WO2010088178A1 - High side inductive energy clamp - Google Patents

High side inductive energy clamp Download PDF

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Publication number
WO2010088178A1
WO2010088178A1 PCT/US2010/021951 US2010021951W WO2010088178A1 WO 2010088178 A1 WO2010088178 A1 WO 2010088178A1 US 2010021951 W US2010021951 W US 2010021951W WO 2010088178 A1 WO2010088178 A1 WO 2010088178A1
Authority
WO
WIPO (PCT)
Prior art keywords
inductive
diode
clamp
inductive load
voltage range
Prior art date
Application number
PCT/US2010/021951
Other languages
French (fr)
Inventor
Mauricio Eduardo Hernandez-Distancia
Peter Narbus
Original Assignee
Continental Automotive Systems Us, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Continental Automotive Systems Us, Inc. filed Critical Continental Automotive Systems Us, Inc.
Publication of WO2010088178A1 publication Critical patent/WO2010088178A1/en

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
    • H03K17/081—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit
    • H03K17/0814—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit by measures taken in the output circuit
    • H03K17/08142—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit by measures taken in the output circuit in field-effect transistor switches

Definitions

  • This application relates to inductive clamps, and more particularly to a high side inductive clamp.
  • Inductive clamps have been used to dissipate inductive energy from inductive loads. In some applications, inductive clamping is necessary to prevent damage to circuit components, such as solid state switches.
  • Prior art inductive clamps been connected to a negative terminal of a DC power source and have included the DC power source in a discharge loop of the inductive clamp.
  • An inductive clamping circuit includes an inductive load connected to a positive terminal of a DC power source.
  • a solid state switch is operable to turn the inductive load ON or OFF.
  • An inductive clamp is connected to the positive terminal of the DC power source, and is connected in parallel to the inductive load. The inductive clamp dissipates inductive energy when the solid state switch turns the inductive load OFF.
  • a method of dissipating inductive energy includes connecting an inductive load to a positive terminal of a DC power source.
  • a high side inductive clamp is connected in parallel to the inductive load.
  • a solid state switch is commanded to disconnect the inductive load and the inductive clamp from a negative terminal of the DC power source.
  • Inductive energy in the inductive clamp is dissipated as heat to protect the solid state switch.
  • Figure 1 schematically illustrates an inductive clamping circuit including a high side inductive clamp.
  • Figure 2 is a table comparing the high side inductive clamp of Figure 1 and a prior art low side inductive clamp at various temperatures.
  • Figure 3 schematically illustrates the high side inductive clamp of Figure 1 in an automobile environment.
  • FIG. 1 schematically illustrates an inductive clamping circuit 30 that includes a high side inductive clamp 32.
  • the inductive clamp 32 is a "high side" inductive clamp because the inductive clamp 32 is connected to a positive terminal of the battery 34.
  • the clamping circuit 30 also includes a battery 34 that powers an inductive load 36.
  • the inductive load 36 is illustrated as including an inductor 37 connected in series to a resistor 40.
  • the inductive load 36 could include other components as long as it the load 36 was inductive.
  • the inductive load 36 could include a solenoid, a relay, or an actuator that may correspond to part of a vehicle fuel injector and/or a vehicle HVAC system.
  • a solid state switch 38 is operable to turn the inductive load 36 ON or OFF in response to a control signal 42.
  • the inductive load 36 is ON, and when the solid state switch 38 turns OFF, the inductive load 36 turns OFF and the inductive clamp 32 dissipates inductive energy as heat to prevent damage to the solid state switch 38.
  • the inductive clamp 32 may be in contact with a heat sink to assist in heat dissipation, it is understood that a heat sink would be optional and would not be required.
  • the inductive clamp 32 includes a first diode 44 that is a zener diode and a second diode 46.
  • a cathode of the first diode 44 is connected to a cathode of the second diode 46.
  • An anode of the first diode 44 is connected to a positive terminal of the battery 34 and an input of the inductive load 36 via node 48.
  • An anode of the second diode 46 is connected to an output of the inductive load 36.
  • the zener diode 44 is forward-biased in a first voltage range, and is reverse-biased in a second voltage range that is greater than the first voltage range. The second voltage range exceeds a breakdown voltage of the zener diode 44, and thus the zener diode 44 may be selected to achieve a desired second voltage range.
  • the second diode 46 blocks a flow of current in a first direction from node 48 through the second diode 46.
  • the second diode 46 permits a flow in a second direction opposite the first direction (from the second diode 46 to the node 48) such that current flows in a discharge loop that includes the inductive clamp 32 and the inductive load 36 (in the example of Figure 1 in a counterclockwise direction).
  • the high side inductive clamp 32 discharge loop includes only the inductive clamp 32 and the inductive load 36, and does not include the battery 34.
  • FIG. 2 is a table comparing the high side inductive clamp 32 of Figure 1 and a prior art low side inductive clamp at various temperatures. As shown in Figure 2, at 25 0 C, -4O 0 C and at 105 0 C the high side clamp 32 dissipates considerably less power than a prior art low side clamp. At each of the temperatures the power consumed by the high side clamp 32 is approximately 64% -67% less than would be consumed by a prior art low side inductive clamp. Thus, the high side clamp 32 is able to achieve a significant reduction in wasted power as compared to a prior art low side clamp.
  • FIG 3 schematically illustrates the clamping circuit of Figure 1 in an automobile environment.
  • a battery 34 acts as a DC voltage source to provide power to a powertrain 33 and ultimately an inductive load 72.
  • the powertrain 33 includes the inductive clamp 32.
  • the example inductive load 72 is a fuel injector. However, other inductive devices would benefit from the example clamping circuit 32. Also, it is possible that there could be many inductive loads 72, in which case the powertrain 33 may include a plurality of high side inductive clamps 32. In one example, each inductive load 36 has its own corresponding inductive clamp 32. Further, several inductive loads 72 could be arranged in communication with a single inductive clamp 32. [0016] Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.

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Abstract

An inductive clamping circuit includes an inductive load connected to a positive terminal of a DC power source. A solid state switch is operable to turn the inductive load ON or OFF. An inductive clamp is connected to the positive terminal of the DC power source, and is connected in parallel to the inductive load. The inductive clamp dissipates inductive energy when the solid state switch turns the inductive load OFF.

Description

HIGH SIDE INDUCTIVE ENERGY CLAMP
BACKGROUND
[0001] The application claims priority to U.S. Provisional Application No. 61/148,200 which was filed on January 29, 2009.
[0002] This application relates to inductive clamps, and more particularly to a high side inductive clamp. Inductive clamps have been used to dissipate inductive energy from inductive loads. In some applications, inductive clamping is necessary to prevent damage to circuit components, such as solid state switches. Prior art inductive clamps been connected to a negative terminal of a DC power source and have included the DC power source in a discharge loop of the inductive clamp.
SUMMARY
[0003] An inductive clamping circuit includes an inductive load connected to a positive terminal of a DC power source. A solid state switch is operable to turn the inductive load ON or OFF. An inductive clamp is connected to the positive terminal of the DC power source, and is connected in parallel to the inductive load. The inductive clamp dissipates inductive energy when the solid state switch turns the inductive load OFF.
[0004] A method of dissipating inductive energy includes connecting an inductive load to a positive terminal of a DC power source. A high side inductive clamp is connected in parallel to the inductive load. A solid state switch is commanded to disconnect the inductive load and the inductive clamp from a negative terminal of the DC power source. Inductive energy in the inductive clamp is dissipated as heat to protect the solid state switch.
[0005] These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Figure 1 schematically illustrates an inductive clamping circuit including a high side inductive clamp.
[0007] Figure 2 is a table comparing the high side inductive clamp of Figure 1 and a prior art low side inductive clamp at various temperatures. [0008] Figure 3 schematically illustrates the high side inductive clamp of Figure 1 in an automobile environment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0009] Prior art inductive clamps been connected to a negative terminal of a DC power source and have included the DC power source in a discharge loop of the inductive clamp. Because of the connection to a negative terminal of a DC power source, these inductive clamps may be referred to as "low side" inductive clamps.
[0010] Figure 1 schematically illustrates an inductive clamping circuit 30 that includes a high side inductive clamp 32. The inductive clamp 32 is a "high side" inductive clamp because the inductive clamp 32 is connected to a positive terminal of the battery 34. The clamping circuit 30 also includes a battery 34 that powers an inductive load 36. The inductive load 36 is illustrated as including an inductor 37 connected in series to a resistor 40. Of course, this is only schematic, and the inductive load 36 could include other components as long as it the load 36 was inductive. For example, the inductive load 36 could include a solenoid, a relay, or an actuator that may correspond to part of a vehicle fuel injector and/or a vehicle HVAC system.
[0011] A solid state switch 38 is operable to turn the inductive load 36 ON or OFF in response to a control signal 42. When the solid state switch 38 is ON, the inductive load 36 is ON, and when the solid state switch 38 turns OFF, the inductive load 36 turns OFF and the inductive clamp 32 dissipates inductive energy as heat to prevent damage to the solid state switch 38. Although the inductive clamp 32 may be in contact with a heat sink to assist in heat dissipation, it is understood that a heat sink would be optional and would not be required.
[0012] The inductive clamp 32 includes a first diode 44 that is a zener diode and a second diode 46. A cathode of the first diode 44 is connected to a cathode of the second diode 46. An anode of the first diode 44 is connected to a positive terminal of the battery 34 and an input of the inductive load 36 via node 48. An anode of the second diode 46 is connected to an output of the inductive load 36. The zener diode 44 is forward-biased in a first voltage range, and is reverse-biased in a second voltage range that is greater than the first voltage range. The second voltage range exceeds a breakdown voltage of the zener diode 44, and thus the zener diode 44 may be selected to achieve a desired second voltage range.
[0013] In the first voltage range (when switch 38 is ON and inductive load 36 is ON), the second diode 46 blocks a flow of current in a first direction from node 48 through the second diode 46. In the second voltage range (when switch 38 is OFF and inductive load 36 is OFF or is turning OFF), the second diode 46 permits a flow in a second direction opposite the first direction (from the second diode 46 to the node 48) such that current flows in a discharge loop that includes the inductive clamp 32 and the inductive load 36 (in the example of Figure 1 in a counterclockwise direction). Thus, unlike the prior art "low side" inductive clamps that include a DC power source in an inductive clamp discharge loop, the high side inductive clamp 32 discharge loop includes only the inductive clamp 32 and the inductive load 36, and does not include the battery 34.
[0014] The "high side" configuration of the inductive clamp 32 provides a substantial efficiency improvement over the prior art "low side" configuration because the battery 34 is excluded from the discharge loop of the inductive clamp 32. Figure 2 is a table comparing the high side inductive clamp 32 of Figure 1 and a prior art low side inductive clamp at various temperatures. As shown in Figure 2, at 250C, -4O0C and at 1050C the high side clamp 32 dissipates considerably less power than a prior art low side clamp. At each of the temperatures the power consumed by the high side clamp 32 is approximately 64% -67% less than would be consumed by a prior art low side inductive clamp. Thus, the high side clamp 32 is able to achieve a significant reduction in wasted power as compared to a prior art low side clamp.
[0015] Figure 3 schematically illustrates the clamping circuit of Figure 1 in an automobile environment. A battery 34 acts as a DC voltage source to provide power to a powertrain 33 and ultimately an inductive load 72. The powertrain 33 includes the inductive clamp 32. The example inductive load 72 is a fuel injector. However, other inductive devices would benefit from the example clamping circuit 32. Also, it is possible that there could be many inductive loads 72, in which case the powertrain 33 may include a plurality of high side inductive clamps 32. In one example, each inductive load 36 has its own corresponding inductive clamp 32. Further, several inductive loads 72 could be arranged in communication with a single inductive clamp 32. [0016] Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.

Claims

CLAIMSWhat is claimed is:
1. An inductive clamping circuit, comprising: an inductive load connected to a positive terminal of a DC power source; a solid state switch operable to turn the inductive load ON or OFF; and an inductive clamp connected to the positive terminal of the DC power source, and connected in parallel to the inductive load, the inductive clamp dissipating inductive energy when the solid state switch turns the inductive load OFF.
2. The inductive clamping circuit of claim 1, wherein when the inductive clamp dissipates inductive energy, current flows in a discharge loop that includes the inductive clamp and the inductive load but excludes the DC power source.
3. The circuit of claim 1, wherein the inductive clamp includes: a first diode comprising a zener diode; and a second diode, a cathode of the first diode being connected to a cathode of the second diode, and an anode of the first diode being connected to the positive terminal of the DC power source, the second diode blocking a flow of current in a first direction from the first diode to an anode of the second diode at a first voltage range, and the second diode permitting a flow of current through the inductive clamp in a second direction opposite the first direction at a second voltage range that exceeds a breakdown voltage of the first diode, the first diode being forward-biased in the first voltage range and being reverse-biased in the second voltage range.
4. The circuit of claim 3, wherein the inductive clamp is subjected to the second voltage range when the solid state switch turns the inductive load OFF.
5. The circuit of claim 1, wherein the DC power source is an automobile battery.
6. The circuit of claim 1, wherein the inductive load includes at least one inductor connected in series to at least one resistor.
7. The circuit of claim 1, wherein the inductive load includes at least one of a solenoid, a relay or an actuator.
8. The circuit of claim 1, wherein the inductive load is ON when the solid state switch is ON, and wherein the inductive load turns OFF when the solid state switch is OFF.
9. A method of dissipating inductive energy, comprising: connecting an inductive load to a positive terminal of a DC power source; connecting a high side inductive clamp in parallel to the inductive load; commanding a solid state switch to disconnect the inductive load and the inductive clamp from a negative terminal of the DC power source; and dissipating inductive energy in the inductive clamp as heat to protect the solid state switch.
10. The method of claim 9, wherein said dissipating inductive energy in the inductive clamp as heat to protect the solid state switch includes facilitating a flow of current in a discharge loop that includes the inductive clamp and the inductive load but excludes the DC power source.
11. The method of claim 9, the inductive clamp including a first diode and a second diode, the first diode comprising a zener diode, the second diode blocking a flow of current in a first direction from the first diode to an anode of the second diode at a first voltage range, and the second diode permitting a flow of current through the inductive clamp in a second direction opposite the first direction at a second voltage range that exceeds a breakdown voltage of the first diode, the first diode being forward-biased in the first voltage range and being reverse-biased in the second voltage range.
12. The method of claim 11, wherein the inductive clamp is subjected to the second voltage range in response to said commanding a solid state switch to disconnect the inductive load and the inductive clamp from a negative terminal of the DC power source.
13. The method of claim 11, wherein the first diode is connected to an input of the inductive load and the second diode is connected to an output of the inductive load.
14. The method of claim 9, wherein the inductive load includes at least one inductor connected in series to at least one resistor.
15. The method of claim 9, wherein the DC power source is an automobile battery, and wherein the inductive load includes at least one of a solenoid, a relay or an actuator.
16. The method of claim 9, wherein the inductive load is ON when the solid state switch is ON, and wherein the inductive load turns OFF when the solid state switch is OFF.
17. An automotive control system, comprising: an actuator for controlling an operating parameter, the actuator comprising an inductive load; and a control circuit for controlling actuation of the inductive load, the control circuit including an inductive clamp connected to a positive terminal of a DC power source and in parallel with the inductive load, wherein the inductive clamp dissipates energy from the inductive load when the inductive load is turned OFF.
18. The control system of claim 17, the inductive clamp comprising: a first diode comprising a zener diode; and a second diode, the second diode blocking a flow of current in a first direction from the first diode to an anode of the second diode at a first voltage range, and the second diode permitting a flow of current through the inductive clamp in a second direction opposite the first direction at a second voltage range that exceeds a breakdown voltage of the first diode, the first diode being forward-biased in the first voltage range and being reverse-biased in the second voltage range.
19. The control system of claim 18, wherein the inductive clamp is subjected to the second voltage range when the solid state switch turns the inductive load OFF.
20. The control system of claim 18, wherein the first diode is connected to an input of the inductive load and the second diode is connected to an output of the inductive load.
PCT/US2010/021951 2009-01-29 2010-01-25 High side inductive energy clamp WO2010088178A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US14820009P 2009-01-29 2009-01-29
US61/148,200 2009-01-29

Publications (1)

Publication Number Publication Date
WO2010088178A1 true WO2010088178A1 (en) 2010-08-05

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230261655A1 (en) * 2022-02-16 2023-08-17 Lite-On Technology Corporation Switch control module

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2257854A (en) * 1991-07-16 1993-01-20 Motorola Inc Drive circuits
US20030025546A1 (en) * 2001-07-26 2003-02-06 Autonetworks Technologies, Ltd. Protection circuit
DE10228340B3 (en) * 2002-06-25 2004-02-26 Infineon Technologies Ag Control circuit for inductive load e.g. electric motor, relay or valve, has free-running circuit with diode and Zener diode connected across connection terminals for switched inductive load

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2257854A (en) * 1991-07-16 1993-01-20 Motorola Inc Drive circuits
US20030025546A1 (en) * 2001-07-26 2003-02-06 Autonetworks Technologies, Ltd. Protection circuit
DE10228340B3 (en) * 2002-06-25 2004-02-26 Infineon Technologies Ag Control circuit for inductive load e.g. electric motor, relay or valve, has free-running circuit with diode and Zener diode connected across connection terminals for switched inductive load

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230261655A1 (en) * 2022-02-16 2023-08-17 Lite-On Technology Corporation Switch control module

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