External Clamping

Application Note, Rev. 1.0, April 2008
Application Note
TLE8110EE
External Clamping with the TLE8110EE
By Max Bacher
Automotive Power
Application Note
External Clamping with the TLE8110EE
1
Abstract .......................................................................................................................................3
2
2.1
2.2
Introduction.................................................................................................................................3
Basic setup and graphical calculation of the clamping energy ......................................................3
Calculate clamping energy............................................................................................................5
3
3.1
3.2
3.3
External Zener diode ..................................................................................................................6
Application circuit..........................................................................................................................6
Measurements..............................................................................................................................7
Conclusion..................................................................................................................................12
4
4.1
4.2
4.3
External free wheeling diode ...................................................................................................14
Application circuit........................................................................................................................14
Measurements............................................................................................................................15
Conclusion..................................................................................................................................16
5
5.1
5.2
5.3
External resistor .......................................................................................................................17
Application circuit........................................................................................................................17
Measurements............................................................................................................................18
Conclusion..................................................................................................................................20
6
6.1
6.2
6.3
External resistor with free wheeling diode .............................................................................22
Application circuit........................................................................................................................22
Measurements............................................................................................................................23
Conclusion..................................................................................................................................25
7
7.1
7.2
Appendix ...................................................................................................................................27
Table of Figures..........................................................................................................................27
Revision History Table Example .................................................................................................28
Application Note
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Application Note
External Clamping with the TLE8110EE
1
Abstract
The objective of this application note is to demonstrate the external clamping behavior of the TLE8110EE
with external Zener Diode. The other two possibilities (external free wheeling diode and external free
wheeling resistor) are not the focus of this application note - but they are briefly illustrated. The test
conditions, the lab setup, the measurements and differences between the methods are described.
The clamping energy which can be safely dissipated inside the TLE8110EE is restricted to the energy values
given in the data sheet. When there are loads with a higher clamping energy it is necessary to have an
external clamping unit. For an overview of the permitted loads for the TLE8110EE, please refer to the
relevant section of the data sheet.
The TLE8110EE is a member of the Flex family and is a smart 10 channel low-side switch for engine
management loads (injectors, solenoids, relays, unipolar stepper motors…).
For a more detailed appreciation of the capabilities of the TLE8110EE, please refer to the data sheet.
2
Introduction
Note:
•
All measurements in this application note have been undertaken accurately but the results are not
guaranteed. This application note can be changed without prior notification
•
Please refer to the official TLE8110EE data sheet for detailed technical descriptions.
2.1
Basic setup and graphical calculation of the clamping energy
Figure 1 shows the circuit with the TLE8110EE for the first measurements to declare the internal clamping
behavior. The colored marked signals in Figure 1 are plotted in Figure 2.
Basic setup (this setup is used as basic setup for all circuits in this application note):
•
Vbat…14 V
•
Vdd…5 V
•
Vcc...5 V
•
R…9 Ohm
•
L…15 mH
•
Channel under test is Ch2
•
Output current is in the range of 1.55 A
The reason to choose this load was that we are able to compare the behaviors from external clamping in a
direct way with the TLE8110EE clamping. There are no problems for the TLE8110EE without external
clamping with this load.
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Application Note
External Clamping with the TLE8110EE
5V
5V
5V
Vdd
14V
Vcc
Vbat
SPI_CS
OutI
TLE8110EE
SPI_CLK
µC
A MP-Ch3
R = 9 Ohm
L = 15 mH
SPI_SI
SPI_SO
R
OutV
L
V MP-Ch2
InV
V MP-Ch1
Max Bacher
TLE8110EE_Circuit.vsd
GND
Figure 1 TLE8110EE connected to a load
Figure 2 shows the clamping behavior. The “Math Channel” (the red one) describes the clamping power and
is calculated as channel 2 (output voltage) multiplied by channel 3 (the output current).
Temperature: 25°C, Clamping Energy
Clamping Voltage: 55V
Clamping Voltage: 55V
Max. Clamping Power: 84.4W
Saturation Time: 7.9ms
Max. Current: 1.55A
Clamping Time: 520us
Clamping Time: 0.52ms
Clamping Energy TLE8110EE, 25°C
Max. Clamping Power: 84.4W
Max Bacher
Energy_25C4ms.emf
Clamping Energy (graphical): 21.9mJ
Clamping Energy TLE8110EE, 25°C, Detail
Max Bacher
Energy_25C4ms.emf
Figure 2 Clamping with inductive and ohmic load to show the clamping energy
The clamping energy can be calculated in a graphical way. The approximate clamping energy which is easy
to calculate is the area below the dashed blue line marked with dotted blue lines, seen on the right side of
Figure 2. When we calculate the energy graphical we get this value: E = 21.94mJ (Max. clamping power *
0.5 * clamping time = 84.4W * 520µs * 0.5).
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External Clamping with the TLE8110EE
2.2
Calculate clamping energy
There are two well-known equations to calculate the clamping energy for an inductive load. Equation 1 has
to be used when there is also an ohmic part for the load. Equation 2 could be used when there is no ohmic
part - or the ohmic part is near zero - for the load.
Abbreviations for the Equations:
•
VAZ…Voltage Active Zener Clamping (for low side switches: VAZ = VDS(CL))
•
VDS(CL)…Voltage Drain Source during Clamping
•
Vbat..Battery Voltage
•
I0…Saturation Current
Vbat − VDS (CL ) 


R ⋅ I0
 + I0  ⋅ L
E = VDS (CL ) ⋅ 
⋅ ln1 −
 V −V

R

 R
bat
DS ( CL ) 

Equation 1 For the clamping energy of a low side switch with an ohmic part of the inductive load
E=
VDS (CL )
1
2
⋅ L ⋅ I0 ⋅
2
VDS (CL ) − Vbat
Equation 2 For the clamping energy of a low side switch with no ohmic part of the inductive load
For the basic setup - shown in Figure 1 - we calculate with the Equation 1 the clamping energy: E =
19.79mJ. Please be aware: We have to use the Equation 1 because there is an ohmic part for the load.
When we calculate with Equation 2 than we get: E = 24.17mJ.
An overview about the different possibilities to get a result for the clamping energy:
•
With graphical calculation:
E = 21.94mJ
•
With Equation 1:
E = 19.79mJ
•
With Equation 2:
E = 24.17mJ
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External Clamping with the TLE8110EE
3
External Zener diode
3.1
Application circuit
Figure 3 shows the circuit of the TLE8110EE with Zener diode for external clamping. The colored marked
signals in Figure 3 are plotted in Figure 4 to Figure 15 to have a better overview.
5V
5V
Vdd
5V
14V
Vcc
OutI
SPI_CS
SPI_CLK
TLE8110EE
A MP-Ch3
R = 9 Ohm
L = 15 mH
DZ = 39V, 3A
SPI_SI
µC
Vbat
SPI_SO
R
OutV
V MP-Ch2
InV
V MP-Ch1
GND
L
Zener Diode
DZ
Max Bacher
ZDiode_Circuit.vsd
Figure 3 TLE8110EE with Zener diode for external clamping
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External Clamping with the TLE8110EE
3.2
Measurements
Figure 4 to Figure 6 show the clamping behavior with the Zener diode for -40°C. This is the temperature for
the TLE8110EE and also for the Zener diode. The figures show always the comparisons with the original
TLE8110EE clamping. The setup and the load are always the basic setup shown in chapter 2.1.
Figure 4 Comparing the clamping voltages for internal and external clamping with Zener diode at 40°C
Temperature: -40°C, Clamping Time
Ex. Zener Diode
Clamping Voltage: 54V
Clamping Voltage: 34.4V
Clamping Time: 520us
Clamping Time: 880us
Clamping TLE8110EE, -40°C
Max Bacher
TLE8110EE_-40C100us.emf
Clamping external Zener Diode, -40°C
Max Bacher
ZDode_BZG_-40C100us.emf
Figure 5 Comparing the clamping time for internal and external clamping with Zener diode at -40°C
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External Clamping with the TLE8110EE
Figure 6 Comparing the voltage peak for internal and external clamping with Zener diode at -40°C
Figure 7 to Figure 9 show the clamping behavior with the Zener diode for 25°C. This is the temperature for
the TLE8110EE and also for the Zener diode. The figures show always the comparisons with the original
TLE8110EE clamping. The setup and the load are always the basic setup shown in chapter 2.1.
Figure 7 Comparing the clamping voltages for internal and external clamping with Zener diode at
25°C
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External Clamping with the TLE8110EE
Figure 8 Comparing the clamping time for internal and external clamping with Zener diode at 25°C
Figure 9 Comparing the voltage peak for internal and external clamping with Zener diode at 25°C
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External Clamping with the TLE8110EE
Figure 10 to Figure 12 show the clamping behavior with the Zener diode for 125°C. This is the temperature
for the TLE8110EE and also for the Zener diode. The figures show always the comparisons with the original
TLE8110EE clamping. The setup and the load are always the basic setup shown in chapter 2.1.
Figure 10 Comparing the clamping voltages for internal and external clamping with Zener diode at
125°C
Figure 11 Comparing the clamping time for internal and external clamping with Zener diode at 125°C
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External Clamping with the TLE8110EE
Figure 12 Comparing the voltage peak for internal and external clamping with Zener diode at 125°C
Figure 13 to Figure 15 show the clamping behavior with the Zener diode for 150°C. This is the temperature
for the TLE8110EE and also for the Zener diode. The figures show always the comparisons with the original
TLE8110EE clamping. The setup and the load are always the basic setup shown in chapter 2.1.
Figure 13 Comparing the clamping voltages for internal and external clamping with Zener diode at
150°C
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External Clamping with the TLE8110EE
Temperature: 150°C, Clamping Time
Ex. Zener Diode
Clamping Voltage: 54.8V
Clamping Voltage: 43.4V
Clamping Time: 520us
Clamping Time: 675us
Clamping TLE8110EE, 150°C
Max Bacher
TLE8110EE_150C100us.emf
Clamping external Zener Diode, 150°C
Max Bacher
ZDode_BZG_150C100us.emf
Figure 14 Comparing the clamping time for internal and external clamping with Zener diode at 150°C
Temperature: 150°C, Detail
Ex. Zener Diode
No Peak at the clamping
voltage of 54.8V
Clamping TLE8110EE, 150°C
Peak with 5.6V above the
clamping voltage of 43.4V
Max Bacher
TLE8110EE_150C4us.emf
Clamping external Zener Diode, 150°C
Max Bacher
ZDode_BZG_150C4us.emf
Figure 15 Comparing the voltage peak for internal and external clamping with Zener diode at 150°C
3.3
Conclusion
A temperature-dependant behavior for external clamping with a Zener diode can be observed. Figure 16
shows the characteristic curve of the used Zener diode over temperature. Zener voltage increases with
temperature, but clamping time decreases. There is always a voltage peak for 1µs with near 5.5V
overvoltage when the clamping with Zener diode starts.
The worst behavior with the Zener diode for external clamping is measured at -40°C. With this temperature a
clamping voltage in the range of 34.4 Volt is obtained. This voltage could be a problem with load dump when
there is no lower load-dump protection such as additional clamping. Also the clamping time at 880µs is much
longer than the clamping time of the TLE8110EE which is 520µs.
The use of this circuit is, however, not common. The use of a (schottky) diode in series to the Zener diode is
highly recommended. With this circuit it is possible to avoid problems with reverse currents – just like wrong
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External Clamping with the TLE8110EE
polarity with the battery. In case of a reverse current it is possible destroy the Zener diode without the polarity
protection of an additional diode.
A Zener diode with nominal 3A and 39V was selected to ensure operation is always below the minimum
clamping voltage of the TLE8110EE. For the normal operating temperature of 125°C a clamping voltage in
the range of 42.5V is obtained from the 39V Zener diode. With 150°C a clamping voltage in the range of 43.4
Volt is obtained - rather near the minimum clamping voltage for the TLE8110EE. For exact values and
thresholds for the clamping voltages of the device, please refer to the data sheet of the TLE8110EE. The
maximum clamping voltage of the Zener diode must not reach or exceed the minimum clamping voltage of
the TLE8110EE. Calculation and comparison of the possible thresholds of the clamping voltages, to avoid
destruction of the TLE8110EE through use of a setup which could reach a higher energy than permitted in
the data sheet, is strongly recommended.
No distinct temperature-dependant behavior for the TLE8110EE clamping parameters, such as current
behavior, clamping time and clamping voltage, was observed.
Characteristic curve of the used Zener diode over temperature
1,20E-01
Load Dump Threshold: 40V
1,00E-01
ID Ampere
8,00E-02
6,00E-02
-40°C mA
25°C mA
125°C mA
150°C mA
4,00E-02
2,00E-02
44,7
44,4
44,1
43,8
43,5
43,2
42,9
42,6
42
42,3
41,7
41,4
41,1
40,8
40,5
40,2
39,9
39,6
39
39,3
38,7
38,4
38,1
37,8
37,5
37,2
36,9
36,6
36
36,3
35,7
35,4
35,1
0,00E+00
-2,00E-02
VD Volt
Figure 16 Characteristic curve of the used Zener diode over temperature
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External Clamping with the TLE8110EE
4
External free wheeling diode
4.1
Application circuit
Figure 17 shows the circuit of the TLE8110EE with FWD (Free Wheeling Diode) for external clamping. The
colored marked signals in Figure 17 are plotted in Figure 18 and Figure 19 to have a better overview.
5V
5V
Vdd
5V
14V
Vcc
Vbat
SPI_CS
SPI_CLK
TLE8110EE
R = 9 Ohm
L = 15 mH
FWD = 40V, 3A
SPI_SI
µC
SPI_SO
OutV
FWD
R
InV
L MP-Ch3
A
V MP-Ch2
V MP-Ch1
GND
Max Bacher
FWD_Circuit.vsd
Figure 17 TLE8110EE with FWD for external clamping
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External Clamping with the TLE8110EE
4.2
Measurements
Figure 18 and Figure 19 show the clamping behavior with the FWD for 25°C. This is the temperature for the
TLE8110EE and also for the FWD. The figures show always the comparisons with the original TLE8110EE
clamping. The setup and the load are always the basic setup shown in chapter 2.1.
Figure 18 Comparing the clamping voltages for internal and external clamping with FWD at 25°C
Temperature: 25°C, Detail
No Peak at the clamping
voltage of 55V
External FWD
Peak with 6,4V above the
clamping voltage of 14.5V
Clamping TLE8110EE, 25°C
Max Bacher
TLE8110EE_25C4us.emf
Max Bacher
FWD_25C4us.emf
Clamping external FWD, 25°C
Figure 19 Comparing the voltage peak for internal and external clamping with FWD at 25°C
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External Clamping with the TLE8110EE
4.3
Conclusion
With FWD the expected behavior was observed. A 3A schottky diode with a maximum repetitive reverse
voltage in the range of 40V was used. Figure 20 shows the characteristic curve of this schottky diode for
25°C and from 0 to 1A.
The clamping time has increased by an order of magnitude (15 times, to be more exact) compared to
TLE8110EE and is now in the same range as the saturation time. However, the clamping voltage is very
small. There is always a voltage peak for 1µs with near 6.5V overvoltage when the clamping with the FWD
starts.
The use of this circuit is, however, not common. In case of wrong polarity of the battery there could be a
large reverse current which could destroy the devices.
Characteristic curve of the used schottky diode for 25°C
1,20000
1,00000
ID Ampere
0,80000
to I A
0,60000
0,40000
0,20000
1,4
1,44
1,36
1,32
1,28
1,2
1,24
1,16
1,12
1,08
1
1,04
0,96
0,92
0,88
0,8
0,84
0,76
0,72
0,68
0,6
0,64
0,56
0,52
0,48
0,4
0,44
0,36
0,32
0,28
0,2
0,24
0,16
0,12
0,08
0
0,04
0,00000
VD Volt
Figure 20 Characteristic curve of the used schottky diode
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External Clamping with the TLE8110EE
5
External resistor
5.1
Application circuit
Figure 21 shows the circuit of the TLE8110EE with parallel resistor (Rp) for external clamping. The colored
marked signals in Figure 21 are plotted in Figure 22 to Figure 27 to have a better overview.
5V
5V
Vdd
5V
SPI_CS
SPI_CLK
TLE8110EE
A MP-Math
Rp:
Case A = 19.5 Ohm
Case B = 27.2 Ohm
SPI_SO
Vbat
R = 9 Ohm
L = 15 mH
SPI_SI
µC
14V
Vcc
Rp
OutV
R
InV
MP-Ch4
A
L
MP-Ch3
A
V MP-Ch2
V MP-Ch1
GND
Max Bacher
Rp_Circuit.vsd
Figure 21 TLE8110EE with parallel resistor for external clamping
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External Clamping with the TLE8110EE
5.2
Measurements
Figure 22 to Figure 24 show the clamping behavior with parallel resistor of 19.5 Ohm at 25°C. This is the
temperature for the TLE8110EE and also for Rp. The figures show always the comparisons with the original
TLE8110EE clamping. The setup and the load are always the basic setup shown in chapter 2.1.
The “Math Channel” (the red one) describes the current “MP-Math” in Figure 21 and is calculated as channel
3 (MP-Ch3 – the load current) plus channel 4 (MP-Ch4 – the Rp current).
Figure 22 Comparing the clamping time for internal and external clamping with Rp=19.5Ohm
Figure 23 Comparing the currents for internal and external clamping with Rp=19.5Ohm
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External Clamping with the TLE8110EE
Figure 24 Comparing the voltage peak for internal and external clamping with Rp=19.5Ohm
Figure 25 to Figure 27 show the clamping behavior with parallel resistor of 27.2 Ohm at 25°C. This is the
temperature for the TLE8110EE and also for Rp. The figures show always the comparisons with the original
TLE8110EE clamping. The setup and the load are always the basic setup shown in chapter 2.1.
The “Math Channel” (the red one) describes the current “MP-Math” in Figure 21 and is calculated as channel
3 (MP-Ch3 – the load current) plus channel 4 (MP-Ch4 – the Rp current).
Rp = 27.2 Ohm, Saturation and Clamping Times, 25°C
External Resistor
Clamping Voltage: 55V
Clamping Voltage: 54V
Saturation Time: 7.9ms
Clamping Time: 520us
Saturation Time: 7.9ms
Clamping TLE8110EE, 25°C
Max Bacher
TLE8110EE_25C4ms.emf
Clamping Time: 2.4ms
Max Bacher
Rp27.2_25C4ms.emf
Clamping with Rp, 25°C
Figure 25 Comparing the clamping time for intern and external clamping with Rp=27.2Ohm
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External Clamping with the TLE8110EE
Figure 26 Comparing the currents for internal and external clamping with Rp=27.2Ohm
Figure 27 Comparing the voltage peak for internal and external clamping with Rp=27.2Ohm
5.3
Conclusion
The expected behavior with the parallel resistor was observed. The output current for the channel is much
higher because there is now the additional current of the parallel resistor. The amount of the additional
current depends upon the value of the used parallel resistor and is easy to calculate (IL/Ip=Rp/RL).
To observe the effects resulting from the presence of different amounts of parallel resistance, the behavior
with two different parallel resistors was measured.
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External Clamping with the TLE8110EE
The values of the resistors are chosen:
A.) to be under the minimum clamping voltage of the TLE8110EE. Rp=19.5Ohm, which causes a
clamping voltage of 43V.
B.) to be under the typical clamping voltage of the TLE8110EE. Rp=27.2Ohm, which causes a clamping
voltage of 53V.
Case A (Rp=19.5Ohm):
The clamping time has significantly increased (5.5 times, to be more exact) compared to TLE8110EE. The
additional current is in the range of 850mA. A voltage peak for 1µs with near 5V overvoltage when the
clamping with the parallel resistor starts, was observed.
Case B (Rp=27.2Ohm):
The clamping time has significantly increased (4.5 times, to be more exact) compared to TLE8110EE. The
additional current is in the range of 500mA. No voltage peak was observed in this case because above 55V
the internal clamping from the TLE8110EE is activated.
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External Clamping with the TLE8110EE
6
External resistor with free wheeling diode
6.1
Application circuit
Figure 28 shows the circuit of the TLE8110EE with parallel resistor (Rp) and FWD for external clamping. The
colored marked signals in Figure 28 are plotted in Figure 29 to Figure 34 to have a better overview.
5V
5V
Vdd
5V
TLE8110EE
A MP-Math
Rp:
Case A = 16.8 Ohm
Case B = 26.4 Ohm
SPI_SI
µC
Vbat
R = 9 Ohm
L = 15 mH
FWD = 40V, 3A
SPI_CS
SPI_CLK
14V
Vcc
SPI_SO
OutV
Rp
FWD
MP-Ch4
A
R
L
MP-Ch3
A
InV
V MP-Ch2
V MP-Ch1
GND
Max Bacher
DRp_Circuit.vsd
Figure 28 TLE8110EE with FWD and parallel resistor (Rp) for external clamping
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External Clamping with the TLE8110EE
6.2
Measurements
Figure 29 to Figure 31 show the clamping behavior with parallel resistor of 16.8 Ohm and FWD at 25°C. This
is the temperature for the TLE8110EE and also for the Rp and the FWD. The figures show always the
comparisons with the original TLE8110EE clamping. The setup and the load are always the basic setup
shown in chapter 2.1.
The “Math Channel” (the red one) describes the current “MP-Math” in Figure 28and is calculated as channel
3 (MP-Ch3 – the load current) plus channel 4 (MP-Ch4 – the FWD-Rp current).
Figure 29 Comparing the clamping time for internal and external clamping with FWD and
Rp=16.8Ohm
Figure 30 Comparing the currents for internal and external clamping with FWD and Rp=16.8Ohm
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External Clamping with the TLE8110EE
Figure 31 Comparing the voltage peak for internal and external clamping with FWD and Rp=16.8Ohm
Figure 32 to Figure 34 show the clamping behavior with parallel resistor of 26.4 Ohm and FWD at 25°C. This
is the temperature for the TLE8110EE and also for the Rp and the FWD. The figures show always the
comparisons with the original TLE8110EE clamping. The setup and the load are always the basic setup
shown in chapter 2.1.
The “Math Channel” (the red one) describes the current “MP-Math” in Figure 28and is calculated as channel
3 (MP-Ch3 – the load current) plus channel 4 (MP-Ch4 – the FWD-Rp current).
Figure 32 Comparing the clamping time for internal and external clamping with FWD and
Rp=26.4Ohm
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External Clamping with the TLE8110EE
Figure 33 Comparing the currents for internal and external clamping with FWD and Rp=26.4Ohm
Figure 34 Comparing the voltage peak for internal and external clamping with FWD and Rp=26.4Ohm
6.3
Conclusion
The expected behavior with the parallel resistor and the FWD was observed. The big advantage against the
external Rp clamping without FWD is that there is now no additional current when the output is switched on.
The other effect (longer clamping time) is still apparent. To observe the effects resulting from the presence of
different amounts of parallel resistance, the behavior with two different parallel resistors was measured.
The values of the resistors are chosen:
C.) to be under the minimum clamping voltage of the TLE8110EE. Rp=16.8Ohm, which causes a
clamping voltage of 43V.
D.) to be under the typical clamping voltage of the TLE8110EE. Rp=26.4Ohm, which causes a clamping
voltage of 53V.
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External Clamping with the TLE8110EE
Case A (Rp=16.8Ohm):
The clamping time has significantly increased (5.5 times, to be more exact) compared to TLE8110EE. A
voltage peak for 1µs with near 5V overvoltage when the clamping with the parallel resistor starts, was
observed.
Case B (Rp=24.4Ohm):
The clamping time has significantly increased (4 times, to be more exact) compared to TLE8110EE. No
voltage peak was observed in this case because above 55V the internal clamping from the TLE8110EE is
activated.
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External Clamping with the TLE8110EE
7
Appendix
7.1
Table of Figures
Figure 1 TLE8110EE connected to a load ................................................................4
Figure 2 Clamping with inductive and ohmic load to show the clamping energy ......4
Figure 3 TLE8110EE with Zener diode for external clamping...................................6
Figure 4 Comparing the clamping voltages for internal and external clamping with
Zener diode at -40°C ................................................................................................7
Figure 5 Comparing the clamping time for internal and external clamping with Zener
diode at -40°C ..........................................................................................................7
Figure 6 Comparing the voltage peak for internal and external clamping with Zener
diode at -40°C ..........................................................................................................8
Figure 7 Comparing the clamping voltages for internal and external clamping with
Zener diode at 25°C .................................................................................................8
Figure 8 Comparing the clamping time for internal and external clamping with Zener
diode at 25°C ...........................................................................................................9
Figure 9 Comparing the voltage peak for internal and external clamping with Zener
diode at 25°C ...........................................................................................................9
Figure 10 Comparing the clamping voltages for internal and external clamping with
Zener diode at 125°C .............................................................................................10
Figure 11 Comparing the clamping time for internal and external clamping with
Zener diode at 125°C .............................................................................................10
Figure 12 Comparing the voltage peak for internal and external clamping with Zener
diode at 125°C .......................................................................................................11
Figure 13 Comparing the clamping voltages for internal and external clamping with
Zener diode at 150°C .............................................................................................11
Figure 14 Comparing the clamping time for internal and external clamping with
Zener diode at 150°C .............................................................................................12
Figure 15 Comparing the voltage peak for internal and external clamping with Zener
diode at 150°C .......................................................................................................12
Figure 16 Characteristic curve of the used Zener diode over temperature .............13
Figure 17 TLE8110EE with FWD for external clamping..........................................14
Figure 18 Comparing the clamping voltages for internal and external clamping with
FWD at 25°C ..........................................................................................................15
Figure 19 Comparing the voltage peak for internal and external clamping with FWD
at 25°C ...................................................................................................................15
Figure 20 Characteristic curve of the used schottky diode .....................................16
Figure 21 TLE8110EE with parallel resistor for external clamping..........................17
Figure 22 Comparing the clamping time for internal and external clamping with
Rp=19.5Ohm..........................................................................................................18
Figure 23 Comparing the currents for internal and external clamping with
Rp=19.5Ohm..........................................................................................................18
Figure 24 Comparing the voltage peak for internal and external clamping with
Rp=19.5Ohm..........................................................................................................19
Application Note
27
2008-04-30
Application Note
External Clamping with the TLE8110EE
Figure 25 Comparing the clamping time for intern and external clamping with
Rp=27.2Ohm..........................................................................................................19
Figure 26 Comparing the currents for internal and external clamping with
Rp=27.2Ohm..........................................................................................................20
Figure 27 Comparing the voltage peak for internal and external clamping with
Rp=27.2Ohm..........................................................................................................20
Figure 28 TLE8110EE with FWD and parallel resistor (Rp) for external clamping..22
Figure 29 Comparing the clamping time for internal and external clamping with
FWD and Rp=16.8Ohm..........................................................................................23
Figure 30 Comparing the currents for internal and external clamping with FWD and
Rp=16.8Ohm..........................................................................................................23
Figure 31 Comparing the voltage peak for internal and external clamping with FWD
and Rp=16.8Ohm ...................................................................................................24
Figure 32 Comparing the clamping time for internal and external clamping with
FWD and Rp=26.4Ohm..........................................................................................24
Figure 33 Comparing the currents for internal and external clamping with FWD and
Rp=26.4Ohm..........................................................................................................25
Figure 34 Comparing the voltage peak for internal and external clamping with FWD
and Rp=26.4Ohm ...................................................................................................25
7.2
Revision History Table Example
Previous Version:
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Application Note
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Subjects (major changes since last revision)
28
2008-04-30
Edition 2006-02-01
Published by
Infineon Technologies AG
81726 Munich, Germany
© Infineon Technologies AG 2008.
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