|
|
||
|
Tech
Support: Applications Note 25 |
|
||||||||||||||||||||||||||||||
OPTIONAL OPTOISOLATED I2C INTERFACE The SMH4804 and SMT4004 are usually connected to separate I2C busses, one on the Primary and the other on the Secondary-side of the line card (connected separately to J1 and J5 SMX3200 I2C Headers). However, an optional optically-isolated I2C serial programming bus extends the usefulness of the programmable circuits mentioned herein beyond simple tweaking to field applications where system maintenance, cycling or repairs must be made with minimal down-time. A readily available, low-voltage CMOS logic-level opto-isolator with open drain outputs allows programming of the primary and secondary-side components using the same I2C serial bus (Figure 8). The addition of a low-power, isolated DC-DC converter (U12) allows the system card to be removed for closer inspection. Shown here on the primary-side, the converter is as easily used on the secondary-side if required (Figure 13).
Vendor Part Numbers & Contact Info: 3.3V Digital
Opto-Coupler, HCPL-063L: DC-DC
Converter, B1-0505SSH: Caution:
If the system card is live when a programming interface
cable is connected, be certain the GND connection of the
interface cable is not connected to earth. Otherwise damage
and or injury may result.
 Figure 6: Optional Isolated I2C Interface: Powered and Driven from the Primary-Side |
||||||||||||||||||||||||||||||
|
SPECIAL
NOTE: The HTML version of the application
note has been divided into multiple pages
to mimic the PDF version. You may use the
menu here or at the bottom of the page to
jump to any of the other pages. You may
also download/view the entire application
note in PDF format [PDF
format].
|
||||||||||||||||||||||||||||||
Figure
11: Isolated I2C Interface: Powered from
the Primary-Side, the rise time of the SDA
Secondary-Side Waveforms
Figure
12: Isolated I2C Interface: Powered from
the Primary-Side, the fall time of the SDA
Secondary-Side Waveforms
|
||||||||||||||||||||||||||||||
|
SPECIAL
NOTE: The HTML version of the application
note has been divided into multiple pages
to mimic the PDF version. You may use the
menu here or at the bottom of the page to
jump to any of the other pages. You may
also download/view the entire application
note in PDF format [PDF
format].
|
||||||||||||||||||||||||||||||
SUMMIT Microelectronics, Inc. reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. SUMMIT Microelectronics, Inc. assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained herein reflect representative operating parameters, and may vary depending upon a user's specific application. While the information in this publication has been carefully checked, SUMMIT Microelectronics, Inc. shall not be liable for any damages arising as a result of any error or omission. SUMMIT Microelectronics, Inc. does not recommend the use of any of its products in life support or aviation applications where the failure or malfunction of the product can reasonably be expected to cause any failure of either system or to significantly affect their safety or effectiveness. Products are not authorized for use in such applications unless SUMMIT Microelectronics, Inc. receives written assurances, to its satisfaction, that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; and (c) potential liability of SUMMIT Microelectronics, Inc. is adequately protected under the circumstances.
Copyright © 2002 SUMMIT MICROELECTRONICS, Inc. I2C is a trademark of Philips Corporation. |
||||||||||||||||||||||||||||||
return
to top