cd00205733

AN2813
Application note
TDE1708DFT in IO-Link applications
1
Introduction
This application note investigates the possibility of using a TDE1708DFT switch for the
physical layer transmitter realization of 3-wire IO-Link sensors.
The TDE1708DFT is an integrated power switch especially dedicated to proximity detectors.
It can deliver up to 250 mA, enables high-side and low-side configurations and includes
a number of protections.
According to the IO-Link Communication Specification (see Section 8: References -3. and
for the TDE1708DFT features - see Section 8: References - 1.) two basic slave transmitter
configurations were tested (see Figure 1):
■
p-switching (high-side) driver
■
p-switching driver with an additional n-switching (low-side) driver (push-pull operation)
Figure 1.
P-switching slave drive and p-switching with n-switching slave drive
PSWITCHINGSLAVEDRIVE
SLAVE LINE
PSWITCHINGWITHNSWITCHINGSLAVEDRIVER
MASTER
SLAVE
,
LINE
MASTER
,
ON
OFF ON
OFF #1
#13
#1
#1-
),,-
,n
ON
OFF #13
#1-
),,-
,n
!-
In the following test arrangements the input load current (ILLM) is fixed to 10 mA which
represents the average master current sink value specified for a 3-wire system. The master
(CQM), slave (CQL), and line capacitances are set together at 4.7 nF, corresponding to the
maximum parasitic capacitance of the system.
February 2011
Doc ID 14923 Rev 1
1/25
www.st.com
Contents
AN2813
Contents
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2
TDE1708DFT in high-side configuration . . . . . . . . . . . . . . . . . . . . . . . . . 5
3
2.1
High-side configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2
High-side configuration with a capacitive load . . . . . . . . . . . . . . . . . . . . . . 7
TDE1708DFT in low-side configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1
Low-side configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2
Low-side configuration with a capacitive load . . . . . . . . . . . . . . . . . . . . . 11
4
Push-pull configuration with TDE1708DFT . . . . . . . . . . . . . . . . . . . . . . 13
5
Performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6
5.1
Dynamic information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.2
Temperature characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Alternative driving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.1
Temperature characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
8
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
9
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2/25
Doc ID 14923 Rev 1
AN2813
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Push-pull configuration dynamic information
(VCC = 24 V; TJ = 25 °C; CL = 4.7 nF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Dynamic information (VCC = 24 V; TJ = 25 °C; IL = 10 mA) . . . . . . . . . . . . . . . . . . . . . . . . 18
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Doc ID 14923 Rev 1
3/25
List of figures
AN2813
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
4/25
P-switching slave drive and p-switching with n-switching slave drive. . . . . . . . . . . . . . . . . . 1
High-side switch test configuration schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
High-side switch configuration turn-on behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
High-side switch configuration turn-off behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
High-side switch test configuration schematic with a capacitive load . . . . . . . . . . . . . . . . . . 7
High-side switch configuration with a capacitive load turn-on behavior . . . . . . . . . . . . . . . . 8
High-side switch configuration with a capacitive load turn-off behavior . . . . . . . . . . . . . . . . 8
Low-side switch test configuration schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Low-side switch configuration turn-on behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Low-side switch configuration turn-off behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Low-side switch test configuration schematic with a capacitive load . . . . . . . . . . . . . . . . . 11
Low-side switch configuration with a capacitive load turn-on behavior . . . . . . . . . . . . . . . 12
Low-side switch configuration with capacitive load turn-off behavior . . . . . . . . . . . . . . . . . 12
Push-pull test configuration schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Push-pull configuration with capacitive load rising edge . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Push-pull configuration with capacitive load falling edge . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Software timing example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Propagation turn-on time vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Propagation turn-off time vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Alternative driving schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Alternative driving timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Delay propagation turn-on time vs. temperature (H. S. configuration) . . . . . . . . . . . . . . . . 22
Delay propagation turn-on time vs. temperature (L. S. configuration) . . . . . . . . . . . . . . . . 22
Propagation turn-off time vs. temperature (H. S. configuration) . . . . . . . . . . . . . . . . . . . . . 23
Propagation turn-off time vs. temperature (L. S. configuration) . . . . . . . . . . . . . . . . . . . . . 23
Doc ID 14923 Rev 1
Doc ID 14923 Rev 1
'.$
VOLTAGE LEVEL 6
PULSE WIDTH
FREQUENCYK( Z
).054
'.$
#
N&
/54
, 3
6S
'.$
'.$
(3/54
,%$$2)6%2
$%,!9
).
6
2%'6
5
4$%$&4
HIGHSIDEDRIVER
#
N&
'.$
6##
/54054
'.$
1
"#
#
2
TDE1708DFT in high-side configuration
2.1
High-side configuration
!-
'.$
$
43
2
'.$
$
"!4
6##
CURRENTSINKM!
Figure 2.
GENERATOR
AN2813
TDE1708DFT in high-side configuration
High-side switch test configuration schematic
5/25
TDE1708DFT in high-side configuration
Figure 3.
AN2813
High-side switch configuration turn-on behavior(1)
1. CH1: input voltage, CH2: output voltage, CH4: output current (x10).
Figure 4.
High-side switch configuration turn-off behavior(1)
1. CH1: input voltage, CH2: output voltage, CH4: output current (x10).
6/25
Doc ID 14923 Rev 1
Doc ID 14923 Rev 1
'.$
VOLTAGELEVEL 6
PULSEWIDTH
FREQUENCYK(Z
).054
'.$
#
N&
$%,!9
'.$
'.$
(3/54
6
2%'6 6S
, 3/54
). ,%$$2)6%2
5
4$%$&4
'.$
#
N&
6##
/54054
'.$
#
N&
#1
'.$
2
1
"#
!-
'.$
$
#
43 —&
2
'.$
$
"!4
6##
CURRENT SINKM!
Figure 5.
HIGHSIDEDRIVER
2.2
GENERATOR
AN2813
TDE1708DFT in high-side configuration
High-side configuration with a capacitive load
High-side switch test configuration schematic with a capacitive load
7/25
TDE1708DFT in high-side configuration
Figure 6.
AN2813
High-side switch configuration with a capacitive load turn-on behavior(1)
1. CH1: input voltage, CH2: output voltage, CH4: output current (x10).
Figure 7.
High-side switch configuration with a capacitive load turn-off behavior(1)
1. CH1: input voltage, CH2: output voltage, CH4: output current (x10).
8/25
Doc ID 14923 Rev 1
Doc ID 14923 Rev 1
'.$
VOLTAGELEVEL6
PULSEWIDTH
FREQUENCYK(Z
).054
'.$
#
N&
'.$
'.$
(3/54
,%$$2)6%2
$%,!9
).
6S
, 3/54
62%'6
5
4$%$&4
LOWSIDEDRIVER
'.$
6##
#
N&
/54054
$
"!4
1
"#
2
6##
'.$
6##
!-
$
43 #
2
6##
CURRENT SOURCEM!
Figure 8.
GENERATOR
AN2813
TDE1708DFT in low-side configuration
3
TDE1708DFT in low-side configuration
3.1
Low-side configuration
Low-side switch test configuration schematic
9/25
TDE1708DFT in low-side configuration
Figure 9.
AN2813
Low-side switch configuration turn-on behavior(1)
1. CH1: input voltage, CH2: output voltage, CH4: output current (x10).
Figure 10. Low-side switch configuration turn-off behavior(1)
1. CH1: input voltage, CH2: output voltage, CH4: output current (x10).
10/25
Doc ID 14923 Rev 1
Doc ID 14923 Rev 1
'.$
VOLTAGE LEVEL6
PULSEWIDTH
FREQUENCYK(Z
).054
'.$
#
N&
'.$
'.$
(3/54
$%,!9
6
6 6S
2%'
,3/54
). ,%$$2)6%2
5
4$%$&4
LOWSIDEDRIVER
'.$
#
N&
6##
/54054
'.$
#
N&
#1
2
$
43
6##
$
"!4 '.$
1
"#
2
6##
!-
#
6##
CURRENTSOURCEM!
3.2
GENERATOR
AN2813
TDE1708DFT in low-side configuration
Low-side configuration with a capacitive load
Figure 11. Low-side switch test configuration schematic with a capacitive load
11/25
TDE1708DFT in low-side configuration
AN2813
Figure 12. Low-side switch configuration with a capacitive load turn-on behavior(1)
1. CH1: input voltage, CH2: output voltage, CH4: output current (x10).
Figure 13. Low-side switch configuration with capacitive load turn-off behavior(1)
1. CH1: input voltage, CH2: output voltage, CH4: output current (x10).
12/25
Doc ID 14923 Rev 1
AN2813
4
Push-pull configuration with TDE1708DFT
Push-pull configuration with TDE1708DFT
The following push-pull driver configuration was designed based on the previous single
driver measurements. In this proposed schematic (see Figure 14) two additional
components (R3, D3) must be added to speed up the turning off of the driver in the low-side
configuration. The resistor R3 creates a weak pull-up while the diode D3 separates the lowside output from the high-side. The reason for this being that if the low-side driver is forced
high in a short time after turning off then it stays turned on with all the subsequent effects.
Doc ID 14923 Rev 1
13/25
14/25
Doc ID 14923 Rev 1
'.$
,3).054
VOLTAGELEVEL 6
PULSEWIDTH
FREQUENCYK(Z
GENERATOR
(3).054
'.$
#
N&
'.$
#
N&
'.$
'.$
'.$
(3/54
,%$$2)6%2
$%,!9
).
/54
, 3
6
6S
2%'6
5
4$%$&4
LOWSIDEDRIVER
'.$
$%,!9
(3/54
6
6S
2%'6
/54
, 3
). ,%$$2)6%2
5
4$%$&4
HIGHSIDEDRIVER
'.$
#
N&
6##
'.$
#
N&
6##
, 3/54054
2
6##
$
"!4
(3/54054
'.$
#
N&
#1
'.$
2
1
"#
#
!-
'.$
$
43
2
'.$
$
"!4
6##
CURRENT SINKM!
Push-pull configuration with TDE1708DFT
AN2813
Figure 14. Push-pull test configuration schematic
The low-side driver helps to reduce the falling time with the capacitive load, the rest of the
circuit works exactly the same way as that described in Section 2.1. Figure 17 shows a
software timing example in accordance with Table 2 and a dead time between the driver
outputs of 1 µs.
AN2813
Push-pull configuration with TDE1708DFT
Table 1.
Push-pull configuration dynamic information
(VCC = 24 V; TJ = 25 °C; CL = 4.7 nF)
Test conditions
Min
Typ
Max
Unit
Turn-on time
Vi = 0 to 5 V
800
ns
Turn-off time
Vi = 0 to 5 V
2
µs
Figure 15. Push-pull configuration with capacitive load rising edge(1)
1. CH1: input voltage, CH2: (H. S.) output voltage, CH3: input voltage, CH4: (L. S.) output voltage.
Doc ID 14923 Rev 1
15/25
Push-pull configuration with TDE1708DFT
Figure 16. Push-pull configuration with capacitive load falling edge (1)
1. CH1: input voltage, CH2: (H. S.) output voltage, CH3: input voltage, CH4: (L. S.) output voltage.
16/25
Doc ID 14923 Rev 1
AN2813
AN2813
Push-pull configuration with TDE1708DFT
Figure 17. Software timing example
Doc ID 14923 Rev 1
17/25
Performance characteristics
AN2813
5
Performance characteristics
5.1
Dynamic information
Table 2.
Dynamic information (VCC = 24 V; TJ = 25 °C; IL = 10 mA)
Test conditions
5.2
Min
Typ
Max
Unit
Propagation turn-on time
Vi = 0 to 5 V
16
µs
Propagation turn-off time
Vi = 0 to 5 V
8
µs
Temperature characteristics
Figure 18. Propagation turn-on time vs. temperature
n
n
4EMPERATURE #
!-
Figure 19. Propagation turn-off time vs. temperature
n
n
4EMPERATURE #
!-
18/25
Doc ID 14923 Rev 1
AN2813
6
Alternative driving
Alternative driving
The larger temperature propagation turn-on time dependence of the TDE1708DFT,
described in the previous section (Section 5: Performance characteristics), has led to the
development of an alternative kind of driving which would not suffer from this problem. The
presented driving configuration (see Figure 20) uses both the input signal “IN” together with
the open collector pin “DELAY” (originally dedicated to delay adjustment). The IN signal
controls only the turning off of the switch (the output is blocked by the DELAY pin during its
high state), while the DELAY signal then controls the turning on of the switch (see
Figure 21). This principle results in more positive temperature characteristics (Section 6.1:
Temperature characteristics).
Doc ID 14923 Rev 1
19/25
Alternative driving
AN2813
'.$
$%,!9
'.$
(3/54
'.$
VOLTAGE LEVEL 6
PULSE WIDTH
FREQUENCYK(Z
GENERATOR
).054
2
#
N&
'.$
,3/54
,%$$2)6%2
).
62%' 6
5
4$%$&4
DRIVER
6S
6##
'.$
#
N&
!-
Figure 20. Alternative driving schematics
1. The resistor R1 prevents the circuit from the cross conduction between the push-pull output of the
generator and the open collector DELAY pin.
20/25
Doc ID 14923 Rev 1
AN2813
Alternative driving
Figure 21. Alternative driving timings
/.
/54 /&&
).
$%,!9
—S
3TATE 3TATE 3TATE 3TATE 3TATE 3TATE 3TATE 3TATE 3TATE
!-
1. Delay propagation turn-on time (see Figure 22 and Figure 23).
2. Propagation turn-off time (see Figure 24 and Figure 25).
3. State 1: DELAY releases the output.
4. State 3: IN goes low and turns off the switch.
5. State 4: IN goes high, the output is blocked by the DELAY signal (the monostable circuit time meanwhile runs).
Doc ID 14923 Rev 1
21/25
Alternative driving
6.1
AN2813
Temperature characteristics
Figure 22. Delay propagation turn-on time vs. temperature (H. S. configuration)
n
n
4EMPERATURE #
!-
Figure 23. Delay propagation turn-on time vs. temperature (L. S. configuration)
n
n
4EMPERATURE #
!-
22/25
Doc ID 14923 Rev 1
AN2813
Alternative driving
Figure 24. Propagation turn-off time vs. temperature (H. S. configuration)
n
n
4EMPERATURE #
!-
Figure 25. Propagation turn-off time vs. temperature (L. S. configuration)
n
n
4EMPERATURE #
!-
Doc ID 14923 Rev 1
23/25
Conclusion
7
AN2813
Conclusion
With respect to the results obtained, the TDE1708DFT may be used in the operating mode
COM1 (4.8 kBaud) in p-switching (high-side) 3-wire sensors and up to operating mode
COM2 (38.4 kBaud) in push-pull 3-wire sensors.
Note:
In the case of push-pull configuration a precise compensation of the propagation turn-on
time temperature drift (Figure 18) is necessary to avoid cross conduction of the two
switches. The alternative driving configuration (Section 6: Alternative driving) partially
solves this issue for the price of employing two input pins for one switch.
8
References
9
1.
TDE1708DFT datasheet.
2.
AN495 application note.
3.
IO-Link Communication Specification, Version 0.98, February 2007 - see:
www.io-link.com/share/Downloads/IOL-Comm-Spec_10002_V10_090118.pdf.
Revision history
Table 3.
24/25
Document revision history
Date
Revision
09-Feb-2011
1
Changes
Initial release.
Doc ID 14923 Rev 1
AN2813
Please Read Carefully:
Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the
right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any
time, without notice.
All ST products are sold pursuant to ST’s terms and conditions of sale.
Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no
liability whatsoever relating to the choice, selection or use of the ST products and services described herein.
No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this
document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products
or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such
third party products or services or any intellectual property contained therein.
UNLESS OTHERWISE SET FORTH IN ST’S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED
WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS
OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT.
UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE, ST PRODUCTS ARE NOT
RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING
APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY,
DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE
GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER’S OWN RISK.
Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void
any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any
liability of ST.
ST and the ST logo are trademarks or registered trademarks of ST in various countries.
Information in this document supersedes and replaces all information previously supplied.
The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners.
© 2011 STMicroelectronics - All rights reserved
STMicroelectronics group of companies
Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America
www.st.com
Doc ID 14923 Rev 1
25/25
Similar pages