CN109496315B - Fingerprint detection coding device, fingerprint detection system and electronic equipment - Google Patents
Fingerprint detection coding device, fingerprint detection system and electronic equipment Download PDFInfo
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- CN109496315B CN109496315B CN201880002331.5A CN201880002331A CN109496315B CN 109496315 B CN109496315 B CN 109496315B CN 201880002331 A CN201880002331 A CN 201880002331A CN 109496315 B CN109496315 B CN 109496315B
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Abstract
The disclosure relates to the technical field of fingerprint detection, and discloses a fingerprint detection coding device, a fingerprint detection system and an electronic device. Fingerprint detection coding device includes: the fingerprint detection chip comprises a code printing signal generation module and an edge time adjustment module, wherein the code printing signal generation module is used for generating spread spectrum random code printing signals, and the edge time adjustment module is used for adjusting the edge time of the spread spectrum random code printing signals to obtain dynamic edge code printing signals. The spread spectrum random code printing signal is adopted to drive the fingerprint detection chip, so that the EMI of the code printing signal to the radio frequency communication of the mobile equipment can be effectively reduced, and the edge time of the spread spectrum random code printing signal is increased by adopting the edge time adjusting module, so that the interference can be further reduced.
Description
Technical Field
The disclosure relates to the technical field of fingerprint detection, in particular to a fingerprint detection coding device, a fingerprint detection system and an electronic device.
Background
Fingerprints are unique and unique as human-specific biological features and can be used for individual identification. The fingerprint detection function is generally realized by a fingerprint detection chip, and the fingerprint detection chip needs to be driven by a code printing signal for working. Currently, a fingerprint detection chip mostly adopts a fixed sequence coding signal to drive the fingerprint detection chip, however, an Electromagnetic Interference (EMI) generated by the fixed sequence coding signal in a full frequency band is relatively large, and thus, radio frequency communication of a mobile device is relatively easily interfered.
Disclosure of Invention
Aiming at the problems in the background art, the purpose of the disclosure is to provide a fingerprint detection coding device, which effectively reduces the EMI of coding signals to the radio frequency communication of mobile equipment during fingerprint detection, and can realize the effect of high-voltage coding by adopting a low-voltage driving chip; it is another object of the present disclosure to provide a fingerprint detection system; it is yet another object of the present disclosure to provide an electronic device.
One embodiment of the present disclosure provides a fingerprint detection coding device, including: the fingerprint detection chip comprises a code printing signal generation module and an edge time adjustment module; the code printing signal generating module is used for generating spread spectrum random code printing signals, and the edge time adjusting module is used for adjusting the edge time of the spread spectrum random code printing signals to obtain dynamic edge code printing signals.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the coding signal generation module includes a random signal generation module, and the random signal generation module is configured to generate an irregular random signal.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the coding signal generation module further includes an amplitude quantization module, and the amplitude quantization module is configured to perform digital quantization on the random signal to obtain a digital quantization signal.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the coding signal generation module further includes a pulse width adjustment module, and the pulse width adjustment module is configured to perform pulse width adjustment on the digital quantization signal to obtain a pulse width adjustment signal.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the coding signal generation module further includes a spread spectrum random coding module, and the spread spectrum random coding module is configured to perform a spread spectrum operation on the pulse width adjustment signal to obtain the spread spectrum random coding signal. The spread spectrum random code-printing signal comprises a standard high level and a standard low level in one period, the standard high level and the standard low level are respectively levels with specific time length, the number of the standard high level and the standard low level is respectively fixed, the standard high level and the standard low level are randomly distributed in one period, and the total time length of the standard high level and the standard low level is one period length.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the edge time adjustment module includes an edge time adjustment circuit, a first current branch and a second current branch, where the first current branch or the second current branch is connected to the edge time adjustment circuit to provide a charging current, and the charging current provided by the second current branch is greater than the charging current provided by the first current branch.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the edge time adjustment module further includes a switch, where the switch is configured to switch on and off between the edge time adjustment circuit and the first current branch or between the edge time adjustment circuit and the second current branch, and further control the edge time of the spread spectrum random coding signal entering the edge time adjustment module.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, after the spread spectrum random coding signal enters the edge time adjustment module, the switch switches the on/off between the edge time adjustment circuit and the first current branch, so as to increase the edge time of the spread spectrum random coding signal; the change-over switch switches on and off between the edge time adjusting circuit and the second current branch circuit, so that the edge of the spread spectrum random code printing signal quickly reaches a preset level, and the preset level is a high level or a low level of the spread spectrum random code printing signal.
As an optional implementation scheme of the fingerprint detection coding device provided by the disclosure, the fingerprint detection chip further comprises a main chip circuit, and the main chip circuit is used for receiving a power supply signal provided by the outside to realize normal communication and work of the fingerprint detection chip.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the fingerprint detection coding device further includes a voltage boost circuit, the dynamic edge coding signal output by the edge time adjustment module is used as an input signal of the voltage boost circuit, the voltage boost circuit is configured to convert the dynamic edge coding signal into two sets of high-voltage coding signals with the same frequency, which are a chip power signal and a chip ground signal respectively, and a difference between amplitudes of each point of the chip power signal and the chip ground signal is kept constant. The chip power signal and the chip ground signal provide power for the main chip circuit to ensure normal communication and work of the fingerprint detection chip.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the voltage boost circuit includes a coding signal receiving terminal, a plurality of voltage boost branches, and a plurality of voltage conversion branches.
The code printing signal receiving end is used for receiving the dynamic edge code printing signal;
the plurality of boosting branches are used for respectively boosting the voltage amplitude of the dynamic edge coding signal for multiple times to form two groups of high-voltage coding signals with the same frequency, and the two groups of high-voltage coding signals are respectively used as the chip power signal and the chip ground signal;
the plurality of voltage conversion branches are used for starting the boosting processing states of the plurality of boosting branches, and when the plurality of voltage conversion branches are simultaneously and respectively connected with the plurality of boosting branches, the voltage amplitude of the dynamic edge coding signal is promoted.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the voltage boost circuit further includes a high voltage power supply output terminal and a high voltage signal ground output terminal. The high-voltage power supply output end and the high-voltage signal ground output end are respectively used for outputting the chip power supply signal and the chip ground signal.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the fingerprint detection chip further includes a chip power receiving terminal and a chip ground terminal, where the chip power receiving terminal and the chip ground terminal are respectively configured to receive the chip power signal and the chip ground signal.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the plurality of voltage conversion branches include a first voltage conversion branch, a second voltage conversion branch, and a third voltage conversion branch.
The first voltage conversion branch comprises a power receiving end and a first switch, and the power receiving end is directly connected with the first switch. The power receiving end is used for receiving an analog power supply provided by the outside so as to supply power to the booster circuit.
The second voltage conversion branch comprises a power receiving end, a first diode and a second switch, the power receiving end is connected with the anode of the first diode, and the cathode of the first diode is connected with the second switch.
The third voltage conversion branch comprises a power receiving end, a second diode and a third switch, the power receiving end is connected with the anode of the second diode, the cathode of the second diode is connected with one end of the third switch, and the other end of the third switch is connected with the high-voltage signal ground output end.
The fourth voltage conversion branch comprises a power receiving end and a third diode, the power receiving end is connected with the anode of the third diode, and the cathode of the third diode is connected with the output end of the high-voltage power supply.
The first switch, the second switch, and the third switch are a first set of switches.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the plurality of boosting branches include a first boosting branch, a second boosting branch and a third boosting branch.
The first boost branch comprises a first capacitor and a fourth switch. The negative electrode of the first capacitor is grounded through the fourth switch, a first boosting node is arranged between the negative electrode of the first capacitor and the fourth switch, and the first voltage conversion branch circuit is connected with the first boosting node through the first switch; the positive electrode of the first capacitor is connected with a second boosting node, and the second boosting node is connected with the second voltage conversion branch circuit and is connected between the negative electrode of the first diode and the second switch.
The second boost branch comprises a second capacitor and a fifth switch. The negative electrode of the second capacitor is grounded through the fifth switch, a third boosting node is arranged between the negative electrode of the second capacitor and the fifth switch, and the second voltage conversion branch circuit is connected with the third boosting node through the second switch; and the anode of the second capacitor is connected with a fourth boosting node, and the fourth boosting node is connected with the third voltage conversion branch and is connected between the cathode of the second diode and the third switch.
The third boost branch comprises a third capacitor and a sixth switch. The negative electrode of the third capacitor is grounded through the sixth switch, a fifth boost node is arranged between the negative electrode of the third capacitor and the sixth switch, the third voltage conversion branch is connected with the fifth boost node through the third switch, and the fifth boost node is positioned between the third switch and the high-voltage signal ground output end; the positive electrode of the third capacitor is connected with a sixth boosting node, the fourth voltage conversion branch circuit is connected with the sixth boosting node through the negative electrode of the third diode, and the sixth boosting node is located between the third diode and the output end of the high-voltage power supply.
The fourth switch, the fifth switch, and the sixth switch are a second group of switches.
As an optional implementation scheme of the fingerprint detection coding device provided by the present disclosure, the input signal of the voltage boost circuit further includes an inverse signal of the dynamic edge coding signal, the dynamic edge coding signal controls the first group of switches, and the inverse signal controls the second group of switches.
As an optional implementation of the fingerprint detection coding device provided in the present disclosure, the reverse signal is obtained by passing the dynamic edge coding signal through an inverter.
As an optional implementation of the fingerprint detection coding device provided in the present disclosure, the first group of switches and the second group of switches are both active at a high level, and when the high level of the dynamic edge coding signal arrives, the first group of switches is closed and the second group of switches is opened; when the high level of the reverse signal arrives, the first group of switches is opened and the second group of switches is closed.
One embodiment of the present disclosure provides a fingerprint detection system including a fingerprint detection coding device as described above.
As an optional implementation of the fingerprint detection system provided by the present disclosure, the fingerprint detection system further includes a host control module, where the host control module is configured to provide an analog power supply for the voltage boost circuit.
As an optional implementation scheme of the fingerprint detection system provided by the present disclosure, the fingerprint detection system further includes a level conversion module, where the level conversion module is configured to convert a level between the host control module and the fingerprint detection chip, so that the level between the host control module and the fingerprint detection chip is matched.
An embodiment of the present disclosure provides an electronic device, including the display screen and being located the fingerprint detection of display screen below beats the sign indicating number device, fingerprint detection beats the sign indicating number device and includes as above fingerprint detection beats the sign indicating number device.
The present disclosure has the following beneficial effects: the fingerprint detection code printing device provided by the embodiment of the disclosure comprises a fingerprint detection chip, wherein the fingerprint detection chip comprises a code printing signal generation module and an edge time adjustment module, the code printing signal generation module is used for generating spread spectrum random code printing signals, and the edge time adjustment module is used for adjusting the edge time of the spread spectrum random code printing signals to obtain dynamic edge code printing signals. Adopt the spread spectrum to beat sign indicating number signal drive fingerprint detection chip at random and can effectively reduce the EMI of beating the sign indicating number signal to mobile device radio frequency communication, adopt border time adjustment module to increase the border time of the spread spectrum signal of beating the sign indicating number at random and can further reduce above-mentioned interference, simultaneously fingerprint is beaten sign indicating number detection device and is still included boost circuit for adopt low pressure drive chip alright realize the effect of high pressure beating the sign indicating number.
Drawings
One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.
FIG. 1 is a schematic block diagram of a fingerprint detection system according to one embodiment of the present disclosure;
FIG. 2 is a schematic diagram of a structure of a code signal generating module according to the embodiment in FIG. 1;
FIG. 3 is a schematic diagram illustrating a waveform structure of a spread spectrum random code-printing signal generated by the code-printing signal generation module according to the embodiment in FIG. 1;
FIG. 4 is a schematic diagram of an edge time adjustment module according to the embodiment in FIG. 1;
FIG. 5 is a schematic diagram of a boost circuit according to the embodiment in FIG. 1;
FIG. 6 is a schematic diagram of a simulation curve of EMI values generated by a spread spectrum random code signal and a fixed sequence code signal over a full frequency band according to an embodiment of the present disclosure;
FIG. 7 is a schematic structural diagram of a fingerprint detection coding device according to one embodiment of the present disclosure;
fig. 8 is a schematic structural diagram of an electronic device according to one embodiment of the present disclosure.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that in the embodiments of the disclosure, numerous technical details are set forth in order to provide a better understanding of the disclosure. However, the claimed subject matter may be practiced without these specific details or with various changes and modifications based on the following embodiments.
Fig. 1 is a schematic structural diagram of a fingerprint detection system according to one embodiment of the present disclosure. The fingerprint detection system 5 includes: fingerprint detection chip 1, boost circuit 2, host control module 3 and level transition module 4.
The fingerprint detection chip 1 includes: the chip comprises a chip power receiving end 11a, a chip ground end 11b, a main chip circuit 12, a code printing signal generating module 13 and an edge time adjusting module 14.
The main chip circuit 12 receives power signals provided by the outside through the chip power receiving terminal 11a and the chip ground terminal 11b to realize normal communication and work of the fingerprint detection chip 1.
The code signal generating module 13 is configured to generate a spread spectrum random code signal TX; the spread spectrum random code-printing signal TX includes a standard high level and a standard low level in one period, the standard high level and the standard low level are levels having a specific time length, respectively, and the numbers of the standard high level and the standard low level are fixed, respectively, the standard high level and the standard low level are randomly distributed in one period, and the total time length of the standard high level and the standard low level is one period length.
The edge time adjusting module 14 is configured to adjust the edge time of the spread spectrum random coding signal TX to obtain a dynamic edge coding signal TXd.
The booster circuit 2 includes: a code signal receiving end 25, a power receiving end 28, a high voltage power output end 29a and a high voltage signal ground output end 29 b.
After receiving the dynamic edge coding signal TXd through the coding signal receiving terminal 25, the booster circuit 2 converts the dynamic edge coding signal TXd into two groups of high-voltage coding signals with the same frequency, which are a chip power signal SVCC and a chip ground signal SGND respectively, and the difference between the amplitudes of each point of the chip power signal SVCC and the chip ground signal SGND is kept constant.
The power receiving terminal 28 is configured to receive an analog power supply AVDD provided from the outside to provide power for the voltage boost circuit 2, so as to ensure that the voltage boost circuit 2 works normally.
The high-voltage power output end 29a and the high-voltage signal ground output end 29b are respectively connected with the chip power receiving end 11a and the chip ground end 11b of the fingerprint detection chip 1. The chip power signal SVCC and the chip ground signal SGND are respectively output to the chip power receiving terminal 11a and the chip ground terminal 11b through the high voltage power output terminal 29a and the high voltage signal ground output terminal 29b, and then provide power for the main chip circuit 12 to ensure normal communication and operation of the fingerprint detection chip 1.
The host control module 3 includes a power output terminal 31 for outputting the analog power AVDD to supply power to the boost circuit 2 to ensure the normal operation of the boost circuit 2. The host control module 3 may be a host control module or other functional modules of a mobile device such as a mobile phone having functions of providing power and controlling.
The level conversion module 4 is used for converting the level between the host control module 3 and the fingerprint detection chip 1, so that the level between the host control module 3 and the fingerprint detection chip 1 is matched.
Fig. 2 is a schematic structural diagram of a coding signal generating module according to the embodiment in fig. 1. As shown in fig. 2, the code signal generating module 13 includes: a random signal generation module 131, an amplitude quantization module 132, a pulse width adjustment module 133, and a spread spectrum random coding module 134.
The random signal generating module 131 is used to generate an irregular random signal 135. The random signal generating module 131 includes a random number generator, which may be a thermal noise random number generator, a quantum random number generator, or the like, as long as the random signal 135 can be generated.
The amplitude quantization module 132 is configured to quantize the random signal 135 to obtain a digital quantized signal 136. Since the amplitude of the random signal 135 generated by the random signal module 131 is random, it needs to be quantized. A specific quantization method may be to select a critical value between the minimum value and the maximum value of the amplitude of the random signal 135, quantize the random signal 135 to a high level at a point greater than or equal to the critical value, and quantize the random signal 135 to a low level at a point smaller than the critical value. Finally, the random signal 135 is converted into the digital quantized signal 136.
The pulse width adjusting module 133 is configured to perform pulse width adjustment on the digital quantized signal 136, and adjust the interval between the high levels of the digital quantized signal 136 to be the same time interval, so as to obtain a pulse width adjusted signal 137.
The spread spectrum random code-printing module 134 is configured to perform a spread spectrum operation on the pulse width adjustment signal 137 to obtain a spread spectrum random code-printing signal 138. The spread spectrum random code signal 138 includes a standard high level and a standard low level in one period, the standard high level and the standard low level are levels having a specific time length, respectively, and the numbers of the standard high level and the standard low level are fixed, respectively, the standard high level and the standard low level are randomly distributed in one period, and the total time length of the standard high level and the standard low level is one period length. The spread spectrum random code signal 138 is the spread spectrum random code signal TX provided to the edge timing adjustment module 14 as shown in fig. 1.
A specific embodiment of the spread spectrum random code signal 138 can be seen in fig. 3.
Fig. 3 is a schematic diagram of a waveform structure of a spread spectrum random code-printing signal generated by the code-printing signal generation module according to the embodiment in fig. 1. Fig. 3 shows a spread spectrum random coded signal 138 in three cycles, each cycle containing 4 standard low levels 1380 and 3 standard high levels 1381, but the standard low levels 1380 and the standard high levels 1381 are randomly distributed within each cycle. The standard low level 1380 and the standard high level 1381 may be equal or different in time length, as long as the spread spectrum random code signal 138 of each period is guaranteed to have the same time length. Optionally, in this embodiment, the time length of the standard low level 1380 is equal to that of the standard high level 1381. The standard low level 1380 and the standard high level 1381 are used to represent binary "0" and "1", respectively, and according to this rule, the spread spectrum random code signal 138 shown in fig. 3 can be represented as {1010100, 1100010, 0111000, … … } from left to right in sequence. Although the code values "1" and "0" in each period are in different orders, each period includes three "1" s and four "0" s, that is, the spread spectrum random coding module 134 performs the spreading operation on the pulse width adjustment signal 137 as shown in fig. 2, and the spread spectrum random coding signal 138 is obtained.
Fig. 4 is a schematic structural diagram of an edge time adjustment module according to the embodiment in fig. 1. The edge time adjustment module 14 includes: the circuit comprises a signal input end 141, an edge time adjusting circuit 142, a switch 143, a first current branch 144a, a second current branch 144b and a signal output end 145.
The first current branch 144a or the second current branch 144b is connected to the edge time adjustment circuit 142 to provide a charging current, and the charging current provided by the second current branch 144b is greater than the charging current provided by the first current branch 144 a.
After the spread spectrum random code-printing signal 138 generated by the code-printing signal generating module 13 enters the edge time adjusting module 14 from the signal input terminal 141, the switch 143 first switches on the edge time adjusting circuit 142 and the first current branch 144a to provide a charging current for increasing the edge time of the rising edge of the spread spectrum random code-printing signal 138. After a predetermined charging time, the switch 143 turns on the edge time adjustment circuit 142 and the second current branch 144b to make the rising edge reach a high level quickly. Similar operation can be adopted for the falling edge of the spread spectrum random coding signal 138, so that the edge time of the falling edge is increased, and finally, after the spread spectrum random coding signal 138 passes through the edge time adjusting module 14, a dynamic edge coding signal 146 is obtained; the dynamic edge coding signal 146 is the dynamic edge coding signal TXd provided to the boost circuit 2 as shown in fig. 1.
It should be noted that the number of the first current branch 144a and the second current branch 144b is not limited, and can be set according to the requirement of the actual product. Meanwhile, the on/off of the connection between the first current branch 144a and the second current branch 144b and the edge time adjusting circuit 142 can be controlled by controlling the switching of the switch 143 through programmable software, and the switching frequency of the switch 143 is not limited. The dynamic edge coding signal 146 may be an axisymmetric signal as shown in fig. 4 or an asymmetric signal.
Fig. 5 is a schematic diagram of a structure of the booster circuit according to the embodiment in fig. 1. The booster circuit 2 in this embodiment includes a plurality of voltage converting branches 201a to 201d and a plurality of booster branches 202a to 202c, in addition to the coded signal receiving terminal 25, the power receiving terminal 28, the high voltage power output terminal 29a and the high voltage signal ground output terminal 29b shown in the booster circuit 2 in fig. 1, where the power receiving terminal 28 is included in the plurality of voltage converting branches 201a to 201 d. The power receiving terminal 28 is configured to receive the analog power supply AVDD output by the host control module 3 through the power output terminal 31 to ensure that the voltage boost circuit 2 works normally.
The plurality of boosting branches 202a to 202c are configured to perform boosting processing on the voltage amplitudes of the dynamic edge coding signal 146 for multiple times, so as to form two groups of high-voltage coding signals with the same frequency, and the two groups of high-voltage coding signals are respectively used as the chip power supply signal SVCC and the chip ground signal SGND.
The plurality of voltage conversion branches 201a to 201d are configured to start the boost processing states of the plurality of boost branches 202a to 202c, and when the plurality of voltage conversion branches 201a to 201d are simultaneously and respectively connected to the plurality of boost branches 202a to 202c, the voltage amplitude of the dynamic edge coding signal 146 is increased.
The input signals of the boost circuit 2 include a dynamic edge coding signal 25a and an inversion signal 25b, and the inversion signal 25b can be obtained from the dynamic edge coding signal 25a through an inverter 26, as shown in fig. 5. The dynamic edge coding signal 25a is the dynamic edge coding signal 146 output by the edge time adjusting module 14 shown in fig. 4. The output signal of the boosting circuit 2 includes the chip power supply signal SVCC and the chip ground signal SGND. The chip power signal SVCC and the chip ground signal SGND are respectively output to the chip power receiving terminal 11a and the chip ground terminal 11b through the high voltage power output terminal 29a and the high voltage signal ground output terminal 29b, so as to provide power to the main chip circuit 12 to ensure normal communication and operation of the fingerprint detection chip 1.
In the embodiment shown in fig. 5, the boosting circuit 2 specifically takes three boosting branches 202a to 202c as an example, but it should be understood that in other alternative embodiments, the number of boosting branches of the boosting circuit 2 may be determined according to the amplitude requirement of the high-frequency code-printing signal. The three boost legs 202a-202c are respectively identified as a first boost leg 202a, a second boost leg 202b, and a third boost leg 202 c.
In the embodiment shown in fig. 5, the boosting circuit 2 specifically takes four voltage converting branches 201a to 201d as an example, but it should be understood that in other alternative embodiments, the number of voltage converting branches of the boosting circuit 2 may be determined according to the number of boosting branches. The four voltage converting branches 201a to 201d are respectively denoted as a first voltage converting branch 201a, a second voltage converting branch 201b, a third voltage converting branch 201c and a fourth voltage converting branch 201 d.
The four voltage conversion branches 201a to 201d and the three voltage boosting branches 202a to 202c may specifically include the power receiving terminal 28; diode 21a, diode 21b, diode 21 c; a capacitor 22a, a capacitor 22b, a capacitor 22 c; switch 23a, switch 23b, switch 23c, switch 24a, switch 24b, switch 24 c. The switches 23a, 23b and 23c are a first group of switches, and the switches 24a, 24b and 24c are a second group of switches.
After the boost circuit 2 receives the dynamic edge coding signal 25a through the coding signal receiving terminal 25 (not shown in fig. 5), the dynamic edge coding signal 25a is provided to the first group of switches 23a to 23c to control the on/off state of the first group of switches 23a to 23 c. On the other hand, the dynamic edge coding signal 25a is converted into the inverted signal 25b by the inverter 26, and then is provided to the second set of switches 24a to 24c to control the on/off states of the second set of switches 24a to 24 c.
The first voltage conversion branch 201a includes the power receiving terminal 28 and the switch 23a, and the power receiving terminal 28 is directly connected to the switch 23 a.
The second voltage converting branch 201b includes the power receiving terminal 28, the diode 21a and the switch 23b, the power receiving terminal 28 is connected to the anode of the diode 21a, and the cathode of the diode 21a is connected to the switch 23 b.
The third voltage converting branch 201c includes the power receiving terminal 28, the diode 21b and the switch 23c, the power receiving terminal 28 is connected to the anode of the diode 21b, the cathode of the diode 21b is connected to one end of the switch 23c, and the other end of the switch 23c is connected to the high-voltage signal ground output terminal 29 b.
The fourth voltage converting branch 201d includes the power receiving terminal 28 and the diode 21c, the power receiving terminal 28 is connected to the anode of the diode 21c, and the cathode of the diode 21c is connected to the high-voltage power output terminal 29 a.
The first boost branch 202a includes the capacitor 22a and the switch 24 a. The negative electrode of the capacitor 22a is grounded through the switch 24a, a boost node 210 is included between the negative electrode of the capacitor 22a and the switch 24a, and the first voltage conversion branch 201a is connected with the boost node 210 through the switch 23 a; the positive electrode of the capacitor 22a is connected to a boost node 211a, and the boost node 211a is connected to the second voltage converting branch 201b and connected between the negative electrode of the diode 21a and the switch 23 b.
The second boost branch 202b includes the capacitor 22b and the switch 24 b. The negative electrode of the capacitor 22b is grounded through the switch 24b, a boost node 211b is included between the negative electrode of the capacitor 22b and the switch 24b, and the second voltage conversion branch 201b is connected with the boost node 211b through the switch 23 b; the positive electrode of the capacitor 22b is connected to a boost node 212a, and the boost node 212a is connected to the third voltage converting branch 201c and connected between the negative electrode of the diode 21b and the switch 23 c.
The third boost branch 202c includes the capacitor 22c and the switch 24 c. The cathode of the capacitor 22c is grounded through the switch 24c, a boost node 212b is included between the cathode of the capacitor 22c and the switch 24c, the third voltage converting branch 201c is connected to the boost node 212b through the switch 23c, and the boost node 212b is located between the switch 23c and the high-voltage signal ground output terminal 29 b; the positive electrode of the capacitor 22c is connected to a boost node 213, the fourth voltage converting branch 201d is connected to the boost node 213 through the negative electrode of the diode 21c, and the boost node 213 is located between the diode 21c and the high-voltage power output terminal 29 a.
The operating principle of the booster circuit 2 is as follows: the first set of switches 23a-23c and the second set of switches 24a-24c are both active high, and the dynamic edge coding signal 25a controls the first set of switches 23a-23 c; the inverted signal 25b controls the second set of switches 24a-24 c.
When the reverse signal 25b goes high, the first group of switches 23a-23c are opened and the second group of switches 24a-24c are closed, the analog power supply AVDD flows through the diode 21a, the diode 21b and the diode 21c to charge the capacitor 22a, the capacitor 22b and the capacitor 22c, respectively, and the high-voltage signal ground output terminal 29b outputs a low level of 0V;
when the dynamic edge coding signal 25a goes high, the first group of switches 23a-23c are closed and the second group of switches 24a-24c are opened, and due to the presence of the diodes 21a-21c, the connection between the analog power supply AVDD and the capacitors 22a-22c is cut off, so that the capacitors 22a, 22b and 22c are connected in series, the voltages of the chip power supply signal SVCC and the chip ground signal SGND are raised due to the bootstrap effect of the capacitors, and the output voltage of the chip ground signal SGND has a magnitude of 3 × analog power supply AVDD, wherein the waveform of the chip ground signal SGND is shown as 27.
Fig. 6 is a schematic diagram of a simulation curve of EMI values generated by a spread spectrum random code signal and a fixed sequence code signal in a full frequency band according to an embodiment of the disclosure. As shown in fig. 6, in the rectangular coordinate system, a solid line 11 represents a variation trend of the EMI value generated by the fixed sequence code signal with frequency, and a dashed line 12 represents a variation trend of the EMI value generated by the spread spectrum random code signal with frequency. Compared with the EMI value generated by the fixed sequence code printing signal in the full frequency band, the EMI value generated by the spread spectrum random code printing signal in the full frequency band is integrally lower. Further, as the frequency increases, the absolute value of the slope of the broken line 12 becomes larger after the second inflection point in the direction of increasing the frequency than that of the solid line 11 at the same frequency. That is, the EMI value generated by the spread spectrum random coding signal is reduced at a faster rate after the second inflection point of the dotted line 12, which indicates that the EMI generated in the full frequency band can be effectively reduced by driving the fingerprint detection chip with the spread spectrum random coding signal, and the interference of the coding signal to the radio frequency communication of the mobile device can be effectively reduced when the fingerprint detection is performed.
Fig. 7 is a schematic structural diagram of a fingerprint detection coding device according to an embodiment of the present disclosure. The fingerprint detection coding device 6 comprises a fingerprint detection chip 1 and a booster circuit 2 shown in fig. 1. The booster circuit 2 may refer to the structure of the booster circuit shown in fig. 5.
Fig. 8 is an electronic device according to one embodiment of the present disclosure. The electronic equipment 7 comprises a display screen 8 and a fingerprint detection coding device 6 positioned below the display screen 8, wherein the fingerprint detection coding device 6 is shown in fig. 7.
While this disclosure contains many specifics, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features that are described in this patent document can also be implemented in combination in a single embodiment, in the context of separate embodiments. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the various individual system components in the embodiments described in this patent document are not to be construed as requiring such separation in all embodiments.
It will be understood by those of ordinary skill in the art that the embodiments described above are specific embodiments for carrying out the present application and that various changes in form and details may be made therein without departing from the scope of the present application in practice.
Claims (20)
1. A fingerprint detection coding device is characterized by comprising: the fingerprint detection chip comprises a code printing signal generation module and an edge time adjustment module;
the code printing signal generating module is used for generating spread spectrum random code printing signals, and the edge time adjusting module is used for adjusting the edge time of the spread spectrum random code printing signals to obtain dynamic edge code printing signals;
the fingerprint detection chip also comprises a main chip circuit and a booster circuit, wherein the main chip circuit is used for receiving power signals provided by the outside to realize normal communication and work of the fingerprint detection chip;
the dynamic edge code printing signal output by the edge time adjusting module is used as an input signal of the booster circuit, the booster circuit is used for converting the dynamic edge code printing signal into two groups of high-voltage code printing signals with the same frequency, the two groups of high-voltage code printing signals are respectively a chip power signal and a chip ground signal, the difference between the amplitude of each point of the chip power signal and the amplitude of each point of the chip ground signal are kept constant, and the chip power signal and the chip ground signal provide power for the main chip circuit to ensure the normal communication and the work of the fingerprint detection chip.
2. The fingerprint detection coding device of claim 1, wherein the coding signal generation module comprises a random signal generation module, and the random signal generation module is configured to generate an irregular random signal.
3. The fingerprint detection coding device of claim 2, wherein the coding signal generation module further comprises an amplitude quantization module, and the amplitude quantization module is configured to digitally quantize the random signal to obtain a digitally quantized signal.
4. The fingerprint detection coding device of claim 3, wherein the coding signal generation module further comprises a pulse width adjustment module, and the pulse width adjustment module is configured to perform pulse width adjustment on the digital quantization signal to obtain a pulse width adjustment signal.
5. The fingerprint detection coding device according to claim 4, wherein the coding signal generating module further includes a spread spectrum random coding module, the spread spectrum random coding module is configured to perform a spread spectrum operation on the pulse width adjustment signal to obtain the spread spectrum random coding signal, the spread spectrum random coding signal includes a standard high level and a standard low level in one period, the standard high level and the standard low level are levels having a specific time length, and the numbers of the standard high level and the standard low level are fixed respectively, the standard high level and the standard low level are randomly distributed in one period, and the total time length of the standard high level and the standard low level is one period length.
6. The fingerprint detection coding device according to claim 1, wherein the edge time adjustment module includes an edge time adjustment circuit, a first current branch and a second current branch, the first current branch or the second current branch connects the edge time adjustment circuit to provide a charging current, and the charging current provided by the second current branch is greater than the charging current provided by the first current branch.
7. The fingerprint detection coding device according to claim 6, wherein the edge time adjustment module further comprises a switch, and the switch is configured to switch the edge time adjustment circuit to be connected to or disconnected from the first current branch or the second current branch, so as to further control the edge time of the spread spectrum random coding signal entering the edge time adjustment module.
8. The fingerprint detection coding device according to claim 7, wherein after the spread spectrum random coding signal enters the edge time adjustment module, the switch switches the on/off between the edge time adjustment circuit and the first current branch to increase the edge time of the spread spectrum random coding signal; the change-over switch switches on and off between the edge time adjusting circuit and the second current branch circuit, so that the edge of the spread spectrum random code printing signal quickly reaches a preset level, and the preset level is a high level or a low level of the spread spectrum random code printing signal.
9. The fingerprint detection coding device according to claim 1, wherein the voltage boost circuit comprises a coding signal receiving end, a plurality of voltage boost branches and a plurality of voltage conversion branches;
the code printing signal receiving end is used for receiving the dynamic edge code printing signal;
the plurality of boosting branches are used for respectively boosting the voltage amplitude of the dynamic edge coding signal for multiple times to form two groups of high-voltage coding signals with the same frequency, and the two groups of high-voltage coding signals are respectively used as the chip power signal and the chip ground signal;
the plurality of voltage conversion branches are used for starting the boosting processing states of the plurality of boosting branches, and when the plurality of voltage conversion branches are simultaneously and respectively connected with the plurality of boosting branches, the voltage amplitude of the dynamic edge coding signal is promoted.
10. The fingerprint detection coding device according to claim 9, wherein the voltage boost circuit further comprises a high voltage power output terminal and a high voltage signal ground output terminal, the high voltage power output terminal and the high voltage signal ground output terminal are respectively configured to output the chip power signal and the chip ground signal.
11. The fingerprint detection coding device of claim 1, wherein the fingerprint detection chip further comprises a chip power receiving terminal and a chip ground terminal, the chip power receiving terminal and the chip ground terminal being configured to receive the chip power signal and the chip ground signal, respectively.
12. The fingerprint detection coding device according to claim 10, wherein the plurality of voltage conversion branches includes a first voltage conversion branch, a second voltage conversion branch, a third voltage conversion branch, and a fourth voltage conversion branch;
the first voltage conversion branch comprises a power supply receiving end and a first switch, the power supply receiving end is directly connected with the first switch, and the power supply receiving end is used for receiving an analog power supply provided by the outside so as to supply power for the booster circuit;
the second voltage conversion branch comprises a power receiving end, a first diode and a second switch, the power receiving end is connected with the anode of the first diode, and the cathode of the first diode is connected with the second switch;
the third voltage conversion branch comprises a power receiving end, a second diode and a third switch, the power receiving end is connected with the anode of the second diode, the cathode of the second diode is connected with one end of the third switch, and the other end of the third switch is connected with the high-voltage signal ground output end;
the fourth voltage conversion branch comprises a power supply receiving end and a third diode, the power supply receiving end is connected with the anode of the third diode, and the cathode of the third diode is connected with the output end of the high-voltage power supply;
the first switch, the second switch, and the third switch are a first set of switches.
13. The fingerprint detection coding device according to claim 12, wherein the plurality of voltage boosting branches include a first voltage boosting branch, a second voltage boosting branch, and a third voltage boosting branch;
the first voltage boosting branch circuit comprises a first capacitor and a fourth switch, the negative electrode of the first capacitor is grounded through the fourth switch, a first boosting node is arranged between the negative electrode of the first capacitor and the fourth switch, and the first voltage conversion branch circuit is connected with the first boosting node through the first switch; the positive electrode of the first capacitor is connected with a second boosting node, and the second boosting node is connected with the second voltage conversion branch circuit and is connected between the negative electrode of the first diode and the second switch;
the second voltage boosting branch circuit comprises a second capacitor and a fifth switch, the negative electrode of the second capacitor is grounded through the fifth switch, a third boosting node is arranged between the negative electrode of the second capacitor and the fifth switch, and the second voltage conversion branch circuit is connected with the third boosting node through the second switch; the anode of the second capacitor is connected with a fourth boosting node, and the fourth boosting node is connected with the third voltage conversion branch and is connected between the cathode of the second diode and the third switch;
the third boosting branch circuit comprises a third capacitor and a sixth switch, the negative electrode of the third capacitor is grounded through the sixth switch, a fifth boosting node is arranged between the negative electrode of the third capacitor and the sixth switch, the third voltage conversion branch circuit is connected with the fifth boosting node through the third switch, and the fifth boosting node is positioned between the third switch and the high-voltage signal ground output end; the positive electrode of the third capacitor is connected with a sixth boosting node, the fourth voltage conversion branch circuit is connected with the sixth boosting node through the negative electrode of the third diode, and the sixth boosting node is positioned between the third diode and the output end of the high-voltage power supply;
the fourth switch, the fifth switch, and the sixth switch are a second group of switches.
14. The fingerprint detection coding device according to claim 13, wherein the input signal of the voltage boost circuit further comprises an inverted signal of the dynamic edge coding signal, the dynamic edge coding signal controls the first set of switches, and the inverted signal controls the second set of switches.
15. The fingerprint detection coding device of claim 14, wherein the inversion signal is obtained by passing the dynamic edge coding signal through an inverter.
16. The fingerprint detection coding device according to claim 14, wherein the first set of switches and the second set of switches are both active high, and when the high level of the dynamic edge coding signal arrives, the first set of switches are closed and the second set of switches are open; when the high level of the reverse signal arrives, the first group of switches is opened and the second group of switches is closed.
17. A fingerprint detection system comprising a fingerprint detection coding device according to any one of claims 1 to 16.
18. The fingerprint detection system of claim 17, further comprising a host control module to provide an analog power supply to the boost circuit.
19. The fingerprint detection system of claim 18, further comprising a level shifting module configured to shift a level between the host control module and the fingerprint detection chip such that the level between the host control module and the fingerprint detection chip matches.
20. An electronic device comprising a display screen and a fingerprint detection coding device located below the display screen, the fingerprint detection coding device comprising the fingerprint detection coding device according to any one of claims 1 to 16.
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| PCT/CN2018/112038 WO2020082323A1 (en) | 2018-10-26 | 2018-10-26 | Fingerprint detection coding apparatus, fingerprint detection system and electronic device |
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| WO2022056860A1 (en) * | 2020-09-18 | 2022-03-24 | 深圳市汇顶科技股份有限公司 | Touch chip, coding method and electronic device |
| CN114256864B (en) * | 2021-12-13 | 2023-10-13 | 湖南大学 | Fixed time control method and device for SVCC in high-voltage direct-current transmission system |
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