Hello and welcome to training on general purpose 24 volt motor drivers. I’m Paul Dieffenderfer & I will be your host for this presentation prepared by H. Tanaka of the LSI Division.

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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.

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There are many applications for motor drivers. These include ATMs, change machines, vending, slot machines, automation, textile machines, and to control the claw in the crane game just to name a few. The design you are working on may not be one of these exact applications, but what is being controlled is probably very similar. Lets take a closer look at some these applications.

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Here can be seen the purpose of the motors in each application, the recommended products, and the motor type. The machines that handle money need motors for handling currency, access cards, and receipts. Games have motors to move drums and crane arms. Office equipment have time cards and print head control. The industrial market has many applications of motors. Vending machines need to move goods out to the consumer, and the textile industry deals with moving all sorts of material.

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Here is a block diagram for an automated teller machine. Due to the confidential nature of this machine, the exact architecture is not known. ATM makers have requested 20 to 50 stepper motors per unit. Some of the uses of motors in an ATM are to drive the printer for the deposit record, to insert the access card, to open and close the cover of the bill dispenser, and to suck in check and cash deposits. There are also many mechanisms inside the machine that the user does not interface with.

The design cycle of these devices is long, over 5 years. However, once you are selected, the business lasts for a long time at high margins.

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Let’s take a look at the LV8731V in the application for ATM use. With low power, safety, and easy PCB layout as a goal, this is the part to choose. For low power, the DMOS process enables it to use less than 1 uA of current during standby and the low Ron of the FET also dissipates less power than what a power transistor could achieve. Safety functions such as thermal shut down, over current protection, and under voltage lock out are incorporated. To facilitate an easy PCB layout for the designer, the same package and pin outs are used for different current rated parts. This enables the designer to easily put a more or less power driver in the same socket as motor requirements change.

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In this block diagram of a cash machine, there are three separate units, the bill handling unit, coin handling unit, and the coin hopper. The bill and coin units have to align the currency for sensors to validate them as well as deliver them out to the user. The coin hopper will return what has been inputted if the user pushes the return button. While some of these units are stand alone for making change, most of them are usually part of bigger machine like a candy or beverage dispenser. The standard power supply in these machines produces 24 volts. Each of these units has multiple applications of 24 volt motors.

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The forward reverse DC motor is typically used for the cash machine. With low power, safety, and easy PCB layout as a goal, the LV8760T is the part to choose. For low power, the DMOS process enables it to use less power than what the bipolar process of the Toshiba products can achieve. Safety functions such as thermal shut down, over current protection, and under voltage lock out are incorporated. To facilitate an easy PCB layout for the designer, the device is available in a much smaller package than the competition.

Once a device is chosen for this application, the PCBs for motor driving stay the same across many models. The original design win becomes like a reference design.

In Asia, Toshiba’s TA8428 & 8429 are commonly used and so the LV8760T was developed using Toshiba devices as the benchmark. As the table shows, the LV8760T is superior in low current consumption.

The package size is also much smaller and the Toshiba devices lack the safety of current limiting found in the LV8760T.

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One armed bandits incorporate motors as well. A 24 volt stepper motor controls the positioning of the drum as it spins by and eventually doesn’t land on what you want it to. On that rare occasion when you do, a motor will reluctantly spit out the coins you have won.

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Slot machine design demands safety, smooth motion of the drum, and the ability to resize the motor with out changing the PCB. The LV873x series of 24 volt stepper motor drivers incorporate protection and current limiting functions such as thermal shut down, over current protection, and undervoltage lock out for safety. The micro stepping capability, 1/8 or 1/16 step size, ensures low motor vibration in the spinning of the drum. The LV873x product family all come in the same pin out and package, making it possible to choose a one amp max drive current all the way up to a 2.5 amp max drive current with out having to change the PCB.

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In a vending machine, stepper, DC brush, and brushless motors can be found. In addition to the motors in the bill and coin handling units already discussed, there are motors used in the refrigeration section and motors used to dispense the food or drinks. Once an item is selected, it is pushed forward by a conveyer belt on to a tray. This tray then travels to the dispensing slot where the customer can obtain their purchase. The tray is on a slider that moves up and down. The tray can move left or right to get the item and to get to the dispensing slot. Stepper motors are often used to control this motion.

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This is a simplified block diagram of knitting or textile machine. Stepper motors are used to precisely feed thread and to control its position. 10 to 20 stepper motor drivers are per unit are typical used. These products also have 40 to 50 MOSFETs used with actuators.

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The upper block diagram is for a liquid soft drink dispenser, not the can type. Because the standard power supply is 24 volts in a vending machine, 24 volt stepper motors and brush motors are used to control the amount of syrup, carbonated water, and to release the cup. In the coffee dispenser example, 24 volt motors are used to measure and move powder.

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The LV873x is a good choice of motor driver for textile and vending machines. With low power, safety, and easy PCB layout as a goal, this is the part to choose. For low power, the DMOS process enables it to use less than 1 uA of current during standby and the low Ron of the FET also dissipates less power than what a power transistor could achieve. Safety functions such as thermal shut down, over current protection, and under voltage lock out are incorporated. To facilitate an easy PCB layout for the designer, the same package and pin outs are used for different current rated parts. This enables the designer to easily put a more or less power driver in the same socket as motor requirements change. The micro stepping capability of this part not only enable more precise positioning, but also makes for a more smooth movement of the motor.

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Let’s take a look at what the motors are doing in the examples we have looked at. A bill validator is a system that carries the currency from where it entered the system and was validated to a stack of other bills of the same value. To carry and align the bills, a 24 V forward reverse brush motor is used.

The coin machine and hopper also uses a 24 V forward reverse brush motor. A sensor counts the number of coins that are being moved while a CPU controls the start and stop of the motor.

The currency counter shown in the bottom right is something that you might see when you exchange currency at the airport. A 24 V forward reverse brush motor is used to align and move the bills so that they can be counted.

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The motion of the drums in slot machines is not random mechanical motion. Because they must be precisely controlled and brought to a sudden stop, a stepper motor is used.

If you have ever played the crane game, you know that it is not precisely controlled! There are five brush motors in use, one for each axis of motion and two in the claw as shown on the right.

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Vending machines have evolved over the years. Originally, the contents they contained were of similar size and shape. The object being sold was also very durable and could be dropped from the top shelf to the bottom of the dispenser with worry that it would be damaged. You just had to be careful when you opened your carbonated beverage! The newer vending machines are being asked to dispense a wide variety of products with different sizes, shapes, and durability. To do this, a tray is brought to where the item sits on the shelf, the item is moved onto the shelf, and then it is brought to a dispensing window where the purchaser can access it. This tray must be precisely controlled so a stepper is usually used for the controlling it. Brush motors are used for moving the object forward and opening the dispensing door.

Textile machines need precise control. The processor needs to accurately feed things out and control their positions. Typically a lot is going on at once that needs to be precisely coordinated. These devices will have 10 to 20 motor drivers on the same board.

Drink dispensers, where the serving is in a cup and not a box or can, use motors to control the amount of syrup, carbonated water, and ice that gets mixed into the cup. The control is very similar to valve control discussed in the 3 – 15 V general purpose motor driver presentation. The ingredients of coffee and tea are powder and so often a brush motor is used. In these dispensers, the strength of the coffee and tea, and the amount of sugar and cream are adjusted by stepper motors.

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What is available across all of SANYO for motor drivers, not just the System LSI Division

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The stepper motor and forward reverse 24 V DC motor driver portfolio is quite broad. There are motor drivers ICs from the Standard LSI division, Hybrid IC division, and from the HyperDevice division. This chart shows how they are segmented by current, voltage, and motor application type. For bipolar stepper motor drivers up to 2.5 amps, the Standard LSI division’s products are mainly used. This division also supports up to 4 amps. If you need greater current, the HIC division has parts to support you. Most of these stepper motor drivers are unipolar. DMOS refers to a process that uses FETs for the output. With the lower power consumption of the DMOS products comes higher current ratings than that produced on a bipolar process.

For forward reverse DC brush motor drivers, the System LSI products support typically up to 3 amps with 5 amps supported depending on the use in the application. The HIC division can support up to 12 amps. To understand how that is done, please watch the HIC training.

The product offering for 24 V DC motor drivers is one of the largest in the industry with wide selection of current ratings. No other company can support this wide range.

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Packages are unified across current ratings with in a family of parts. They share the same foot print and pin out so that as current ratings change, and IC change is all that is needed, not a PCB change. The stepper motor drivers can also be used as two channel forward reverse motor drivers.

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Motor drivers are not something that SANYO has just recently decided to develop. They have been around as a focus product for over 3o years. We have been leading the way to meet requirements of new design requirements. For example when lower power was needed, the DMOS process met that challenge. Enhanced safety features, which we discussed earlier in the presentation came next along with pin compatible line ups, external part integration, silent drive, and so on.

We will continue to innovate and as an example we are pursuing three phase stepper motor drivers and ultra-micro steps.

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Here’s an example of how to become successful. Toshiba has the TA8428/8429 to dirve 24 V forward reverse brush motors in the industrial and cash machines. These were quite old models, but in those days, there were very few 24 V H-bridge drivers that could support 2 to 3 amps. Because they were first, they were the standard. As mentioned earlier, once a part is designed in in these industries, it lasts a long time. You will still find designs using these Toshiba parts today. These ICs were targeted with the DMOS process to drastically enhance their performance, giving the equipment designers a good reason to re-look at their designs. Many designers were doubtful that such a small part could support so much current. Take a look at the packages in the upper right corner. The Toshiba parts dwarf the SANYO equivalents. Once they realized that the technology in the SANYO part was developed 20 years after what was in their current designs, they began to switch over. Find out what is being used in your territory. Chance are we have a better part for the same application.

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How do you select the right driver for your application?

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

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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 lower voltage drivers in shaded area are discussed in a separate presentation.

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Using this flow chart, you can narrow down the driver selection for the motors in your cash machine. There are motors for moving bills, the coin hopper, deposit recording, and dealing with access cards to name a few. Almost all of these machines work from a 24 V DC source, but check with the designer to make sure. Once you understand what type of motor is being used, use the lists on slides 24 and 25, or check the web for the latest information to get the current range correct. Thankfully, if you get that wrong, most of the families have compatible packages and pin outs so you can upgrade to a higher current later or to a lower current part with out impacting the schedule. The last three steps will narrow down the selection the rest of the way. If you are still not sure, don’t be afraid to check with the applications for assistance.

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The flow chart for industrial machines is identical to the cash machine. Just remember that stepper motors are for precise positioning control and if they have micro stepping capability, they can also be used to reduce the vibration in the motors. Brushed DC motors and their drivers are typically less expensive than their stepper counterparts. Therefore if precise positioning is not critical, this type of motor is usually chosen. Some of these H-bridge drivers support more than one channel so make sure you understand how many channels are needed.

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The next three 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.

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Remember the crane game we went over? This is the H-bridge motor driver that was chosen to operate the claw. It used two motors so this dual channel part was a good match for the application. The FETS that drive motors have a low on resistance so not much power is lost in the driver. It will operate from 9 to 35 V and can provide 2.5 amps of output current. It is in a 44 pin SSOP package and has an evaluation board available.

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The LV8731V is a stepper motor driver that has found homes in textile and slot machines. You can work all day with one and then lose what you earned in the evening with another. It can also behave as a 2 channel H-Bridge driver. That way a board set up as a stepper driver it can be repurposed to drive two brush motors as well. It will operate from 9 to 32 volts and provide up to 2 amps of output current. Micro stepping is available for accurate positioning and the motor current can be selected in four steps. An evaluation board is available for this part.

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The LV8760T comes in a space saving 20 pin TSSOP package. It is a one channel H-bridge motor driver capable of delivering 3 amps of output current. It operates from 9 to 35 volts, a standby current of less than 1 uA, and is highly efficient due to the DMOS technology FETs low on resistance. The short circuit protection function is very important in the cash machine application. You wouldn’t want your money to catch on fire. This part also has applications in ATMs, printers, office equipment and toys. An evaluation board is available for this part.

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This has been a presentation on 24 V general purpose motor drivers. Thank you for your time and attention.

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