supply system 400, the power supply module 1 adopts a CLC coil structure, that is, one end of the power supply coil 15 is coupled to the resonance capacitor 14 and the other end is coupled to the other resonance capacitor 141, so that the power supply driving device 13 can be A resonant capacitor is driven. In addition, in the power supply module 1 in the inductive power supply system 400, the switch module 44 further includes a switch 443, which is coupled between one end of the power supply coil 15 and the ground terminal. In this example, the switches 441, 442, and 443 are all included in the switch module 44, which can be implemented by a chip. However, in other embodiments, each switch can be set independently. In addition, a resistor R1 is provided at the output end of the high-frequency driving device 43 to reduce the output power of the high-frequency driving device 43 driving the power supply coil 15.

In the power supply module 1 of the inductive power supply system 400, the high-frequency driving device 43 is coupled to the power supply coil 15 through resonance capacitors 451 and 452, respectively, and the switch module 44 can choose to turn on the switch 441 or 442 to pass the resonance capacitor 451 or 452 resonate. Preferably, the resonance capacitors 451 and 452 have different capacitance values, so that the high-frequency driving device 43 can generate resonances of different frequencies on the coil signal Vc through the different resonance capacitors 451 and 452 to perform smart card detection in different frequency bands. Can be used for different types or smart cards with different specifications. In one embodiment, the switches 441 or 442 in the switch module 44 can be turned on at the same time, so that the resonant capacitors 451 and 452 are connected in parallel to form another capacitance value, thereby generating another different resonant frequency. In addition, more than two capacitors may be provided between the high-frequency driving device 43 and the power supply coil 15. The switch module 44 may control the high-frequency driving device 43 to be coupled to the power supply coil 15 through any one or more capacitors. In order to achieve more different kinds of resonance on the coil signal Vc. The number and setting method of the capacitors and their corresponding resonance frequencies can be determined according to various smart card specifications and detection requirements, which should not be a limitation of the present invention.

In another embodiment, in addition to the high-frequency driving device 43, an additional one or more high-frequency driving devices capable of outputting different detection signals may be provided in the power supply module 1. Different resonance frequencies are generated on the signal Vc, which are used to detect different types of intelligence with different specifications card.

Please continue to refer to Figure 4. In the power supply module 1 of the inductive power supply system 400, during the power output of the power supply coil 15, all the switches 441 and 442 for the high-frequency drive device 43 can be turned off to avoid the strong output of the power supply drive device 13. The driving signal is transmitted to the high-frequency driving device 43 and the high-frequency driving device 43 is damaged. During the smart card detection, in addition to turning on the switches 441 and / or 442 for the high-frequency driving device 43, the switch 443 can be controlled to be turned on, so that the other end of the power supply coil 15 is coupled to the ground terminal as a resonance reference point. Similarly, in the power supply module 1 in FIG. 1, the power supply driving device 13 also has a switch that can be connected to the ground terminal, which can be turned on during the smart card detection.

In addition, the capacitor used to resonate with the high-frequency driving device 43 may be set in other ways. For example, please refer to FIG. 5, which is a schematic diagram of another inductive power supply system 500 according to an embodiment of the present invention. The structure of the inductive power supply system 500 is similar to that of the inductive power supply system 100, so signals or components having the same function are represented by the same symbols. The main difference between the inductive power supply system 500 and the inductive power supply system 100 is that the power supply module 1 of the inductive power supply system 500 further includes a resonance capacitor 141, which is coupled between the power supply coil 15 and the power supply driving device 13, The resonance capacitor 141, the power supply coil 15 and the resonance capacitor 14 form a coil structure of the CLC. In addition, in the power supply module 1 of the inductive power supply system 500, a resonance capacitor 451 for resonating with the high-frequency drive device 43 is connected in parallel with the power supply coil 15, and the high-frequency drive device 43 and the power supply coil 15 are connected in parallel. Another inductor 152 is added in between (can be realized with a smaller coil).

In the power supply module 1 of the inductive power supply system 500, the resonance capacitors 14 and 141 and the power supply coil 15 constitute a lower-frequency resonance circuit, and resonance occurs when the power supply driving device 13 is driven. The resonance capacitor 451 is connected to the power supply coil 15 and the inductor 152 to form a high-frequency resonance circuit, which can detect intelligence During the card period, a high-frequency resonance signal is generated by the driving of the high-frequency driving device 43. Since the value of the resonance capacitor 451 is much smaller than the resonance capacitors 14 and 141, when the power supply driving device 13 pushes the CLC structure of the resonance capacitor 141, the power supply coil 15 and the resonance capacitor 14 to output power, its frequency is much lower than the resonance formed by the resonance capacitor 451. Therefore, the influence of the resonance capacitor 451 can be ignored.

In summary, the present invention provides a signal detection method that can be used in an inductive power supply to detect whether a smart card exists in the coil power supply range of the inductive power supply to avoid the inductive power supply. Excessive energy output from the power supply coil caused the smart card to burn out. In the embodiment of the present invention, power output and smart card detection can be realized through the same coil and performed in a time-sharing manner. Signal detection on smart cards can be performed while the power supply coil is suspending power output. When the processor detects a reflected signal and determines that the smart card is present, it can control the power supply coil to stop sending power or not start sending power. The processor only It is necessary to determine whether a smart card exists, and it is not necessary to decode the reflected signal to obtain other information of the smart card. In addition, in the embodiment of the present invention, the power supply coil of the inductive power supply system can realize the functions of transmitting power and detecting the smart card, so there is no need to set up a card reader, which can save the cost of card reader setup, and , Users can set different numbers of capacitors with different values, and / or use multiple high-frequency drive circuits corresponding to different resonance frequencies to detect at different frequency bands, so that the invention can be applied to many different types of Smart card detection.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the scope of patent application of the present invention shall fall within the scope of the present invention.

Claims (20)

A power supply module for an inductive power supply system. The power supply module includes: a power supply coil; a first driving device coupled to the power supply coil for driving the power supply coil to transmit power; a first Two driving devices are coupled to the power supply coil to control the power supply coil to output a detection signal; and a signal detection module is coupled to the power supply coil to detect one of the detection signals corresponding to the detection signal. Reflected signal. The power supply module according to claim 1, further comprising: a first resonance capacitor coupled between the power supply coil and the first driving device; and a second resonance capacitor coupled between the power supply coil and Between the second driving device; wherein the capacitance value of the first resonance capacitor is greater than the capacitance value of the second resonance capacitor. The power supply module according to claim 1, further comprising a processor, wherein when the signal detection module determines that the power supply coil receives the reflected signal, the processor determines that it is within a power supply range of the power supply coil. There is a smart card. The power supply module according to claim 3, wherein when the processor determines that the smart card exists in the power supply range of the power supply coil, the processor controls the power supply coil to stop transmitting power or not to start transmitting power. The power supply module according to claim 3, further comprising: a prompting device for generating a prompting signal to the inductive type when the processor determines that the smart card exists in the power supply range of the power supply coil. One of the users of the power supply system. The power supply module according to claim 1, wherein when the power supply coil receives the reflected signal, the processor does not decode the reflected signal. The power supply module according to claim 1, wherein the signal detection module includes: a digital to analog converter (DAC) to provide a reference voltage; and a comparator coupled to The digital analog converter is used to compare the reference voltage with a coil signal of the power supply coil to determine whether the reflected signal is received. The power supply module according to claim 2, further comprising: at least a third resonance capacitor coupled between the power supply coil and the second driving device, wherein the capacitance values of the at least one third resonance capacitor are mutually Different, and different from the capacitance value of the second resonance capacitor; and a switch module for controlling the second driving device to be selectively connected through at least one of the second resonance capacitor and the at least one third resonance capacitor To the power supply coil. The power supply module according to claim 8, wherein the switch module further controls the power supply coil to be coupled to a ground terminal. The power supply module according to claim 1, wherein the second driving device stops driving the power supply coil and restarts driving the power supply coil a number of times as specified by a smart card specification to control the power supply coil to output the detection signal. The power supply module according to claim 1, further comprising: at least a third driving device coupled to the power supply coil for controlling the power supply coil to output another detection signal; wherein the at least one third drive The frequency at which the device drives the power supply coil resonance is different from each other, and is different from the frequency at which the second drive device drives the power supply coil resonance. The power supply module according to claim 1, further comprising: a resistor coupled between the power supply coil and the second driving device. The power supply module according to claim 1, further comprising: a first resonance capacitor coupled between the power supply coil and the first driving device; a second resonance capacitor coupled with the power supply coil in parallel Connected; and an inductor coupled between the power supply coil and the second driving device. A signal detection method for a power supply module of an inductive power supply system. The power supply module includes a power supply coil. The signal detection method includes: stopping driving by a first driving device to control the power supply. The coil suspends outputting power; during the period when the power supply coil suspends outputting power, drives the power supply coil to resonate through a second driving device; detects a coil signal of the power supply coil to obtain a peak voltage level of the coil signal; Set a reference voltage at the peak voltage level minus a preset voltage; the second driving device stops driving the power supply coil and restarts driving the power supply coil a number of times as specified by a smart card specification to output a detection Signal; and after outputting the detection signal, comparing the reference voltage with the coil signal to determine whether a reflection signal corresponding to the detection signal is received. The signal detection method according to claim 14, wherein the magnitude of the preset voltage is close to but not more than one tenth of a resonance amplitude of the second driving device driving the power supply coil to resonate. The signal detection method according to claim 14, wherein after the detection signal is output, comparing the reference voltage with the coil signal to determine whether the reflection signal corresponding to the detection signal is received includes: When it is detected that a peak voltage of the coil signal is lower than the reference voltage within a period after the detection signal is output, it is judged that the reflected signal is received. The signal detection method according to claim 14, further comprising: when determining that the reflected signal is received, determining that a power supply range of one of the power supply coils is stored in a smart card. The signal detection method according to claim 17, further comprising: when determining that the smart card exists in the power supply range of the power supply coil, the power supply coil stops transmitting power or does not start transmitting power. The signal detection method according to claim 17, further comprising: when determining that the smart card exists in the power supply range of the power supply coil, generating a prompt signal to a user of the inductive power supply system. The signal detection method according to claim 14, wherein when the power supply coil receives the reflected signal, the power supply module does not decode the reflected signal.