3Circuitdesign(140401)

Robotics Exp. 1

Dept. of Robot Engineering

Yeungnam Univ.

3. Circuit Design

Table of Contents

1. Introduction

2. Mechanical Design

3. Circuit Design

4. Sensor Control

5. Motor Control

6. Communication

7. Navigation

8. SLAM

9. Multirobots

3.1 Select Microcontroller

3.2 Circuit Design

3.2.1 Useful circuits

3.2.2 Type of Circuit

3.2.3 OrCAD

3.3 Layout

How to build a mobile robot

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3. Circuit Design

3.2.1 Useful circuits

The purpose of circuit design

Ex : power circuit, motor drive, sensor drive, control circuit, etc.)

Based on the designed circuit, we need to select suitable parts.

2

Back-And-Forth robot schematic.

Example)

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3. Circuit Design

Device types (IC package types)

3

DIP SMD SOJ

Dual Inline Package. Surface Mounted Devices Small Outline J-Bend Package

Package attributes that are taken into consideration when choosing a

package type for a particular semiconductor device include: size, lead count, power dissipation, field operating conditions, cost.

Examples)

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3. Circuit Design

a) Regulator

Power Circuit

Power Supply

Battery

Power

Circuit

Motor

MCU

Sensor1

Sensor2

Etc…

A voltage regulator

automatically

maintain a constant

voltage level.

A voltage regulator is designed to automatically maintain a constant

voltage level.

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3. Circuit Design

78xx LM1117

The 78xx lines are positive voltage

regulators; For ICs within the family, the xx

is replaced with two digits, indicating the

output voltage. (ex: the 7805 has a 5 volt

output, while the 7812 produces 12 volts).

79xx devices are complementary negative

voltage regulators. (ex: 5V, 6V, 8V, 9V, 10V,

12V, 15V, 18V, 24V )

-A low power positive-voltage regulator designed

to meet 1A output current.

-a good choice for use in battery-powered

applications.

-It features very low quiescent current and very

low dropout voltage of 1V at a full load and

lower as output current decreases.

-Available as an adjustable or fixed 1.2V, 1.5V,

1.8V, 2.5V, 2.85, 3.3V, and 5.0V output voltages.

SMD DIP

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3. Circuit Design

6

Voltage regulator Typical voltage regulator circuit

In circuit design, datasheet of the electronic parts is used to meet the circuit

requirement.

Constant current source Variable voltage source

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3. Circuit Design

7

Example: 7805- voltage regulator design using OrCAD.

LED (+ resistor): To monitor switching (SW 1)

For 12V of input voltage, both of 12 V and 5 V output can be generated

(cf: 5 V output from 7805).

In pin connection, pin allocation of IC can be found in datasheet.

Circuit diagram

voltage regulator

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3. Circuit Design

b) Level Shift

Level shifting: Changing the logic level at the interface between

two different semiconductor logic systems.

8

The interface between two modules operating at 3.3 V and 5.0 V respectively

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3. Circuit Design

9

Op amp level shifter

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3. Circuit Design

10

Level Shifting Between TTL and CMOS

IC's of mixed logic families can require a voltage translation to get

working correctly.

When signaling between a CMOS IC and a TTL IC, there can be a

problem because each logic family defines the valid range of voltage

that make up a valid HIGH and valid LOW and the logic families

don't agree on the range.

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3. Circuit Design

c) Pull up/down resistor

Pull-up and pull-down resistor is a common mechanism used in basic

electronic circuits.

Pull-up means connection of a line or chip, with supply voltage

though a resistor with a value of few kOhms. This kind of

connection results in maintaining high state, when the external

devices are disconnected or do not give signals, and protects against

unknown states.

Pull-down resistors operate in an analogous manner. A pull-up

resistor is a resistor connecting an input to VCC, and on the other

side - a pull-down resistor is used for the connection of an input and

GND.

As it is called, it pulls the signal to high (pull-up resistor) or low

state (pull-down resistor), and of course, it also limits the current.

usually between 10k and 100k to define the input state when no signal

source is connected.

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3. Circuit Design

More on Pull Up and Pull Down Resistors

BASIC Stamp I/O pins defined as inputs have high-impedance. Pins

can be in an unpredictable HIGH or LOW state when charged are

discharged by leakage paths on the printed circuit board.

Many misbehaving CMOS circuits or micro-controller programs can

be traced to unconnected input pins.

All inputs should be properly terminated with a high value resistor to

either VCC (a pull up) or GND (pull down). Termination to VCC

with a pull up resistor is usually the preferred method.

The value a pull resistor depends on your power budget, the max

current/voltage/power the output components can deliver and what

voltage/current the input requires to see a steady state that is opposite

to the "driven" output state.

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3. Circuit Design

Pull-up resistor

used to ensure that a wire is pulled to a high logical level in the

absence of an input signal.

used in electronic logic circuits to ensure that inputs to logic

systems settle at expected logic levels if external devices are

disconnected or high-impedance is introduced.

Pull-up resistor circuit Example) Optocouplers need pull-up resistors

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3. Circuit Design

Pull-down resistor

It works in the same way but is connected to ground.

It holds the logic signal near zero volts when no other active device

is connected.

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3. Circuit Design

d) Amplifiers

d-1) OP-AMP (Operational amplifier)

15

Pinout

op-amp: a DC-coupled high-gain electronic voltage amplifier with a

differential input and, usually, a single-ended output.

Applications: signal processing circuits, control circuits, and

instrumentation, etc.

Application examples

741 op amp

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3. Circuit Design

d-2) TR(Transistor) amplifier

16

Amplifier circuit, common-emitter configuration.

Transistor: three terminal devices(solid state) that replaced vacuum tubes.

– Amplification

– Switching

– Detecting Light

http://upload.wikimedia.org/wikipedia/commons/b/be/Common_emitter.png

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3. Circuit Design

17

The larger collector current IC is proportional to the base current IB according

to the relationship IC =βIB , or more precisely it is proportional to the base-

emitter voltage VBE . The smaller base current controls the larger collector

current, achieving current amplification.

The analogy to a valve:

The smaller current in the base acts as a "valve", controlling the larger

current from collector to emitter.

A "signal" in the form of a variation in the base current is reproduced

as a larger variation in the collector-to-emitter current, achieving an

amplification of that signal.

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3. Circuit Design

e) Active filters

High pass filter

a device that passes high frequencies and attenuates frequencies lower

than its cutoff frequency.

18

http://upload.wikimedia.org/wikipedia/commons/8/87/Active_Highpass_Filter_RC.png

http://upload.wikimedia.org/wikipedia/commons/4/4d/75_Hz_HPF_on_Smaart.jpg

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3. Circuit Design

Low pass filter

It passes low-frequency signals but attenuates signals with frequencies

higher than the cutoff frequency.

19

http://en.wikipedia.org/wiki/File:Active_Lowpass_Filter_RC.svg

http://upload.wikimedia.org/wikipedia/commons/6/60/Butterworth_response.svg

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3. Circuit Design

Band pass filter

It passes frequencies within a certain range and rejects (attenuates)

frequencies outside that range.

20

R2

R1

vin

C1

C2

Rf1

Rf2

C4

C3

R3

R4

+V

-V

vout

Rf3

Rf4

+

-

+

-

+V

-V

Stage 1

Two-pole low-pass

Stage 2

Two-pole high-pass

http://upload.wikimedia.org/wikipedia/commons/6/6b/Bandwidth_2.svg

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3. Circuit Design

Band rejection(Notch) filter

It passes most frequencies unaltered, but attenuates those in a specific

range to very low levels. It is the opposite of a band-pass filter.

21

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3. Circuit Design

f) Schmitt trigger

Threshold circuits with positive feedback having a loop gain > 1.

The circuit is named "trigger" because the output retains its value until

the input changes sufficiently to trigger a change:

in the non-inverting configuration, when the input is higher than a certain

chosen threshold, the output is high;

when the input is below a different (lower) chosen threshold, the output is

low;

when the input is between the two, the output retains its value.

22

The symbol of Schmitt trigger Schmitt trigger implemented by

a non-inverting comparator

http://en.wikipedia.org/wiki/File:Schmitt_trigger_symbol.svg

http://upload.wikimedia.org/wikipedia/commons/6/64/Op-Amp_Schmitt_Trigger.svg

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3. Circuit Design

A practical Schmitt trigger

configuration with precise thresholds

23

The effect of using a Schmitt trigger (B)

instead of a comparator (A).

http://en.wikipedia.org/wiki/File:Opampschmitt_realistic_xcircuit.svg

http://upload.wikimedia.org/wikipedia/commons/a/a9/Smitt_hysteresis_graph.svg

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3. Circuit Design

g) Motor drive

24

Motor Drive Schematic

Motor drive components

(i) Electric machines - ac or dc

(ii) Power converter - rectifiers,choppers, inverters, and cycloconverters

(iii) Controllers -matching the motor and power converter to meet the load

requirements

(iv) Load

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3. Circuit Design

Motor Drive Schematic

Controllers embody the control laws governing the load and motor

characteristics and their interaction.

Torque/speed/

position commands

Torque/speed/

position feedback

Other sensor

feedback

Vc, fc, start,

shut-out,

signals, etc. Controller

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3. Circuit Design

The controllers implement the control strategy governing the load and motor characteristics.

To match the load and motor, the input to the power converter is controlled (manipulated) by the controller

Controllers

26

Three types of Motor Load

Motor loads Description Examples

Constant

torque loads

Output power varies but

torque is constant

Conveyors, rotary kilns,

constant-displacement

pumps

Variable torque

loads

Torque varies with square

of operation speed

Centrifugal pumps, fans

Constant

power loads

Torque changes inversely

with speed

Machine tools

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3. Circuit Design

Schematic of the Pololu Dual High Current Motor Driver Carrier

27

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3. Circuit Design

28

DC Motor-Driver H-Bridge Circuit

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3. Circuit Design

29

Motor driving circuit Motor control module

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3. Circuit Design

3.2.3 OR CAD

Circuit design

30

Orcad is a suite of tools from Cadence for the design and layout of printed

circuit boards (PCBs).

Cadence OrCAD PCB Designer with PSpice comprises three main applications.

Capture is used to drawn a circuit on the screen, known formally as

schematic capture. It offers great flexibility compared with a traditional

pencil and paper drawing, as design changes can be incorporated and errors

corrected quickly and easily. (On the other hand, it is much faster to develop

the outline of a circuit using pencil and paper.)

PSpice simulates the captured circuit. You can analyse its behaviour in many

ways and confirm that it performs as specified.

PCB Editor is used to design printed circuit boards. The output is a set of

files that can be sent to a manufacturer or the electronics workshop in the

Rankine Building. I do not cover PCBs in this handout.

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3. Circuit Design

31

The first step in creating PCB's is to lay out our circuit design using

PCB design software or a CAD program. This software is can be

obtained online for free. The circuit layout should include all the traces

and pads needed for your circuit to work.

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3. Circuit Design

32

the completed board

https://www.google.co.kr/url?q=http://www.wallsave.com/wallpaper/1024x768/electrical-engineering-circuit-design-seesaa-jp-197891.html&sa=U&ei=nvwoU9PhI4bykAWCooDwCg&ved=0CH4Q9QEwKQ&usg=AFQjCNFqxX1ciiSrslBpHO_8Zh4sxo6Prg

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3. Circuit Design

OrCAD의 시작

1) 2)

3) 4)

Tool bar

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3. Circuit Design

• Select : 임의의 객체 선택.

• Place part : 부품 불러오기.

• Place wire : 부품이나 심벌간 배선 연결.

• Place net alias : 배선과 버스에 임의의 이름 부여.

• Place bus : Multi로 연결되는 신호에 대한 버스라인 형성.

• Place junction : 배선과 배선의 접속점 표시.

• Place bus entry : 버스와 일반 wire와의 연결 부분 지정.

• Place power : 회로도에 전원신호 연결.

• Place ground : 회로도에 접지신호 연결.

• Place hierarchical block : 회로도에 계층구조의 블록 설정.

• Place [hierarchical] port : 계층구조 핀과 연결되어 사용되는 포트.

• Place [hierarchical] pin : 계층구조 블록 위에 핀 배치.

• Place off-page connector : 평면구조의 회로도 연결 시 사용되는 포트.

• Place no connect : 부품의 pin에 배선 등을 연결시키지 않을 때 사용.

• Place line : 전기적 속성을 지니지 않은 일반 선 그리기.

• Place polyline : 전기적 속성을 지니지 않은 일반 다각도 선 그리기.

• Place rectangle : 전기적 속성을 지니지 않은 일반 직사각형 그리기.

• Place ellipse : 전기적 속성을 지니지 않은 일반 타원형 그리기.

• Place arc : 전기적 속성을 지니지 않은 일반 원호 그리기.

• Place text : 임의의 구역에 글자 삽입.

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3. Circuit Design

Circuit Design – 기초 그리기

35

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3. Circuit Design

Circuit Design – 라이브러리 없는 부품 그리기 #1

36

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3. Circuit Design

Circuit Design – 라이브러리 없는 부품 그리기 #2

37

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3. Circuit Design

Circuit Design – 데이터 시트 보고 그리기

To find datasheet : http://www.alldatasheet.co.kr/

38

C110uF

5V

J1

CON2

12

U1

LM1117-5.0

3

1

2VIN

ADJ

VOUT

D1 LED

330R

C110uF

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3. Circuit Design

Circuit Design – Motor Control Circuit #1

39

R111K

C5

0.01uF

R230K

C4

220uF

Power State LED

C6

10uF

SW2

S/W

Vcc-15

D2

Red

D3

Red

C7

10uFC8

220uF

C2

10uF

C3

10uF

R38.2K

Vcc-15

Vcc-5

Vcc-15

L2

15uH

U2

TPS5430

BOOT1

NC2

NC3

VSENSE4

ENA5GND6VIN7PH8

Pw

Pd

9

VSNS1D4

B340A VSNS1

Vcc-3.3

R411K

L1

15uH

U1

TPS5430

BOOT1

NC2

NC3

VSENSE4

ENA5GND6VIN7PH8

Pw

Pd

9

VSNS2D1

B340A VSNS2

Vcc-3.3Vcc-5

R7330SW1

S/W

Vcc-24

Connector Regulator

R539K

J1

HEADER 2

12

R8220

J2

HEADER 2

12

R63.9K

C1

0.01uF

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3. Circuit Design


40

B9_CAP5_QEP4B10_CAP6_PEQ12

U11

SN74LVC4245A

VCCA1

DIR2

A13

A24

A35

A46

A57

A68

A79

A810

GND11

GND12

GND13B814B715B616B517B418B319B220B121OE22VCCB23VCCB24

Vcc-5 Vcc-3.3

Phase_A_A

Phase_A_IPhase_A_B

A10_CAP3_QEP11A9_CAP2_QEP2A8_CAP1_QEP1

Phase_B_A

RS485_RXD

Phase_B_I

G5_SCIRXDB

Phase_B_B

U9

MC3486

1B1

1A2

1Y3

1,2EN4

2Y5

2A6

2B7

GND8

3B93A103Y113,4EN124Y134A144B15VCC16

Vcc-5

Vcc-5

Encoder_A_APhase_A_A

Phase_A_I

Encoder_A_/A

Encoder_A_/B

Encoder_A_/IEncoder_A_I B8_CAP4_QEP3

Phase_A_BEncoder_A_B

R16

2K

Motor Driver

Encoder_A_BEncoder_A_I

EF

_1

Encoder_A_/A

J8

HEADER 5X2

246810

13579

Encoder_A_/BEncoder_A_/I

R17

2K

J6

HEADER 2

12

Vcc-5

OUT1_AOUT2_A

U7TLE5206-2G

OU

T1

1

EF

2

IN1

3

GN

D4

IN2

5

Vs

6

OU

T2

7

GN

D8

A0_P

WM

1

A1_P

WM

2

Encoder_A_A

Vcc-5

EF

_2

EF

_1

OU

T1_A

OU

T2_A

Vcc-24

Vcc-5

F10_MFSXA F11_MFSRAF12_MDXA

A0_PWM1

F4_SCITXDA

F13_MDRA

B8_CAP4_QEP3

G4_SCITXDB

A8_CAP1_QEP1

B9_CAP5_QEP4B10_CAP6_PEQ12

A9_CAP2_QEP2

A3_PWM4A2_PWM3

F5_SCIRXDA

A1_PWM2G5_SCIRXDB

A10_CAP3_QEP11

J10

HEADER 40x2

2468101214161820222426283032343638404244464850525456586062646668707274767880

13579

1113151719212325272931333537394143454749515355575961636567697173757779

Vcc-3.3

F8_MXLKXA F9_MCLKRA

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3. Circuit Design


D9

LE

D

F12_MDXA

F8_MXLKXA

Vcc-3.3

F10_MFSXA

R10

220

F13_MDRA

U3

74LVC3G14

1A1

3Y2

2A3

GND4

2Y53A61Y7VCC8

U4

74LVC3G14

1A1

3Y2

2A3

GND4

2Y53A61Y7VCC8

STATE LED PART

D5

LE

D

F9_MCLKRA

R11

220

F11_MFSRA

R12

220

R13

220

R14

220

D6

LE

D

R9

220

D7

LE

D

D8

LE

D

D10

LE

D

RS-232 Driver

F4_SCITXDA

F5_SCIRXDA

J3

HEADER 3

123

C18 0.1uF

C19 0.1uFC20

0.1uF

Vcc-5

Vcc-5

C21

0.1uF

C17 0.1uF

U5

MAX3232

GND15

VCC16

R1IN13

R2IN8

T2IN10

T1IN11

C1+1

C1-3

C2+4

C2-5

R1OUT12

R2OUT9

T1OUT14

T2OUT7

V+2

V-6

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3. Circuit Design

Circuit Design – Power

42

D5

Red

SW2

S/W

SW1

S/W

Motor_P

Vcc-7

Vcc-5 Vcc-3.3

R41K

J1

POWER_IN

12

R51K

D2

Red

D3

Blue

R91K

Vcc-7

R111K

R230K

C4

220uF

C2

10uF

R38.2K

C3

10uF

Vcc-3.3

L1

15uH

VSNS2

U1

TPS5430

BOOT1

NC2

NC3

VSENSE4

ENA5GND6VIN7PH8

Pw

Pd

9

D1

B340A VSNS2

C1

0.01uF

R739K

R83.9K

Vcc-7

C6

10uF

C7

10uF

C8

220uF

Vcc-5

L2

15uH

VSNS1

U2

TPS5430

BOOT1

NC2

NC3

VSENSE4

ENA5GND6VIN7PH8

Pw

Pd

9

D4

B340A VSNS1

R611K

C5

0.01uF

Motor_P

J3

Motor-Power

12 C9

0.1uFVcc-5

Vcc-3.3

C100.1uF

C110.1uF

J2

CON10A

1 23 45 67 89 10

TP1

T POINT A

TP2

T POINT A

TP3

T POINT A

TP4

T POINT A

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3. Circuit Design

Circuit Design – Motor

43

SHIFT_G23_LASER_RX_B

SHIFT_G29_MOTOR_RX_A

AVR_TX_1AVR_TX_2J3

Motor_Right

1 23 45 6

PWM1 PWM2

PWM3 PWM4

Vcc-5

SHIFT_CAMERA_RX

Vcc-5

L_encoder_A

J2

Motor_Lef t

1 23 45 6 L_encoder_B

R_encoder_BR_encoder_A

L_encoder_AL_encoder_B

R_encoder_BR_encoder_A

U1

SN74LVC4245A

VCCA1

DIR2

A13

A24

A35

A46

A57

A68

A79

A810

GND11

GND12

GND13B814B715B616B517B418B319B220B121OE22VCCB23VCCB24

Vcc-5 Vcc-3.3

5V -> 3.3V

Laser_TXD

G21_A_EQEP1BG20_A_EQEP1A

G24_A_EQEP1BG25_A_EQEP2B R

42

20

D1

LE

DG

14

_A

_L

ED

1

G15

_A

_L

ED

2

Vcc-3.3

D2

LE

D

R3

22

0

G0_A_PWM1 G2_A_PWM3G1_A_PWM2

C2

0.1uF

U2

L298/SO

GN

D1

IN17

IN29 IN3

13

IN415

GN

D20

OUT14

OUT25 OUT3

16

OUT417

GN

D10

GN

D11

VS6

VSS12

SENA2

SENB19ENA

8ENB

14

NC

3

NC

18

NC

21

C3

0.1uF

G3_A_PWM4

R81/1W

PWM1PWM2

PWM3

R9

1/1W

PWM4

D8DIODE

Vcc-7

D9DIODE

D10DIODE

D11DIODE

D12DIODE

D13DIODE

D14DIODE

D15DIODE

Vcc-5

G19_A_ENA_BG18_A_ENA_A

G14_A_LED1 G15_A_LED2

G22_LASER_TX_B

SHIFT_G29_MOTOR_RX_AG28_MOTOR_TX_A

SHIFT_G23_LASER_RX_B

J4

MOTOR_TMS320F2808

1 23 45 67 89 10

11 1213 1415 1617 1819 2021 2223 2425 2627 2829 30

31 3233 3435 3637 3839 4041 4243 4445 4647 4849 50

51525354555657585960

G0_A_PWM1G2_A_PWM3

G18_A_ENA_A

G24_A_EQEP1B

G20_A_EQEP1A

G3_A_PWM4G1_A_PWM2

G19_A_ENA_BG21_A_EQEP1B

G25_A_EQEP2B

Vcc-5

TP3

GNDTP1

T POINT A

TP2

T POINT A

J5

CAMERA->MOTOR

1 23 45 67 8

Laser_TXD G22_LASER_TX_B

Vcc-5Vcc-3.3

CAMERA_TX SHIFT_CAMERA_RX

C70.1uFC6

0.1uF

Vcc-3.3Vcc-3.3

R61K

R71K

SH

IFT

_G

29

_M

OT

OR

_R

X_

A

G28

_M

OT

OR

_T

X_

A

D6

Red

D7

Red

J6

MOTOR->SENSOR

1234567

AVR_TX_1

AVR_TX_2

Vcc-5

G28_MOTOR_TX_A

C4

0.1uF

C5

0.1uF

Vcc-3.3

CAMERA_TX

Robotics Exp. 1


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3. Circuit Design

3.3 ORCAD Suite Using Layout

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3. Circuit Design

Motivation

ORCAD is an entire software suite

Schematic

Simulation

Layout

ECO (Engineering Change Order)

Seamless conversion between different

components of software package

Online DRC (Design Rule Checking)

Industry standard software tool

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3. Circuit Design

Must use parts

Drawing boxes/lines/poly/…… to create parts will NOT

WORK!!! You must create parts!

Use off--page connectors, ports, hierarchal blocks, and busses to

clean up schematics

Schematics

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3. Circuit Design

Creating Parts

•1. Create a new library (A library is a collection of

parts)

File>New-->Library

•2. Create a new part

Right click on the library-->Add New Part

Name the part, don’’t change anything else

•3. Draw the part outline using the Place Rectangle tool

•4. Add pins using the Place Pin or the Place Pin Array tool

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3. Circuit Design

Migrating to Layout

• 1. Select the main design in the design window (the .dsn file)

•2. Select Tools-->Create Netlist

•3. Select the Layout Tab

•4.Check ““Run ECO to Layout

•5. Select OK

•6. Open ORCAD Layout

•7.Select File-->New

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Yeungnam Univ.

3. Circuit Design

Migrating to Layout

•8. Open the default technology (or a custom one)

•9. Open the netlist created in ORCAD Capture

•10. Select a filename to save the file as

•11. Select footprints for parts

If a footprint does not already exist, choose

ANY part that has the same number or more

pins than your part. We will create the footprint

later.

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Yeungnam Univ.

3. Circuit Design

ORCAD Layout

Layout is based on a set of spreadsheets

Commonly used spreadsheets:

Layers – – Contains information about all of the

available layers on the board

Nets – – Contains all of the nets imported from the

netlist

Footprints– Contains all of the footprints in the

design

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3. Circuit Design

Glossary

•Footprint – – Outline of a part and collection of pads

•Pad – – An area on the board for a pin to connect to

•Padstack – – A collection of pads for a part or project

•Traces – – Interconnection between different pads (nets)

•Via(Blind, buried) – – Via’s interconnect different layers

•Ratsnest – – All of the unrouted wires

•Copper Pour – – Large area of copper material (can be used to

make ground planes and many other things)

•Thermal Relief – – Copper pour on board to help with heat

dissipation

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3. Circuit Design

DRC – – Design Rule Check

Silkscreen (Nomenclature) – – Text printed on board

Solder Mask – – Chemical treatment on finished board to aid in

manufacturability and ease assembly. Also protects board againstt

minor abrasions and the environment

SMD – – Surface Mount Devices (vs Through Hole Devices)

Glossary

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Yeungnam Univ.

3. Circuit Design

Layout Toolbar

Board Outline

• 1.Select the Obstacle Tool

• 2.Right click and select new

• 3.Right click and select properties

• 4.Change the Obstacle Type to Board Outline

• 5.Change the Width to 12

• 6.Change the Obstacle Layer to Global Layer

• 7.Select OK

• 8.Left click and draw board, double click when

finished

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Yeungnam Univ.

3. Circuit Design

Board Outline

NOTE:

Boards can only have one board outline, make sure its on the

global layer!

Some manufactures will not do fancy board outlines or cutouts

in the middle of the board. Check with manufacturer or just

keep it simple!

The pullback width is 1/2 the width of the board outline.

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3. Circuit Design

•1.Start the Library Manager

•2.Click on Create New Footprint

•3.Name the footprint

•4.Create the following obstacles:

Place Outline (Top Layer, width 6)

Detail Outline (SST Layer, width 6)

Detail Outline (AST Layer, width 6)

•5.Open the padstacks spreadsheet

Creating Footprints

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3. Circuit Design

Creating Footprints

• 6.Create pads for the pins that you need

This is only required if the pads are not in the default technology file.

Most pads are…this should only be necessary for special surface

mount parts!

• 7.Select the Pin tool

• 8.Place all the pins

• 9.Edit the text on the SST and AST layers

• 10.Save! Do not forget to save.

• NOTE:

All of the information about the package is found in the datasheet, look

it up! Don’t try and guess the size of the parts!!

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3. Circuit Design

Placing Components

• 1.Turn on reconnect mode (this hides the ratsnest and makes it easier

• 2.Turn off the DRC

• 3.Select the component tool

• 4.Click on a component and move it to a new location (it must be

Inside of the board outline)

To rotate a part, press R while the part is selected

To place a part on the other side of the board, press 1 (for top

layer)or 2 (for bottom layer) while the part is selected

• 5.Repeat step 4 until all components have been placed

• 6.Turn on the DRC

• 7.Turn off reconnect mode

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3. Circuit Design

Placing Components

• 8.Check for placement errors by clicking on Design Rule Check

• 9.To view errors, select the Errors spreadsheet

• 10.Fix all placement errors

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3. Circuit Design

Routing

• 1.Open the layers spreadsheet

• 2.Setup the layers by changing layer type between

{Unused, Routing, and Plane}

Single sided board – – Bottom (Routing), all others (Unused)

Double sided board – – Top & Bottom (Routing), all outers

(unused)

Multilayer board – – Top, Bottom, inner layers (Routing or Plane),

all others (unused)

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3. Circuit Design

Autorouting vs Manual

• Autorouting

Traces are routed by the tool Unfortunately, the autorouter that comes

with the free version of ORCAD is not very good..

There are 3rd party tools that are VERY good, but also very expensive

• Manual Routing

Time consuming

Ultimate control

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3. Circuit Design

Manual Routing

Select either the Edit Segment or the Add/Edit Route tool

The different tools work slightly differently, use

which ever you are more comfortable with

2. Click on an unrouted net and route the net

To insert a via (connection between traces on different layers or

traces and planes), press ‘‘V’’ or click the mouse to end a segment

and press the layer number (1– top, 2– bottom, 3– ground, 4 –

power, ……)

If you have a plane layer, a connection is made to the plane

layer by simply inserting a via (for through hole components, the

connection is already made)

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3. Circuit Design

Autorouting

• Select Auto-->Autoroute-->Board from the menu

Depending on the complexity of the board,this may take a very

long time.

Do not think that this is the one step solution!You will need to go

back and manual fix up the design.

• Cleanup the design

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3. Circuit Design

Routing Tips

• Always route power and ground traces first

• Always route high frequency traces next

• Avoid square corners, 45 and 135 are better

• Avoid exiting pads at odd angles

• Make traces sufficiently large for current

• Capacity

• Minimize the number of vias

• Avoid loops in ground traces, a plane or star

• configuration are the best

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Yeungnam Univ.

3. Circuit Design

Mounting Holes

• 1. Select the component tool

• 2. Right click and create a new component

• 3. Name the component

• 4. Change the footprint to“MTHOLE1”

• 5. Place the component on the board

If you want to connect the hole to a net (say GND),

use the connection tool to draw a net to ground

If you want smaller/larger mounting holes change

the size of the footprint for MTHOLE1

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Yeungnam Univ.

3. Circuit Design

Nomenclature

• 1. Select the text tool

• 2. Move around the text on the SST or SSB layers (do not worry about

AST/ASB)

• 3.Right click and select new to add new text

Check with your manufacturer on the minimum line

width.

Do not place nomenclature over vias, pads, or holes. It can go

over traces but may not look quite as you expect it to.

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3. Circuit Design

Post Processing

• 1. Verify that there are no errors in the design (Auto-->Design Rule

Check)

• 2. Cleanup any errors before continuing

• 3.Run the post processor (Auto-->Run Post Processor)

This will generate the Gerber files that the manufacturer will

need to create the PCB. Download a free Gerber view and

check your files before you send them off.

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Yeungnam Univ.

3. Circuit Design

PCB tips

• Main idea is to join the component pins that need to be joined, but

there are some tips:

• Ground and power conductors should be large, as straight and direct

as possible.

• All conductors should be as short and direct as possible (avoid sharp

turns which increase inductance).

• For two-sided boards, it often helps to prefer horizontal runs on one

side, vertical on the other.

• Keep large signals away from small ones.

• Place bypass capacitors physically close to the pins being bypassed.

• Use sockets for expensive components, or components that may

need to be replaced.

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3. Circuit Design

the pull-down resistor pulls the voltage down to zero.

If the pull-up switch is pressed, it pulls the voltage up to whatever the + supply is.

the pull-up resistor pulls the voltage up to whatever the + supply is.

If the pull-down switch is pressed, it pulls the voltage down to zero

68

Solved problems

Problem 3.2.1 Explain the operation of the following circuit.

Sol)

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3. Circuit Design

Review questions

Question 3.2.1 Explain the following terms.

a) Active filter,

Question 3.2.2 What is the primary difference between the NPN and PNP

amplifiers?

Question 3.2.3 Explain the Voltage Regulator Circuit Diagram shown below.

69

http://www.researchcell.com/wp-content/uploads/2010/01/Voltage-Regulator-Circuit-Diagram.gif

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3. Circuit Design

Question 3.2.4 Explain the following “interfacing of four different modules

using conventional level shifters”.

Question 3.2.5 Draw voltage regulator with LM2575 using OrCAD.

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3. Circuit Design

71

1. http://www.avrmall.com/ishop/goods_detail.php?goodsIdx=4205

References

Documents

3Circuitdesign(140401)