AN1451 APPLICATION NOTE

2/43

Table of Contents

1

INTRODUCTION ................................................................................................................................1

2

DESIGNING AN APPLICATION WITH L6208 ...................................................................................3

2.1

Current Ratings ........................................................................................................................3

2.2

Voltage Ratings and Operating Range ....................................................................................3

2.3

Choosing the Bulk Capacitor....................................................................................................5

2.4

Layout Considerations .............................................................................................................6

2.5

Sensing Resistors ....................................................................................................................8

2.6

Charge pump external components .........................................................................................9

2.7

Sharing the Charge Pump Circuitry .......................................................................................10

2.8

Reference Voltage for PWM Current Control.........................................................................11

2.9

Input Logic pins ......................................................................................................................12

2.10

EN pin ....................................................................................................................................12

2.11

Programmable off-time Monostable ......................................................................................13

2.11.1 Off-time Selection and minimum on-time ........................................................................15

2.11.2 Decay Modes ..................................................................................................................16

2.12

Over Current Protection ........................................................................................................18

2.13

Power Management ..............................................................................................................21

2.13.1 Maximum output current vs. selectable devices..............................................................22

2.13.2 Power Dissipation Formulae for different sequences ......................................................22

2.14

Choosing the Decay Mode....................................................................................................25

2.15

Choosing the Stepping Sequence.........................................................................................26

2.16

Microstepping........................................................................................................................27

3

APPLICATION EXAMPLE................................................................................................................30

3.1

Decay mode, sensing resistors and reference voltage. .........................................................30

4

APPENDIX - EVALUATION BOARDS .............................................................................................31

4.1

PractiSPIN..............................................................................................................................31

4.2

EVAL6208N ...........................................................................................................................33

4.2.1 Important Notes ................................................................................................................34

4.2.2 Thermal Impedance .........................................................................................................34

4.3

EVAL6208PD .........................................................................................................................38

4.3.1 Important Notes ................................................................................................................39

4.3.2 Thermal Impedance .........................................................................................................39

5

REFERENCES.................................................................................................................................43