1. EDGE™ Output driver circuit is the electronics between the low power control electronics and the output device. prepared by Prof. George Slack (EE) Copyright © 2006 Rochester Institute of Technology All rights reserved. Output Driver Circuit Practical Design Considerations

2. EDGE™ When is this needed? Senior Design I – –Paper Design wks 1-8 – "Fail Often, Fail Fast, Fail Cheap" –Lab feasibility "Fail Often, Fail Fast, Fail Cheap" wks 3-7 (i.e. evaluation, characterization, shortfalls) Senior Design II – –Prototype device testing wks 1- 3. – –Pre-integration testing with lab equipment DUT (device under test). Wks 3- 6

3. EDGE™ Driver Circuit Interface Input: Logic/ Microcontroller to input of electronics drivers.Input: Logic/ Microcontroller to input of electronics drivers. Driver Circuit: (typically voltage to voltage, voltage to current.)Driver Circuit: (typically voltage to voltage, voltage to current.) Output: Driver device.Output: Driver device. –Motors, Linear Actuators –Solenoids –Storage Capacitors –HVPS

4. EDGE™ What are the key considerations and tools? Bandwidth, frequency response, rf to dcBandwidth, frequency response, rf to dc Impedance matchingImpedance matching Low Voltage to High CurrentLow Voltage to High Current Low Voltage to High VoltageLow Voltage to High Voltage Low Current to High CurrentLow Current to High Current Low to Current to High VoltageLow to Current to High Voltage Circuit protection electronicsCircuit protection electronics –Surge protection techniques –Debugging can become somewhat frantic with a potential for shorting or over powering. Though electronic devices may be inexpensive, the re-ordering time and re-soldering takes time.

5. EDGE™ 1. 1.If considering various output devices, review various manufactures specification sheets. 2. 2.Current (i.e. CMOS versus TTL ) needs, sink, source or both Vdd/Vcc. 3. 3.Control Voltage (Vdd vary from 1.5 VDC to 12 VDC typically) 4. 4.Frequency Response. 5. 5.Heat and EMI Noise considerations 6. 6.RLC loads (& potential for dangerous current and voltage spikes) 7. 7.Apply to Thevenin Equivalent Circuits – –Source electronics – –Device being driven Applying Specification Needs

6. EDGE™ Types of Drive Components Transistors: Single stage and Darlington up.Transistors: Single stage and Darlington up. Op AmpsOp Amps JFETsJFETs MOS FETMOS FET IGBT DC to AC inverters (hybrid cars, mass transit)IGBT DC to AC inverters (hybrid cars, mass transit) Optical Switching devicesOptical Switching devices

7. EDGE™ Example of Driver Circuit Input: PIC18F2455 MicroControllerInput: PIC18F2455 MicroController –See attached pdf to the right. Driver Circuit – Opto 22 ODC5Driver Circuit – Opto 22 ODC5 –See attached pdf to the right. Output Device – 2.5a, 50 vdc Inductive LoadOutput Device – 2.5a, 50 vdc Inductive Load

8. EDGE™ Specific Applications: H bridge – DC MotorsH bridge – DC Motors Optical Isolators- Power Supply SeparationOptical Isolators- Power Supply Separation Optical DriversOptical Drivers Fiber Optics and Fiber Optics I/0 DevicesFiber Optics and Fiber Optics I/0 Devices DC to DC convertersDC to DC converters –voltage boasting/ ± polarity –current boasting

9. EDGE™ H Bridge Considerations Motors or whenever you need to direct current.Motors or whenever you need to direct current. Introduction to H bridge operation:Introduction to H bridge operation: –http://www.dprg.org/tutorials/1998-04a/ http://www.dprg.org/tutorials/1998-04a/ Designing an H-Bridge and PWM Circuits and CodeDesigning an H-Bridge and PWM Circuits and Code –http://www.learn-c.com/experiment7.htm http://www.learn-c.com/experiment7.htm Debugging: Initial reset may close a short circuit or stress on the H bridge. Symptom: Motor shaft may pulse or flinch at power on. May cause immediate failure.Debugging: Initial reset may close a short circuit or stress on the H bridge. Symptom: Motor shaft may pulse or flinch at power on. May cause immediate failure. Design Needs: Inductive loads and protection diode.Design Needs: Inductive loads and protection diode.

10. EDGE™ components and spec sheets Manufacturer’s Home Pages http://www.findchips.com/ Google http://cmpmedia.globalspec.com/ Suppliers: DigiKey, Mouser and Allied offer good on-line spec sheets. RIT Library services microcontroller evaluation kits http://www.esacademy.com/automation/ faq/primer/6.htmmicrocontroller evaluation kits http://www.esacademy.com/automation/ faq/primer/6.htm http://www.esacademy.com/automation/ faq/primer/6.htm http://www.esacademy.com/automation/ faq/primer/6.htm

11. EDGE™ Rochester source When you want to look at what you are buying:When you want to look at what you are buying: http://www.glenwoodsales.com/http://www.glenwoodsales.com/http://www.glenwoodsales.com/ GLENWOOD SALES COMPANY 594 HAGUE STREET ROCHESTER, NEW YORK 14606 USAGLENWOOD SALES COMPANY 594 HAGUE STREET ROCHESTER, NEW YORK 14606 USA Tax free with RIT PO (contract Chris Fisher for form)Tax free with RIT PO (contract Chris Fisher for form)