CN1251395C - Method for Eliminating the Interference of Noise Generated by Stepper Motors on Photosensitive Devices - Google Patents

Abstract

A method for eliminating the interference of noise generated by the movement of a stepping motor to a photosensitive device comprises the following steps: firstly, an exposure clock period is provided, a light source is sensed by the photosensitive device to obtain an exposure energy, and the exposure energy is transferred by the photosensitive device. Then, a motor motion clock cycle is provided, each cycle of the motor motion clock cycle is a plurality of cycles of the exposure clock cycle. And taking one period in the exposure clock period, corresponding to the motor stop period of the motor movement clock period, and sensing and transferring exposure energy by the photosensitive device.

Description

Method for Eliminating the Interference of Noise Generated by Stepper Motors on Photosensitive Devices

technical field

The invention relates to a method for eliminating noise interference to a photosensitive device, and in particular to a method for eliminating noise generated by a stepping motor to interfere with a photosensitive device.

Background technique

The operation of equipment or devices with motors often produces noise during non-continuous operation, such as stepper motors operating in go-stop-go-stop-..., or operating in one step- Two-step-one-step-three-step-... and other situations, when the stepper motor changes in motion, it produces noise that interferes with the signal source.

Fig. 1 is a control circuit diagram of a stepper motor driven by a constant voltage. In Fig. 1, the control circuit 100 of a stepper motor driven by a constant voltage (not shown) is illustrated by taking four groups of switches as an example, and each group of switches uses transistor. The switches 101-104 in the control circuit 100 are respectively connected in series with the loads (Loads) 106-109, and the switches 101-104 respectively receive the control signals C1, C2, C3, C4. When the control signal C1 is "H" (that is, high level), the switch 101 is turned on (on), so that the stepper motor (not shown in the figure) driven by a constant voltage starts to move. Similarly, when the control signals C2, C3, and C4 are "H" respectively or simultaneously, the switches 102-104 are respectively or simultaneously turned on, so that the constant-voltage-driven stepping motor (not shown in the figure) starts to move.

Figure 2 is a diagram of the operating clock cycle of a stepper motor driven by a constant voltage, and is explained with reference to Figure 1. In Figure 2, the stepper motor is driven by a constant voltage with one control signal as "H" and two control signals as "H" "-One control signal is "H"-two control signals are "H"-... as an example, and the constant voltage drive stepper motor can do any different circuit operations according to the needs of users.

In the cycle T1, the control signal C1 is "H", the control signals C2, C3, and C4 are "L" (that is, low level), the switch 101 is turned on, the switches 102-104 are turned off, and the stepping motor is driven by a constant voltage (Fig. not shown in ) to start moving. During the period T2, the control signals C2 and C3 are "H", the control signals C1 and C4 are "L", the switches 102 and 103 are turned on, the switches 101 and 104 are turned off (off), and the stepper motor is driven by a constant voltage (in the figure not shown) start moving again. During the period T3, the control signal C4 is "H", the control signals C1-C3 are "L", the switch 104 is turned on, the switches 101-103 are turned off, and the stepper motor (not shown in the figure) is driven by a constant voltage again start exercising. Under such an operating clock cycle, a stepper motor driven by a constant voltage (not shown in the figure) can complete specified motions according to user requirements.

However, when the stepper motor driven by a constant voltage is applied to a scanner in which the photosensitive device is a charge-coupled device, the noise generated according to the above operation clock cycle is shown in the clock cycle diagram of a known motor-photosensitive device in FIG. 3 . In the period T1 (the same as the period T1 in Figure 2), the exposure energy period TD is transferred in the exposure clock cycle SH, and the photodiode (Photo Diode) (including the charge-coupled device) transfers the sensed exposure energy to the charge-coupled device The analog shift register (CCD Analog Shift Register); the exposure energy period TS is sensed in the exposure clock cycle SH, and the photodiode is sensing the exposure energy. Similarly, in the period T1, during the motor movement period TM of the motor movement clock period MM, the stepper motor is driven to move at a constant voltage; during the motor stop period TI of the motor movement clock period MM, the stepper motor is driven at a constant voltage to stop. During period T2 (the same as period T2 in FIG. 2 ), the exposure clock period SH is the same as the description of the motor movement clock period MM and period T1.

In Figure 2, period T1 is a group of switches conducting, and period T2 is a period of two groups of switches conducting. For the power supply (such as VCC in Figure 1), one group of loads and two groups of loads are changing each other. Therefore, when the load changes from two groups to one group, the voltage of the power supply rises, as shown in Figure 3, period T1; if the load changes from one group to two groups, the voltage of the power supply drops, as shown in Figure 3 The period T2 shown. In this way, when the voltage of the power supply rises or falls, the noise generated by the voltage change will enter the power supply.

At this time, it is the exposure energy transfer period TD in the exposure clock cycle SH, that is, the photodiode transfers the sensed exposure energy to the charge-coupled device analog shift register. Because the power supply of the charge-coupled device is the same as that of the constant-voltage drive stepper motor, when the noise generated by the constant-voltage drive stepper motor enters the power supply, the noise will enter the charge-coupled device from the power supply. For the charge-coupled device with poor anti-noise, the horizontal image will be bright and dark due to noise interference.

Contents of the invention

Therefore the present invention provides a kind of method that eliminates the interference of the noise generated by the stepping motor to the photosensitive device when the stepping motor moves, and solves the noise interference generated when the stepping motor is driven by a constant voltage, and the photosensitive device with poor anti-noise ability (such as a charge Coupling device), without going through cumbersome and greatly changed engineering, can avoid the non-ideal situation such as horizontal stripes in the sensed image.

The present invention provides a method for eliminating the noise generated when the stepping motor moves to interfere with the photosensitive device. The steps include: providing an exposure clock cycle, the photosensitive device senses a light source to obtain an exposure energy, and The device transfers the exposure energy; each cycle in the exposure clock cycle includes a sensing exposure energy period and a transfer exposure energy period; provides a motor motion clock cycle, and each cycle of the motor motion clock cycle is the exposure clock Several cycles of the cycle; each cycle in the motor motion clock cycle includes a motor stop period and a motor motion period; one cycle in the exposure clock cycle corresponds to a motor cycle of one cycle of the motor motion clock cycle During a rest period, the exposure energy is sensed and transferred by the photosensitive device.

The present invention proposes another method for eliminating the noise generated when the stepping motor moves to interfere with the photosensitive device. The steps include: providing an exposure clock cycle, sensing a light source by the photosensitive device to obtain an exposure energy, and using The device transfers the exposure energy; each cycle in the exposure clock cycle includes a sensing exposure energy period and a transfer exposure energy period; provides a motor motion clock cycle; each cycle in the motor motion clock cycle includes a A motor movement period and a motor stop period; during the motor stop period corresponding to the motor movement clock period, the exposure energy is transferred by the photosensitive device; each period of the motor movement clock period and each period of the exposure clock period A phase difference is formed, and the formed phase difference means that the period of the motor movement and the period of transferring the exposure energy do not overlap each other in time. In this way, it can be solved that when the stepper motor is driven by a constant voltage, the noise generated by it interferes with the exposure energy transferred by the photosensitive device.

Description of drawings

Fig. 1 is a control circuit diagram of a stepping motor driven by a constant voltage;

Fig. 2 is an operation clock cycle diagram of a stepping motor driven by a constant voltage;

Fig. 3 is the clock cycle figure of known motor-photosensitive device;

Fig. 4 is the clock cycle figure of motor-photosensitive device of the present invention;

Fig. 5 is a clock cycle diagram of another motor-photosensitive device of the present invention.

The reference signs are respectively:

100: control circuit

101～104: switch

106～109: load

Detailed ways

Embodiment one:

In order to eliminate the interference of the noise generated by the stepper motor driven by a constant voltage to the photosensitive device (hereinafter, the charge-coupled device is taken as an example), so as not to change the period length of the exposure clock cycle of the charge-coupled device (as shown in Figure 3 The cycle length of the exposure clock cycle of the charge-coupled device), and changing the cycle length of the motor motion clock cycle of the stepping motor driven by a constant voltage is one of the methods, as shown in the clock cycle diagram of the motor-photosensitive device of the present invention as shown in Fig. 4 Show.

In FIG. 4 , during period T1 (the same as period T1 in FIG. 2 ), during the transfer exposure energy period TD in the exposure clock period SH, the photodiode transfers the sensed exposure energy to the charge-coupled device analog shift register; During the sensing exposure energy period TS in the exposure clock period SH, the photodiode is sensing the exposure energy. Similarly, in the period T1, during the motor movement period TM of the motor movement clock period MM, the stepper motor is driven to move at a constant voltage; during the motor stop period TI of the motor movement clock period MM, the stepper motor is driven at a constant voltage to stop. And the length of cycle T1 is equal to the sum of the length of a motor movement period TM of the motor movement clock cycle MM and the length of a motor stop period TI; similarly, the length of a cycle T1 is equal to two transfer exposure energy periods of the exposure clock cycle SH The length of TD is the sum of the lengths of the two sensing exposure energy periods TS. Therefore, one period length of the motor movement clock period MM is equal to two period lengths of the exposure clock period SH. During period T2 (the same as period T2 in FIG. 2 ), the exposure clock period SH is the same as the description of the motor movement clock period MM and period T1.

In Figure 2, period T1 is a group of switches conducting, and period T2 is a period of two groups of switches conducting. For the power supply (such as VCC in Figure 1), one group of loads and two groups of loads are changing each other. Therefore, when the load changes from two groups to one group, the voltage of the power supply rises, as shown in the period T1 in Figure 4; when the load changes from one group to two groups, the voltage of the power supply drops, as shown in Figure 4 Period T2 shown. In this way, when the voltage of the power supply rises or falls, the noise generated by the voltage change will enter the power supply. During the period when the photodiode transfers the sensed exposure energy to the analog shift register of the charge-coupled device (that is, the transfer exposure energy period TD in the exposure clock cycle SH), in order to avoid the noise generated by the power supply entering the charge-coupled device interference, the second transfer exposure energy period TD in the exposure clock period SH of the charge-coupled device is used in the period T1 (period T2, ...), which is corresponding to the period T1 (period T2, ...) The interval of the motor stop period TI of the motor movement clock period MM, while avoiding the transfer exposure energy period TD in the exposure clock period SH in the period T1 (period T2, ...) corresponds to the motor movement period of the motor movement clock period MM TM interval. As mentioned above, because during the motor movement period TM of the motor movement clock period MM, the noise generated by driving the stepper motor with a constant voltage will enter the power supply; and during the motor stop period TI of the motor movement clock period MM, the stepper motor is driven with a constant voltage It is stationary, so the stepper motor driven by a constant voltage will not generate noise due to the voltage change of the power supply to affect the exposure energy transferred from the charge-coupled device to the photodiode, which can avoid noise interference and produce horizontal images. dark situation.

In this example, one period length of the motor movement clock period MM is two period lengths of the exposure clock period SH. However, in the method for eliminating the interference of the noise to the sensor caused by the movement of the stepping motor of the present invention, one cycle length of the motor movement clock cycle MM can be three cycle lengths of the exposure clock cycle SH, or even more. It depends on the practical application. However, one cycle length of the motor movement clock cycle MM is more than two cycle lengths of the exposure clock cycle SH, and only one cycle is taken out of the exposure clock cycle SH to transfer the exposure energy of the photodiode to the charge-coupled device analog shift buffer. In order to eliminate the constant voltage drive step The noise generated by the motor in motion interferes with the charge-coupled device.

Embodiment two:

In order to eliminate the interference of the noise generated by the stepper motor driven by constant voltage on the photosensitive device (the charge-coupled device is taken as an example below), so as not to change the period length of the exposure clock cycle of the charge-coupled device and the period of the motor movement clock cycle length (the cycle length of the exposure clock cycle of the charge-coupled device shown in Figure 3 and the cycle length of the motor motion clock cycle of the constant voltage driven stepper motor), and to change the phase relationship between the exposure clock cycle and the motor motion clock cycle as One of the methods is shown in FIG. 5 as a clock cycle diagram of another motor-photosensitive device of the present invention.

In FIG. 5 , during period T1 (the same as period T1 in FIG. 2 ), during the transfer exposure energy period TD in the exposure clock period SH, the photodiode transfers the sensed exposure energy to the charge-coupled device analog shift register; During the sensing exposure energy period TS in the exposure clock period SH, the photodiode is sensing the exposure energy. Similarly, in the period T1, during the motor movement period TM of the motor movement clock period MM, the stepper motor is driven to move at a constant voltage; during the motor stop period TI of the motor movement clock period MM, the stepper motor is driven at a constant voltage to stop. And the length of cycle T1 is equal to the sum of the length of a motor movement period TM of the motor movement clock cycle MM and the length of a motor stop period TI; similarly, the length of a cycle T1 is equal to a transfer exposure energy period TD of the exposure clock cycle SH The sum of the length and the length of one sensing exposure energy period TS. Therefore, one period length of the motor movement clock period MM is equal to one period length of the exposure clock period SH. During period T2 (the same as period T2 in FIG. 2 ), the exposure clock period SH is the same as the description of the motor movement clock period MM and period T1.

In Figure 2, period T1 is a group of switches conducting, and period T2 is a period of two groups of switches conducting. For the power supply (such as VCC in Figure 1), one group of loads and two groups of loads are changing each other. Therefore, when the load changes from two groups to one group, the voltage of the power supply rises, as shown in Figure 5, period T1; when the load changes from one group to two groups, the voltage of the power supply drops, as shown in Figure 5 The period T1. In this way, when the voltage of the power supply rises or falls, the noise generated by the voltage change will enter the power supply. During the period when the photodiode transfers the sensed exposure energy to the analog shift register of the charge-coupled device (that is, the transfer exposure energy period TD in the exposure clock cycle SH), in order to avoid the noise generated by the power supply entering the charge-coupled device Interference, the transfer exposure energy period TD in the exposure clock cycle SH of the charge-coupled device is the interval corresponding to the motor stop period TI of the motor movement clock cycle MM, and avoid the transfer exposure energy period TD in the exposure clock cycle SH An interval of the motor motion period TM corresponding to the motor motion clock cycle MM. In this way, the transfer exposure energy period TD of the exposure clock period SH and the motor movement period TM of the motor movement clock period MM form a phase difference PD. As mentioned above, because during the motor movement period TM of the motor movement clock period MM, the noise generated by driving the stepper motor with a constant voltage will enter the power supply; and during the motor stop period TI of the motor movement clock period MM, the stepper motor is driven with a constant voltage It is stationary, so the phase difference PD formed by the transfer exposure energy period TD of the exposure clock period SH and the motor movement period TM of the motor movement clock period MM can make the stepper motor driven by a constant voltage not generate power due to The noise of the voltage change affects the exposure energy transferred from the photodiode to the analog shift register of the charge-coupled device, which can avoid the noise interference and the situation of one light and one dark image in a row.

Therefore, the advantage of the present invention is to solve the noise interference generated by the stepper motor driven by a constant voltage when it is moving, and the sensor with poor anti-noise ability does not need to go through tedious and greatly changed projects, and can avoid the sensed image from appearing like A non-ideal case of horizontal stripes. .

In summary, although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with the art can make various modifications and changes without departing from the spirit and scope of the present invention. Retouching is included in the protection scope of the present invention.

Claims (6)

1. A method for eliminating the interference of noise generated by stepper motors to photosensitive devices, characterized in that: the steps include: providing an exposure clock cycle, sensing a light source by the photosensitive device to obtain an exposure energy, and transferring the exposure energy by the photosensitive device; each cycle in the exposure clock cycle includes a sensing exposure energy period and a transfer exposure energy period; Provide a motor motion clock cycle, each cycle of the motor motion clock cycle is several cycles of the exposure clock cycle; each cycle in the motor motion clock cycle includes a motor stop period and a motor motion period; Taking one period of the exposure clock period, corresponding to the motor stop period of one period of the motor movement clock period, the exposure energy is sensed and transferred by the photosensitive device. 2. The method for eliminating the interference of the noise generated by the stepping motor to the photosensitive device according to claim 1, characterized in that: the stepping motor is a stepping motor driven by a certain voltage. 3. The method for eliminating the interference of the noise generated when the stepping motor moves to the photosensitive device according to claim 1, characterized in that: the photosensitive device is a charge-coupled device. 4. A method for eliminating the interference of noise generated by the stepper motor to the photosensitive device, characterized in that: the steps include: providing an exposure clock cycle, sensing a light source by the photosensitive device to obtain an exposure energy, and transferring the exposure energy by the photosensitive device; each cycle in the exposure clock cycle includes a sensing exposure energy period and a transfer exposure energy period; Provide a motor motion clock cycle; each cycle in the motor motion clock cycle includes a motor motion period and a motor stop period; During the motor stop period corresponding to the motor movement clock cycle, the exposure energy is transferred by the photosensitive device; a phase difference is formed between each cycle of the motor movement clock cycle and each cycle of the exposure clock cycle, and the formed The phase difference refers to the portion in which the motor movement period and the exposure energy transfer period do not overlap each other in time. 5 . The method for eliminating the interference of the noise generated by the stepping motor to the photosensitive device according to claim 4 , wherein the stepping motor is a stepping motor driven by a certain voltage. 6 . 6 . The method for eliminating the noise generated when the stepping motor moves to interfere with the photosensitive device according to claim 4 , wherein the photosensitive device is a charge-coupled device.

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