阅读说明：本技术 一种数字可调的音圈电机驱动电路 (Digit adjustable voice coil motor drive circuit ) 是由 李坤 李军福 卢灿 仇晨光 贾丹丹 孙凯 于 2019-11-04 设计创作，主要内容包括：本发明公开了一种数字可调的音圈电机驱动电路,包括数字隔离电路、DA转换电路、放大电路、反馈补偿控制电路和输出驱动电路；数字隔离电路将数字控制信号隔离后送至DA转换电路,DA转换电路将数字控制信号转换为模拟电压,转换后的模拟电压经过放大电路放大处理后送至反馈补偿控制电路,控制输出驱动电路产生与数字控制信号相对应的音圈电机驱动电压。(The invention discloses a digital adjustable voice coil motor driving circuit, which comprises a digital isolation circuit, a DA conversion circuit, an amplifying circuit, a feedback compensation control circuit and an output driving circuit, wherein the digital isolation circuit is connected with the DA conversion circuit; the digital isolation circuit isolates the digital control signal and then transmits the digital control signal to the DA conversion circuit, the DA conversion circuit converts the digital control signal into analog voltage, the converted analog voltage is amplified by the amplifying circuit and then transmitted to the feedback compensation control circuit, and the output driving circuit is controlled to generate voice coil motor driving voltage corresponding to the digital control signal.)

1. A voice coil motor drive circuit with adjustable number is characterized by comprising a digital isolation circuit, a DA conversion circuit, an amplification circuit, a feedback compensation control circuit and an output drive circuit;

the digital isolation circuit isolates the digital control signal and then transmits the digital control signal to the DA conversion circuit, the DA conversion circuit converts the digital control signal into analog voltage, the converted analog voltage is amplified by the amplifying circuit and then transmitted to the feedback compensation control circuit, and the output driving circuit is controlled to generate voice coil motor driving voltage corresponding to the digital control signal.

2. The digitally tunable voice coil motor driver circuit of claim 1, wherein the amplifier circuit employs a first operational amplifier.

3. The digitally tunable voice coil motor driving circuit as claimed in claim 2, wherein the analog voltage V1 outputted from the DA converter circuit is inputted to the positive phase input terminal of the first operational amplifier, and the negative phase input terminal of the first operational amplifier is grounded via a tenth resistor; the output end of the first operational amplifier is fed back to the negative phase input end of the first operational amplifier through the eleventh resistor.

4. A digitally tunable voice coil motor driver circuit as claimed in claim 3 in which the output voltage of the first operational amplifier is V2 = V1 x (1+ R11/R10),

the magnification A is:

A=V2/V1=1+R11/R10

in the formula, R10 is the resistance value of the tenth resistor, and R11 is the resistance value of the eleventh resistor.

5. The digitally tunable voice coil motor driver circuit of claim 4,

the feedback compensation control circuit adopts a second operational amplifier, a reference source and a resistor;

the first operational amplifier output voltage V2 is connected with the negative phase input end of the second operational amplifier through a seventh resistor, and meanwhile, the reference source output voltage V3 is connected with the positive phase input end of the second operational amplifier through a sixth resistor R6 and a voice coil motor driving voltage VOUT output by the output driving circuit through a third resistor R3; the output end of the second operational amplifier is connected to the negative phase input end of the second operational amplifier through a ninth resistor in a feedback mode.

6. The digitally tunable voice coil motor driver circuit of claim 5, wherein the second operational amplifier outputs a voltage of:

Vf’=R9×(V3/R6+VOUT/R3-V2/R7) （3）

in the formula, R9, R6, R3 and R7 are resistance values of a ninth resistor, a sixth resistor, a third resistor and a seventh resistor, respectively;

if R9= R6= R3= R7, the output voltage of the second operational amplifier is:

Vf’=V3+VOUT-V2 　 （4）

transforming equation (4) to obtain:

VOUT＝Vf’+V2-V3 　 （5）

the output voltage V3 of the reference source is equal to the output voltage of the second operational amplifier;

the driving voltage of the voice coil motor can be adjusted by a digital control D/A conversion circuit, and VOUT is A multiplied by V1.

Technical Field

The invention relates to a voice coil motor driving circuit, and belongs to the technical field of circuits.

Background

The common driving method of the voice coil motor mainly comprises a linear driving method and a PWM (pulse width modulation) driving method. The linear driving mode is directly driven by a linear power amplifier, and has the advantages of simple control, stable output voltage, large power consumption, low efficiency and efficiency of about 30 percent. It is not beneficial to realize the input digital quantity control. The PWM driving mode has the advantages of low power consumption and high efficiency, and has the defect that the thrust generated by the PWM driving mode has a jitter phenomenon. Especially when the duty ratio of the input PWM signal is small, the jitter does not allow the voice coil motor to obtain the desired dynamic performance. Meanwhile, the PWM driving mode has larger harmonic interference.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a digital adjustable voice coil motor driving circuit.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a digital adjustable voice coil motor driving circuit comprises a digital isolation circuit, a DA conversion circuit, an amplification circuit, a feedback compensation control circuit and an output driving circuit;

the digital isolation circuit isolates the digital control signal and then transmits the digital control signal to the DA conversion circuit, the DA conversion circuit converts the digital control signal into analog voltage, the converted analog voltage is amplified by the amplifying circuit and then transmitted to the feedback compensation control circuit, and the output driving circuit is controlled to generate voice coil motor driving voltage corresponding to the digital control signal.

Further, the amplifying circuit employs a first operational amplifier.

Further, the analog voltage V1 output by the DA conversion circuit enters the positive phase input terminal of the first operational amplifier, and the negative phase input terminal of the first operational amplifier is grounded through the tenth resistor; the output end of the first operational amplifier is fed back to the negative phase input end of the first operational amplifier through the eleventh resistor.

Further, the output voltage of the output terminal of the first operational amplifier V2 = V1 × (1+ R11/R10),

the magnification A is:

A=V2/V1=1+R11/R10

in the formula, R10 is the resistance value of the tenth resistor, and R11 is the resistance value of the eleventh resistor.

Further, the feedback compensation control circuit adopts a second operational amplifier, a reference source and a resistor;

the first operational amplifier output voltage V2 is connected with the negative phase input end of the second operational amplifier through a seventh resistor, and meanwhile, the reference source output voltage V3 is connected with the positive phase input end of the second operational amplifier through a sixth resistor R6 and a voice coil motor driving voltage VOUT output by the output driving circuit through a third resistor R3; the output end of the second operational amplifier is connected to the negative phase input end of the second operational amplifier through a ninth resistor in a feedback mode.

Further, the output voltage of the second operational amplifier is:

Vf’=R9×(V3/R6+VOUT/R3-V2/R7) （3）

in the formula, R9, R6, R3 and R7 are resistance values of a ninth resistor, a sixth resistor, a third resistor and a seventh resistor, respectively;

if R9= R6= R3= R7, the output voltage of the second operational amplifier is:

Vf’=V3+VOUT-V2 　 （4）

transforming equation (4) to obtain:

VOUT＝Vf’+V2-V3 　 （5）

the output voltage V3 of the reference source is equal to the output voltage of the second operational amplifier;

the driving voltage of the voice coil motor can be adjusted by a digital control D/A conversion circuit, and VOUT is A multiplied by V1.

The invention achieves the following beneficial effects:

the isolation between the voice coil motor driving circuit and the control circuit is realized; the driving voltage of the voice coil motor can be digitally adjusted and controlled by the control circuit through changing the voltage of the D/A conversion circuit. The device has the advantages of isolation of control and drive, stable and reliable work, easy realization of digital control and the like.

Drawings

FIG. 1 is a schematic diagram of the present embodiment;

FIG. 2 is a digital isolation circuit diagram;

fig. 3 is a circuit diagram of the present embodiment.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The circuit schematic block diagram of the isolated digital adjustable voice coil motor driving circuit of the embodiment is shown in fig. 1. The circuit comprises a digital isolation circuit, a DA conversion circuit, an amplifying circuit, a feedback compensation control circuit, an output drive circuit and the like. The digital isolation circuit isolates the digital control signal and then transmits the digital control signal to the DA conversion circuit, the DA conversion circuit converts the digital control signal into analog voltage, the converted analog voltage is amplified by the amplifying circuit and then transmitted to the feedback compensation control circuit, and the output driving circuit is controlled to generate voice coil motor driving voltage corresponding to the digital control signal.

The schematic diagram of the circuit is shown in fig. 2 and 3. The digital isolation circuit mainly comprises isolation chips N2 and N3. The DA conversion circuit employs a DA chip N1. The amplifying circuit employs an operational amplifier N2A. The feedback compensation control circuit employs an operational amplifier N2B, a reference source, and a resistor. The output driving circuit adopts a power supply chip U1.

Digital control signal: the enable signal IO _ CS, the clock signal IO _ SCLK and the data signal IO _ Din are sent to the 5-pin enable terminal SYNC, the 6-pin clock terminal SCLK and the 7-pin data input terminal Din of the DA chip N1 through the isolation chips N2 and N3. The D/A chip N1 outputs an analog voltage V1 which is output by a 4-pin output end Vout, and the voltage output range is 0-5V. The output analog voltage V1 enters the positive phase input end of the operational amplifier N2A, the output end of the operational amplifier N2A is fed back to the negative phase input end thereof through a resistor R11, and the negative phase input end of the operational amplifier N2A is grounded through a resistor R10; an in-phase proportional amplifying circuit is formed by resistors R10 and R11, and the amplified output voltage V2 is calculated according to the following formula:

V2=V1×(1+R11/R10) （1）

the magnification A is:

A=V2/V1=1+R11/R10 （2）

the output voltage V2 of the operational amplifier N2A enters the negative input terminal of the operational amplifier N2B through the resistor R7, and the output voltage V3 of the reference source VD1 enters the positive input terminal of the operational amplifier N2B through the resistor R6 and the output voltage VOUT (i.e., the driving voltage of the voice coil motor) of the power chip U1 through the resistor R3. The three inputs form an add-subtract operation circuit through an operational amplifier, wherein the feedback resistance is R9. Therefore, the calculation formula of the output voltage of the operational amplifier N2B is:

Vf’=R9×(V3/R6+VOUT/R3-V2/R7) （3）

when R9= R6= R3= R7 is selected, the output voltage of the operational amplifier N2B is:

Vf’=V3+VOUT-V2 　 （4）

and (5) converting the formula (4) to obtain an output voltage calculation formula:

VOUT＝Vf’+V2-V3 　 （5）

during design, the output voltage V3 of the reference source VD1 is selected to be equal to the feedback terminal voltage Vf of the power chip U1 as much as possible, namely V3 is approximately equal to Vf, and Vf is equal to Vf'. Substituting in equation (5) calculates VOUT ≈ V2. Therefore, it can be concluded that the output voltage value of the circuit is determined by the digital control D/A chip, and VOUT is approximately equal to AxV 1.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.