CN115932414A - Three-in-one sensor of in-ear earphone - Google Patents

Abstract

The invention discloses a three-in-one sensor of an in-ear earphone in the technical field of in-ear earphones, which comprises: a substrate; bare chip, bare chip sets up the top of base plate, bare chip includes differential delay chain, microprocessor and power and clock management unit, differential delay chain with microprocessor electric connection, microprocessor with power and clock management unit electric connection, the top edge of base plate is provided with pin frame, still includes the pin, the pin passes through pin frame sets up the top of base plate, this kind of in-ear earphone's trinity sensor through a high stable internal reference discharge circuit, will carry out the processing of making absolute relatively diffusion time, and then quantizes the discharge circuit that outside awaits measuring electric capacity and internal reference resistance and constitute, realizes the multichannel capacitance measurement of high speed, low-power consumption.

Description

A three-in-one sensor for in-ear headphones

technical field

The invention relates to the technical field of in-ear earphones, in particular to a three-in-one sensor for in-ear earphones.

Background technique

The interaction methods of in-ear headphones mainly include sliding control and pressure-sensitive touch.

Sliding control is mainly based on the judgment of the change in capacitance value caused by the translation of the user's finger from plate A to plate B, or the movement in the opposite direction. As shown in Figure 7a, the principle of capacitive sliding control is simple, easy to implement, and functional. The power consumption is extremely low, but it is very susceptible to interference from external environmental factors, especially misoperation caused by rain, fog, sweat, or other human body parts. From the perspective of the circuit, capacitance measurement needs to be performed through an analog-to-digital converter (ADC). Sampling and processing by a microprocessor (Processor), and its main functional modules are shown in Figure 7b.

Pressure-sensitive touch mainly adopts the principle of piezoresistive strain gauges. The front-end sensitive element C is realized by flexible materials or MEMS technology, usually a Wheatstone bridge, and then the sampling and digital processing are completed through the back-end conditioning circuit D, as shown in Figure 8a. The principle of strain gauge pressure sensitive touch is very mature and has been applied in the field of weighing for decades. But its shortcomings are also very obvious: processing accuracy, including dimensional accuracy and uniformity, is very dependent on equipment, resulting in large differences in consistency; installation process, especially glue overflow during installation with welding glue leads to failure of strain gauges; affected by the characteristics of flexible materials , the temperature range is relatively narrow, and the performance drops below zero. Affected by the characteristics of the MEMS process, the product’s drop resistance is poor, and ultrasonic cleaning cannot be used; at least one sensitive front-end and one back-end conditioning chip are required. The PCB size is large; the linearity regression coefficient of the solution is relatively seriously affected by materials, structure, installation, etc., and is generally lower than 97%; the system power consumption of the solution is severely restricted by the design of the analog-to-digital converter, and the typical value is mA (mA) level, piezoresistive strain gauges, or a typical Wheatstone bridge full bridge structure is shown in Figure 8b, and the functional modules of the piezo-sensitive touch system based on the Wheatstone bridge are shown in Figure 8c.

The principle of capacitive wearing detection is the same as that of capacitive sliding control. But only one capacitive plate is needed to sense whether the earphone is in the wearing state.

To sum up, in order to realize the three human-computer interaction functions of capacitive wearing detection, capacitive sliding control and pressure-sensitive touch in the earphone, these functions are very important for the power consumption control and user experience of the earphone. The mainstream solution requires at least the following 3-4 devices (chips): multi-channel capacitive measurement chip: used for capacitive wearing detection, capacitive sliding control; sensitive front end of piezoresistive strain: used to sense the pressure input behavior of the user during operation; Back-end conditioning of piezoresistive strain: used to sample and process pressure input; external or internal (built-in capacitance measurement chip or piezoresistive strain back-end conditioning chip) microprocessor: used for signal processing required by the above three functions The chip set is shown in Figure 9. The three-in-one sensor of the existing in-ear earphones has the problems of slow capacitance measurement speed and high power consumption.

Contents of the invention

The object of the present invention is to provide a three-in-one sensor for in-ear earphones, to solve the problems of relatively slow capacitance measurement speed and high power consumption in the existing three-in-one sensor for in-ear earphones proposed in the above-mentioned background technology .

In order to achieve the above object, the present invention provides the following technical solutions: a three-in-one sensor for in-ear earphones, comprising:

Substrate;

a die, the die is arranged on the top of the substrate, the die includes a differential delay chain, a microprocessor, and a power and clock management unit, the differential delay chain is electrically connected to the microprocessor, the The microprocessor is electrically connected with the power supply and clock management unit.

Preferably, a lead frame is provided at the top edge of the substrate.

Preferably, pins are also included, and the pins are arranged on the top of the substrate through the lead frame.

Preferably, connection keys are uniformly arranged on the top edge of the bare chip, and wires are arranged on the top of the connection keys, and the ends of the wires away from the die are connected to the pins.

Preferably, the bare chip also includes an internal discharge circuit, a storage area and an interface circuit;

The internal discharge circuit is electrically connected to the differential delay chain;

The storage area is electrically connected to the microprocessor;

The interface circuit is electrically connected with the microprocessor.

Preferably, an encapsulation plastic body is also included, the encapsulation plastic body is arranged on the top of the substrate, and the encapsulation plastic body covers the outside of the die and the pins.

Compared with the prior art, the beneficial effect of the present invention is: the three-in-one sensor of the earphone, through a highly stable internal reference discharge circuit, absolutizes the relative diffusion time, and then the external capacitance to be measured The discharge circuit composed of the internal reference resistor is quantified to realize high-speed, low-power multi-channel capacitance measurement.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic side view of the present invention;

Fig. 3 is a block diagram of the absolute quantization processing system of the present invention;

Fig. 4 is the flowchart of relative quantization ion diffusion time of differential delay chain circuit of the present invention;

Fig. 5 is a three-in-one schematic block diagram of wearing, sliding and pressure-sensitive touch according to the present invention;

6 is a schematic diagram of a single chain of a differential delay chain in the present invention;

7 is a schematic diagram of the main functional modules of the capacitive sliding control and capacitance measuring circuit of the present invention;

Fig. 8 is a functional block diagram of piezoresistive strain gauge type pressure-sensitive touch, Wheatstone full-bridge piezoresistive strain gauge and pressure-sensitive touch system of the present invention;

FIG. 9 is a schematic block diagram of a chipset with three functions of capacitive wearing, sliding control and pressure-sensitive touch according to the present invention.

In the figure: 100 substrates, 200 bare chips, 210 connection keys, 220 wires, 300 pins, and 400 packaging plastic bodies.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The invention provides a three-in-one sensor for in-ear earphones, which involves a three-in-one single-chip solution with three functions of capacitive wearing, sliding control, and pressure-sensitive touch. The impact of the ion diffusion velocity in the P-type trench is relatively high-precision measurement (hundreds of picoseconds) through the differential delay chain, and then the stress, strain-relative diffusion time linearization process is completed in the back-end processor, and the In addition, through a highly stable internal reference discharge circuit, the relative diffusion time is absolutized, and then the discharge circuit composed of the external capacitor to be measured and the internal reference resistance is quantified to achieve high-speed, low-power Compared with the current mainstream solutions, the single-chip solution involved in this application has at least the following advantages:

Single chip: PCB size reduced by 60-90%;

Low power consumption: the overall power consumption is reduced from milliamps (mA) to tens of microamps (μA), reducing more than 90%;

High reliability: produced by standard CMOS process, without the coating process required for flexible material piezoresistive strain gauges, with higher reliability and stability;

High performance: stable temperature characteristics and wider temperature range (-40 to 85°C). In addition, the linearity regression coefficient can reach up to 99.91%;

Costs are more controllable;

Please refer to FIG. 1 , including: a substrate 100 , a bare chip 200 , pins 300 and a package plastic body 400 ;

A lead frame is arranged at the top edge of the substrate 100, and a die 200 is arranged on the top of the substrate 100. The die 200 includes a differential delay chain, a microprocessor, and a power and clock management unit, and the differential delay chain is electrically connected to the microprocessor. , the microprocessor is electrically connected to the power supply and the clock management unit, the top edge of the bare chip 200 is evenly provided with connection keys 210, the top of the connection key 210 is provided with a wire 220, and the end of the wire 220 away from the bare chip 200 and the pin 300, the bare chip 200 also includes an internal discharge circuit, a storage area and an interface circuit, the internal discharge circuit is electrically connected to the differential delay chain, the storage area is electrically connected to the microprocessor, and the interface circuit is electrically connected to the microprocessor. The pin 300 is arranged on the top of the substrate 100 through the lead frame, the packaging plastic body 400 is arranged on the top of the substrate 100, and the packaging plastic body 400 covers the outside of the die 200 and the pin 300;

The differential delay chain array in this application is shown in Figure 6, which is used for relative quantification of the ion diffusion speed of the N-type and P-type grooves of the silicon substrate;

The stress input by the user is transmitted to the chip package through the pressure-sensitive touch area of the handle of the earphone. Regardless of whether the substrate or the lead frame is used, the stress will be concentrated on the inner centered die, which will cause the strain of the silicon substrate, as shown in Figure 1. A schematic diagram of packaging with a substrate, and Figure 2 is a schematic diagram of packaging with a metal lead frame;

The strain of the silicon substrate causes the change of ion diffusion speed. The start and stop signals are given by the built-in microprocessor, and the interval between the start and stop signals is controlled based on the frequency division of the internal clock. At the same time, the signal passes through the differential delay chain unit The number is accumulated, and the relative quantification of the stress-ion diffusion time can be carried out by comparing the accumulated number under different stress and strain;

The specific workflow is shown in Figure 4.

Assume that the preset time after clock frequency division is T, and the unit is picoseconds, and the number of cumulative delay chain units not affected by external stress and strain is N, and the unit is one;

The number of cumulative delay chain units under the action of external stress and strain is N', and the unit is one;

By linearizing the relationship function between the external stress F and ΔT, the value of the external stress can be obtained through ΔT, where ΔT is as follows:

Assuming that the external stress F1, F2 is ΔT1, ΔT2 for the measured ion diffusion time difference as follows:

F ₁ →ΔT ₁

F ₂ →ΔT ₂

Through two-point calibration, the functional relationship between the external stress F and ΔT can be obtained as follows:

where k is the slope of the first-order function, dimensionless,

The above process has carried out relative quantification on the ion diffusion time of the N-channel and P-channel of the silicon substrate caused by stress and strain. If the relative quantification time can be processed absolutely, the external capacitance to be measured can be measured. The system The block diagram is shown in Figure 3;

Assuming the internal reference discharge circuit is Rref and Cref, the absolute discharge time constant is:

T _a = R _ref x C _ref

The measured relative time of ion diffusion can be absoluteized as follows:

T=kT _a =kx(R _ref ×C _ref )

The system-on-chip shown in Figure 3 can not only measure the stress and strain transmitted to the package, but also measure the capacitance of the external capacitor to be measured. Therefore, through this core solution - differential delay chain technology with internal discharge The circuit can be used for capacitive wearing detection, capacitive sliding control and pressure-sensitive touch of in-ear earphones. The stress and capacitive fusion sensor system-on-a-chip of the differential delay chain, with a maximum size of 2mmx3mmx0.9mm, meets the functions of earphone wearing, sliding control detection and pressure-sensitive touch, while the power consumption is only 10%-20% of competing solutions.

While the invention has been described above with reference to the embodiments, various modifications may be made thereto and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention can be used in combination with each other in any way, and the description of these combinations is not exhaustive in this specification only to show In consideration of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims (6)

1. The utility model provides a trinity sensor of in-ear earphone which characterized in that: the method comprises the following steps:

a substrate (100);

a die (200), the die (200) disposed on top of the substrate (100), the die (200) including a differential delay chain, a microprocessor, and a power and clock management unit, the differential delay chain electrically connected with the microprocessor, the microprocessor electrically connected with the power and clock management unit.

2. The three-in-one sensor for an in-ear headphone as recited in claim 1, wherein: a leadframe is disposed at a top edge of the substrate (100).

3. The three-in-one sensor for an in-ear headphone as defined in claim 2, wherein: also included are leads (300), the leads (300) being disposed on top of the substrate (100) through the lead frame.

4. The three-in-one sensor for an in-ear headphone as defined in claim 3, wherein: the top edge of the bare chip (200) is uniformly provided with connecting keys (210), the top of the connecting keys (210) is provided with a conducting wire (220), and one end of the conducting wire (220) far away from the bare chip (200) is connected with the pins (300).

5. The three-in-one sensor for an in-ear headphone as recited in claim 4, wherein: the die (200) further includes internal discharge circuitry, a memory region, and interface circuitry;

the internal discharge circuit is electrically connected with the differential delay chain;

the storage area is electrically connected with the microprocessor;

the interface circuit is electrically connected with the microprocessor.

6. The three-in-one sensor for an in-ear headphone as recited in claim 5, wherein: the packaging plastic body (400) is arranged on the top of the substrate (100), and the packaging plastic body (400) covers the bare chip (200) and the outer side of the pin (300).

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