CN108693402B - LRA resonant frequency detection device - Google Patents

LRA resonant frequency detection device Download PDF

Info

Publication number
CN108693402B
CN108693402B CN201810326141.0A CN201810326141A CN108693402B CN 108693402 B CN108693402 B CN 108693402B CN 201810326141 A CN201810326141 A CN 201810326141A CN 108693402 B CN108693402 B CN 108693402B
Authority
CN
China
Prior art keywords
transistor
current
driving
module
drain
Prior art date
Legal status (The legal status 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 status listed.)
Active
Application number
CN201810326141.0A
Other languages
Chinese (zh)
Other versions
CN108693402A (en
Inventor
肖文润
王江
冯根强
张伟
门洪达
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shenzhen Tianmicro Electronic Co ltd
Original Assignee
Shenzhen Tianmicro Electronic Co ltd
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 Shenzhen Tianmicro Electronic Co ltd filed Critical Shenzhen Tianmicro Electronic Co ltd
Priority to CN201810326141.0A priority Critical patent/CN108693402B/en
Publication of CN108693402A publication Critical patent/CN108693402A/en
Application granted granted Critical
Publication of CN108693402B publication Critical patent/CN108693402B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
    • G01R23/02—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Gyroscopes (AREA)
  • Electronic Switches (AREA)

Abstract

The application discloses a detection device of LRA resonant frequency, which comprises a driving module, a current sampling module, a current comparison module and a threshold current generation module; the driving module is used for sending driving voltages with different frequencies to the LRA and sending a driving completion signal to the current sampling module; the current sampling module is used for sampling the driving current of the driving module and generating sampling current after receiving the driving completion signal, and outputting the sampling current to the first input end of the current comparison module; the second input end of the current comparison module is connected with the output end of the threshold current generation module, and the threshold current generation module is used for generating a threshold current in the current comparison module; the output end of the current comparison module is connected with the driving module and used for comparing the sampling current with the threshold current and sending a feedback signal to the driving module, and if the sampling current is smaller than the threshold current, the driving module determines that the current driving frequency of the LRA is the resonant frequency.

Description

LRA resonant frequency detection device
Technical Field
The invention relates to the technical field of tactile feedback, in particular to a device for detecting LRA resonant frequency.
Background
With the development of technology, touch screen electronic devices are becoming the mainstream of applications. A Linear Resonance Actuator (LRA) is widely used in a plurality of new electronic devices as a new generation of haptic feedback technology for implementing haptic feedback and vibration alert.
Typically, the LRA is a vibration motor that generates an oscillating force on a single shaft. The LRA mainly comprises a magnet to which a spring is attached. The magnet serves as a moving mass, surrounded by a coil, and placed in a box-shaped housing. The LRA vibrates in a linear motion. The resonant frequency of the LRA is related to the spring constant of the spring, which changes with loss of the spring, temperature fluctuations, or other environmental factors.
In the conventional technology, the LRA needs a specific driving frequency, and when the driving frequency of the LRA is not equal to the resonant frequency thereof, the LRA needs a larger power consumption to generate vibrations with equal amplitude, i.e. the operating efficiency and performance of the LRA are also reduced.
Disclosure of Invention
In view of this, it is necessary to provide a detection apparatus capable of ensuring an LRA resonant frequency at which the drive frequency of the LRA is equal to the resonant frequency thereof, in order to solve the technical problems of increased power consumption and reduced performance of the LRA caused by a change in the resonant frequency of the LRA.
A detection device for LRA resonant frequency comprises a driving module, a current sampling module, a current comparison module and a threshold current generation module; the driving module is used for sending driving voltages with different frequencies to the LRA and sending a driving completion signal to the current sampling module; the current sampling module is used for sampling the driving current of the driving module and generating sampling current after receiving the driving completion signal, and outputting the sampling current to the first input end of the current comparison module; the second input end of the current comparison module is connected with the output end of the threshold current generation module, and the threshold current generation module is used for generating a threshold current in the current comparison module; the output end of the current comparison module is connected with the driving module and used for comparing the sampling current with the threshold current and sending a feedback signal to the driving module, and if the sampling current is smaller than the threshold current, the driving module determines that the current driving frequency of the LRA is the resonant frequency.
In one embodiment, the driving module comprises a driving unit, a transistor MP1, a transistor MP2, a transistor MN1 and a transistor MN 2. The grid electrode of the transistor MP1 and the grid electrode of the transistor MN1 are both connected with the positive driving end of the control chip; the grid electrode of the transistor MP2 and the grid electrode of the transistor MN2 are both connected with the reverse driving end of the control chip; the common connection point of the drain of the transistor MP1 and the drain of the transistor MN1 is connected with one end of the LRA; the common connection point of the drain of the transistor MP2 and the drain of the transistor MN2 is connected to one end of the LRA far away from the transistor MP 1. The common connection point of the source of the transistor MP1 and the source of the transistor MP2 is connected with the power supply voltage. The common connection point of the source of the transistor MN1 and the source of the transistor MN2 is grounded. The common connection point of the drain of the transistor MP2, the drain of the transistor MN2 and the LRA is connected with the current sampling module.
In one embodiment, the current sampling module is configured to sample a driving current in any one of the transistors MP1, MP2, MN1, MN 2.
In one embodiment, the current sampling module comprises an operational amplifier, a transistor M1, a transistor M2, a transistor M3; the non-inverting input end of the operational amplifier is connected with the common connection point of the drain electrode of the transistor MP2 and the drain electrode of the transistor MN 2; the inverting input end of the operational amplifier is connected with the common connection point of the drain electrode of the transistor M1 and the source electrode of the transistor M2, the grid electrode of the transistor M1 is connected with the positive driving end of the driving unit, and the source electrode of the transistor M1 is grounded; the output end of the operational amplifier is connected with the source electrode of the transistor M3, and the gate electrode of the transistor M3 is connected with the single-time driving completion end of the driving unit; the drain of the transistor M3 is connected with the gate of the transistor M2; the drain of the transistor M2 is connected to the current comparison module.
In one embodiment, the current comparison module comprises a first inverter, a resistor R1, a resistor R2, a transistor M4, a transistor M5, a transistor M6, a transistor M7, a transistor M8, a transistor M9; the drain of the transistor M2 is connected with the common connection point of one end of the resistor R2 and the source of the transistor M8; the common connection point of the gate of the transistor M8, the gate of the transistor M7 and the drain of the transistor M7 is connected with the drain of the transistor M5, the source of the transistor M5 is connected with the drain of the transistor M9, and the source of the transistor M6 is connected with the drain of the transistor M4; one end of the resistor R1 is connected with the source electrode of the transistor M7, and the other end is connected with power voltage; the common connection point of the resistor R2 and the source electrode of the transistor M8 is connected with the current sampling module, and one end of the resistor R2 far away from the source electrode of the transistor M8 is connected with a power supply voltage; the common connection point of the source of the transistor M9 and the source of the transistor M4 is grounded; the common connection point of the drain electrode of the transistor M8 and the drain electrode of the transistor M6 is connected with the input end of the first inverter, and the output end of the first inverter is connected with the feedback end of the driving unit; the common connection point of the gate of the transistor M4 and the gate of the transistor M9 is connected with the first bias voltage output by the threshold current generation module; the common connection point of the gate of the transistor M5 and the gate of the transistor M6 is connected with a second bias voltage.
In one embodiment, the threshold current generation module comprises a resistor R3, a resistor R4, a transistor M10, a transistor M11, a transistor M12, a transistor M13, a transistor M14, a transistor M15, and a transistor M16. The resistor R3 is connected with a power voltage at one end and with the other end connected with the common connection point of the grid electrode of the transistor M13, the drain electrode of the transistor M13, the drain electrode of the transistor M12 and the grid electrode of the transistor M14. The source of the transistor M10, the source of the transistor M16, the source of the transistor M13 and the source of the transistor M14 are all connected to a power supply voltage. One end of the resistor R4 is connected to a common connection point of the drain of the transistor M16, the gate of the transistor M10, the gate of the transistor M16, the drain of the transistor M14 and the drain of the transistor M15, and the other end is grounded. The transistor M11 source, the transistor M12 source, and the transistor M15 source are all grounded. The drain of the transistor M10 is connected to the common node of the gate of the transistor M11, the gate of the transistor M12 and the drain of the transistor M11. The common connection point of the grid electrode of the transistor M15 and the grid electrode of the transistor M12 is connected with the current comparison module and outputs the first bias voltage.
In one embodiment, the resistance R3 is equal to the resistance R4.
In one embodiment, the apparatus further comprises a transistor M17 and a second inverter; the input end of the second inverter is connected with the single-time driving completion end of the driving unit, and the output end of the second inverter is connected with the grid electrode of the transistor M17; the source of the transistor M17 is grounded; the drain of the transistor M17 is connected to the gate of the transistor M2.
In one embodiment, the driving module receives a feedback signal sent by the current comparison module, and if the sampling current is greater than the threshold current, the driving module adjusts the driving frequency sent to the LRA and sends the driving voltage to the LRA at the adjusted driving frequency.
In one embodiment, the preset range of the driving frequency is 80% f0 to 120% f0, where f0 is a resonance frequency set when the LRA leaves the factory.
In the LRA resonant frequency detection device, the driving module drives the LRA to work by sending the driving voltages with different frequencies, after one-time driving is completed, the current in the LRA coil is detected by the current sampling module in a smaller time period, and the sampled current in the LRA coil is compared with the threshold current generated by the threshold current generating module in the current comparing module by the current comparing module, so that whether the driving frequency reaches the resonant frequency is judged. And if the sampling current is smaller than the threshold current, determining the current driving frequency of the LRA as the resonant frequency by the driving module, and driving the LRA to work at the frequency.
Drawings
FIG. 1 is a schematic diagram of an embodiment of an apparatus for detecting LRA resonant frequency;
FIG. 2 is a schematic diagram of a drive module in one embodiment;
FIG. 3 is a schematic circuit diagram of an embodiment of an LRA resonant frequency detection device;
FIG. 4 is a circuit schematic of a threshold current generation module in one embodiment;
fig. 5 is a schematic circuit diagram of an apparatus for detecting the LRA resonant frequency in yet another embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In one embodiment, referring to fig. 1, an apparatus for detecting an LRA resonant frequency according to an embodiment of the present application is provided, for detecting whether a driving frequency is the LRA resonant frequency before driving the LRA each time, the apparatus includes a driving module 140, a current sampling module 130, a current comparing module 120, and a threshold current generating module 110. Wherein the device can detect the resonant frequency of the LRA 150 in a frequency sweeping manner.
Specifically, the driving module 140 is configured to send driving voltages with different frequencies to the LRA 150 and send a driving completion signal to the current sampling module 130. For example, the driving module 140 may sequentially send driving voltages of different driving durations T to the LRA 150 from small to large. The driving module 140 may transmit a driving signal of one frequency to the LRA 150 every driving. It will be appreciated that each drive may correspond to a different drive duration T, there being a corresponding relationship between drive duration T and resonant frequency. For example, the drive duration T may be one-quarter of the LRA 150 resonant period. The driving duration corresponding to the current driving voltage may be equal to the last driving duration, or may not be equal to the last driving duration. The current sampling module 130 is configured to sample the driving current of the driving module 140 and generate a sampling current after receiving the driving completion signal, and output the sampling current to the first input terminal of the current comparing module 120. A second input terminal of the current comparing module 120 is connected to an output terminal of the threshold current generating module 110, and the threshold current generating module 110 is configured to generate a threshold current in the current comparing module 120. The output end of the current comparing module 120 is connected to the driving module 140, and is configured to compare the sampling current with the threshold current, and send a feedback signal to the driving module 140, where if the sampling current is smaller than the threshold current, the driving module 140 determines that the driving frequency corresponding to the driving duration T is the current resonant frequency of the LRA 150.
In one embodiment, the driving module 140 receives the feedback signal sent by the current comparing module 120, and if the sampled current is greater than the threshold current, the driving module 140 adjusts the driving frequency sent to the LRA 150 and sends a corresponding driving voltage to the LRA 150 at the adjusted driving frequency. Specifically, if there is a one-to-one correspondence relationship between the driving frequency and the driving time period T, the driving module 140 may adjust the driving time period T of the driving voltage sent to the LRA 150, and send the corresponding driving voltage to the LRA 150 with the adjusted driving time period T. For example, the driving module 140 may increase the driving time period T, and drive the LRA 150 to operate by sending the driving voltage corresponding to the increased driving time period to the LRA 150, where each driving corresponds to a different driving time period T.
In the above apparatus for detecting LRA resonant frequency, the driving module 140 drives the LRA 150 to operate by sending driving voltages with different driving frequencies, after one driving is completed, the current in the LRA 150 is detected by the current sampling module 130 within a small time period, and the current in the LRA 150 is compared with the threshold current generated by the threshold current generating module 110 in the current comparing module 120 by the current comparing module 120, so as to determine whether the driving frequency reaches the resonant frequency. If the sampling current is less than the threshold current, the driving module 140 determines that the transmitted driving frequency is the current resonant frequency of the LRA 150, and the driving module 140 continues to drive the LRA to operate at the frequency. If the sampling current is greater than the threshold current, the current driving frequency of the LRA 150 is adjusted, and the above steps are repeated until the sampling current is determined to be less than the threshold current, that is, the resonant frequency of the LRA 150 is determined, so that the driving module 140 drives the LRA to work at the resonant frequency.
In one embodiment, referring to fig. 2 and 3, the driving module 140 includes a driving unit 210, a transistor MP1, a transistor MP2, a transistor MN1, and a transistor MN 2.
Wherein, drive unit 210 is provided with input and output, specifically, drive unit 210's input includes: the system clock CLK, the signal reset terminal RSTN, the work enable terminal EN and the feedback terminal DET _ DONE. The output terminal of the driving unit 210 includes: a forward driving terminal OUTP, a reverse driving terminal OUTN, and a single-time driving completion terminal OUT _ DONE.
The gate of the transistor MP1 and the gate of the transistor MN1 are both connected to the positive driving terminal OUTP of the driving unit 210. The gate of the transistor MP2 and the gate of the transistor MN2 are both connected to the reverse driving terminal OUTN of the driving unit 210. The common connection point of the drain of the transistor MP1 and the drain of the transistor MN1 is connected to one end of the LRA 150. The common connection point of the drain of the transistor MP2 and the drain of the transistor MN2 is connected to the end of the LRA 150 remote from the transistor MP 1. The common connection point of the source of the transistor MP1 and the source of the transistor MP2 is connected with the power supply voltage. The common connection point of the source of the transistor MN1 and the source of the transistor MN2 is grounded. The common connection point of the drain of the transistor MP2, the drain of the transistor MN2 and the LRA 150 is connected with the current sampling module 130.
In the present embodiment, the current sampling module 130 is used for sampling the driving current in any one of the transistors in the driving module 140. Namely, the current sampling module 130 is used for sampling the driving current in any one of the transistors MP1, MP2, MN1 and MN 2.
Based on all the above embodiments, the operation of the LRA resonant frequency detection device is as follows:
when the enable terminal EN is enabled, the single-drive-completion terminal OUT _ DONE outputs a low level, the driving unit 210 starts to operate, the forward driving terminal OUTP outputs a high level, and the reverse driving terminal OUTN outputs a low level for a certain period of time to drive the LRA 150. When the driving is completed, the reverse driving terminal OUTN outputs a high level, and the single driving completion terminal OUT _ DONE outputs a high level, which indicates that the single driving is completed. When the driving unit 210 finishes driving, the current comparison module outputs a feedback signal to the feedback terminal DET _ DONE of the driving unit 210 within a small time delay.
When the single-drive completion terminal OUT _ DONE is at a high level, the current sampling module 130 starts sampling the drive current in any one of the transistors in the drive module 140. The current comparison module 120 compares the sampled current from any one of the transistors in the driver module 140 with a threshold current. If the sampling current is less than the threshold current, that is, the feedback signal output by the feedback terminal DET _ DONE is 0, the driving module 140 determines that the transmitted driving frequency corresponds to the current resonant frequency of the LRA 150, and the driving module 140 continues to drive the LRA to operate at the frequency. If the sampling current is greater than the threshold current, that is, the feedback signal output by the feedback terminal DET _ DONE is 1, waiting for a period of time, after the LRA 150 stops working, the driving unit 210 adjusts the current driving frequency, and repeats the above steps until the sampling current is determined to be less than the threshold current, that is, the resonant frequency of the LRA 150 is determined, so that the driving module 140 drives the LRA to work at the resonant frequency.
In one embodiment, the driving frequency f is adjusted in the range of 80% f0 to 120% f0, and f0 is the resonance frequency of the LRA when shipped. Specifically, the driving time period T is set according to practical conditions, the driving time period T corresponds to the driving frequency f, and f is 1/(4T). If the sampling current is greater than the threshold current, that is, the feedback signal output by the feedback terminal DET _ DONE is 1, waiting for a period of time, and after the LRA 150 stops working, the driving unit 210 adjusts the current driving frequency, for example, the driving unit 210 may increase the driving duration T, and repeat the above steps, so that the driving module 140 drives the LRA to work at the resonant frequency.
In one embodiment, the current sampling module 130 includes an operational amplifier a1, a transistor M1, a transistor M2, and a transistor M3. The non-inverting input of the operational amplifier a1 is connected to the LRA 150.
The inverting input of the operational amplifier A1 is connected to the common connection point of the drain of the transistor M1 and the source of the transistor M2, the gate of the transistor M1 is connected to the forward driving terminal OUTP of the driving unit 210, and the source of the transistor M1 is connected to ground.
The output terminal of the operational amplifier a1 is connected to the source of the transistor M3, and the gate of the transistor M3 is connected to the single-drive-completion terminal OUT _ DONE of the driving unit 210. The drain of the transistor M3 is connected to the gate of the transistor M2. The drain of the transistor M2 is connected to the current comparison module 120.
Based on the above embodiment, taking the driving current in the sampling transistor MN2 as an example, as shown in fig. 3, the common connection point between the drain of the non-inverting input terminal transistor MP2 and the drain of the transistor MN2 of the operational amplifier a1 illustrates the operation of the LRA resonant frequency detection apparatus as follows:
when the operation enable terminal EN is active, the single-drive completion terminal OUT _ DONE outputs a low level, the driving unit 210 starts to operate, the positive-direction driving terminal OUTP outputs a high level, the transistor MN2 is turned on, the transistor MN1 is turned off, and the transistor M1 is turned on. The back-driving terminal OUTN outputs a low level for a certain period of time to drive the LRA 150. When the driving is completed, the reverse driving terminal OUTN outputs a high level, and the single driving completion terminal OUT _ DONE outputs a high level, which indicates that the single driving is completed.
When the single-driving completion terminal OUT _ DONE is low, i.e., the driving unit 210 drives the LRA 150, the feedback signal of the feedback terminal DET _ DONE of the driving unit 210 is inactive. When the single-drive-completion terminal OUT _ DONE is at a high level, the transistors M2 and M3 are both turned on, and the current sampling module 130 starts to detect the drive current in the transistor MN2 of the LRA 150. Since the feedback loop formed by the operational amplifier a1 and the transistor M2 makes Vds of the transistor MN2 and the transistor M1 equal, Vgs of the transistor MN2 and the transistor M1 equal, and sizes of the transistor MN2 and the transistor M1 match, a current flowing through the transistor MN2 can be proportionally sampled to the transistor M1, that is, a current flowing through the transistor M1 is a sampling current.
When the single-drive complete terminal OUT _ DONE is high, the current comparing module 120 compares the sampled current flowing through the transistor M1 with the threshold current. If the sampling current flowing through the transistor M1 is less than the threshold current, that is, the feedback signal output by the feedback terminal DET _ DONE is 0, the driving module 140 determines that the transmitted driving frequency corresponds to the current resonant frequency of the LRA 150, and the driving module 140 drives the LRA to operate at the frequency. If the sampling current flowing through the transistor M1 is greater than the threshold current, that is, the feedback signal output by the feedback terminal DET _ DONE is 1, wait for a period of time, after the LRA 150 stops operating, the driving unit 210 adjusts the current driving frequency, and repeats the above steps until the sampling current is determined to be less than the threshold current, that is, the resonant frequency of the LRA 150 is determined, so that the driving module 140 drives the LRA to operate at the resonant frequency.
In one embodiment, the current comparison module 120 includes a first inverter a2, a resistor R1, a resistor R2, a transistor M4, a transistor M5, a transistor M6, a transistor M7, a transistor M8, a transistor M9; the drain of the transistor M2 is connected to the common connection point of one end of the resistor R2 and the source of the transistor M8. The connection relationship is as follows:
the common connection point of the gate of the transistor M8, the gate of the transistor M7 and the drain of the transistor M7 is connected to the drain of the transistor M5, the source of the transistor M5 is connected to the drain of the transistor M9, and the source of the transistor M6 is connected to the drain of the transistor M4.
One end of the resistor R1 is connected to the source of the transistor M7, and the other end is connected to the power voltage.
The common connection point of the resistor R2 and the source of the transistor M8 is connected with the current sampling module 130, namely the common connection point of the resistor R2 and the source of the transistor M8 is connected with the drain of the transistor M2. The resistor R2 is connected to the power supply voltage at the end far away from the source of the transistor M8.
The common connection point of the source of the transistor M9 and the source of the transistor M4 is grounded.
The common connection point of the drain of the transistor M8 and the drain of the transistor M6 is connected to the input terminal of the first inverter a2, and the output terminal of the first inverter a2 is connected to the feedback terminal DET _ DONE of the driving unit.
The common connection point of the gate of the transistor M4 and the gate of the transistor M9 is connected to the first bias voltage output by the threshold current generating module 110.
The common connection point of the gate of the transistor M5 and the gate of the transistor M6 is connected to the second bias voltage VREF 2. The second bias voltage VREF2 is applied to the common connection point of the gate of the transistor M5 and the gate of the transistor M6, so that the gain can be increased, and the judgment of the sampling current and the threshold current by the current comparison module 120 is more sensitive and accurate.
Based on the above embodiment, taking the driving current in the sampling transistor MN2 as an example, as shown in fig. 3, the common connection point between the drain of the non-inverting input terminal transistor MP2 and the drain of the transistor MN2 of the operational amplifier a1 illustrates the operation of the LRA resonant frequency detection apparatus as follows:
when the single-driving completion terminal OUT _ DONE is low, i.e., the driving unit 210 drives the LRA 150, the feedback signal of the feedback terminal DET _ DONE of the driving unit 210 is inactive. When the single-drive-completion terminal OUT _ DONE is at a high level, the transistors M2 and M3 are both turned on, and the current sampling module 130 starts to detect the driving current in the transistor MN2 of the LRA 150. Since the feedback loop formed by the operational amplifier a1 and the transistor M2 makes Vds of the transistor MN2 and the transistor M1 equal, Vgs of the transistor MN2 and the transistor M1 equal, and sizes of the transistor MN2 and the transistor M1 match, a current flowing through the transistor MN2 can be proportionally sampled to the transistor M1, that is, a current flowing through the transistor M1 is a sampling current.
The transistor M4, the transistor M5, the transistor M6, and the transistor M9 form a cascode current mirror, and the first bias voltage output by the threshold current module 110 acts on the transistor M9 and the transistor M4 to generate the same current I0. A second bias voltage is applied to the common junction of the gate of transistor M5 and the gate of transistor M6. Transistor M7 and transistor M8 are matched, and transistor M7 and transistor M8 form a current mirror. In the critical state of the circuit, the currents flowing through the transistors M4 and M8 are equal, and the level of the input terminal of the first inverter a2 is very variable. Since the transistor M7 and the transistor M8 are matched, the current flowing through the transistor M7 and the transistor M8 are also equal in the critical state. At the common connection point of the drain of the transistor M2 connected to the resistor R2 and the source of the transistor M8, the threshold current Ith is (R1/R2-1) × I0 as known from kirchhoff's first law.
When the current flowing through the transistor M1 is greater than the threshold current Ith, the input terminal of the first inverter a2 is at a low level, and the feedback signal at the feedback terminal DET _ DONE of the driving unit 210 is 1. Waiting for a period of time, and after the LRA 150 stops working, the driving unit 210 adjusts the current driving frequency, and repeats the above steps; when the current flowing through the transistor M1 is less than the threshold current Ith, the input terminal of the first inverter a2 is at a high level, and the feedback signal at the feedback terminal DET _ DONE of the driving unit 210 is 0. Thus, the driving module 140 determines that the frequency corresponding to the period 4T is the current resonant frequency of the LRA 150, and the driving module 140 drives the LRA to operate at the frequency.
In one embodiment, referring to fig. 4, the threshold current generating module 110 includes a resistor R3, a resistor R4, a transistor M10, a transistor M11, a transistor M12, a transistor M13, a transistor M14, a transistor M15, and a transistor M16.
One end of the resistor R3 is connected with the power supply voltage, and the other end is connected with the common connection point of the grid electrode of the transistor M13, the drain electrode of the transistor M13, the drain electrode of the transistor M12 and the grid electrode of the transistor M14.
The source of the transistor M10, the source of the transistor M16, the source of the transistor M13 and the source of the transistor M14 are all connected to the power supply voltage.
One end of the resistor R4 is connected to the common connection point of the drain of the transistor M16, the gate of the transistor M10, the gate of the transistor M16, the drain of the transistor M14 and the drain of the transistor M15, and the other end is grounded.
The source of the transistor M11, the source of the transistor M12 and the source of the transistor M15 are all grounded.
The drain of the transistor M10 is connected to the common node of the gate of the transistor M11, the gate of the transistor M12 and the drain of the transistor M11.
The common connection point of the grid of the transistor M15 and the grid of the transistor M12 is connected with the current comparison module and outputs a first bias voltage.
Specifically, referring to fig. 4, the resistance values of the resistor R3 and the resistor R4 are equal and denoted as R. The transistor M16 and the transistor M10 constitute a current mirror, the transistor M11 and the transistor M12 constitute a current mirror, and the transistor M13 and the transistor M14 constitute a current mirror. The currents flowing through the transistor M16, the transistor M10, the transistor M11, the transistor M12 and the transistor M15 are equal and are denoted as I1. The current through transistor M13 and transistor M14 are also equal, denoted as I2. The voltage at the common connection point of the gate of the transistor M13, the drain of the transistor M13, the drain of the transistor M12 and the gate of the transistor M14 is denoted as V2, and the voltage at the common connection point of one end of the resistor R4 and the drains of the transistor M16, the transistor M10, the transistor M16, the drain of the transistor M14 and the transistor M15 is denoted as V1, then:
Figure BDA0001626624600000111
Figure BDA0001626624600000112
since V1 is approximately equal to V2, it can be known that the current I0 output by the threshold current module 110 is VDD/R. That is, the current I0 generated by the threshold current generating module 110 on the transistor M9 increases linearly with the increase of VDD, so that the increase of the driving current due to the increase of VDD can be compensated appropriately.
In one embodiment, referring to fig. 5, the device further comprises a transistor M17 and a second inverter A3. The input terminal of the second inverter A3 is connected to the single-drive-completion terminal OUT _ NONE of the driving unit 210, and the output terminal of the second inverter A3 is connected to the gate of the transistor M17. The source of transistor M17 is connected to ground. The drain of the transistor M17 is connected to the gate of the transistor M2. Passes through the transistor M17 and the second inverter A3, and connects the input terminal of the second inverter A3 with the one-time-drive-completion terminal OUT _ NONE of the driving unit 210. When the driving unit 210 drives the LRA 150, the single-drive-completion terminal OUT _ NONE is at a low level, the gate of the transistor M17 is at a high level after passing through the second inverter a3, and the transistor M17 is turned on, so that the current output by the current sampling module 130 is limited to zero, and power consumption is reduced.
Based on the above embodiment, when the operation enable terminal EN is active, and the single-drive-completion terminal OUT _ DONE outputs a low level, that is, the driving unit 210 drives the LRA 150, the feedback signal of the feedback terminal DET _ DONE of the driving unit 210 is inactive, and the transistors M2 and M3 are both turned off. After passing through the second inverter a3, the gate of M17 is at a high level, M17 is turned on, and the common node between the drain of the transistor M3 and the gate of the transistor M2 is grounded. The current output by the current sampling module 130 is limited to zero. The back-driving terminal OUTN outputs a low level for a certain period of time to drive the LRA 150. When the driving is completed, the reverse driving terminal OUTN outputs a high level, and the single driving completion terminal OUT _ DONE outputs a high level, which indicates that the single driving is completed.
When the single-drive-completion terminal OUT _ DONE is at a high level, the transistors M2 and M3 are both turned on, the gate of M17 is at a low level, M17 is turned off, and the current sampling module 130 starts to detect the drive current in the transistor MN2 of the LRA 150. Since the feedback loop formed by the operational amplifier a1 and the transistor M2 makes Vds of the transistor MN2 and the transistor M1 equal, Vgs of the transistor MN2 and the transistor M1 equal, and sizes of the transistor MN2 and the transistor M1 match, a current flowing through the transistor MN2 can be proportionally sampled to the transistor M1, that is, a current flowing through the transistor M1 is a sampling current.
The operation of the current comparing module 120 is the same as that described above, and will not be described herein.
In the present application, the transistors MP1, MP2, M7, and M8 are P-channel MOS transistors, and the transistors MN1, MN2, M1, M2, M3, M4, M5, M6, and M9 are N-channel MOS transistors. The application discloses a circuit for detecting current flowing through a transistor MN1 and a transistor MN 2. Since the circuit for detecting the current flowing through the transistors MP1 and MP2 has symmetry with the detection circuit disclosed in the present application, the circuit for detecting the current flowing through the transistors MP1 and MP2 is well known to those skilled in the art and will not be described herein. It is understood that the present application is not limited to sampling the current in any one of the transistors, and that the present application is within the scope of the present application regardless of which one of the transistors is sampled.
It should be noted that the terms "first", "second", etc. used herein may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first inverter may be referred to as a second inverter, and similarly, a second inverter may be referred to as a first inverter, without departing from the scope of the present application. The first inverter and the second inverter are both inverters, but they are not the same inverter.
The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. The device for detecting the LRA resonant frequency is characterized by comprising a driving module, a current sampling module, a current comparison module and a threshold current generation module;
the driving module is used for sequentially sending driving voltages with different driving frequencies to the LRA and sending a driving completion signal to the current sampling module;
the current sampling module is used for sampling the driving current of the driving module and generating sampling current after receiving the driving completion signal, and outputting the sampling current to the first input end of the current comparison module;
the second input end of the current comparison module is connected with the output end of the threshold current generation module, and the threshold current generation module is used for generating a threshold current in the current comparison module;
the output end of the current comparison module is connected with the driving module and used for comparing the sampling current with the threshold current and sending a feedback signal to the driving module, if the sampling current is smaller than the threshold current, the driving module determines that the current driving frequency of the LRA is the resonant frequency and continues to drive the LRA with the resonant frequency.
2. The apparatus of claim 1, wherein the driving module comprises a driving unit, a transistor MP1, a transistor MP2, a transistor MN1, and a transistor MN 2;
the grid electrode of the transistor MP1 and the grid electrode of the transistor MN1 are both connected with the positive driving end of the control chip; the grid electrode of the transistor MP2 and the grid electrode of the transistor MN2 are both connected with the reverse driving end of the control chip; the common connection point of the drain of the transistor MP1 and the drain of the transistor MN1 is connected with one end of the LRA; the common connection point of the drain of the transistor MP2 and the drain of the transistor MN2 is connected with one end of the LRA far away from the transistor MP 1;
the common connection point of the source of the transistor MP1 and the source of the transistor MP2 is connected with the power supply voltage;
the common connection point of the source of the transistor MN1 and the source of the transistor MN2 is grounded;
the common connection point of the drain of the transistor MP2, the drain of the transistor MN2 and the LRA is connected with the current sampling module.
3. The apparatus of claim 2, wherein the current sampling module is configured to sample the driving current of any one of the transistors MP1, MP2, MN1, MN 2.
4. The apparatus of claim 3, wherein the current sampling module comprises an operational amplifier, a transistor M1, a transistor M2, a transistor M3; the non-inverting input end of the operational amplifier is connected with the common connection point of the drain electrode of the transistor MP2 and the drain electrode of the transistor MN 2;
the inverting input end of the operational amplifier is connected with the common connection point of the drain electrode of the transistor M1 and the source electrode of the transistor M2, the grid electrode of the transistor M1 is connected with the positive driving end of the driving unit, and the source electrode of the transistor M1 is grounded;
the output end of the operational amplifier is connected with the source electrode of the transistor M3, and the gate electrode of the transistor M3 is connected with the single-time driving completion end of the driving unit; the drain of the transistor M3 is connected with the gate of the transistor M2; the drain of the transistor M2 is connected to the current comparison module.
5. The apparatus of claim 4, wherein the current comparison module comprises a first inverter, a resistor R1, a resistor R2, a transistor M4, a transistor M5, a transistor M6, a transistor M7, a transistor M8, a transistor M9; the drain of the transistor M2 is connected with the common connection point of one end of the resistor R2 and the source of the transistor M8;
the common connection point of the gate of the transistor M8, the gate of the transistor M7 and the drain of the transistor M7 is connected with the drain of the transistor M5, the source of the transistor M5 is connected with the drain of the transistor M9, and the source of the transistor M6 is connected with the drain of the transistor M4;
one end of the resistor R1 is connected with the source electrode of the transistor M7, and the other end is connected with power voltage;
the common connection point of the resistor R2 and the source electrode of the transistor M8 is connected with the current sampling module, and one end of the resistor R2 far away from the source electrode of the transistor M8 is connected with a power supply voltage;
the common connection point of the source of the transistor M9 and the source of the transistor M4 is grounded;
the common connection point of the drain electrode of the transistor M8 and the drain electrode of the transistor M6 is connected with the input end of the first inverter, and the output end of the first inverter is connected with the feedback end of the driving unit;
the common connection point of the gate of the transistor M4 and the gate of the transistor M9 is connected with the first bias voltage output by the threshold current generation module;
the common connection point of the gate of the transistor M5 and the gate of the transistor M6 is connected with a second bias voltage.
6. The apparatus of claim 5, wherein the threshold current generation module comprises a resistor R3, a resistor R4, a transistor M10, a transistor M11, a transistor M12, a transistor M13, a transistor M14, a transistor M15, a transistor M16;
the resistor R3 is connected with a power voltage at one end and is connected with the common connection point of the grid electrode of the transistor M13, the drain electrode of the transistor M13, the drain electrode of the transistor M12 and the grid electrode of the transistor M14 at the other end;
the source of the transistor M10, the source of the transistor M16, the source of the transistor M13 and the source of the transistor M14 are all connected with a power voltage;
one end of the resistor R4 is connected with a common connection point of the drain of the transistor M16, the gate of the transistor M10, the gate of the transistor M16, the drain of the transistor M14 and the drain of the transistor M15, and the other end is grounded;
the source of the transistor M11, the source of the transistor M12 and the source of the transistor M15 are all grounded;
the drain of the transistor M10 is connected to the common connection point of the gate of the transistor M11, the gate of the transistor M12 and the drain of the transistor M11;
the common connection point of the grid electrode of the transistor M15 and the grid electrode of the transistor M12 is connected with the current comparison module and outputs the first bias voltage.
7. The apparatus of claim 6, wherein the resistor R3 is equal to the resistor R4.
8. The apparatus of any of claims 4 to 7, further comprising a transistor M17 and a second inverter;
the input end of the second inverter is connected with the single-time driving completion end of the driving unit, and the output end of the second inverter is connected with the grid electrode of the transistor M17; the source of the transistor M17 is grounded; the drain of the transistor M17 is connected to the gate of the transistor M2.
9. The apparatus of claim 1, wherein the driving module receives a feedback signal sent by the current comparing module, and if the sampled current is greater than the threshold current, the driving module adjusts a driving frequency sent to the LRA and sends a driving voltage to the LRA at the adjusted driving frequency.
10. The apparatus of claim 1, wherein the preset range of the driving frequency is 80%. f0 to 120%. f0, wherein f0 is a resonance frequency set when the LRA leaves the factory.
CN201810326141.0A 2018-04-12 2018-04-12 LRA resonant frequency detection device Active CN108693402B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810326141.0A CN108693402B (en) 2018-04-12 2018-04-12 LRA resonant frequency detection device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810326141.0A CN108693402B (en) 2018-04-12 2018-04-12 LRA resonant frequency detection device

Publications (2)

Publication Number Publication Date
CN108693402A CN108693402A (en) 2018-10-23
CN108693402B true CN108693402B (en) 2020-12-01

Family

ID=63844921

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810326141.0A Active CN108693402B (en) 2018-04-12 2018-04-12 LRA resonant frequency detection device

Country Status (1)

Country Link
CN (1) CN108693402B (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111552380B (en) * 2020-04-20 2023-05-26 瑞声科技(新加坡)有限公司 Haptic vibration self-adjustment method, apparatus, device and medium
CN112798954B (en) * 2020-12-29 2022-06-21 歌尔股份有限公司 Detection method and device for vibration motor
CN112946362B (en) * 2021-03-31 2022-06-21 歌尔股份有限公司 Resonance frequency detection method and device of vibration motor, terminal equipment and storage medium
CN113311226B (en) * 2021-04-30 2022-06-21 歌尔股份有限公司 Resonance frequency detection method and device of vibration motor, terminal equipment and storage medium
CN114705910A (en) * 2022-01-12 2022-07-05 歌尔股份有限公司 Method and device for detecting motor resonant frequency, electronic equipment and storage medium

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203365544U (en) * 2013-05-30 2013-12-25 快捷半导体(苏州)有限公司 Detection circuit for resonant frequency and integrated circuit
CN103576858A (en) * 2013-09-26 2014-02-12 蔡从中 Drive device and drive method for tracking and detecting resonance of LRA (linear resonant actuator)
CN104215832A (en) * 2013-05-30 2014-12-17 快捷半导体(苏州)有限公司 Integrated circuit and resonant frequency detection method and circuit
CN106230340A (en) * 2016-07-21 2016-12-14 瑞声科技(新加坡)有限公司 Linear electric machine oscillator vibration realtime monitoring system and monitoring method

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI369850B (en) * 2008-03-31 2012-08-01 Leadtrend Tech Corp Motor driving circuit and method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203365544U (en) * 2013-05-30 2013-12-25 快捷半导体(苏州)有限公司 Detection circuit for resonant frequency and integrated circuit
CN104215832A (en) * 2013-05-30 2014-12-17 快捷半导体(苏州)有限公司 Integrated circuit and resonant frequency detection method and circuit
CN103576858A (en) * 2013-09-26 2014-02-12 蔡从中 Drive device and drive method for tracking and detecting resonance of LRA (linear resonant actuator)
CN106230340A (en) * 2016-07-21 2016-12-14 瑞声科技(新加坡)有限公司 Linear electric machine oscillator vibration realtime monitoring system and monitoring method

Also Published As

Publication number Publication date
CN108693402A (en) 2018-10-23

Similar Documents

Publication Publication Date Title
CN108693402B (en) LRA resonant frequency detection device
JP4786608B2 (en) Magnetic field detector
WO2005081385A1 (en) Current direction determining circuit, and switching regulator having the same
US7288978B2 (en) Delay circuit and ring oscillator using the same
CN108536206B (en) Voltage regulator and voltage regulating method
US8400185B2 (en) Driving circuit with zero current shutdown and a driving method thereof
EP1630952A2 (en) Signal determining apparatus including amplifier circuit with variable response speed
JP2018088249A (en) Power source control circuit and environment power generator
JP5999590B2 (en) Frequency adjustment circuit
KR100815183B1 (en) Internal voltage generator
KR100909636B1 (en) Dual power up signal gernerator
KR20120138681A (en) Driving circuit of single phase brushless motor
TWI497257B (en) Frequency modulating circuit of cpu
US9454174B2 (en) Power supply voltage monitoring circuit, and electronic circuit including the power supply voltage monitoring circuit
JP2009296123A (en) Buffer circuit, and signal transmitter using the same
KR20150019000A (en) Reference current generating circuit and method for driving the same
CN217404784U (en) Over-temperature protection circuit based on CMOS chip
US20060181336A1 (en) Bandgap reference voltage generator without start-up failure
US20080260185A1 (en) Method And Apparatus For Automatically Detecting Audio Signal And Sending Control Signal
CN117559914A (en) Low-power consumption oscillating circuit with temperature compensation and electronic equipment
US8040019B2 (en) Driver and driving method
JP7186134B2 (en) Semiconductor device and semiconductor system with the same
JP2009164875A (en) Duty ratio adjusting circuit
JP2011188361A (en) Power-on reset circuit
KR100814919B1 (en) Oscillation stabilization detecting circuit

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant