Hello and welcome to training on general purpose motor drivers in the 3 to 15 volt range. I’m Paul Dieffenderfer & I will be your host for this presentation prepared by H. Tanaka of the LSI Division.

1

In this presentation, we will look at several examples where stepper motor drivers and DC brushed motors are used. We will then dig deeper into these examples, examining their block diagrams to make a proper part selection for each motor driver application. In this presentation, STM is used to abbreviate stepper motor and DCM is used for DC brush motor.

Later in the presentation, we will look at what the motor is controlling in more detail. We will then finish with a selection guide and flow chart for aiding the designer in choosing the best motor driver.

2

There are many applications for 3 to 15 volt DC motor drivers. Security cameras, video projectors, toys, and valve control in water and gas applications. The design you are working on may not be one of these exact applications, but what is being controlled is probably very similar. Let’s take a closer look at some of these applications.

3

Here can be seen the purpose of the motors in each application, the recommended products, and the motor type. Security cameras need motors for panning, and tilting as well as for focusing and zooming the lens. If higher torque is required for panning and tilting, a 24 V motor may be required.

For the toy application, a motor is used to steer left and right and one is used to move the wheels forward and backward.

In the video projector, lens driving is the main application. In the mid to high-end models, motors can control the zoom and focus. In some high end projectors, lens shift and iris control is motor driven.

Whether for controlling gas flow or water, the housing equipment application is typically valve control.

4

Here is a block diagram for a security camera. The tilt and pan functions are controlled by stepper motors. Sometimes the torque requirements, due to size of the motor selected, will require a motor with higher voltage specifications. The recommended stepper motor drivers for these applications are the LV871, LV854, and the LV873 series of steeper motor drivers. The LV873 series is the higher voltage, 24 V, capable driver.

The zoom and focus control motors are typically brushed DC motors in the 3 to 5 volt range. For these applications, the LV804 and LV805 series of motor drivers are a good choice.

5

Let’s take a look at the LV8548MC in the application of pan and tilt drive in a low end security camera. If low cost, lower power, safety, and design simplicity are the goal, this is the part to choose. It uses less than 1 uA of current during standby, can operate from 4 to 16 volts and can safely tolerate excursions up to 20 volts. For simplicity it only needs one power supply and one external component.

6

One of the chief design concerns of a security camera is low power consumption. Our current products are developed on a DMOS process technology that employs a low Ron FET. A bipolar process would have to use a transistor, which inherently uses more power. The mid to high-end models request low vibration in their motors. This minimizes the shaking of the image and yields better video. Micro stepping the position of the motors results in smooth pan and tilt.

7

The LV8044LP is good choice for the zoom and focus drive of a closed circuit television camera. It is a one chip IC that integrates the necessary functions for the lens drive of a security camera. Because the lens driver IC is mounted on a small board located near the lens, the design typically calls for a small package. The LV8044LP includes all the necessary features and is in a small 5 mm x 5 mm package. Pin count is reduced by using the SPI serial interface to its functions.

A single LV8044LP can drive 2 Stepper motors, for Zoom and Focus and it can also control a neutral density filter with the integrated dual H bridge circuitry. The LV8044LP is compatible with a wide variety of specifications making it suitable for many different security camera designs.

With this part the design gets a reduced part count and small footprint, easing the workload for the designer which all lead to the reduction of the total system cost.

8

Let’s now take a look at the block diagram of very small remote control car. A forward reverse brush motor is used to move the steering left and right and to move the wheels forward and back. The LB1836M was used in the DigiO toy car because the board area was so small, there was only room for one motor control IC. The same device can be used to control the motors in toy robot joints.

9

Let’s take a closer look at the LB1836M and how it applies to toy, or small brush DC motors. The process technology used in this device enables low saturation, low voltage drive, and low cost at the same time, utilizing a PNP transistor for the high side motor output. By separating the control power supply this device supports a motor power supply of 1.8 V min. This allows motor operation with 2 batteries.

As shown in the lower left, Sanyo’s process technology incorporates the protection diode for the high-side PNP transistor while it is necessary for the competition to add an external one or use die space to do this internally.

The figure in the lower right illustrates the low saturation voltage and low voltage drive advantages of this part. In the case of a power supply voltage of 2.4 V, the competition can only deliver about 1.5 V to the motor, while the SANYO part delivers 2.3 V.

These technology and design advantages provide the design with board space reduction as well as longer battery life.

10

The next example where motor drivers are commonly found is in the video projector. Most mid-end projectors will have motor driven zoom and focus. In lower-end models, this is done manually. When the projector is mounted in a remote place, like a high ceiling, it is important to be able to adjust the zoom and focus without having to get out a ladder. High end models could include a motor for lens shift and an iris function. Lens shift is the ability to control the position of the lens in all directions. Some projectors have a swivel function, enabling the chassis to move right and left.

11

The LV8405V is the right part for stepper motor control of zoom and focus in a video projector application.

Video projectors in the mid to high-end use motors that are fairly large to drive the larger lens that they contain. In this case, higher torque is needed from the motor and high current capability is required for the motor driver.

The package size of LV8405V is small but it incorporates 2 H bridges with a maximum current capability of 1.4A. Hence this device can support one stepper motor or two DC motors. Also with its low 0.75 ohm on resistance, voltage loss during motor driving is low thus generating less heat. The output transistor H bridge is N channel-N channel. This means the gate voltage on the high side N channel FET is generated from an internal charge pump circuit, enabling low on resistance.

Some motor drivers will use a P channel – N channel transistor configuration. The advantage it has is that no charge pump is necessary for the P channel FET to turn fully on. The disadvantage is that a P channel FET will require nearly four times as much die area to have the same RDS on as an N channel. The space required by the charge pump circuit is considerably less. In addition, the charge pump is able to fully turn on the FET over a wide input voltage range.

Because of its wide tolerances, once a designer becomes familiar with this part, it will be used in many other motor driver applications.

12

This high efficiency method of producing residential hot water is in use in Japan and will likely start to spread to other areas.

The block diagram consists of three main sections; the remote unit, the tank unit, and the pump unit.

Inside the tank unit, motors are used to control opening and closing of valves as well as opening or closing in varying amounts. A driver array is sufficient for a simple movement of opening and closing, but if inflow control is required; for example temperature control by mixing hot and cold water, a stepper motor is used.

The LB1948MC is used in many gas hot water supply units in Japan. These units are very similar to heat pumps used in air conditioning systems. The tank unit is equivalent to the indoor unit while the pump unit compares to the air conditioning outdoor unit. Hence many white good manufacturers make both products at the same manufacturing site.

13

You may remember this part from slide 6, the driver for pan and tilt of a security camera. Just like in that example, the design of hot water supply equipment requires low cost, low power consumption, safety and ease of design.

The LV8548MC matches these requirements. Low power usage is obtained by the FET outputs, less than one uA in standby, and safety is met by having a 20 V excursion tolerate Vmax. This means that even when a surge or external voltage finds its way to the 12 V power supply of the motor, the IC has sufficient margin to be protected.

Another safety feature is the dead time between turning on the high and low FETs to prevent through current. The wave form in the bottom left of the slide shows what happens if one FET turns on before the other finishes turning off. A current pulse occurs like shown on the bottom waveform. Pulses that are too big will lead to IC breakdown. The SANYO DMOS product waveforms can be seen under the “No flow through current” heading. Here you can see the waveforms with timing to prevent through current.

14

Let’s take a closer look at what the motors are doing in these applications. In housing equipment or white goods, valve control is the most typical use of a motor. If precision is required for inflow control, a stepper motor is used. For simple opening and closing movement, a forward reverse brush motor is used. At the top of this slide is the example of controlling a valve by hand. You have probably seen the do it yourself sprinkler systems that use garden hoses. The low current consumption drivers you have seen can run these for many months without a need to change the batteries.

The operation of panning and tilting is shown next. Panning is the left and right motion while tilting is up and down. Low vibration is required for lens with higher magnification because even the smallest shaking will blur the image. Using a micro stepping capable stepper is the best way to reduce vibrations caused by the motor drive.

For toys, Lego is using the LB1836M in many of their products. The bulldozer not only moves its blade and ripper up and down, but is capable of forward, reverse and spinning left and right. The winding up of the winch is also implemented using this part. Brush motors are used in these applications.

In the toy industry, design cycles are very short. There is usually no additional production once the first run of products runs out unless the toy is successful. If not, production is terminated immediately. Designers tend to have many development projects running concurrently. This tends to cause them to use easily access-able devices. Sometimes the samples provided for evaluation are used in their prototypes. If you have this type of application, it is recommended that you provide a selection of products because they often design in what they have in their desk or lab.

15

Let’s take a look at motor usage in the lens of cameras.

For auto focus, a stepper motor is used. This application requires 2 lens as the figures in the upper right show. There is a main lens and the focusing lens. By adjusting the position of this lens, the object will come into focus. This requires precision, so a 3 – 5 V stepper motor is used.

Zoom does not required precision in position control that focus does so often a brush motor is used.

The iris controls how much light gets to the sensor. A motor is used to make this opening larger or smaller. A stepper or brush motor is used to position the blades that control the size of the opening.

16

How about controlling gas flow for a cook top? The modern gas cook tops control the heat level electrically rather than manually. The valve control unit will look something like the picture in the upper right. You can see that in addition to the on/off valve of the whole unit, there are four separate controls for the individual burners. A stepper motor is used adjust the gas flow of each burner. The safety valve is simply an on or off type of control and does not need to be controlled by the precision of a stepper motor. If a sensor detects a potential danger, it shuts of the gas supply to all burners using this motor.

To drive this motor, a forward-reverse brush motor driver like the LB1848MC and LB1973JA can be used.

Gas cook tops run the motor and driver by an internal battery, since a gas stove does not need electricity to work. Therefore the design will call for a motor driver IC which has low current consumption and can be driven from a low voltage source.

17

Here are some examples of how a motor driver can be used other than driving a motor. The first example is to control the movement of a solenoid. By providing current to a coil from the out pins of the driver, the iron core is moved. You can change the direction of motion by changing the direction of current flow. This is how a valve can be opened and closed.

Another application can be the electrolysis of water. The cathode and anode can be reversed by changing the direction of current flow.

18

Most of Sanyo’s 3 – 15 V DC motor drivers are monolithic ICs. As the chart shows, there are four types of motor drivers with different voltage levels and control methods. For lens drivers, the 3 – 5V DC motor driver is recommended. There are two control methods for these products. The PWM control method uses internal control to do the chopping while the full on type would be controlled externally for the chopping. The same is true for the 5 – 15 V DC motor drivers.

Internal PWM control is used when high precision is required like for micro-stepping. When simplicity and cost is the priority, the full-on method is used.

19

20

If your application calls for a stepper motor, you can chose from one of these. The drivers in blue will be discussed in a separate presentation. Remember, stepper motors are used for precise control and micro-stepping is used to reduce motor vibration.

21

If you application calls for a DC brush motor, there are many H-bridge drivers to choose from. Some of these devices have the ability to drive multiple motors or gang outputs together to provide more current. The higher voltage devices will be covered in a different presentation.

22

Using this flow chart, you can narrow down the driver selection for a security camera application.

In a security camera motors are used in two places. They are used to control where the camera points and they are used to control the functioning of the lens.

For panning and tilting, a stepper motor is usually used. For the lens driver, a stepper is commonly used for the autofocus and forward reverse brush motor is used for zoom.

After having identified the motor type, you can check the voltage and current requirements with the list of parts that meet the other criteria. Further selection is done by steps 4 through 6.

23

How about valve control? If precise position and not just on and off are needed, a stepper motor is most commonly used. For on and off, H-bridge drivers for brush DC motors are chosen. There are dual H-bridge parts available, so you need to know how many channels will be controlled. Once the motor type is identified, the supply voltage range and current requirements can be compared to the charts on pages 21 and 22. For the latest information, you should check on the web. If you don’t see what you need, do not hesitate to call for help. The last three steps narrow down the selection even further..

To further narrow down the selection obtain the information needed to answer questions 4 to 6.

24

The next slides are one pagers on different motor driver products offered by SANYO. Please feel free to hit your pause button so that you can read the details provided on each slide.

25

The LB1948MC is a single channel low saturation stepper motor driver. It can also be used as a 2 channel driver for a forward reverse DC motor driver. It is highly efficient with zero stand-by current and operates from 2.5 – 16 V. There is an evaluation board available for this device.

26

You should recognize the LV8548MC. It was discussed in the security camera example as well as in the valve control example. It can be used as a single channel stepper motor driver or as a two channel H-bridge DC motor driver. It has a built in low voltage detection circuit and can source one amp. There is an evaluation board available for this device.

27

The LV8044LP is a 6 channel micro-step motor driver designed for camera applications. It has the ability to micro-step up to 64 steps. Even though this device supports 6 channels, it fits in a small 5 x 5 mm package that is 0.85 mm thin. The micro-stepping leads to a reduction of motor noise and vibration. In addition to other features, it has a built in photo sensor drive transistor that is commonly needed in camera applications. There is an evaluation board available for this device.

28

The LB1973JA is one channel stepper motor driver that has been designed into gas cooktops in Japan. This device works down to 1.8 volts and has very low stand-by current, making it very useful for portable applications. There is an evaluation board available for this device.

29

The LB1846MC is one channel stepper motor driver that has also been designed into gas cooktops in Japan. The half stepping capability of this device helps reduce motor noise.

30

This has been a presentation on SANYO 3 to 15 volt general purpose motor drivers. Thank you for your time and attention.

31