WO2024011519A1 - 超声波指纹检测装置和电子设备 - Google Patents

超声波指纹检测装置和电子设备 Download PDF

Info

Publication number
WO2024011519A1
WO2024011519A1 PCT/CN2022/105775 CN2022105775W WO2024011519A1 WO 2024011519 A1 WO2024011519 A1 WO 2024011519A1 CN 2022105775 W CN2022105775 W CN 2022105775W WO 2024011519 A1 WO2024011519 A1 WO 2024011519A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
control
module
circuit
ultrasonic fingerprint
Prior art date
Application number
PCT/CN2022/105775
Other languages
English (en)
French (fr)
Inventor
杜灿鸿
Original Assignee
深圳市汇顶科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 深圳市汇顶科技股份有限公司 filed Critical 深圳市汇顶科技股份有限公司
Priority to PCT/CN2022/105775 priority Critical patent/WO2024011519A1/zh
Priority to PCT/CN2022/144383 priority patent/WO2023241017A1/zh
Priority to CN202211733544.XA priority patent/CN116140169A/zh
Priority to US18/455,554 priority patent/US20240021008A1/en
Priority to US18/455,690 priority patent/US20230401887A1/en
Publication of WO2024011519A1 publication Critical patent/WO2024011519A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/12—Fingerprints or palmprints
    • G06V40/13—Sensors therefor
    • G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters

Definitions

  • the present application relates to the technical field of fingerprint detection, and more specifically, to an ultrasonic fingerprint detection device and electronic equipment.
  • fingerprint detection technology is increasingly used in smart terminal devices such as mobile phones and computers, thereby improving people's experience in using smart terminal devices.
  • fingerprint detection can be achieved through two chip structures.
  • one chip is a transmitting chip used to generate high-voltage driving signals
  • the other chip is a receiving chip used to receive high-voltage driving signals and emit ultrasonic waves to fingers to detect finger prints.
  • the "dual-chip" architecture means large size, complex circuitry and high cost.
  • the present application provides an ultrasonic fingerprint detection device and electronic equipment, which can reduce the size, circuit complexity and cost of the ultrasonic fingerprint detection device.
  • an ultrasonic fingerprint detection device including: a signal generating circuit and an ultrasonic fingerprint sensor chip; wherein, the signal generating circuit is composed of discrete components and the signal generating circuit includes: a control circuit and a resonant circuit, and the control circuit is used to receive ultrasonic waves
  • the fingerprint sensor chip provides a control signal and generates an excitation signal under the action of the control signal.
  • the resonant circuit is used to receive the excitation signal and form a driving signal under the action of the excitation signal; the ultrasonic fingerprint sensor chip is used to receive the driving signal and
  • the ultrasonic signal used for fingerprint detection is generated under the action of the driving signal.
  • an ultrasonic fingerprint detection device with a "single-chip" architecture which includes an ultrasonic fingerprint sensor chip and a signal generating circuit composed of discrete devices.
  • the signal generating circuit includes a control circuit and a resonant circuit.
  • the circuit structure of the resonant circuit is relatively simple and easy to implement and control, and can achieve good voltage boosting effect, and the control circuit can obtain control signals from the ultrasonic fingerprint sensor chip without obtaining control signals from other external control devices. Therefore, the ultrasonic fingerprint detection device according to the embodiment of the present application has a relatively simple circuit structure, a smaller circuit area, and a lower manufacturing cost.
  • control circuit includes two switching tubes connected in series between the input power supply and the ground.
  • the two switching tubes are alternately conducted under the action of the control signal to generate a pulse excitation signal;
  • the resonant circuit includes two switching tubes connected in series between the input power supply and the ground.
  • the capacitance and inductance between the control circuit and the ground resonate under the action of the pulse excitation signal to generate a sine wave driving signal.
  • the switch tube connected to the input power supply among the two switch tubes is a PMOS tube
  • the switch tube connected to the ground among the two switch tubes is an NMOS tube.
  • the switch tube connected to the input power supply in the signal generating circuit is set as a PMOS tube, and the switch tube connected to the ground is set as an NMOS tube.
  • the control signal provided by the ultrasonic fingerprint sensor chip can effectively control the two switch tubes, and no additional circuits and signals are needed to drive and control the two switch tubes.
  • the signal generating circuit has low circuit structure complexity and low manufacturing cost.
  • the other of the two switch tubes changes from off to on.
  • the two switching tubes are also turned on alternately in opposite phases under the action of the control signal to generate an anti-phase pulse excitation signal.
  • the anti-phase pulse signal is used to damp the resonance of the resonant circuit to reduce the sine wave drive.
  • the resonant energy of the signal is also turned on alternately in opposite phases under the action of the control signal to generate an anti-phase pulse excitation signal.
  • the signal generating circuit also includes: a braking circuit, the braking circuit includes a damping resistor, and the damping resistor is connected between the resonant circuit and the control circuit.
  • a brake circuit including a damping resistor is added to the signal generating circuit to absorb the excess signal energy generated by the resonant circuit when it is expected that the resonant circuit stops outputting the driving signal, thereby improving the sine wave output by the resonant circuit.
  • the aftershock of the driving signal improves the quality of the driving signal.
  • one end of the damping resistor is connected between the resonant circuit and the control circuit, and the other end of the damping resistor is connected to ground.
  • a damping resistor when the control circuit is open, a damping resistor is connected in series between the resonant circuit and the ground.
  • the damping resistor is used to damp the resonance of the resonant circuit to reduce the resonant energy of the driving signal.
  • the circuit structure of the braking circuit is relatively simple and the cost is low.
  • the braking circuit on the basis of ensuring that the signal generating circuit can output a driving signal with higher quality, it can also further reduce the The overall cost of the signal generating circuit and the ultrasonic fingerprint detection device.
  • the resistance value of the damping resistor is between 0.8*Z and 2*Z, where Z is the characteristic impedance of the resonant circuit.
  • the ultrasonic fingerprint sensor chip includes: a control module, a transducer module and a detection module; the control module is used to provide a control signal to the signal generating circuit to control the signal generating circuit to generate a driving signal; the transducing module is used to The drive signal is received to generate an ultrasonic signal. The ultrasonic signal is reflected by the user's finger to generate an echo signal. The transducer module is used to convert the echo signal into an electrical signal; the detection module is used to detect the electrical signal to detect the fingerprint of the user's finger.
  • the control module in the ultrasonic fingerprint sensor chip through the control module in the ultrasonic fingerprint sensor chip, unified control of the overall fingerprint detection process of the ultrasonic fingerprint detection device can be achieved, thereby ensuring the orderly conduct of the fingerprint detection process to ensure fingerprint detection.
  • the ultrasonic fingerprint detection device can further simplify the circuit structure and reduce the circuit complexity of the ultrasonic fingerprint detection device.
  • control module is used to send control signals to the signal generating circuit multiple times to control the signal generating circuit to generate multiple driving signals;
  • the transducing module is used to receive multiple driving signals to generate multiple ultrasonic signals, And convert multiple echo signals corresponding to multiple ultrasonic signals into multiple electrical signals;
  • the detection module is used to detect multiple electrical signals to detect the fingerprint of the user's finger.
  • control module is used to periodically send a control signal to the signal generating circuit to control the signal generating circuit to periodically generate the driving signal; the control module is used to control the transducing module to periodically receive the driving signal to Generate ultrasonic signals; the control module is used to control the detection module to periodically detect electrical signals to detect the fingerprint of the user's finger.
  • control module can periodically send control signals to the signal generating circuit to realize convenient control of the signal generating circuit, and the control module can also periodically control the transducing module and the detection module, This enables the ultrasonic fingerprint sensor chip to periodically detect the user's fingerprint.
  • the detection module includes: a receiving module, a detection module and a signal accumulation module; the receiving module is used to receive multiple electrical signals; the detection module is used to detect the amplitudes of multiple electrical signals; and the signal accumulation module is used to The amplitudes of multiple electrical signals are accumulated to obtain a signal accumulation value, and the signal accumulation value is used for average calculation to detect the fingerprint of the user's finger.
  • the noise in the signal can be reduced, thereby improving the signal-to-noise ratio of fingerprint detection, thereby improving the fingerprint detection accuracy of the ultrasonic fingerprint sensor chip.
  • the signal accumulation module is an analog accumulator.
  • the simulated signal accumulation value can be quickly stored in the signal accumulation module without analog-to-digital conversion. Therefore, the circuit structure of the signal accumulation module is relatively simple and can reduce the circuit cost of the ultrasonic fingerprint sensor chip. the complexity.
  • the ultrasonic fingerprint sensor chip also includes: a readout module, an analog-to-digital conversion module and an interface module; the readout module is used to read the accumulated value of the signal to the analog-to-digital conversion module; the analog-to-digital conversion module is used to Convert the accumulated value of the signal into a digital signal; the interface module is used to transmit the digital signal to an external device so that the digital signal is averaged and calculated to detect the fingerprint of the user's finger.
  • the readout module, the analog-to-digital conversion module and the interface module are provided in the ultrasonic fingerprint sensor chip, which can facilitate the transmission of the digital signal corresponding to the signal accumulation value to the external device of the ultrasonic fingerprint sensor chip for rapid user processing. Fingerprint detection, thereby improving fingerprint detection efficiency.
  • the voltage value of the input power supply of the signal generating circuit and the voltage value of the input power supply of the ultrasonic fingerprint sensor chip are the same.
  • the ultrasonic fingerprint detection device provided by the embodiment of the present application only needs one power supply, and does not need to connect multiple types of power supplies from the outside, thereby further reducing the circuit complexity of the ultrasonic fingerprint detection.
  • the voltage value of the input power supply of the signal generating circuit and the voltage value of the input power supply of the ultrasonic fingerprint sensor chip are between 3V and 4.5V.
  • the commonly used power supply voltage value is between 3V and 4.5V.
  • the signal generating circuit in the ultrasonic fingerprint detection device and the input power supply of the ultrasonic fingerprint sensor chip can both be terminal The power supply of the device does not require an additional power supply with a higher voltage, thereby saving the overall power consumption of the ultrasonic fingerprint detection device.
  • an electronic device including: a cover, and the ultrasonic fingerprint detection device in the first aspect or any possible implementation of the first aspect; wherein the cover is used to receive the press of the user's finger, and the ultrasonic fingerprint
  • the fingerprint detection device is disposed under the cover and is used to detect the fingerprint of the user's finger pressed against the cover.
  • the electronic device further includes: a display screen, the cover is disposed above the display screen, and the ultrasonic fingerprint detection device is disposed below the display screen.
  • Figure 1 is a schematic structural block diagram of an ultrasonic fingerprint detection device provided by an embodiment of the present application.
  • FIG. 2 is a schematic structural block diagram of another ultrasonic fingerprint detection device provided by an embodiment of the present application.
  • FIG. 3 is a schematic circuit diagram of a signal generating circuit provided by an embodiment of the present application.
  • Figure 4 is a schematic waveform diagram of a control signal, an excitation signal and a driving signal provided by an embodiment of the present application.
  • FIG. 5 is a schematic circuit diagram of another signal generating circuit provided by an embodiment of the present application.
  • FIG. 6 is another waveform diagram of a control signal, an excitation signal and a driving signal provided by an embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of another ultrasonic fingerprint detection device provided by an embodiment of the present application.
  • FIG. 8 is another waveform diagram of the control signal, excitation signal and driving signal provided by the embodiment of the present application.
  • Figure 9 is an enlarged schematic diagram of the waveform of the control signal in the excitation stage in Figure 8.
  • Figure 10 is a schematic structural block diagram of an ultrasonic fingerprint sensor chip provided by an embodiment of the present application.
  • FIG 11 is a schematic structural block diagram of another ultrasonic fingerprint sensor chip provided by an embodiment of the present application.
  • FIG. 12 is a schematic diagram of the working state of the ultrasonic fingerprint sensor chip provided by the embodiment of the present application.
  • Figure 13 is a schematic structural block diagram of another ultrasonic fingerprint detection device provided by an embodiment of the present application.
  • the ultrasonic fingerprint detection device provided by the embodiment of the present application can be applied in smartphones, tablet computers, smart wearable devices, smart door locks, or other types of electronic devices. More specifically, in the above-mentioned electronic device, the ultrasonic fingerprint detection device can be disposed on any surface where the electronic device interacts with the user, including but not limited to the front of the electronic device.
  • FIG. 1 shows a schematic structural block diagram of an ultrasonic fingerprint detection device 100 provided by an embodiment of the present application.
  • the ultrasonic fingerprint detection device 100 includes: a transmitting (Tx) chip 110 and a receiving (Rx) chip 120 .
  • the Tx chip 110 can be connected to the power supply VDD.
  • the Tx chip 110 includes a two-stage boost circuit 111 and 112 to boost and amplify the input power supply VDD voltage, so that the Tx chip 110 can generate a higher voltage to the Rx chip. drive signal.
  • the first-stage boost circuit 111 may be a Boost boost circuit
  • the second-stage boost circuit 112 may be a resonant boost circuit.
  • the first-stage boost circuit 111 can boost 3V to 30V
  • the second-stage boost circuit 112 can further boost 30V to 140V.
  • the Rx chip 120 may include an ultrasonic transducer 121 and an echo detection circuit 122 .
  • the ultrasonic transducer 121 can receive the high-voltage driving signal generated by the Tx chip 110 to generate ultrasonic waves.
  • the echo detection circuit 122 is used to receive and detect the electrical signal.
  • the electrical signal carries information about the ridges, valleys, or other details of the fingerprint. Therefore, the Rx chip 120 can detect the fingerprint of the user's finger by detecting the electrical signal.
  • the Tx chip 110 needs to generate a high-voltage driving signal up to 100V. This level of voltage is not compatible with the manufacturing process of the Rx chip 120. Therefore, the Tx chip 110 and the Rx chip 120 are generally designed as two separate chips. If the Tx chip 110 and the Rx chip 120 are to be integrated into the same chip, the Rx chip 120 also needs to use a high-voltage process, which will increase the cost.
  • the boost circuit in the Tx chip 110 has a relatively complex circuit structure, and an independent control circuit 113 needs to be provided in the Tx chip 110 to control the boost circuit.
  • the "dual-chip" architecture of the ultrasonic fingerprint detection device 100 means large size, complex circuitry, and high cost.
  • the present application provides an ultrasonic fingerprint detection device with a "single-chip” architecture, which can reduce the size, circuit complexity and cost of the above-mentioned ultrasonic fingerprint detection device.
  • FIG. 2 shows a schematic structural block diagram of an ultrasonic fingerprint detection device 200 provided by an embodiment of the present application.
  • the ultrasonic fingerprint detection device 200 includes: a signal generating circuit 210 and an ultrasonic fingerprint sensor chip 220 .
  • the signal generating circuit 210 is composed of discrete components and includes: a boost circuit, which is used to boost the input power supply to form a driving signal, and the voltage value of the driving signal is greater than the voltage value of the input power supply. Voltage value.
  • the ultrasonic fingerprint sensor chip 220 is configured to receive the driving signal and generate an ultrasonic signal for fingerprint detection under the action of the driving signal.
  • the signal generating circuit 210 is not a chip, but a circuit structure composed of discrete components. Therefore, compared with the "dual-chip" architecture, the ultrasonic fingerprint detection device 200 provided in the embodiment of the present application only includes one ultrasonic fingerprint sensor chip 220, and the overall manufacturing cost will be greatly reduced.
  • the signal generating circuit 210 only includes a one-stage boost circuit, which is used to boost the input power supply to form a driving signal with a higher voltage, thereby improving the driving signal for the ultrasonic fingerprint sensor.
  • the driving effect of the chip 220 is to ensure the detection performance of the ultrasonic fingerprint sensor chip 220.
  • the embodiment of the present application reduces the circuit structure, thereby reducing the overall circuit complexity and overall complexity of the ultrasonic fingerprint detection device 200. size.
  • the boost circuit in the signal generating circuit 210 may include a resonant circuit, and the resonant circuit may generate a high-voltage driving signal by forming resonance.
  • the circuit structure of the resonant circuit is relatively simple and easy to implement, which can further reduce the overall circuit complexity and overall cost of the ultrasonic fingerprint detection device 200.
  • the ultrasonic fingerprint sensor chip 220 may include an ultrasonic transducer 121 and an echo detection circuit 122 as shown in the Rx chip 120 in FIG. 1 .
  • the ultrasonic transducer 121 can generate an ultrasonic signal under the action of the driving signal provided by the signal generating circuit 210, and can receive the echo signal reflected by the user's finger to generate an electrical signal.
  • the echo detection circuit 122 can detect the electrical signal to perform fingerprint detection.
  • the ultrasonic transducer 121 may include a piezoelectric layer and upper and lower electrode layers.
  • the piezoelectric material in the piezoelectric layer includes, but is not limited to, polyvinylidene fluoride (PVDF), polyvinylidene fluoride (PVDF), Fluoride-trifluoroethylene (polyvinylidene fluoride–Trifluoroethene, PVDF-TrFE) copolymer, etc.
  • PVDF polyvinylidene fluoride
  • PVDF polyvinylidene fluoride
  • Fluoride-trifluoroethylene polyvinylidene fluoride–Trifluoroethene
  • PVDF-TrFE Fluoride-trifluoroethylene copolymer
  • a "single-chip" architecture ultrasonic fingerprint detection device 200 which includes an ultrasonic fingerprint sensor chip 220 and a signal generating circuit 210 composed of discrete components.
  • the signal generating circuit 210 includes a
  • the step-up circuit also has a relatively simple circuit structure, a smaller circuit area, and a lower manufacturing cost. . Therefore, compared with the ultrasonic fingerprint detection device with a "dual-chip" architecture, the technical solution of the embodiment of the present application can reduce the size, circuit complexity, and manufacturing cost of the ultrasonic fingerprint detection device.
  • the voltage value of the input power supply of the signal generating circuit 210 and the voltage value of the input power supply of the ultrasonic fingerprint sensor chip 220 are the same.
  • the signal generating circuit 210 and the ultrasonic fingerprint sensor chip 220 can be connected to the same power supply, so that the same power supply provides power to both.
  • the ultrasonic fingerprint detection device 200 provided by the embodiment of the present application only needs one power supply, and does not need to access multiple types of power supplies from the outside, thereby further reducing the circuit complexity of the ultrasonic fingerprint detection. .
  • the voltage value of the input power supply of the signal generating circuit 210 and the voltage value of the input power supply of the ultrasonic fingerprint sensor chip 220 are between 3V and 4.5V.
  • the commonly used power supply voltage value is between 3V and 4.5V.
  • the input power supply of the signal generating circuit 210 in the ultrasonic fingerprint detection device 200 and the ultrasonic fingerprint sensor chip 220 are both The power supply can be used as a power supply for the terminal device without requiring an additional power supply with a higher voltage, thereby saving the overall power consumption of the ultrasonic fingerprint detection device 200 .
  • Figure 3 shows a schematic circuit diagram of a signal generating circuit 210 provided by an embodiment of the present application.
  • the above-mentioned boost circuit includes a control circuit 211 and a resonance circuit 212 .
  • the control circuit 211 is connected to the input power supply VDD.
  • the control circuit 211 is used to receive the control signal provided by the ultrasonic fingerprint sensor chip 220 and generate an excitation signal under the action of the control signal and the input power supply.
  • the resonant circuit 212 is connected to the control circuit 211.
  • the resonant circuit 212 is used to receive an excitation signal provided by the control circuit 211 and form a driving signal under the action of the excitation signal.
  • the resonant circuit 212 may include an inductor L and a capacitor C connected in series to form an LC series resonant circuit.
  • the inductor L may have an equivalent resistance R, and the resistance R may be regarded as being connected in series with the LC to form the LC series resonant circuit.
  • the capacitance C can be the equivalent capacitance of the ultrasonic transducer in the ultrasonic fingerprint sensor chip 220, or the capacitance C can also be the equivalent capacitance of the ultrasonic transducer and the overall equivalent capacitance of other adjustable capacitances.
  • the capacitor C may also be connected in series with an equivalent resistance of the ultrasonic transducer. That is, the resonant circuit 212 may include, in addition to the equivalent resistance R of the inductor L, the equivalent resistance of the ultrasonic transducer.
  • the control circuit 211 may receive a control signal sent by the ultrasonic fingerprint sensor chip 220 and generate an excitation signal for exciting the LC series resonant circuit under the action of the control signal. Under the action of the excitation signal, the LC series resonant circuit can resonate a driving signal with a higher voltage, and the voltage value of the driving signal is greater than the voltage value of the input power supply of the signal generating circuit 210 .
  • the signal generating circuit 210 can include a control circuit 211 and a resonant circuit 212.
  • the circuit structure of the resonant circuit 212 is relatively simple and easy to implement and control, and can achieve a good voltage boosting effect.
  • the control circuit 211 can obtain control signals from the ultrasonic fingerprint sensor chip 220 without obtaining control signals from other external control devices. Therefore, in addition to controlling the relevant operations of its own components, the ultrasonic fingerprint sensor chip 220 can also The relevant operation of the signal generating circuit 210 is controlled to ensure the normal operation of the entire ultrasonic fingerprint detection device 200 .
  • the control circuit 211 includes two switching tubes Q1 and Q2 connected in series between the input power supply VDD and the ground.
  • the two switching tubes Q1 and Q2 function as control signals.
  • the switch is turned on and off to output the excitation signal SW at the node between the two switching tubes Q1 and Q2.
  • the ultrasonic fingerprint sensor chip 220 can provide a control signal to the control circuit 211.
  • the control signal is processed by devices inside the control circuit 211 to generate two control signals S1 and S2.
  • the first switch Q1 is in the third
  • the first switch Q2 is turned on and off under the action of a control signal S1
  • the second switch Q2 is turned on and off under the action of the second control signal S2.
  • the ultrasonic fingerprint sensor chip 220 may also directly provide two control signals S1 and S2 to the control circuit 211, thereby directly controlling the two switching transistors Q1 and Q2 to turn on and off.
  • the resonant circuit 212 includes a capacitor C and an inductor L connected in series between the control circuit 211 and the ground.
  • the capacitor C and the inductor L can generate the driving signal V TX under the action of the above-mentioned pulse excitation signal.
  • the resonant circuit 212 may further include a resistor R connected to the capacitor C and the inductor L.
  • FIG. 4 shows a schematic waveform diagram of the control signals S1 and S2, the excitation signal SW and the drive signal V TX provided by the embodiment of the present application.
  • the working states of the signal generating circuit 210 include: waiting stage, excitation stage and inverting stage.
  • the resonance circuit 212 does not generate resonance.
  • the first control signal S1 is at a low level to control the first switch Q1 to turn off
  • the second control signal S2 is at a high level to control the second switch Q2 to turn on.
  • the excitation signal SW output by the control circuit 211 and the drive signal V TX output by the resonant circuit 212 are both low level.
  • the two switching transistors Q1 and Q2 in the control circuit 211 can be turned on alternately under the action of the control signal to generate the pulse excitation signal SW. Further, the inductor L and the capacitor C in the resonant circuit 212 can resonate under the action of the pulse excitation signal SW to generate a sine wave driving signal V TX .
  • the first control signal S1 and the second control signal S2 may be pulse signals with opposite phases to each other.
  • the frequency of the pulse signal may be equal to the resonant frequency of the LC series resonant circuit 212, so that both ends of the capacitor C resonate to generate a high-voltage sine wave driving signal V TX . That is, the frequency f of the pulse signal satisfies the following formula:
  • L and C in this formula represent the sizes of the inductor L and capacitor C respectively.
  • the waveform of the pulse excitation signal SW output by the control circuit 211 may be the same as the waveform of the control signal S1 of the first switching tube Q1.
  • the first switch Q1 When the first control signal S1 is high level and the second control signal S2 is low level, the first switch Q1 is turned on, the second switch Q2 is turned off, and the output pulse excitation signal SW is high level; when When the first control signal S1 is low level and the second control signal S2 is high level, the first switch Q1 is turned off, the second switch Q2 is turned on, and the output pulse excitation signal SW is low level.
  • the sine wave driving signal V TX can be a sine wave signal with a gradually increasing amplitude.
  • both switching tubes Q1 and Q2 can be turned off, so that the output pulse excitation signal SW remains at a low level, and the resonance is reset to zero through the resistor R. But in fact, since the oscillation energy of the resonant circuit cannot disappear immediately, the sine wave drive signal V Tx slowly drops to zero. Therefore, before turning off the switching tubes Q1 and Q2, the reverse-phase driving method can be used, that is, the pulse excitation signal SW reverses phase, thereby accelerating the resonant energy of the resonant circuit to zero.
  • the two switching tubes Q1 and Q2 can be turned on alternately in opposite phases under the action of the control signal to generate an inverse pulse excitation signal.
  • the phase of the inverse pulse excitation signal is the same as the pulse excitation signal SW generated during the above excitation stage. opposite to each other.
  • the inverted pulse signal is used to damp the resonance of the resonant circuit 212 to reduce the resonant energy of the sine wave driving signal V TX generated by it.
  • the reverse-phase driving time should not be too long.
  • FIG. 4 shows that the reverse-phase driving time is one signal period. In this inverting driving stage, the two switching transistors Q1 and Q2 are turned on and off alternately, but the switching phase and the excitation stage are completely inverted.
  • FIGS. 3 and 4 are only for illustration and not limitation, showing the circuit structure of the resonant circuit 212 and the control circuit 211 and the corresponding signal waveform diagrams in one embodiment.
  • the resonant circuit 212 and the control circuit 211 can also adopt other circuit structures, so that the two can cooperate to achieve the effect of resonant boosting of the input power supply.
  • the resonant circuit 212 The specific circuit structure of the control circuit 211 is not limited.
  • the driving signal SW in the excitation stage only shows a pulse signal of 2 periods.
  • the 2-period pulse signal is only for illustration.
  • the driving signal SW in the excitation stage is also It can be any other pulse signal with any number of cycles. This application does not limit the number of cycles of the pulse signal of the drive signal SW in the excitation stage.
  • control signals S1 and S2 first control the first switch Q1 to turn on and then control the second switch Q2.
  • control signal S1 S2 can also control the second switch Q2 to turn on first and then control the first switch Q1 to turn on. This application does not limit the turn-on sequence of the first switch Q1 and the second switch Q2.
  • FIG. 5 shows a schematic circuit diagram of another signal generating circuit 210 provided by an embodiment of the present application.
  • the signal generating circuit 210 in addition to the above-mentioned control circuit 211 and the resonant circuit 212, also includes a braking circuit 213.
  • the braking circuit includes a damping resistor R1, and the damping resistor R1 is connected between the resonant circuit 212 and the resonant circuit 212. between control circuit 211.
  • a braking circuit 213 including a damping resistor R1 is added to the signal generating circuit 210 to absorb the excess signal energy generated by the resonant circuit 212 when it is expected that the resonant circuit 212 stops outputting the sine wave drive signal Tx.
  • the residual vibration of the sine wave driving signal output by the resonant circuit 212 is improved, and the quality of the sine wave driving signal is improved.
  • one end of the damping resistor R1 is connected between the resonant circuit 212 and the control circuit 211 , and the other end of the damping resistor R1 is connected to ground.
  • the two switching tubes Q1 and Q2 in the control circuit 211 are both turned off. At this time, the control circuit 211 is disconnected, and the damping resistor R1 can be connected in series with the resonant circuit 212.
  • the damping resistor R1 is used to damp the resonance of the resonant circuit 212 to reduce the resonance energy of the sine wave driving signal Tx generated by it, so that the resonance of the resonant circuit 212 quickly returns to zero.
  • the resistance value of the damping resistor R1 is related to the characteristic impedance Z of the resonant circuit 212 .
  • the resistance value of the damping resistor R1 can be between 0.8*Z and 2*Z, where, L and C are the values of the inductor L and the capacitor C in the resonant circuit 212, respectively.
  • the resistance value of the damping resistor R1 includes but is not limited to 1.4*Z.
  • the inductor L in the resonant circuit 212 also has an equivalent resistance R.
  • This resistance R can work together with the above-mentioned damping resistor R1 to damp and "brake" the LC resonance. Therefore, the sum of the resistance values of the damping resistor R1 and the resistor R may be between 0.8*Z and 2*Z.
  • the sum of the resistance values of the damping resistor R1 and the resistor R includes but is not limited to 1.4*Z.
  • the circuit structure of the brake circuit 213 is relatively simple and the cost is low.
  • the brake circuit 213 on the basis of ensuring that the signal generating circuit 210 can output a driving signal with higher quality, it can also further The overall cost of the signal generating circuit 210 and the ultrasonic fingerprint detection device 200 is reduced.
  • the excitation signal SW of the resonant circuit 212 can be further inverted, thereby further accelerating the resonance return to zero of the resonant circuit 212 .
  • FIG. 6 shows another waveform diagram of the control signals S1 and S2, the excitation signal SW and the drive signal V TX according to the embodiment of the present application.
  • the working states of the signal generating circuit 210 include: waiting stage, excitation stage, inversion stage and damping braking stage.
  • both the first control signal S1 and the second control signal S2 are low level to control the first switch Q1 and the second switch Q2 to be turned off.
  • the resonant circuit 212 passes Brake circuit 213 is connected to ground.
  • the excitation signal SW output by the control circuit 211 and the drive signal V TX output by the resonant circuit 212 are both low level.
  • the two switching transistors Q1 and Q2 in the control circuit 211 can be turned on alternately under the action of the control signal to generate the pulse excitation signal SW. Further, the inductor L and the capacitor C in the resonant circuit 212 can resonate under the action of the pulse excitation signal SW to generate a sine wave driving signal V TX .
  • the two control signals S1 and S2 are in phase with each other.
  • the two switching transistors Q1 and Q2 are still turned on and off alternately, but the switching phase and the excitation phase are completely inverted. Therefore, the two switching transistors Q1 and Q2 are completely in phase.
  • the pulse excitation signal SW generated by the switching transistors Q1 and Q2 also generates a corresponding inversion, thereby reducing the resonant energy of the resonant circuit 212.
  • the damping resistor R1 therein can further accelerate the reduction of the resonant energy of the resonant circuit 212.
  • the damping resistor R1 in the braking circuit 213 can continue to act as a damping "brake" on the resonance of the resonant circuit 212, so as to quickly reduce the resonant energy of the resonant circuit 212 and make the resonance quickly return to zero.
  • the braking circuit 213 may further include other devices, such as a switching tube.
  • the damping resistor R1 can have a positive impact on the resonant circuit during the damping braking stage.
  • the resonance of 212 acts as a "damping" brake, but during the excitation stage, it will not affect the resonance effect of the resonant circuit 212.
  • the brake circuit 213 can only be provided with a damping resistor R1 without requiring an additional switch tube and a control signal to control the switch tube. Therefore, compared with other types of brake circuits 213 , the brake circuit 213 of the embodiment shown in Figure 5 has a lower cost.
  • the voltage value of the input power supply VDD of the signal generating circuit 210 is generally relatively low.
  • the voltage value of the input power supply VDD can be between 3V and 4.5V. Therefore, even if the damping resistor R1 in the brake circuit 213 is connected between the output terminal of the control circuit 211 and ground, when the control signal SW output by the output terminal of the control circuit 211 is high level, a current will be generated in the damping resistor R1, but due to The voltage value of the input power supply VDD is small, and the current generated on the damping resistor R1 can be correspondingly small, without causing large power consumption.
  • FIG. 7 shows a schematic structural diagram of another ultrasonic fingerprint detection device 200 provided by an embodiment of the present application.
  • the switch tube connected to the input power supply VDD among the two switch tubes is a P-type metal oxide semiconductor (positive channel Metal Oxide).
  • Semiconductor, PMOS P-type metal oxide semiconductor
  • the switch tube connected to the ground i.e., the second switch tube Q2
  • the switch tube connected to the ground is an N-type metal oxide semiconductor (positive channel Metal Oxide Semiconductor, NMOS) field effect tube, or it can also be referred to as an NMOS tube.
  • the ultrasonic fingerprint sensor chip 220 is used to provide control signals S1 and S2 to the control circuit 211 in the signal generating circuit 210 to control the above-mentioned PMOS tube and NMOS tube respectively.
  • the first control signal S1 is used to control the on and off of the PMOS tube.
  • the first control signal S1 is low level
  • the PMOS tube is turned on.
  • the first control signal S1 is high level
  • the PMOS tube is turned off. Break.
  • the second control signal S2 is used to control the on and off of the NMOS transistor.
  • the second control signal S2 is at a high level
  • the NMOS transistor is turned on.
  • the second control signal S2 is at a low level, the NMOS transistor is turned off.
  • the high level of the first control signal S1 and the second control signal S2 may be consistent with the voltage value of the input power supply VDD of the ultrasonic fingerprint sensor chip 220 , for example, the first control signal S1 and the second control signal S2
  • the high level can be 3V on average.
  • the low levels of the first control signal S1 and the second control signal S2 may be ground, that is, 0V.
  • the input power supplies of the ultrasonic fingerprint sensor chip 220 and the signal generating circuit 210 may be the same power supply VDD.
  • the control signal provided by the ultrasonic fingerprint sensor chip 220 can be effectively realized. Effective control of the first switching tube Q1 and the second switching tube Q2 does not require additional circuits and signals to drive and control the first switching tube Q1 and the second switching tube Q2.
  • the circuit structure of the signal generating circuit 210 is complex. degree and manufacturing costs are low.
  • the first switching transistor Q1 and the second switching transistor Q2 in the signal generating circuit 210 are both configured as PMOS transistors or both are configured as NMOS transistors, at least one of the two switching transistors
  • FIG. 8 shows a schematic waveform diagram of the control signals S1 and S2 provided by the ultrasonic fingerprint sensor chip 220 , the excitation signal SW output by the control circuit 211 , and the drive signal V TX output by the resonant circuit 212 .
  • the first control signal S1 since the first control signal S1 is used to control the PMOS transistor (the first switching transistor Q1), the first control signal S1 controls the first switching transistor Q1 when it is at a low level. is turned on, and the first switching tube Q1 is controlled to be turned off when the level is high.
  • the first control signal S1 controls the first switch Q1 to be turned on when at a high level, and controls the first switch Q1 to be turned off when at a low level. Therefore, the first control signal S1 in the embodiment shown in FIG. 8 may be inverse phase with the first control signal S1 in the embodiment shown in FIG. 6 above.
  • the first control signal S1 of the first switch Q1 The control process is the same.
  • the two switching tubes Q1 and Q2 cannot be turned on at the same time, otherwise the input power supply VDD and ground will be short-circuited to form a large current, thereby affecting the switching tubes Q1 and Q2. . Therefore, under the action of the control signals S1 and S2, after the state of one of the two switching tubes Q1 and Q2 changes from on to off for a preset time, the other of the two switching tubes The state changes from off to on.
  • This time gap can be called the "dead time".
  • the dead time the two switching tubes Q1 and Q2 are both off.
  • FIG. 9 shows an enlarged schematic diagram of the waveforms of the control signals S1 and S2 in the excitation stage in FIG. 8 .
  • the dead time is a preset time.
  • the second control signal S2 After a preset time of the rising edge of the first control signal S1, the second control signal S2 generates a rising edge, that is, the first switch transistor Q1 (PMOS transistor) controlled by the first control signal S1 changes from on to off.
  • the second switch transistor Q2 After a preset time after being turned off, the second switch transistor Q2 (NMOS transistor) controlled by the second control signal S2 changes from off to on.
  • the dead time is a preset time.
  • the first control signal S1 after a preset time of the falling edge of the second control signal S2, the first control signal S1 generates a falling edge, that is, the second switch transistor Q2 (NMOS transistor) controlled by the second control signal S2 changes from on to off.
  • the first switch transistor Q1 PMOS tube controlled by the first control signal S1 changes from off to on.
  • the above embodiment introduces the signal generating circuit 210 in the ultrasonic fingerprint detection device 200 provided by the present application with reference to FIGS. Fingerprint sensor chip 220 is illustrated.
  • FIG. 10 shows a schematic structural block diagram of an ultrasonic fingerprint sensor chip 220 provided by an embodiment of the present application.
  • the ultrasonic fingerprint sensor chip 220 includes: a control module 221 , a transducer module 222 and a detection module 223 .
  • the control module 221 is used to provide a control signal to the signal generating circuit 210 to control the signal generating circuit 210 to generate a driving signal.
  • the transducer module 222 is used to receive the driving signal to generate an ultrasonic signal.
  • the ultrasonic signal is reflected by the user's finger to generate an echo signal.
  • the transducer module 222 is used to convert the echo signal into an electrical signal.
  • the detection module 223 is used to detect the electrical signal to detect the fingerprint of the user's finger.
  • the transducer module 222 may include the ultrasonic transducer 121 in the embodiment shown in FIG. 1 above.
  • the detection module 223 may include the echo detection circuit 122 in the above embodiment.
  • the control module 221 may be a controller in the ultrasonic fingerprint sensor chip 220, which may be connected to the above-mentioned transducing module 222 and the detection module 223, and control the operation of the transducing module 222 and the detection module 223.
  • the control module 221 can also be used to provide a control signal to the signal generating circuit 210 to control the operation of the signal generating circuit 210 .
  • the overall fingerprint detection process of the ultrasonic fingerprint detection device 200 can be uniformly controlled, thereby ensuring the orderly conduct of the fingerprint detection process to ensure the fingerprint detection effect, and furthermore
  • the circuit structure of the ultrasonic fingerprint detection device 200 is simplified and the circuit complexity of the ultrasonic fingerprint detection device 200 is reduced.
  • the voltage value of the input power supply of the signal generating circuit 210 is low, for example, the voltage value is 3V. In this case, even if The signal generating circuit 210 boosts the 3V voltage of the input power supply, and the voltage value of the output driving signal VTX is generally about 20V. Compared with the technical solution in the related art of boosting the driving signal to above 100V through two-stage voltage boosting, the voltage value of the driving signal V TX output by the above-mentioned signal generating circuit 210 is lower, which will affect the ultrasonic fingerprint to a certain extent. Fingerprint detection effect of sensor chip 220.
  • the control module 221 can be used to send multiple control signals to the signal generating circuit 210 to control the signal generating circuit 210 to generate multiple driving signals.
  • the transducer module 222 is configured to receive the plurality of driving signals to generate a plurality of ultrasonic signals, and convert a plurality of echo signals corresponding to the plurality of ultrasonic signals into a plurality of electrical signals.
  • the detection module 223 is used to detect the multiple echo signals to detect the fingerprint of the user's finger.
  • the control module 221 can send the first control signal S1 and the second control signal S2 of a preset duration to the signal generating circuit 210.
  • Both the control signal S1 and the second control signal S2 may include multiple periods of pulse signals.
  • the specific waveforms and related technical solutions of the first control signal S1 and the second control signal S2 can be seen in Figure 4, Figure 6 or The technical solution of any embodiment in Figure 8.
  • the first control signal S1 and the second control signal S2 can control the signal generating circuit 210 to operate in the waiting phase, the excitation phase, the reverse phase, the damping braking phase and the waiting phase in sequence.
  • the signal generating circuit 210 When the control module 221 sends a control signal to the signal generating circuit 210, the signal generating circuit 210 generates a driving signal V TX under the action of the control signal.
  • the transducing module 222 receives the driving signal V TX and generates an ultrasonic signal under the action of the driving signal V TX .
  • the ultrasonic signal is reflected by the user's finger and forms an echo signal.
  • the transducing module 222 receives the echo signal and converts it into a corresponding electrical signal, so that the detection module 223 detects the electrical signal.
  • the above process can be understood as a “one-time detection” of the user’s fingerprint by the ultrasonic fingerprint sensor chip 220 .
  • “multiple detections” of the user's finger prints by the ultrasonic fingerprint sensor chip 220 can be achieved.
  • the fingerprint results obtained through “multiple detections” have higher accuracy, which can improve the fingerprint detection of the ultrasonic fingerprint sensor chip 220 Effect.
  • control module 221 may be configured to periodically send a control signal to the signal generating circuit 210 to control the signal generating circuit 210 to generate a driving signal.
  • the control module 221 is used to control the transducer module 222 to periodically receive the driving signal to generate ultrasonic signals.
  • control module 221 is used to control the detection module 223 to periodically detect electrical signals to detect the fingerprint of the user's finger.
  • the control module 221 can control the signal generating circuit 210 to periodically generate the driving signal by periodically sending a control signal, and then the control module 221 can periodically control the transducing module 222 to receive the driving signal.
  • the driving signal is to generate an ultrasonic signal
  • the transducer module 222 can periodically receive the echo signal after the ultrasonic signal is reflected by the user's finger under the control of the control module 221, and convert the periodically received echo signal into a corresponding electrical signal.
  • the control module 221 can also control the detection module 223 to periodically receive and detect the electrical signal to achieve fingerprint detection of the user's finger.
  • the period of the control signal sent by the control module 221 to the signal generating circuit 210 may be determined according to the chip structure and data processing speed of the ultrasonic fingerprint sensor chip 220 .
  • the sending period cannot be too long, otherwise the fingerprint detection efficiency of the ultrasonic fingerprint sensor chip 220 will be affected.
  • the transmission period cannot be too short and must be longer than the processing time for the ultrasonic fingerprint sensor chip 220 to generate ultrasonic signals and receive echo signals.
  • the transmission period is usually less than 10 ⁇ s, and the maximum does not exceed 50 ⁇ s.
  • control module 221 can periodically send control signals to the signal generating circuit 210 to realize convenient control of the signal generating circuit 210, and the control module 221 can also periodically send control signals to the transducing module 222 and the signal generating circuit 210.
  • the detection module 223 performs control to realize periodic detection of the user's fingerprint by the ultrasonic fingerprint sensor chip 220 .
  • FIG. 11 shows a schematic structural block diagram of another ultrasonic fingerprint sensor chip 220 provided by an embodiment of the present application.
  • the above-mentioned detection module 223 may include: a receiving module 2231, a detection module 2232 and a signal accumulation module 2233.
  • the receiving module 2231 is used to receive multiple electrical signals.
  • the detection module 2232 is used to detect the amplitudes of the plurality of electrical signals.
  • the signal accumulation module 2233 is used to accumulate the amplitudes of multiple electrical signals to obtain a signal accumulation value.
  • the signal accumulation value is used to average and calculate to detect the fingerprint of the user's finger.
  • the detection module 223 may include multiple sub-modules to implement detection of electrical signals corresponding to echo signals.
  • the detection module 223 may include a signal accumulation module 2233, which may be used to accumulate the amplitudes of multiple electrical signals detected by the detection module 2232 to obtain a signal accumulation value. After the signal accumulation value is averaged, the noise in the signal can be reduced, thereby improving the signal-to-noise ratio (SNR) of fingerprint detection, thereby improving the fingerprint detection accuracy of the ultrasonic fingerprint sensor chip 220.
  • SNR signal-to-noise ratio
  • control module 221 is used to control the signal generation circuit 210 and the ultrasonic fingerprint sensor chip 220 to detect the user's fingerprint N times.
  • the detection module 223 can receive N electrical signals, then the signal accumulation module 2233 will respond to the N electrical signals. The amplitudes are accumulated to obtain the signal accumulation value.
  • the signal accumulation module 2233 can be an analog signal accumulator, that is, the signal accumulation module 2233 is used to receive multiple simulated electrical signals and accumulate them, and the output accumulated signal value is also an analog signal.
  • the analog signal The signal accumulation value can be quickly stored in the signal accumulation module 2233 without analog-to-digital conversion. Therefore, the circuit structure of the signal accumulation module 2233 is relatively simple and can reduce the circuit complexity of the ultrasonic fingerprint sensor chip 220.
  • the signal accumulation module 2233 can be an integrator, and the detection module 2232 can be a detector. As an example, the whole of the detection module 2232 and the signal accumulation module 2233 can be an integrating detector. Of course, in other alternative implementations, the signal accumulation module 2233 and the detection module 2232 can also be other types of circuit structures or devices, which are not specifically limited in the embodiments of the present application.
  • the ultrasonic fingerprint sensor chip 220 also includes: a readout module 224 , an analog-to-digital conversion module 225 and an interface module 226 .
  • the reading module 224 is used to read the signal accumulation value generated by the signal accumulation module 2233 to the analog-to-digital conversion module 225 .
  • the analog-to-digital conversion module 225 is used to convert the signal accumulation value into a digital signal.
  • the interface module 226 is used to transmit the digital signal (shown as fingerprint data in FIG. 11) to an external device so that the digital signal is averaged and calculated to detect the fingerprint of the user's finger.
  • the readout module 224 may be a readout circuit.
  • the analog-to-digital converter module 225 may be an analog-to-digital converter (Analog-to-Digital Converter, ADC).
  • the interface module 226 includes but is not limited to a serial peripheral interface (Serial Peripheral Interface, SPI) interface.
  • the signal accumulation module 2233 is an analog signal accumulator
  • the readout module 224, the analog-to-digital conversion module 225 and the interface module 226 are provided in the ultrasonic fingerprint sensor chip 220, which can facilitate the transmission of the digital signal corresponding to the signal accumulation value to the ultrasonic sensor chip 220.
  • the external device of the fingerprint sensor chip 220 can quickly detect the fingerprint of the user's finger, thereby improving the efficiency of fingerprint detection.
  • the above-mentioned readout module 224, analog-to-digital conversion module 225 and interface module 226 may not be integrated into the ultrasonic fingerprint sensor chip 220, but may be provided outside the ultrasonic fingerprint sensor chip 220, thereby reducing The ultrasonic fingerprint sensor chip 220 requires an installation space.
  • the above-mentioned control module 221 may include: a loop control module 2211 and a transmission control module 2212.
  • the loop control module 2211 can be understood as the main control module of the ultrasonic fingerprint sensor chip 220, which connects and controls the emission control module 2212 and the above-mentioned receiving module 2231 and signal accumulation module 2233.
  • the loop control module 2211 can send a control signal to the signal generation circuit 210 through the transmission control module 2212.
  • the cycle control module 2211 can periodically send a control signal to the signal generation circuit 210 through the transmission control module 2212.
  • the cycle control module 2211 can control the receiving module 2231 to receive the electrical signal obtained by converting the echo signal by the transducing module 222.
  • the cycle control module 2211 can control the receiving module 2231 to receive the electrical signal periodically.
  • the loop control module 2211 can also control the signal accumulation module 2233 to accumulate the amplitudes of the multiple electrical signals detected by the detection module 2232.
  • the emission control module 2212 and the cycle control module 2211 can be two separate controllers as shown in FIG. 11 , or the emission control module 2212 and the cycle control module 2211 can also be integrated into one controller.
  • FIG. 12 shows a schematic diagram of the working state of the ultrasonic fingerprint sensor chip 220 in the embodiment shown in FIG. 11 .
  • the ultrasonic fingerprint sensor chip 220 may be in a periodic working state. In one cycle, the ultrasonic fingerprint sensor chip 220 can operate in the transmitting state and the receiving state respectively.
  • the ultrasonic fingerprint sensor chip 220 can send a control signal to the signal generating circuit 210 through the loop control module 2211 and the transmitting control module 2212, so that the signal generating circuit 210 periodically generates the excitation signal SW under the action of the control signal. and drive signal V TX .
  • the period of the excitation signal SW and the driving signal V TX may be Trp, and the Trp may be the same as the period of the control signal sent by the control module 221 to the signal generating circuit 210 .
  • the Trp can be determined according to the chip structure and data processing speed of the ultrasonic fingerprint sensor chip 220 . Generally speaking, the Trp is usually less than 10 ⁇ s, and the maximum does not exceed 50 ⁇ s.
  • the ultrasonic fingerprint sensor chip 220 can also send an ultrasonic signal to the user's finger through the transducer module 222, so that the ultrasonic signal is reflected by the user's finger to generate an echo signal.
  • the ultrasonic fingerprint sensor chip 220 can convert the echo signal into an electrical signal through the transducer module 222, and the ultrasonic fingerprint sensor chip 220 can control the receiving module 2231, the detection module 2232 and the signal accumulation through the loop control module 2211.
  • Module 2233 receives and detects electrical signals, and accumulates the electrical signals.
  • the ultrasonic fingerprint sensor chip 220 can detect the accumulated signal value of n electrical signals.
  • the ultrasonic fingerprint sensor chip 220 can enter the data conversion & readout state, that is, through the readout module 224 and analog-to-digital conversion.
  • Module 225 reads out the accumulated value of the signal and performs analog-to-digital conversion. Then, the ultrasonic fingerprint sensor chip 220 can enter the data transmission stage, that is, transmit the digital signal corresponding to the signal accumulation value to an external device through the interface module 226 for fingerprint detection.
  • FIG. 13 shows a schematic structural block diagram of another ultrasonic fingerprint detection device 200 provided by an embodiment of the present application.
  • the ultrasonic fingerprint sensor chip 220 and the signal generating circuit 210 both receive the power supply voltage VDD output by the same interface.
  • the capacitor C in the embodiment shown in FIG. 7 may include the adjustable capacitor C1 in the embodiment of the present application and the equivalent capacitance of the ultrasonic transducer in the ultrasonic fingerprint sensor chip 220.
  • the signal generating circuit 210 may receive two control signals S1 and S2 provided by the ultrasonic fingerprint sensor chip 220 to control the two switch transistors Q1 and Q2 respectively.
  • the signal generating circuit 210 may also receive a control signal provided by the ultrasonic fingerprint sensor chip 220. After the control signal is processed by other devices, it forms two control signals S1 and S2 that respectively control the two Q1 and Q2. .
  • the two switching transistors Q1 and Q2 can be integrated into a driver for exciting the resonant circuit 212.
  • the driver can also include other signal processing devices.
  • the embodiment of the present application The specific structure of the driver is not limited.
  • the specific structure of the ultrasonic fingerprint sensor chip 220 may be similar to the embodiment shown in FIG. 11 above.
  • the ultrasonic fingerprint sensor chip 220 may include a pixel array (Pixel Array) used for ultrasonic fingerprint imaging, and the pixel array is composed of a plurality of pixel units (Pixel Cell).
  • Each pixel unit may include: an upper electrode, a piezoelectric layer, and a lower electrode.
  • the upper electrodes of the plurality of pixel units can be connected to each other to form an integral upper electrode.
  • the integral upper electrode point can be electrically connected to a TX interface, and the TX interface can receive the driving signal V TX generated by the signal generating circuit 210 .
  • the lower electrodes of the plurality of pixel units can be arranged separately from each other, that is, the lower electrodes of the plurality of pixel units can form a lower electrode array, and the plurality of lower electrodes in the lower electrode array have the same structure and are arranged on the same plane.
  • the lower electrode in the pixel unit may also be called a pixel electrode.
  • each pixel unit the combination of the upper electrode, the piezoelectric layer and the lower electrode can form an ultrasonic transducer unit, and multiple ultrasonic transducer units of the plurality of pixel units can form an ultrasonic transducer (i.e., the above
  • the transducer module 222) described in the embodiment can be used to generate an ultrasonic signal under the action of the driving signal V TX , and can also receive an echo signal of the ultrasonic signal to generate a corresponding electrical signal.
  • the lower electrode is connected to the ground through the first switch CK1 and connected to the receiving module 2231 through the second switch CK2.
  • the first switch CK1 When the signal generating circuit 210 outputs the driving signal V TX , the first switch CK1 is turned on, and the transducing module 222 is in a transmitting state and emits ultrasonic waves. After the transmission is completed, the first switch CK1 is turned off and waits for a period of time to receive the echo signal. When the echo signal reaches the transducer module 222, the second switch CK2 is closed, and the transducer module 222 converts the echo signal into an electrical signal. The signal is transmitted to the receiving module 2231 and the detection module 2232 through the second switch CK2 to complete the reception and detection of the echo signal, and is transmitted to the signal accumulation module 2233.
  • the first switch CK1 and the second switch CK2 can be cycled through the control module 2211, thereby controlling the operating state of the transducer module 222.
  • a receiving module 2231 and a detection module 2232 may be provided correspondingly.
  • the same receiving module 2231 and detection module 2232 can be provided for the ultrasonic transducer units of multiple pixel units.
  • An embodiment of the present application also provides an electronic device, including a cover plate and the ultrasonic fingerprint detection device 200 in any of the above embodiments.
  • the cover is used to provide a pressing interface for the user's fingers and receive the pressing from the user's fingers.
  • the ultrasonic fingerprint detection device 200 is disposed under the cover and is used to detect the fingerprint of the user's finger pressed against the cover.
  • the electronic device further includes a display screen.
  • the cover is disposed above the display screen, and correspondingly, the ultrasonic fingerprint detection device 200 is disposed below the display screen to realize the under-screen ultrasonic fingerprint recognition function of the electronic device.
  • the ultrasonic signal generated by the ultrasonic fingerprint detection device 200 can penetrate the display screen and reach the cover, and the ultrasonic signal can propagate at the cover and pass through the user's finger pressing on the cover.
  • the reflection forms an echo signal, which can penetrate the display screen and reach the ultrasonic fingerprint detection device 200 so that it can realize the fingerprint detection function.
  • the electronic device includes but is not limited to mobile terminal devices, such as mobile phones, laptops, tablets, etc.
  • any combination of various embodiments of the present application can be carried out. As long as they do not violate the idea of the present application, they should also be regarded as the contents disclosed in the present application.
  • the disclosed systems and devices can be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of modules is only a logical function division. In actual implementation, there may be other division methods.
  • multiple modules or components may be combined or can be integrated into another system, or some features can be ignored, or not implemented.
  • the coupling or direct coupling or communication connection between each other shown or discussed may be indirect coupling or communication connection through some interfaces, devices or modules, or may be electrical, mechanical or other forms of connection.

Landscapes

  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Multimedia (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)

Abstract

一种超声波指纹检测装置和电子设备，能够降低超声波指纹检测装置的尺寸、电路复杂度以及成本。该超声波指纹检测装置（200）包括：信号发生电路（210）和超声波指纹传感器芯片（220）；其中，信号发生电路（210）由分立器件构成且信号发生电路（210）包括：控制电路（211）和谐振电路（212），控制电路（211）用于接收超声波指纹传感器芯片（220）提供的控制信号，并在控制信号的作用下产生激励信号，谐振电路（212）用于接收激励信号，并在激励信号的作用下形成驱动信号；超声波指纹传感器芯片（220）用于接收驱动信号，并在驱动信号的作用下产生用于指纹检测的超声波信号。通过该技术方案，提供了一种"单芯片"架构的超声波指纹检测装置，其具有较为简单的电路结构、较小的电路面积以及较低的制造成本。

Description

超声波指纹检测装置和电子设备 技术领域
本申请涉及指纹检测技术领域，并且更为具体地，涉及一种超声波指纹检测装置和电子设备。
背景技术
随着科学技术的发展和进步，指纹检测技术越来越多的应用于手机、电脑等智能终端设备中，从而提升人们对于智能终端设备的使用体验。
在超声指纹检测技术的一些商用方案中，可通过两个芯片结构实现指纹检测。其中，一个芯片为发射芯片，用于产生高压驱动信号，另一个芯片为接收芯片，用于接收高压驱动信号并向手指发射超声波，从而对手指指纹进行检测。在该技术方案中，“双芯片”架构意味着尺寸大，电路复杂且成本较高。
鉴于此，如何降低超声波指纹检测装置的尺寸、电路复杂度以及成本，是一项亟待解决的技术问题。
发明内容
本申请提供一种超声波指纹检测装置和电子设备，能够降低超声波指纹检测装置的尺寸、电路复杂度以及成本。
第一方面，提供一种超声波指纹检测装置，包括：信号发生电路和超声波指纹传感器芯片；其中，信号发生电路由分立器件构成且信号发生电路包括：控制电路和谐振电路，控制电路用于接收超声波指纹传感器芯片提供的控制信号，并在控制信号的作用下产生激励信号，谐振电路用于接收激励信号，并在激励信号的作用下形成驱动信号；超声波指纹传感器芯片用于接收驱动信号，并在驱动信号的作用下产生用于指纹检测的超声波信号。
通过本申请实施例的技术方案，提供了一种“单芯片”架构的超声波指纹检测装置，其包括超声波指纹传感器芯片以及由分立器件构成的信号发生电路，该信号发生电路包括控制电路和谐振电路，该谐振电路的电路结构较为简单且易于实现和控制，能够实现良好的升压效果，且控制电路可以从超声波指纹传感器芯片获取控制信号，而不需要从外部的其它控制器件获取控制 信号。因此，本申请实施例的超声波指纹检测装置具有较为简单的电路结构、较小的电路面积以及较低的制造成本。
在一些可能的实施方式中，控制电路包括串联于输入电源和地之间的两个开关管，两个开关管在控制信号的作用下交替导通，以产生脉冲激励信号；谐振电路包括串联于控制电路和地之间的电容和电感，电容和电感在脉冲激励信号的作用下发生谐振，以产生正弦波驱动信号。
在一些可能的实施方式中，两个开关管中连接于输入电源的开关管为PMOS管，两个开关管中连接于地的开关管为NMOS管。
通过该实施方式的技术方案，将信号发生电路中的连接于输入电源的开关管设置为PMOS管，且将连接于地的开关管设置为NMOS管，在超声波指纹传感器芯片与信号发生电路的输入电源为同一电源的情况下，可以有效实现超声波指纹传感器芯片提供的控制信号对该两个开关管的有效控制，也不需额外的其它电路和信号对该两个开关管进行驱动和控制，该信号发生电路的电路结构复杂度以及制造成本较低。
在一些可能的实施方式中，在两个开关管交替导通的过程中，两个开关管中的一个开关管的状态由导通变更为关断的预设时间后，两个开关管中的另一个开关管的状态由关断变更为导通。
通过该实施方式的技术方案，可以保证两个开关管不会同时导通造成在该两个开关管中引入大电流，从而保证控制电路的使用可靠性，且有利于提升控制电路的使用寿命。
在一些可能的实施方式中，两个开关管还在控制信号的作用下反相交替导通，以产生反相脉冲激励信号，反相脉冲信号用于阻尼谐振电路的谐振，以降低正弦波驱动信号的谐振能量。
在一些可能的实施方式中，信号发生电路还包括：刹车电路，刹车电路包括阻尼电阻，阻尼电阻连接在谐振电路与控制电路之间。
通过该实施方式的技术方案，在信号发生电路中增加包括阻尼电阻的刹车电路，以在期望谐振电路停止输出驱动信号时，吸收谐振电路产生的多余的信号能量，从而改善谐振电路输出的正弦波驱动信号的余振，提高驱动信号的质量。
在一些可能的实施方式中，阻尼电阻的一端连接于谐振电路与控制电路之间，阻尼电阻的另一端接地。
在一些可能的实施方式中，在控制电路断路的情况下，阻尼电阻串联于谐振电路与地之间，阻尼电阻用于阻尼谐振电路的谐振，以降低驱动信号的谐振能量。
在该实施方式的技术方案中，该刹车电路的电路结构较为简单且成本较低，通过该刹车电路，在能够保证信号发生电路能够输出质量较高的驱动信号的基础上，还能够进一步降低该信号发生电路以及所在的超声波指纹检测装置的整体成本。
在一些可能的实施方式中，阻尼电阻的电阻值位于0.8*Z至2*Z之间，其中，Z为谐振电路的特征阻抗。
在一些可能的实施方式中，超声波指纹传感器芯片包括：控制模块、换能模块和检测模块；控制模块用于向信号发生电路提供控制信号，以控制信号发生电路产生驱动信号；换能模块用于接收驱动信号以产生超声波信号，超声波信号被用户手指反射后产生回波信号，换能模块用于将回波信号转换为电信号；检测模块用于检测电信号以检测用户手指的指纹。
在该实施方式的技术方案中，通过该超声波指纹传感器芯片中的控制模块，可以实现对超声波指纹检测装置的整体指纹检测过程实现统一控制，从而保证该指纹检测过程的有序进行以保证指纹检测效果，且还能进一步精简该超声波指纹检测装置的电路结构，降低该超声波指纹检测装置的电路复杂度。
在一些可能的实施方式中，控制模块用于多次向信号发生电路发送控制信号，以控制信号发生电路产生多个驱动信号；换能模块用于接收多个驱动信号以产生多个超声波信号，并将多个超声波信号对应的多个回波信号转换为多个电信号；检测模块用于检测多个电信号，以检测用户手指的指纹。
通过该实施方式的技术方案，可以实现超声波指纹传感器芯片对用户手指指纹的“多次检测”，通过“多次检测”得到的指纹结果具有更高的准确度，能够提高超声波指纹传感器芯片的指纹检测效果。
在一些可能的实施方式中，控制模块用于周期性的向信号发生电路发送控制信号，以控制信号发生电路周期性的产生驱动信号；控制模块用于控制换能模块周期性的接收驱动信号以产生超声波信号；控制模块用于控制检测模块周期性的检测电信号，以检测用户手指的指纹。
通过该实施方式的技术方案，控制模块可周期性的向信号发生电路发送 控制信号，以实现对信号发生电路的便捷控制，且控制模块还可周期性的对换能模块和检测模块进行控制，从而实现超声波指纹传感器芯片对用户指纹的周期性检测。
在一些可能的实施方式中，检测模块包括：接收模块、检波模块和信号累加模块；接收模块用于接收多个电信号；检波模块用于检测多个电信号的幅值；信号累加模块用于将多个电信号的幅值进行累加得到信号累加值，信号累加值用于被平均计算后以检测用户手指的指纹。
通过该实施方式的技术方案，检测模块检测得到的信号累加值经过平均之后，可以降低信号中的噪音，从而提高指纹检测的信噪比，进而提升超声波指纹传感器芯片的指纹检测准确度。
在一些可能的实施方式中，信号累加模块为模拟累加器。
通过该实施方式的技术方案，该模拟的信号累加值不需要经过模数转换就能够在信号累加模块中快速存储，因此，该信号累加模块的电路结构较为简单，能够降低超声波指纹传感器芯片的电路复杂度。
在一些可能的实施方式中，超声波指纹传感器芯片还包括：读出模块、模数转换模块和接口模块；读出模块用于将信号累加值读出至模数转换模块；模数转换模块用于将信号累加值转换为数字信号；接口模块用于将数字信号传输至外部器件以使得数字信号被平均计算后以检测用户手指的指纹。
通过该实施方式的技术方案，在超声波指纹传感器芯片中设置读出模块、模数转换模块和接口模块，可以便于对应于信号累加值的数字信号传输至超声波指纹传感器芯片的外部器件以快速进行用户手指的指纹检测，从而提高指纹检测效率。
在一些可能的实施方式中，信号发生电路的输入电源的电压值和超声波指纹传感器芯片的输入电源的电压值相同。
通过该实施方式的技术方案，本申请实施例提供的超声波指纹检测装置仅需一个供电电源即可，不需要从外部接入多种类型的电源，从而进一步降低该超声波指纹检测的电路复杂度。
在一些可能的实施方式中，信号发生电路的输入电源的电压值和超声波指纹传感器芯片的输入电源的电压值在3V至4.5V之间。
在目前手机等终端设备中，常用的供电电压值为3V至4.5V之间，通过该实施方式的技术方案，超声波指纹检测装置中的信号发生电路以及超声波 指纹传感器芯片的输入电源均可以为终端设备的供电电源，而不需要额外的具有更高电压的电源，从而能够节省该超声波指纹检测装置的整体功耗。
第二方面，提供一种电子设备，包括：盖板，以及第一方面或第一方面中任一可能的实施方式中的超声波指纹检测装置；其中，盖板用于接收用户手指的按压，超声波指纹检测装置设置于盖板下方，用于检测按压于盖板的用户手指的指纹。
在一些可能的实施方式中，电子设备还包括：显示屏，盖板设置于显示屏的上方，超声波指纹检测装置设置于显示屏的下方。
附图说明
图1为本申请实施例提供的一种超声波指纹检测装置的示意性结构框图。
图2为本申请实施例提供的另一超声波指纹检测装置的示意性结构框图。
图3为本申请实施例提供的一种信号发生电路的示意性电路图。
图4为本申请实施例提供的控制信号、激励信号以及驱动信号的一种波形示意图。
图5为本申请实施例提供的另一信号发生电路的示意性电路图。
图6为本申请实施例提供的控制信号、激励信号以及驱动信号的另一波形示意图。
图7为本申请实施例提供的另一超声波指纹检测装置的示意性结构图。
图8为本申请实施例提供的控制信号、激励信号以及驱动信号的另一波形示意图。
图9为图8中控制信号在激励阶段的波形放大示意图。
图10为本申请实施例提供的一种超声波指纹传感器芯片的示意性结构框图。
图11为本申请实施例提供的另一超声波指纹传感器芯片的示意性结构框图。
图12为本申请实施例提供的超声波指纹传感器芯片的工作状态的示意图。
图13为本申请实施例提供的另一超声波指纹检测装置的示意性结构框 图。
具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
本申请的技术方案可以应用于超声波指纹检测装置。作为一种常见的应用场景，本申请实施例提供的超声波指纹检测装置可以应用在智能手机、平板电脑、智能穿戴设备、智能门锁或者其它类型的电子设备中。更具体地，在上述电子设备中，超声波指纹检测装置可以设置于电子设备与用户交互的任意面，包括但不限于是电子设备的正面。
图1示出了本申请实施例提供的一种超声波指纹检测装置100的示意性结构框图。
如图1所示，该超声波指纹检测装置100包括：发射(Tx)芯片110和接收(Rx)芯片120。
其中，Tx芯片110可连接至电源VDD。为了保证超声波指纹检测装置100的检测性能，该Tx芯片110包括两级升压电路111和112，以对输入电源VDD电压进行升压放大，以使得该Tx芯片110能够向Rx芯片发生较高电压的驱动信号。
作为示例，第一级升压电路111可以为Boost升压电路，第二级升压电路112可以为谐振升压电路。作为示例，在电源VDD的电压为3V的情况下，该第一级升压电路111可以将3V升压为30V，第二级升压电路112可以进一步对30V二次升压为140V。
Rx芯片120可包括超声波换能器121和回波检测电路122。其中，超声波换能器121可以接收该Tx芯片110产生的高压驱动信号以产生超声波。当超声波向用户手指发射时，其中一部分被手指反射回Rx芯片120的回波信号被超声波换能器121重新接收以转换为电信号，回波检测电路122用于接收并检测该电信号，该电信号携带有手指指纹中脊、谷或者其它细节的相关信息，因此，Rx芯片120可以通过检测该电信号以检测用户手指的指纹。
在该实施方式中，Tx芯片110需要产生高达100V的高压驱动信号，这个级别的电压无法和Rx芯片120的制程相容，因此，Tx芯片110和Rx芯片120一般设计为分立的两个芯片。若要将该Tx芯片110和Rx芯片120集成为同一个芯片，该Rx芯片120也需要采用高压制程，会造成成本上升。
另外，Tx芯片110中的升压电路具有较为复杂的电路结构，需要在Tx芯片110设置独立的控制电路113，以对该升压电路进行相关控制。
因此，在该实施方式中，超声波指纹检测装置100的“双芯片”架构意味着尺寸大，电路复杂，成本高。鉴于此，本申请提供一种“单芯片”架构的超声波指纹检测装置，能够降低上述超声波指纹检测装置的尺寸、电路复杂度以及成本。
图2示出了本申请实施例提供的一种超声波指纹检测装置200的示意性结构框图。
如图2所示，该超声波指纹检测装置200包括：信号发生电路210和超声波指纹传感器芯片220。其中，信号发生电路210由分立器件构成且该信号发生电路包括：升压电路，该升压电路用于对输入电源进行升压以形成驱动信号，该驱动信号的电压值大于所述输入电源的电压值。超声波指纹传感器芯片220用于接收该驱动信号，并在该驱动信号的作用下产生用于指纹检测的超声波信号。
具体地，在本申请实施例中，该信号发生电路210不是一颗芯片，而是由分立器件构成的电路结构。因此，相比于“双芯片”架构，本申请实施例中提供的超声波指纹检测装置200仅包括一颗超声波指纹传感器芯片220，整体的制造成本会大幅降低。
在该信号发生电路210中，其仅包括一级升压电路，该一级升压电路用于对输入电源进行升压以形成具有较高电压的驱动信号，从而提升该驱动信号对于超声波指纹传感器芯片220的驱动效果，以保证超声波指纹传感器芯片220的检测性能。另外，相比于上文图1所示实施例中Tx芯片110中包含的两级升压电路，本申请实施例减少了电路结构，从而降低了超声波指纹检测装置200整体的电路复杂度以及整体尺寸。
在一些实施方式中，该信号发生电路210中的升压电路可以包括谐振电路，该谐振电路可通过形成谐振以产生高压的驱动信号。该谐振电路的电路结构较为简单且易于实现，能够进一步降低超声波指纹检测装置200整体的电路复杂度以及整体成本。
具体地，在超声波指纹传感器芯片220中，其中可包括如图1中Rx芯片120所示的超声波换能器121以及回波检测电路122。该超声波换能器121能够在上述信号发生电路210提供的驱动信号的作用下产生超声波信号，且 能够接收该超声波信号经过用户手指反射后的回波信号以产生电信号。回波检测电路122可对该电信号进行检测以进行指纹检测。
可选地，该超声波换能器121可包括压电层和上下电极层，例如，该压电层中的压电材料包括不限于是聚偏二氟乙烯(polyvinylidene fluoride，PVDF)、聚偏二氟乙烯-三氟乙烯(polyvinylidene fluoride–Trifluoroethene，PVDF-TrFE)共聚物等等。该压电层在受到上下电极层的高压驱动信号时，其会将电能转换为机械能，从而产生超声波信号。对应的，该压电层也能将返回的超声波回波信号由机械能转换为电能，从而产生对应于该回波信号的电信号。
通过本申请实施例的技术方案，提供了一种“单芯片”架构的超声波指纹检测装置200，其包括超声波指纹传感器芯片220以及由分立器件构成的信号发生电路210，该信号发生电路210包括一级升压电路，在对输入电源进行升压产生较高电压的驱动信号以保证超声波指纹传感器芯片220的检测效果以外，还具有较为简单的电路结构、较小的电路面积以及较低的制造成本。因此，相比于“双芯片”架构的超声波指纹检测装置，本申请实施例的技术方案能够降低超声波指纹检测装置的尺寸、电路复杂度以及制造成本。
在一些实施方式中，上述信号发生电路210的输入电源的电压值和超声波指纹传感器芯片220的输入电源的电压值相同。
可选地，该信号发生电路210和超声波指纹传感器芯片220可以连接至同一供电电源，以使得该同一供电电源为二者提供电能。
通过该实施方式的技术方案，本申请实施例提供的超声波指纹检测装置200仅需一个供电电源即可，不需要从外部接入多种类型的电源，从而进一步降低该超声波指纹检测的电路复杂度。
在一些实施方式中，上述信号发生电路210的输入电源的电压值和超声波指纹传感器芯片220的输入电源的电压值在3V至4.5V之间。
在目前手机等终端设备中，常用的供电电压值为3V至4.5V之间，通过该实施方式的技术方案，超声波指纹检测装置200中的信号发生电路210以及超声波指纹传感器芯片220的输入电源均可以为终端设备的供电电源，而不需要额外的具有更高电压的电源，从而能够节省该超声波指纹检测装置200的整体功耗。
图3示出了本申请实施例提供的一种信号发生电路210的示意性电路 图。
如图3所示，在该信号发生电路210中，上述升压电路包括控制电路211和谐振电路212。其中，控制电路211连接于输入电源VDD，该控制电路211用于接收超声波指纹传感器芯片220提供的控制信号，并在该控制信号和输入电源的作用下产生激励信号。谐振电路212连接于控制电路211，该谐振电路212用于接收控制电路211提供的激励信号，并在该激励信号的作用下形成驱动信号。
可选地，如图3所示，该谐振电路212可以包括相互串联的电感L和电容C，以形成LC串联谐振电路。其中，电感L可具有等效电阻R，该电阻R可以视为与LC一同串联形成该LC串联谐振电路。
可选地，上述电容C可以为超声波指纹传感器芯片220中超声波换能器的等效电容，或者，该电容C也可以为超声波换能器的等效电容以及其它可调电容的整体等效电容。可选地，该电容C还可以串联有超声波换能器的等效电阻，即该谐振电路212除了可包括上述电感L的等效电阻R以外，还可以包括超声波换能器的等效电阻。
控制电路211可接收由超声波指纹传感器芯片220发送的控制信号，并在该控制信号的作用下产生用于激励LC串联谐振电路的激励信号。在该激励信号的作用下，LC串联谐振电路可以谐振出具有较高电压的驱动信号，该驱动信号的电压值大于该信号发生电路210的输入电源的电压值。
通过本申请实施例的技术方案，信号发生电路210可以包括控制电路211和谐振电路212，其中，谐振电路212的电路结构较为简单且易于实现和控制，能够实现良好的升压效果。另外，控制电路211可以从超声波指纹传感器芯片220获取控制信号，而不需要从外部的其它控制器件获取控制信号，因此，该超声波指纹传感器芯片220除了可控制其自身部件的相关运行以外，还可以控制信号发生电路210的相关运行，从而保证超声波指纹检测装置200整体的正常运行。
可选地，作为一种示例，如图3所示，控制电路211包括串联于输入电源VDD和地之间的两个开关管Q1和Q2，该两个开关管Q1和Q2在控制信号的作用下导通和关断，以在该两个开关管Q1和Q2之间的节点处输出激励信号SW。
在一些实施方式中，超声波指纹传感器芯片220可向控制电路211提供 一个控制信号，该一个控制信号经过控制电路211内部的器件处理后生成两个控制信号S1和S2，第一开关管Q1在第一控制信号S1的作用下导通和关断，第二开关管Q2在第二控制信号S2的作用下导通和关断。
或者，在另一些实施方式中，超声波指纹传感器芯片220也可直接向控制电路211提供两个控制信号S1和S2，从而直接控制两个开关管Q1和Q2导通和关断。
继续参见图3，作为一种示例，谐振电路212包括串联于控制电路211和地之间的电容C和电感L，该电容C和电感L在上述脉冲激励信号的作用下可产生驱动信号V TX。可选地，该谐振电路212在包括串联的电容C和电感L的基础上，还可以进一步包括与该电容C和电感L的电阻R。
为了便于理解，图4示出了本申请实施例提供的控制信号S1、S2、激励信号SW以及驱动信号V TX的一种波形示意图。
如图4所示，该信号发生电路210的工作状态包括：等待阶段、激励阶段以及反相阶段。
在信号发生电路210的等待阶段，谐振电路212不产生谐振。可选地，在该等待阶段，第一控制信号S1为低电平，以控制第一开关管Q1关断，第二控制信号S2为高电平，以控制第二开关管Q2导通，此时，控制电路211输出的激励信号SW以及谐振电路212输出的驱动信号V TX均为低电平。
在信号发生电路210的激励阶段，控制电路211中的两个开关管Q1和Q2可在控制信号的作用下交替导通，以产生脉冲激励信号SW。进一步地，谐振电路212中的电感L和电容C可在该脉冲激励信号SW的作用下发生谐振，以产生正弦波驱动信号V TX。
可选地，为了实现两个开关管Q1和Q2的交替导通，第一控制信号S1和第二控制信号S2可以为相互反相的脉冲信号。该脉冲信号的频率可以等于LC串联谐振电路212的谐振频率，从而使得电容C的两端谐振产生高压的正弦波驱动信号V TX。即脉冲信号的频率f满足如下公式：
Figure PCTCN2022105775-appb-000001
该公式中的L和C分别表示电感L和电容C的大小。
可选地，在该信号发生电路210的激励阶段，控制电路211输出的脉冲激励信号SW的波形可以与第一开关管Q1的控制信号S1的波形相同。当第一控制信号S1为高电平，且第二控制信号S2为低电平时，第一开关管Q1 导通，第二开关管Q2关断，输出的脉冲激励信号SW为高电平；当第一控制信号S1为低电平，且第二控制信号S2为高电平时，第一开关管Q1关断，第二开关管Q2导通，输出的脉冲激励信号SW为低电平。
在该脉冲激励信号SW的作用下，正弦波驱动信号V TX可以为幅值逐渐递增的正弦波信号。
继续参见图4，当需要停止输出正弦波驱动信号V TX时，可以将两个开关管Q1、Q2均关断，使得输出的脉冲激励信号SW保持低电平，通过电阻R将谐振归零。但实际上，由于谐振电路振荡的能量无法马上消失，正弦波驱动信号V Tx缓慢下降至零，因此，在关断开关管Q1和Q2之前，可以采用反相驱动的方式，即对脉冲激励信号SW反相，从而加速谐振电路的谐振能量归零。
具体地，两个开关管Q1和Q2可在控制信号的作用下反相交替导通，以产生反相脉冲激励信号，该反相脉冲激励信号的相位与上述激励阶段时产生的脉冲激励信号SW相互反相。该反相脉冲信号用于阻尼谐振电路212的谐振，以降低其产生的正弦波驱动信号V TX的谐振能量。
如图4所示，在该信号发生电路210的反相阶段，在增加反相驱动信号的情况下，正弦波驱动信号Tx的余振明显减小。
需要说明的是，在一些实施方式中，反相驱动的时间不宜过长，例如，图4中显示了反相驱动时间为一个信号周期。在该反相驱动阶段，两个开关管Q1、Q2交替导通和关断，但是开关相位和激励阶段完全反相。
可以理解的是，上文图3和图4仅作为示意而非限定，示出了一种实施方式下谐振电路212和控制电路211的电路结构以及对应的信号波形示意图。在一些替代实施方式中，该谐振电路212和控制电路211还可以采用其它电路结构，旨在使得二者配合能够对输入电源进行谐振升压的效果即可，本申请实施例对该谐振电路212和控制电路211的具体电路结构不做限定。
另外，在图4和下文所示的波形示意图中，激励阶段的驱动信号SW仅示出了2个周期的脉冲信号，该2个周期的脉冲信号仅作为示意，该激励阶段的驱动信号SW还可为其它任意周期数量的脉冲信号，本申请对该激励阶段的驱动信号SW的脉冲信号的周期数量不做限定。
再者，在图4和下文所示的波形示意图中，激励阶段开始时，控制信号S1和S2先控制第一开关管Q1导通然后再控制第二开关管Q2，可选地，控 制信号S1和S2也可先控制第二开关管Q2导通然后再控制第一开关管Q1导通，本申请对该第一开关管Q1和第二开关管Q2的先后导通顺序也不做限定。
在上文图3所示实施例的基础上，图5示出了本申请实施例提供的另一信号发生电路210的示意性电路图。
如图5所示，在该信号发生电路210中，除了包括上述控制电路211和谐振电路212以外，还包括刹车电路213，该刹车电路包括阻尼电阻R1，该阻尼电阻R1连接在谐振电路212与控制电路211之间。
通过该实施例的技术方案，在信号发生电路210中增加包括阻尼电阻R1的刹车电路213，以在期望谐振电路212停止输出正弦波驱动信号Tx时，吸收谐振电路212产生的多余的信号能量，从而改善谐振电路212输出的正弦波驱动信号的余振，提高正弦波驱动信号的质量。
作为一种示例，在图5所示实施例中，阻尼电阻R1的一端连接于谐振电路212与控制电路211之间，阻尼电阻R1的另一端接地。
当该信号发生电路210需要停止输出驱动信号Tx时，控制电路211中的两个开关管Q1和Q2均关断，此时，控制电路211断路，该阻尼电阻R1可与谐振电路212相互串联，该阻尼电阻R1用于阻尼谐振电路212的谐振，以降低其产生的正弦波驱动信号Tx的谐振能量，从而使得谐振电路212的谐振快速归零。
在该示例中，阻尼电阻R1的电阻值与谐振电路212的特征阻抗Z相关。为了实现较佳的阻尼“刹车”效果，在一些实施方式中，该阻尼电阻R1的电阻值可以位于0.8*Z至2*Z之间，其中，
Figure PCTCN2022105775-appb-000002
L和C分别为谐振电路212中电感L和电容C的值。可选地，该阻尼电阻R1的电阻值包括但不限于是1.4*Z。
具体地，在图5所示实施例中，谐振电路212中电感L还具有等效电阻R，该电阻R可以与上述阻尼电阻R1共同对LC谐振起到阻尼“刹车”的作用。因此，该阻尼电阻R1与电阻R的电阻值之和可以位于0.8*Z至2*Z之间。可选地，该阻尼电阻R1与电阻R的电阻值之和包括但不限于是1.4*Z。
在该示例的实施方式中，该刹车电路213的电路结构较为简单且成本较低，通过该刹车电路213，在能够保证信号发生电路210能够输出质量较高的驱动信号的基础上，还能够进一步降低该信号发生电路210以及所在的超 声波指纹检测装置200的整体成本。
可选地，在增加该刹车电路213的情况下，还可以进一步对谐振电路212的激励信号SW进行反相，从而进一步加快该谐振电路212的谐振归零。
为了便于理解，图6示出了本申请实施例控制信号S1、S2、激励信号SW以及驱动信号V TX的另一波形示意图。
如图6所示，该信号发生电路210的工作状态包括：等待阶段、激励阶段、反相阶段以及阻尼刹车阶段。
在信号发生电路210的等待阶段，第一控制信号S1和第二控制信号S2均为低电平，以控制第一开关管Q1和第二开关管Q2均关断，此时，谐振电路212通过刹车电路213连接至地。控制电路211输出的激励信号SW以及谐振电路212输出的驱动信号V TX均为低电平。
在信号发生电路210的激励阶段，控制电路211中的两个开关管Q1和Q2可在控制信号的作用下交替导通，以产生脉冲激励信号SW。进一步地，谐振电路212中的电感L和电容C可在该脉冲激励信号SW的作用下发生谐振，以产生正弦波驱动信号V TX。
在信号发生电路210的反相阶段，两个控制信号S1和S2相互反相，两个开关管Q1、Q2依然交替导通和关断，但是开关相位和激励阶段完全反相，因此该两个开关管Q1和Q2产生的脉冲激励信号SW也产生了对应的反相，从而降低谐振电路212的谐振能量。在该反相阶段，通过设置刹车电路213，其中的阻尼电阻R1能够进一步加速降低谐振电路212的谐振能量。
该激励阶段和反相阶段的信号相关技术方案可以与上文图4所示实施例中的激励阶段相同，具体实现可参见上文描述，此处不做过多赘述。
在信号发生电路210的阻尼刹车阶段，两个控制信号S1和S2均为低电平，两个开关管Q1、Q2均关断。此时刹车电路213中的阻尼电阻R1可继续对谐振电路212的谐振起到阻尼“刹车”的作用，以快速降低谐振电路212的谐振能量，使得谐振快速归零。
可选地，刹车电路213除了包括如图5所示的阻尼电阻R1以外，还可以进一步包括其它器件，例如开关管等，通过控制该开关管，可以使得阻尼电阻R1在阻尼刹车阶段对谐振电路212的谐振起到“阻尼”刹车作用，而在激励阶段，不会影响谐振电路212的谐振效果。
但在图5所示实施例中，刹车电路213可以仅设置有一个阻尼电阻R1， 而不需要额外的开关管和对该开关管进行控制的控制信号，因而相比于其它类型的刹车电路213，图5所示实施例的刹车电路213成本较低。
另外，在图5所示实施例中，信号发生电路210的输入电源VDD的电压值一般比较低，例如，如上文所述，该输入电源VDD的电压值可以为3V至4.5V之间，因此，即使刹车电路213中的阻尼电阻R1连接于控制电路211的输出端与地之间，在控制电路211的输出端输出的控制信号SW为高电平时，会在阻尼电阻R1产生电流，但由于输入电源VDD的电压值较小，该阻尼电阻R1上产生的电流可相应较小，不会造成产生较大的功耗。
图7示出了本申请实施例提供的另一超声波指纹检测装置200的示意性结构图。
如图7所示，在信号发生电路210的控制电路211中，两个开关管中连接于输入电源VDD的开关管(即第一开关管Q1)为P型金属氧化物半导体(positive channel Metal Oxide Semiconductor，PMOS)场效应管，或者也可简称PMOS管。两个开关管中连接于地的开关管(即第二开关管Q2)为N型金属氧化物半导体(positive channel Metal Oxide Semiconductor，NMOS)场效应管，或者也可简称NMOS管。
可选地，如图7所示，超声波指纹传感器芯片220用于向信号发生电路210中的控制电路211提供控制信号S1和S2，以分别控制上述PMOS管和NMOS管。
具体地，第一控制信号S1用于控制PMOS管的导通和关断，第一控制信号S1为低电平时，PMOS管导通，反之，第一控制信号S1为高电平时，PMOS管关断。第二控制信号S2用于控制NMOS管的导通和关断，第二控制信号S2为高电平时，NMOS管导通，反之，第二控制信号S2为低电平时，NMOS管关断。
可选地，该第一控制信号S1和第二控制信号S2的高电平可以与超声波指纹传感器芯片220的输入电源VDD的电压值一致，例如，该第一控制信号S1和第二控制信号S2的高电平均可以为3V。该第一控制信号S1和第二控制信号S2的低电平可以为地，即0V。
可选地，在图7所示实施例中，超声波指纹传感器芯片220与信号发生电路210的输入电源可以为同一电源VDD。
在该情况下，将信号发生电路210中的第一开关管Q1设置为PMOS管， 且将第二开关管Q2设置为NMOS管，则可以有效实现超声波指纹传感器芯片220提供的控制信号对该第一开关管Q1和第二开关管Q2的有效控制，也不需额外的其它电路和信号对该第一开关管Q1和第二开关管Q2进行驱动和控制，该信号发生电路210的电路结构复杂度以及制造成本较低。
在一些替代实施方式中，例如，将信号发生电路210中的第一开关管Q1和第二开关管Q2均设置为PMOS管或均设置为NMOS管的情况下，该两个开关管中的至少一个需要增加额外的驱动电路或者接入其它输入电源，才能在超声波指纹传感器芯片220提供的控制信号下实现导通和关断，因此，该替代实施方式的电路复杂度以及制造成本略高。
在本申请实施例中，除了两个开关管Q1和Q2的类型以外，该信号发生电路210的其它电路结构可以与上文图5所示实施例相同。具体电路方案可以参见上文相关描述，此处不做过多赘述。
为了便于理解，图8示出了超声波指纹传感器芯片220提供的控制信号S1、S2、控制电路211输出的激励信号SW以及谐振电路212输出的驱动信号V TX的波形示意图。
如图8所示，在本申请实施例中，除了第一控制信号S1与上文图6所示实施例中所示第一控制信号S1有所区别以外，其它信号的波形特征可以与上文图6所示实施例相同。
具体地，在该图8所示实施例中，由于第一控制信号S1用于控制PMOS管(第一开关管Q1)，因此，该第一控制信号S1在低电平时控制第一开关管Q1导通，且在高电平时控制第一开关管Q1关断。而在图6所示实施例中，第一控制信号S1在高电平时控制第一开关管Q1导通，且在低电平时控制第一开关管Q1关断。因此，该图8所示实施例中的第一控制信号S1可以与上文图6所示实施例中的第一控制信号S1相互反相，但该两个实施例中第一开关管Q1的控制过程相同。
需要注意的是，在该信号发生电路210的激励阶段，两个开关管Q1和Q2不能同时导通，否则会输入电源VDD和地之间短路形成大电流，从而对开关管Q1和Q2造成影响。因此，在控制信号S1和S2的作用下，两个开关管Q1和Q2中的一个开关管的状态由导通变更为关断的预设时间后，该两个开关管中的另一个开关管的状态由关断变更为导通。在两个开关管Q1和Q2开关交替时，控制信号S1和S2会存在一个时间间隙(gap)，该时间 间隙可称之为“死区时间”，在该死区时间内，两个开关管Q1和Q2均处于关断状态。
图9示出了图8中控制信号S1、S2在激励阶段的波形放大示意图。
如图9所示，在本申请实施例中，第一控制信号S1的上升沿与第二控制信号S2的上升沿之间会存在一个死区时间，该死区时间为预设时间。具体地，在第一控制信号S1的上升沿的预设时间后，第二控制信号S2产生上升沿，即第一控制信号S1控制的第一开关管Q1(PMOS管)由导通变更为关断后的预设时间后，第二控制信号S2控制的第二开关管Q2(NMOS管)由关断变更为导通。
类似地，该第一控制信号S1的下降沿与第二控制信号S2的下降沿之间也会存在一个死区时间，该死区时间为预设时间。具体地，在第二控制信号S2的下降沿的预设时间后，第一控制信号S1产生下降沿，即第二控制信号S2控制的第二开关管Q2(NMOS管)由导通变更为关断后的预设时间后，第一控制信号S1控制的第一开关管Q1(PMOS管)由关断变更为导通。
通过该实施例的技术方案，可以保证两个开关管Q1和Q2不会同时导通造成在该两个开关管Q1和Q2中引入大电流，从而保证控制电路211的使用可靠性，且有利于提升控制电路211的使用寿命。
上文实施例结合图3至图9对本申请提供的超声波指纹检测装置200中的信号发生电路210进行了介绍，下面，结合图10至图12，对本申请提供的超声波指纹检测装置200中的超声波指纹传感器芯片220进行说明。
图10示出了本申请实施例提供的一种超声波指纹传感器芯片220的示意性结构框图。
如图10所示，超声波指纹传感器芯片220包括：控制模块221、换能模块222和检测模块223。其中，控制模块221用于向信号发生电路210提供控制信号，以控制该信号发生电路210产生驱动信号。换能模块222用于接收驱动信号以产生超声波信号，该超声波信号被用户手指反射后产生回波信号，换能模块222用于将该回波信号转换为电信号。检测模块223用于检测该电信号以检测该用户手指的指纹。
具体地，在本申请实施例中，换能模块222可以包括上文图1所示实施例中的超声波换能器121。检测模块223可以包括上文实施例中的回波检测电路122。
控制模块221可以为超声波指纹传感器芯片220中的控制器，其可连接于上述换能模块222和检测模块223，并控制该换能模块222和检测模块223的运行。另外，该控制模块221还可用于向信号发生电路210提供控制信号，以控制该信号发生电路210的运行。
通过该超声波指纹传感器芯片220中的控制模块221，可以实现对超声波指纹检测装置200的整体指纹检测过程实现统一控制，从而保证该指纹检测过程的有序进行以保证指纹检测效果，且还能进一步精简该超声波指纹检测装置200的电路结构，降低该超声波指纹检测装置200的电路复杂度。
结合上文实施例中对信号发生电路210的相关技术方案可知，在一些实施方式中，信号发生电路210的输入电源的电压值较低，例如，该电压值为3V，在该情况下，即使信号发生电路210对该输入电源的3V电压进行了升压，输出的驱动信号V TX的电压值也一般在20V左右。相比于相关技术中通过两级升压，将驱动信号升压至100V以上的技术方案，上述信号发生电路210输出的驱动信号V TX的电压值较低，因而会在一定程度上影响超声波指纹传感器芯片220的指纹检测效果。
鉴于此，在本申请实施例提供的超声波指纹传感器芯片220中，控制模块221可用于向信号发生电路210发送多次控制信号，以控制该信号发生电路210产生多个驱动信号。换能模块222用于接收该多个驱动信号以产生多个超声波信号，并将该多个超声波信号对应的多个回波信号转换为多个电信号。检测模块223用于检测该多个回波信号，以检测用户手指的指纹。
具体地，在控制模块221向信号发生电路210发送一次控制信号的过程中，控制模块221可向该信号发生电路210发送预设时长的第一控制信号S1和第二控制信号S2，该第一控制信号S1和第二控制信号S2均可包括多个周期的脉冲信号。
可选地，在控制模块221向信号发生电路210发送一次控制信号的过程中，该第一控制信号S1和第二控制信号S2的具体波形和相关技术方案可以参见上文图4、图6或图8中任一实施例的技术方案。可选地，该第一控制信号S1和第二控制信号S2可以控制信号发生电路210依次运行于等待阶段、激励阶段、反向阶段、阻尼刹车阶段和等待阶段。
当控制模块221向信号发生电路210发送一次控制信号后，该信号发生电路210在该控制信号的作用下，产生一个驱动信号V TX。换能模块222接 收该驱动信号V TX且在该驱动信号V TX的作用下产生一个超声波信号。该超声波信号被用户手指反射后形成一个回波信号，换能模块222接收该回波信号并将其转换为对应的电信号，以使得检测模块223对该电信号进行检测。
上述过程可以理解为超声波指纹传感器芯片220对用户手指指纹的“一次检测”。当重复上述过程，可以实现超声波指纹传感器芯片220对用户手指指纹的“多次检测”，通过“多次检测”得到的指纹结果具有更高的准确度，能够提高超声波指纹传感器芯片220的指纹检测效果。
可选地，在一些实施方式中，控制模块221可用于周期性的向信号发生电路210发送控制信号以控制信号发生电路210产生驱动信号。该控制模块221用于控制换能模块222周期性的接收该驱动信号以产生超声波信号。且该控制模块221用于控制检测模块223周期性的检测电信号，以检测用户手指的指纹。
具体地，在该实施方式的技术方案中，控制模块221可通过周期性的发送控制信号以控制信号发生电路210周期性的产生驱动信号，进而控制模块221可周期性的控制换能模块222接收驱动信号以产生超声波信号，且该换能模块222能够在控制模块221的控制下周期性的接收超声波信号经过用户手指反射后的回波信号，并将该周期性接收的回波信号转换为对应的电信号。进一步地，该控制模块221还可以控制检测模块223周期性的接收并检测该电信号，以实现对用户手指的指纹检测。
可选地，该控制模块221向信号发生电路210发送的控制信号的周期可以根据超声波指纹传感器芯片220的芯片结构和数据处理速度确定。该发送周期不能太长，否则会影响超声波指纹传感器芯片220的指纹检测效率。且该发送周期也不能太短，其需大于超声波指纹传感器芯片220产生超声波信号且接收回波信号的处理时间。一般来讲，该发送周期通常小于10μs，最大也不会超过50μs。
通过该实施方式的技术方案，控制模块221可周期性的向信号发生电路210发送控制信号，以实现对信号发生电路210的便捷控制，且控制模块221还可周期性的对换能模块222和检测模块223进行控制，从而实现超声波指纹传感器芯片220对用户指纹的周期性检测。
图11示出了本申请实施例提供的另一超声波指纹传感器芯片220的示意性结构框图。
如图11所示，在本申请实施例中，上述检测模块223(图11中未示出)可包括：接收模块2231、检波模块2232和信号累加模块2233。其中，接收模块2231用于接收多个电信号。检波模块2232用于检测该多个电信号的幅值。信号累加模块2233用于将多个电信号的幅值进行累加得到信号累加值，该信号累加值用于被平均计算后以检测用户手指的指纹。
具体地，在该实施方式中，检测模块223可以包括多个子模块以实现对回波信号对应的电信号的检测。该检测模块223中可包括信号累加模块2233，该信号累加模块2233可用于对检波模块2232检测得到的多个电信号的幅值进行累加得到信号累加值。该信号累加值经过平均之后，可以降低信号中的噪音，从而提高指纹检测的信噪比(Signal to Noise Ratio，SNR)，进而提升超声波指纹传感器芯片220的指纹检测准确度。
作为示例，控制模块221用于控制信号发生电路210和超声波指纹传感器芯片220对用户指纹执行了N次检测，检测模块223可以接收N个电信号，则该信号累加模块2233对该N个电信号的幅值进行累加得到信号累加值。通过该信号累加值，理论上指纹检测的SNR可以提高sqrt(N)倍。例如，N＝100时，指纹检测的SNR可以提高10倍。
可选地，该信号累加模块2233可以为模拟信号累加器，即该信号累加模块2233用于接收模拟的多个电信号并对其进行累加，且输出的信号累加值同样为模拟信号，该模拟的信号累加值不需要经过模数转换就能够在信号累加模块2233中快速存储，因此，该信号累加模块2233的电路结构较为简单，能够降低超声波指纹传感器芯片220的电路复杂度。
具体地，该信号累加模块2233可以为积分器，检波模块2232可以为检波器。作为一种示例，该检波模块2232和信号累加模块2233的整体可以为积分检波器。当然，在其它替代实施方式，该信号累加模块2233和检波模块2232还可以为其它类型的电路结构或者器件，本申请实施例对此不做具体限定。
可选地，如图11所示，在该实施例中，超声波指纹传感器芯片220还包括：读出模块224、模数转换模块225和接口模块226。其中，该读出模块224用于将上述信号累加模块2233产生的信号累加值读出至模数转换模块225。该模数转换模块225用于将信号累加值转换为数字信号。该接口模块226用于将该数字信号(图11中示为指纹数据)传输至外部器件以使得 该数字信号被平均计算后以检测用户手指的指纹。
可选地，该读出模块224具体可以为读出电路。该模数转换模块225可以为模数转换器(Analog-to-Digital Converter，ADC)。该接口模块226包括但不限于是串行外设接口(Serial Peripheral Interface，SPI)接口。
在信号累加模块2233为模拟信号累加器的情况下，在超声波指纹传感器芯片220中设置读出模块224、模数转换模块225和接口模块226，可以便于对应于信号累加值的数字信号传输至超声波指纹传感器芯片220的外部器件以快速进行用户手指的指纹检测，从而提高指纹检测效率。
可选地，在一些替代的实施方式中，上述读出模块224、模数转换模块225和接口模块226也可不集成于超声波指纹传感器芯片220，而设置于超声波指纹传感器芯片220的外部，从而降低该超声波指纹传感器芯片220所需占用的安装空间。
可选地，如图11所示，在本申请实施例中，上述控制模块221(图11中未示出)可包括：循环控制模块2211和发射控制模块2212。其中，循环控制模块2211可理解为超声波指纹传感器芯片220的主控制模块，其连接并控制该发射控制模块2212以及上述接收模块2231和信号累加模块2233。
具体地，该循环控制模块2211可通过发射控制模块2212向信号发生电路210发送控制信号。例如，该循环控制模块2211可通过发射控制模块2212周期性的向信号发生电路210发送控制信号。
另外，该循环控制模块2211可控制接收模块2231接收换能模块222对回波信号转换得到的电信号，例如，该循环控制模块2211可控制接收模块2231周期性的接收电信号。
再者，该循环控制模块2211还可控制信号累加模块2233将检波模块2232检测得到的多个电信号的幅值进行累加。
可选地，该发射控制模块2212和循环控制模块2211可以如图11所示为分立的两个控制器，或者，该发射控制模块2212和循环控制模块2211也可以集成为一个控制器。
为了便于对上文实施例的理解，图12示出了在图11所示实施方式下，超声波指纹传感器芯片220的工作状态的示意图。
如图12所示，超声波指纹传感器芯片220可处于周期性的工作状态。在一个周期内，超声波指纹传感器芯片220可以分别运行于发射状态和接收 状态。
在发射状态下，该超声波指纹传感器芯片220可通过循环控制模块2211和发射控制模块2212向信号发生电路210发送控制信号，以使得信号发生电路210在控制信号的作用下周期性的产生激励信号SW和驱动信号V TX。
可选地，该激励信号SW和驱动信号V TX的周期可以为Trp，该Trp可以与控制模块221向信号发生电路210发送的控制信号的周期相同。如上所述，该Trp可以根据超声波指纹传感器芯片220的芯片结构和数据处理速度确定。一般来讲，该Trp通常小于10μs，最大也不会超过50μs。
且在该发射状态下，该超声波指纹传感器芯片220还可通过换能模块222向用户手指发送超声波信号，以使得超声波信号被用户手指反射产生回波信号。
在接收状态下，该超声波指纹传感器芯片220可通过换能模块222将回波信号转换为电信号，且该超声波指纹传感器芯片220可通过循环控制模块2211控制接收模块2231、检波模块2232和信号累加模块2233接收并检测电信号，且将电信号进行累加。
通过n个周期的循环运行，超声波指纹传感器芯片220可检测得到n个电信号的信号累加值，该超声波指纹传感器芯片220可进入数据转换&读出状态，即通过读出模块224和模数转换模块225将该信号累加值进行读出以及模数转换。接着，该超声波指纹传感器芯片220可进入数据传输阶段，即通过接口模块226将信号累加值对应的数字信号传输至外部器件以进行指纹检测。
图13示出了本申请实施例提供的另一超声波指纹检测装置200的示意性结构框图。
如图13所示，在本申请实施例中，超声波指纹传感器芯片220和信号发生电路210均接收由同一接口输出的电源电压VDD。
其中，信号发生电路210的具体实施方式可以参见上文图7所示实施例的技术方案。其中，图7所示实施例中的电容C可以包括本申请实施例中的可调电容C1以及超声波指纹传感器芯片220中超声波换能器的等效电容。
可选地，该信号发生电路210可以接收由超声波指纹传感器芯片220提供的两个控制信号S1和S2以分别控制两个开关管Q1和Q2。或者，该信号发生电路210也可以接收由超声波指纹传感器芯片220提供的一个控制信 号，该一个控制信号经过其它器件进行信号处理后，形成分别控制两个Q1和Q2的两个控制信号S1和S2。
可选地，该两个开关管Q1和Q2可以集成为用于激励谐振电路212的驱动器，该驱动器除了可包括两个开关管Q1和Q2以外，还可以包含其它信号处理器件，本申请实施例对该驱动器的具体结构不做限定。
如图13所示，该超声波指纹传感器芯片220的具体结构可以与上文图11所示实施例近似。
具体地，该超声波指纹传感器芯片220可包括用于进行超声指纹成像的像素阵列(Pixel Array)，该像素阵列由多个像素单元(Pixel Cell)组成。每个像素单元可包括：上电极、压电层以及下电极。该多个像素单元的上电极可相互连接形成整体上电极，该整体上电极点可电连接于TX接口，该TX接口可接收由信号发生电路210产生的驱动信号V TX。
该多个像素单元的下电极可相互分离设置，即多个像素单元的下电极可形成下电极阵列，该下电极阵列中的多个下电极结构相同且设置于同一平面。该像素单元中的下电极也可以称之为像素电极。在每个像素单元中，上电极、压电层以及下电极的组合可形成一个超声波换能器单元，该多个像素单元的多个超声波换能器单元可形成超声波换能器(即上文实施例所述的换能模块222)，其可用于在驱动信号V TX的作用下产生超声波信号，也可接收该超声波信号的回波信号以产生对应的电信号。
继续参见图13，在每个像素单元中，下电极通过第一开关CK1连接于地，且通过第二开关CK2连接于接收模块2231。
当信号发生电路210输出驱动信号V TX时，第一开关CK1导通，换能模块222处于发射状态，发出超声波。当发射结束后第一开关CK1断开，等待一段时间接收回波信号，当回波信号抵达换能模块222时，第二开关CK2闭合，换能模块222将回波信号转换为电信号，电信号经过第二开关CK2传输至接收模块2231以及检波模块2232，以完成回波信号的接收以及检波，并传输至信号累加模块2233。
可选地，该第一开关CK1和第二开关CK2可被循环控制模块2211，从而控制该换能模块222的运行状态。
可选地，在一些实施方式中，在每个像素单元中，可对应于设置一个接收模块2231以及检波模块2232。或者，在另一些实施方式中，可对多个像 素单元的超声波换能器单元设置同一个接收模块2231以及检波模块2232。
本申请实施例还提供一种电子设备，包括盖板和上文任一实施例中的超声波指纹检测装置200。其中，该盖板用于提供用户手指的按压界面，并接收用户手指的按压。超声波指纹检测装置200设置于盖板下方，用于检测按压于盖板的用户手指的指纹。
在一些可能的实施方式中，该电子设备还包括显示屏。其中，盖板设置于显示屏的上方，对应的，超声波指纹检测装置200设置于显示屏的下方，以实现电子设备的屏下超声波指纹识别功能。
可以理解的是，在本申请实施例中，超声波指纹检测装置200产生的超声波信号可穿透显示屏到达盖板，且该超声波信号可在盖板处传播并经过按压于盖板的用户手指的反射形成回波信号，该回波信号可穿透显示屏到达超声波指纹检测装置200以使得其实现指纹检测功能。
可选地，该电子设备包括但不限于是移动终端设备，例如：手机、笔记本电脑、平板电脑等等。
应理解，本申请实施例中的具体的例子只是为了帮助本领域技术人员更好地理解本申请实施例，而非限制本申请实施例的范围。
例如，在上述具体实施方式中所描述的各个具体技术特征，在不矛盾的情况下，可以通过任何合适的方式进行组合，为了避免不必要的重复，本申请对各种可能的组合方式不再另行说明。
又例如，本申请的各种不同的实施方式之间也可以进行任意组合，只要其不违背本申请的思想，其同样应当视为本申请所公开的内容。
应理解，在本申请实施例和所附权利要求书中使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本申请实施例。例如，在本申请实施例和所附权利要求书中所使用的单数形式的“一种”、“上述”和“该”也旨在包括多数形式，除非上下文清楚地表示其他含义。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元，能够以电子硬件、计算机软件或者二者的结合来实现，为了清楚地说明硬件和软件的可互换性，在上述说明中已经按照功能一般性地描述了各示例的组成及步骤。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的 范围。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述模块的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个模块或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另外，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口、装置或模块的间接耦合或通信连接，也可以是电的，机械的或其它的形式连接。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到各种等效的修改或替换，这些修改或替换都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (19)

  1. 一种超声波指纹检测装置，其特征在于，包括：信号发生电路和超声波指纹传感器芯片；
    其中，所述信号发生电路由分立器件构成且所述信号发生电路包括：控制电路和谐振电路，所述控制电路用于接收所述超声波指纹传感器芯片提供的控制信号，并在所述控制信号的作用下产生激励信号，所述谐振电路用于接收所述激励信号，并在所述激励信号的作用下形成驱动信号；
    所述超声波指纹传感器芯片用于接收所述驱动信号，并在所述驱动信号的作用下产生用于指纹检测的超声波信号。
  2. 根据权利要求1所述的超声波指纹检测装置，其特征在于，所述控制电路包括串联于输入电源和地之间的两个开关管，所述两个开关管在所述控制信号的作用下交替导通，以产生脉冲激励信号；
    所述谐振电路包括串联于所述控制电路和地之间的电容和电感，所述电容和电感在所述脉冲激励信号的作用下发生谐振，以产生正弦波驱动信号。
  3. 根据权利要求2所述的超声波指纹检测装置，其特征在于，所述两个开关管中连接于所述输入电源的开关管为PMOS管，所述两个开关管中连接于地的开关管为NMOS管。
  4. 根据权利要求2或3所述的超声波指纹检测装置，其特征在于，在所述两个开关管交替导通的过程中，所述两个开关管中的一个开关管的状态由导通变更为关断的预设时间后，所述两个开关管中的另一个开关管的状态由关断变更为导通。
  5. 根据权利要求2至4中任一项所述的超声波指纹检测装置，其特征在于，所述两个开关管还在所述控制信号的作用下反相交替导通，以产生反相脉冲激励信号，所述反相脉冲信号用于阻尼所述谐振电路的谐振，以降低所述正弦波驱动信号的谐振能量。
  6. 根据权利要求1至5中任一项所述的超声波指纹检测装置，其特征在于，所述信号发生电路还包括：刹车电路，所述刹车电路包括阻尼电阻，所述阻尼电阻连接在所述谐振电路与所述控制电路之间。
  7. 根据权利要求6所述的超声波指纹检测装置，其特征在于，所述阻尼电阻的一端连接于所述谐振电路与所述控制电路之间，所述阻尼电阻的另一端接地。
  8. 根据权利要求7所述的超声波指纹检测装置，其特征在于，在所述控制电路断路的情况下，所述阻尼电阻串联于所述谐振电路与地之间，所述阻尼电阻用于阻尼所述谐振电路的谐振，以降低所述驱动信号的谐振能量。
  9. 根据权利要求7或8所述的超声波指纹检测装置，其特征在于，所述阻尼电阻的电阻值位于0.8*Z至2*Z之间，其中，Z为所述谐振电路的特征阻抗。
  10. 根据权利要求1至9中任一项所述的超声波指纹检测装置，其特征在于，所述超声波指纹传感器芯片包括：控制模块、换能模块和检测模块；
    所述控制模块用于向所述信号发生电路提供所述控制信号，以控制所述信号发生电路产生所述驱动信号；
    所述换能模块用于接收所述驱动信号以产生超声波信号，所述超声波信号被用户手指反射后产生回波信号，所述换能模块用于将所述回波信号转换为电信号；
    所述检测模块用于检测所述电信号以检测所述用户手指的指纹。
  11. 根据权利要求10所述的超声波指纹检测装置，其特征在于，所述控制模块用于多次向所述信号发生电路发送所述控制信号，以控制所述信号发生电路产生多个所述驱动信号；
    所述换能模块用于接收多个所述驱动信号以产生多个所述超声波信号，并将多个所述超声波信号对应的多个所述回波信号转换为多个所述电信号；
    所述检测模块用于检测多个所述电信号，以检测所述用户手指的指纹。
  12. 根据权利要求10所述的超声波指纹检测装置，其特征在于，所述控制模块用于周期性的向所述信号发生电路发送所述控制信号，以控制所述信号发生电路周期性的产生所述驱动信号；
    所述控制模块用于控制所述换能模块周期性的接收所述驱动信号以产生所述超声波信号；
    所述控制模块用于控制所述检测模块周期性的检测所述电信号，以检测所述用户手指的指纹。
  13. 根据权利要求11所述的超声波指纹检测装置，其特征在于，所述检测模块包括：接收模块、检波模块和信号累加模块；
    所述接收模块用于接收多个所述电信号；
    所述检波模块用于检测多个所述电信号的幅值；
    所述信号累加模块用于将多个所述电信号的幅值进行累加得到信号累加值，所述信号累加值用于被平均计算后以检测所述用户手指的指纹。
  14. 根据权利要求13所述的超声波指纹检测装置，其特征在于，所述信号累加模块为模拟累加器。
  15. 根据权利要求14所述的超声波指纹检测装置，其特征在于，所述超声波指纹传感器芯片还包括：读出模块、模数转换模块和接口模块；
    所述读出模块用于将所述信号累加值读出至所述模数转换模块；
    所述模数转换模块用于将所述信号累加值转换为数字信号；
    所述接口模块用于将所述数字信号传输至外部器件以使得所述数字信号被平均计算后以检测所述用户手指的指纹。
  16. 根据权利要求1至15中任一项所述的超声波指纹检测装置，其特征在于，所述信号发生电路的输入电源的电压值和所述超声波指纹传感器芯片的输入电源的电压值相同。
  17. 根据权利要求1至16中任一项所述的超声波指纹检测装置，其特征在于，所述信号发生电路的输入电源的电压值和所述超声波指纹传感器芯片的输入电源的电压值在3V至4.5V之间。
  18. 一种电子设备，其特征在于，包括：盖板，以及
    如权利要求1至17中任一项所述的超声波指纹检测装置；
    其中，所述盖板用于接收用户手指的按压，所述超声波指纹检测装置设置于所述盖板下方，用于检测按压于所述盖板的所述用户手指的指纹。
  19. 根据权利要求18所述的电子设备，其特征在于，所述电子设备还包括：显示屏，所述盖板设置于所述显示屏的上方，所述超声波指纹检测装置设置于所述显示屏的下方。
PCT/CN2022/105775 2022-06-14 2022-07-14 超声波指纹检测装置和电子设备 WO2024011519A1 (zh)

Priority Applications (5)

Application Number Priority Date Filing Date Title
PCT/CN2022/105775 WO2024011519A1 (zh) 2022-07-14 2022-07-14 超声波指纹检测装置和电子设备
PCT/CN2022/144383 WO2023241017A1 (zh) 2022-06-14 2022-12-30 超声波收发系统和电子设备
CN202211733544.XA CN116140169A (zh) 2022-06-14 2022-12-30 超声波收发系统和电子设备
US18/455,554 US20240021008A1 (en) 2022-07-14 2023-08-24 Ultrasonic fingerprint detection device and electronic device
US18/455,690 US20230401887A1 (en) 2022-06-14 2023-08-25 Ultrasonic transceiver system and electronic device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2022/105775 WO2024011519A1 (zh) 2022-07-14 2022-07-14 超声波指纹检测装置和电子设备

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/455,554 Continuation US20240021008A1 (en) 2022-07-14 2023-08-24 Ultrasonic fingerprint detection device and electronic device

Publications (1)

Publication Number Publication Date
WO2024011519A1 true WO2024011519A1 (zh) 2024-01-18

Family

ID=89510250

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/105775 WO2024011519A1 (zh) 2022-06-14 2022-07-14 超声波指纹检测装置和电子设备

Country Status (2)

Country Link
US (1) US20240021008A1 (zh)
WO (1) WO2024011519A1 (zh)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013110391A1 (de) * 2012-01-26 2013-08-01 Robert Bosch Gmbh Ansteuerungsschaltung und verfahren zur aktiven dämpfung eines ultraschallwandlers, sowie ultraschall-messsystem
CN107491774A (zh) * 2017-09-30 2017-12-19 苏州迈瑞微电子有限公司 一种指纹传感器及其驱动方法
CN107659204A (zh) * 2017-09-28 2018-02-02 吴露 超声波驱动电路和指纹识别传感器
CN109883494A (zh) * 2019-04-03 2019-06-14 淄博宇声计量科技有限公司 一种超声波换能器的数字信号调制与驱动电路及其工作方法
CN110560347A (zh) * 2019-09-24 2019-12-13 成都大超科技有限公司 超声波驱动电路及驱动方法、指纹识别装置及电子设备
CN113158737A (zh) * 2020-01-23 2021-07-23 上海思立微电子科技有限公司 超声波指纹检测传感器及模组
CN113343800A (zh) * 2021-05-25 2021-09-03 电子科技大学 指纹触控识别模组及指纹触控识别方法、电子设备

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013110391A1 (de) * 2012-01-26 2013-08-01 Robert Bosch Gmbh Ansteuerungsschaltung und verfahren zur aktiven dämpfung eines ultraschallwandlers, sowie ultraschall-messsystem
CN107659204A (zh) * 2017-09-28 2018-02-02 吴露 超声波驱动电路和指纹识别传感器
CN107491774A (zh) * 2017-09-30 2017-12-19 苏州迈瑞微电子有限公司 一种指纹传感器及其驱动方法
CN109883494A (zh) * 2019-04-03 2019-06-14 淄博宇声计量科技有限公司 一种超声波换能器的数字信号调制与驱动电路及其工作方法
CN110560347A (zh) * 2019-09-24 2019-12-13 成都大超科技有限公司 超声波驱动电路及驱动方法、指纹识别装置及电子设备
CN113158737A (zh) * 2020-01-23 2021-07-23 上海思立微电子科技有限公司 超声波指纹检测传感器及模组
CN113343800A (zh) * 2021-05-25 2021-09-03 电子科技大学 指纹触控识别模组及指纹触控识别方法、电子设备

Also Published As

Publication number Publication date
US20240021008A1 (en) 2024-01-18

Similar Documents

Publication Publication Date Title
CN107426434B (zh) 输入装置和电子设备
EP3022634B1 (en) Method and integrated circuit for operating a sensor array
TWI469649B (zh) 數位麥克風系統、音訊控制裝置及其控制方法
TW201349070A (zh) 基於電容性觸摸螢幕驅動檢測方法和設備
CN115188034B (zh) 超声波指纹检测装置和电子设备
JPS6384531A (ja) 超音波診断装置
WO2024011519A1 (zh) 超声波指纹检测装置和电子设备
CN109598258B (zh) 超声波检测电路和图像传感器像素电路以及信号检测方法
WO2019014875A1 (zh) 电源产生电路、电容式阵列传感装置和终端设备
EP3816847A1 (en) Ultrasonic signal detecting circuit, ultrasonic signal detecting method, and display panel
CN110647868B (zh) 超声传感像素电路、栅极驱动电路、显示面板和驱动方法
CN105193450B (zh) 一种超声成像系统的高压电源控制方法
WO2023241017A1 (zh) 超声波收发系统和电子设备
TWI543057B (zh) 觸控通訊系統與觸控通訊方法
WO2022241761A1 (zh) 超声波信号检测电路、检测方法和超声波检测设备
JP2001245881A (ja) 超音波診断装置用送信回路
US20230401887A1 (en) Ultrasonic transceiver system and electronic device
US11776296B2 (en) Ultrasonic fingerprint recognition circuit, method for driving same, and display device
CN115995100A (zh) 超声波检测装置和电子设备
US20220019753A1 (en) Fingerprint sensing apparatus
US8396112B2 (en) Circuitry and method for transferring data, and circuitry and method utilizing clock pulses
CN115412097A (zh) 一种窄脉冲捕获及处理集成设计方法
CN209976755U (zh) 微型压电泵模块
TW202110074A (zh) 微型壓電泵模組
CN113884116B (zh) 超声波驱动电路

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22950643

Country of ref document: EP

Kind code of ref document: A1