CN113437910A

CN113437910A - Motor controller

Info

Publication number: CN113437910A
Application number: CN202010207222.6A
Authority: CN
Inventors: 陈为昱; 蔡庆隆
Original assignee: Global Mixed Mode Technology Inc
Current assignee: Global Mixed Mode Technology Inc
Priority date: 2020-03-23
Filing date: 2020-03-23
Publication date: 2021-09-24

Abstract

A motor controller is used for driving a motor. The motor has a motor coil and a maximum rated current value. The motor controller has a driving circuit, a control unit, a digital-to-analog converter, an operational amplifier, a switching circuit, and a resistor. When the stabilization time required by the motor to a target position needs to be reduced or a vibration is detected in a camera module to start an image stabilization mechanism, a driving current larger than the maximum rated current value can be supplied to the motor coil instantaneously.

Description

Motor controller

Technical Field

The present invention relates to a motor controller, and more particularly, to a motor controller capable of instantaneously supplying a driving Current greater than a Maximum Rated Current (Maximum Rated Current) to a motor coil.

Background

Generally, a motor in a Camera Module (Camera Module) has a maximum rated current value, so as to prevent the motor coil from being damaged due to the current exceeding the maximum rated current value flowing for a long time. There is currently no technical means to achieve this characteristic function when some applications require the ability to instantaneously supply a drive current to the motor coils that is greater than the maximum rated current.

Disclosure of Invention

In view of the foregoing, it is an object of the present invention to provide a motor controller capable of instantaneously supplying a driving current larger than a maximum rated current value to a motor coil.

According to the present invention, a motor controller is provided for driving a motor. The motor has a motor coil and a maximum rated current value. The motor controller has a driving circuit, a control unit, a digital-to-analog converter, an operational amplifier, a switching circuit, and a resistor. When the stabilization time required by the motor to a target position needs to be reduced or a vibration is detected in a camera module to start an image stabilization mechanism, a driving current larger than the maximum rated current value can be supplied to the motor coil instantaneously.

Drawings

Fig. 1 is a schematic diagram of a motor controller according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of a digital-to-analog converter according to an embodiment of the invention.

Description of reference numerals: 10-motor controller; 100-a drive circuit; 110 to a control unit; 120-digital to analog converter; 121,130-operational amplifier; 140-a switching circuit; s1, S2, S10-S19-switch; r1, R11, R12-resistor; 101,102,103, 104-transistors; 122,123,150 and 159-transistors; v1-voltage; vref-reference voltage; IL-drive current; iref — reference current; l-motor coil; multi-control signals; DATA — digital input signal; vd to a voltage source; GND to ground potential.

Detailed Description

The objects, features, and advantages of the present invention will become more apparent from the following description. Preferred embodiments according to the present invention will now be described in detail with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of a motor controller 10 of the present invention. The Motor controller 10 is used to drive a Motor, wherein the Motor may be a Voice-Coil Motor (Voice-Coil Motor). The motor has a motor coil L and a maximum rated current value (Imax). The motor controller 10 has a driving circuit 100, a control unit 110, a digital-to-analog converter 120, an operational amplifier 130, a switching circuit 140, and a resistor R1.

The driving circuit 100 has a transistor 101, a transistor 102, a transistor 103, and a transistor 104 for supplying a driving current IL to the motor coil L. The

transistors

101 and 103 are coupled to a voltage source Vd and the motor coil L, and the

transistors

102 and 104 are coupled to the motor coil L and the resistor R1. The transistors 101,102,103, and 104 can be a PMOS or an NMOS. In fig. 1, the

transistors

101 and 103 are two pmos transistors, and the

transistors

102 and 104 are two nmos transistors.

The control unit 110 is coupled to the

transistors

101 and 103 for controlling the current direction of the driving current IL. The switch circuit 140 has a switch S1 and a switch S2 coupled to the transistor 102 and the transistor 104, respectively, for controlling the conduction of the transistor 102 and the transistor 104. Operational amplifier 130 is coupled to digital-to-analog converter 120, switching circuit 140, and resistor R1. The resistor R1 is coupled to the transistor 102, the transistor 104, and a ground potential GND.

The DAC 120 receives a control signal Multi and a digital input signal DATA to generate a voltage V1 to the operational amplifier 130, such that the driving current IL is proportional to the voltage V1 to control the position of the motor. The control signal Multi is used to determine whether to instantaneously supply a driving current IL larger than the maximum rated current value (Imax) to the motor coil L. In the present invention, the driving current IL may be N times the maximum rated current value, where N > 1. In practical application, 1< N ≦ 2 is the best range of N value.

Fig. 2 is a schematic diagram of the digital-to-analog converter 120 according to the present invention. The digital-to-analog converter 120 of the present invention is a 10-bit current-mode digital-to-analog converter, and the digital input signal DATA is a 10-bit digital input signal, but the present invention is not limited thereto. The DAC 120 has an operational amplifier 121, a transistor 122, a transistor 123, a resistor R11, a

transistor

150 and 159, switches S10-S19, and a resistor R12. The size of the transistor 151 is 2 times that of the transistor 150, and the size of the transistor 152 is 4 times that of the transistor 150, and so on, and thus the description is omitted.

As shown in fig. 2, the operational amplifier 121 is coupled to the transistor 123 and the resistor R11 for generating a reference current Iref according to a reference voltage Vref received. Transistor 122 is coupled to voltage source Vd, transistor 123, and

transistor

150 and 159. The switches S10-S19 are coupled to the transistors 150-159, respectively, wherein the switches S10-S19 are controlled by the 10-bit digital input signal DATA. The resistor R12 is coupled to the switches S10-S19 and the ground potential GND for generating the voltage V1. When the 10-bit digital input signal DATA is 1111111111 and the control signal Multi is at a High level, the driving current IL flowing through the motor coil L is made larger than the maximum rated current value Imax.

Please refer to fig. 1 and fig. 2. When the control signal Multi is at a Low voltage level, the dac 120 is in an original setting state, and cannot supply a driving current IL larger than the maximum rated current Imax to the motor coil L. When the control signal Multi is at the High potential High, the current flowing through the resistor R1 can be N times of an original set value, so that the driving current IL can also be N times of the original set value. In practice, 1< N.ltoreq.2 is the best range for the value of N, for example N may be 1.5 or 2. The specific implementation modes comprise the following four methods:

first, the reference voltage Vref is increased by N times. Second, the current flowing through the transistor 122 is increased by N times. Thirdly, the resistance value of the resistor R12 is increased by N times. Fourthly, the resistance value of the resistor R1 is reduced to 1/N times.

In some applications, for example, when it is required to reduce a Settling Time (Settling Time) required by the motor M to a target position, or when an Image Stabilization (Image Stabilization) mechanism is started by detecting a vibration in a camera module, the control signal Multi may be set to a High level, so that the driving current IL is greater than the maximum rated current value (Imax). Then, the control signal Multi is changed to the Low level, so as to restore to the original setting state. The present invention is described in the context of two applications, but the present invention is not limited thereto.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.

Claims

1. A motor controller for driving a motor having a motor winding and a maximum rated current value, the motor controller comprising:

a driving circuit for supplying a driving current to the motor coil;

a control unit coupled to the driving circuit for controlling the current direction of the driving current;

a switching circuit coupled to the driving circuit; and

a control signal for determining whether to supply the driving current larger than the maximum rated current value to the motor coil, wherein the driving current is N times of the maximum rated current value and N > 1.

2. The motor controller of claim 1, wherein N ≦ 2.

3. The motor controller of claim 1, wherein N is 1.5 or 2.

4. The motor controller of claim 1, wherein the driving circuit comprises:

a first transistor coupled to a voltage source and the motor coil;

a second transistor coupled to the motor coil;

a third transistor coupled to the voltage source and the motor coil; and

a fourth transistor coupled to the motor coil.

5. The motor controller of claim 4, wherein the switching circuit comprises:

a first switch for controlling the conduction of the second transistor; and

a second switch for controlling the conduction of the fourth transistor.

6. The motor controller of claim 5, further comprising a first resistor, wherein the first resistor is coupled to the second transistor and the fourth transistor.

7. The motor controller of claim 1, wherein the motor is a voice coil motor.

8. The motor controller of claim 1, further comprising a digital-to-analog converter, wherein the digital-to-analog converter receives the control signal and a digital input signal to control the position of the motor.

9. The motor controller of claim 8 further comprising a first operational amplifier, wherein the digital-to-analog converter generates a voltage to the first operational amplifier such that the driving current is proportional to the voltage.

10. The motor controller of claim 9 wherein the first operational amplifier is coupled to the switching circuit and the driving circuit.

11. The motor controller as claimed in claim 4, wherein the first transistor and the third transistor are each a P-type metal oxide semiconductor transistor, and the second transistor and the fourth transistor are each an N-type metal oxide semiconductor transistor.

12. The motor controller of claim 8 wherein the digital-to-analog converter is a current mode digital-to-analog converter.

13. The motor controller of claim 8 wherein the digital input signal is a 10-bit digital input signal.

14. The motor controller of claim 8, wherein the digital-to-analog converter comprises:

a fifth transistor;

a second resistor coupled to the fifth transistor;

a second operational amplifier coupled to the second resistor, wherein the second operational amplifier receives a reference voltage for generating a reference current;

a sixth transistor;

a seventh transistor coupled to the sixth transistor;

an eighth transistor coupled to the seventh transistor, wherein the eighth transistor is 2 times the seventh transistor;

a third switch coupled to the seventh transistor;

a fourth switch coupled to the eighth transistor; and

a third resistor coupled to the third switch and the fourth switch.

15. The motor controller of claim 6, wherein the resistance of the first resistor is reduced by a factor of 1/N according to the control signal.

16. The motor controller of claim 14, wherein the reference voltage is increased by a factor of N according to the control signal.

17. The motor controller of claim 14, wherein the current flowing through the sixth transistor increases by a factor of N according to the control signal.

18. The motor controller of claim 14, wherein the resistance of the third resistor increases by a factor of N according to the control signal.

19. The motor controller of claim 1 wherein the motor coil is momentarily supplied with a drive current greater than the maximum rated current value when it is desired to reduce a settling time of the motor to a target position.

20. The motor controller of claim 1, wherein when an image stabilization mechanism is activated by detecting a shock in a camera module, the motor coil is instantaneously supplied with the driving current greater than the maximum rated current value.