GB2396982A - Active safety circuit operated by temperature of solid state relay with crowbar circuit. - Google Patents
Active safety circuit operated by temperature of solid state relay with crowbar circuit. Download PDFInfo
- Publication number
- GB2396982A GB2396982A GB0330093A GB0330093A GB2396982A GB 2396982 A GB2396982 A GB 2396982A GB 0330093 A GB0330093 A GB 0330093A GB 0330093 A GB0330093 A GB 0330093A GB 2396982 A GB2396982 A GB 2396982A
- Authority
- GB
- United Kingdom
- Prior art keywords
- solid state
- state relay
- safety circuit
- switch
- controlled
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
- 239000007787 solid Substances 0.000 title claims abstract description 34
- 230000005669 field effect Effects 0.000 abstract description 2
- 238000013021 overheating Methods 0.000 abstract description 2
- 230000006378 damage Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 1
- 230000010259 detection of temperature stimulus Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/021—Details concerning the disconnection itself, e.g. at a particular instant, particularly at zero value of current, disconnection in a predetermined order
- H02H3/023—Details concerning the disconnection itself, e.g. at a particular instant, particularly at zero value of current, disconnection in a predetermined order by short-circuiting
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
- H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
- H02H5/045—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature using a thermal radiation sensor
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
- H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
- H02H5/047—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature using a temperature responsive switch
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
- H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
-
- 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
- H03K2017/0806—Modifications for protecting switching circuit against overcurrent or overvoltage against excessive temperature
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Protection Of Static Devices (AREA)
Abstract
Controller 4 monitors the temperature of solid state relays 1, 2, 3, using a sensor 10 and if a temperature anomaly such as overheating is detected firstly opens the relays 1, 2, 3. If the temperature anomaly persists for a time period controller 4 then operates safety switch 9 to ground the supply at node 8 and thereby operate current breaker 5. Current breaker 5 may comprise a fuse, solid state relays 1, 2, 3 may comprise a field effect transistor (FET) and safety switch 9 may comprise a relay or a FET. Temperature sensor 10 may comprise a separate sensor (fig 2: 10, 10a and 10b) for each solid state relay 1, 2, 3.
Description
r - - À À . . .
ACTIVE SAFETY CIRCUIT WITH LOADS PROTECTED BY SOLID STATE
RELAYS
Field of the Invention
The present invention concerns electronic safety devices with loads protected by solid state relays, such as field-effect transistor (FET) type switches controlled by microcontroller.
The interest of the proposed safety circuit derives from the current tendency to increase the number of controlled FET type switches, for protecting various loads, for example in automobile electronics.
However, one of the faults of this type of switches, particularly given the nature of the semi-conducting material constituting them, is the particular behaviour of said switches in the way of a shunt resistance with a resistance considerably greater than the nominal resistance (although not as high as that which an open circuit would impose), which causes a significant increase in the temperature of the FET device by dissipation, possibly entailing its destruction and potentially fire and damage to the safety circuit substrate.
Backaround of the Invention
European Patent EP-A-0148370 discloses a safety circuit of an automobile vehicle for protecting an electronic circuitry assembled thereon against an overload coming from the power supply. To this end, said circuit is provided with a fuse inserted in the feeder, a grounded shunt line with an inserted switching transistor connected to said feeder substantially at a point between the fuse and the circuit to be protected. An operational amplifier monitors the voltage in the feeder so that this does not exceed a certain threshold. Also analogically, said amplifier acts on said switching transistor to short circuit said feeder to ground and to immediately blow the d d À , , d À , fuse so as to leave the circuit to be protected in open circuit if the threshold has been exceeded.
The object of the present invention is primarily to prevent overheating with the risk of fire of said group of FET type switches. Indeed, in an indirect manner, the loads or sub-circuits controlled by said FET type switches are also protected against a possible short circuit, ensuring that in case of failure of the FET type switch, this will not be destroyed and the load will not suffer damage.
Although the structure of the protection circuit proposed herein is also based on a shunt circuit with a fuse and a controlled safety switch, the control and monitoring is digital and is not carried out with respect to an overload in the feeder, but is carried out according to the integrity of said FET type switches, measured through its temperature.
To this end, temperature detectors connected to the same microcontroller controlling the FET type switches in its normal operating mode and to which a simple algorithm is incorporated according to the methodology of the present invention, are provided to maintain the grounded shunt line open or to short-circuit it, acting on the safety switch at the appropriate time. Furthermore, unlike the analogue control which is usually of fixed response, digital control conditions allow the use of a microcontroller and provide the advantage whereby said control can be more "intelligent", capable if necessary of providing for more parameters and variants in the decision process. An example of this potential will be shown below.
Brief Description of the Invention
As previously indicated, one of the faults that can occur with FET type switches is that of providing in determined cases a higher impedance than the nominal impedance in conduction (although not as high as in open circuit). In conduction, the current is fixed by the loads, À.' e: Àe e' À le act therefore when increasing the impedance of the FET type switches, the dissipated power therein increases together with its temperature, with the consequent risk of fire on the substrate of the circuit housing the FET type switches.
In keeping with the operations for implementing this invention, after the first detection of temperature increase in at least one of the switches, the microcontroller places said switch in open circuit, waits a certain time to see if the anomaly has disappeared, and if this persists, the microcontroller orders the short circuiting of the shunt circuit, so as to provoke complete opening and isolation from the circuit of the group of FET type switches and their loads dependent on the power supply. This constitutes a good example of the "intelligence" which provides the control with use of digital control rather than analogue control such as that
discussed in the background above.
The features of the invention will be made clearer with the help of a description thereof by means of several embodiments.
Brief Explanation of the Drawings In said drawings: Figure 1 shows a schematic view showing one embodiment of the proposed safety circuit including a temperature detector associated to a series of solid state relays connected to respective loads, said temperature detector being connected to a microcontroller.
Figure 2 shows an alternative embodiment wherein each solid state relay is provided with a dedicated temperature detector.
Detailed Explanation of Several Embodiments As the mentioned figures show, the active safety circuit with loads protected by solid state relays of the invention generally comprises a group of loads (not shown) fed through solid state relays 1, 2, 3 (schematized by À . means of a switch), controlled in turn from a unit such as a microcontroller 4 which is prepared for provoking the opening of said relay(s) 1, 2 and 3, in case an anomaly should occur in said loads, comprising a current breaking device 5 inserted in a power supply network 6 to said solid state relay(s) 1, 2, 3 and a grounded shunt line 7 from point 8 of said power supply network, placed between the breaking device 5 and said solid state relay(s) 1, 2, 3, and a safety switch 9 governed by said microcontroller 4 and inserted in said grounded shunt line 7. According to the principles of the invention, a temperature detector 10 is provided, either associated to each solid state relay 1, 2, 3 (example of figure 2) or commonly shared by several of said solid state relays 1, 2, 3 (example of figure 1), and connected to said microcontroller 4.
Operation of the circuit is as follows: the microcontroller 4 sequentially checks the state of said temperature detector 10 or detectors 10, 10a, 10b to open, if an anomaly in temperature is produced, the corresponding solid state relays 1, 2, 3 (in the case of a dedicated detector being used for each relay 1, 2, 3) and, if the problem persists, to close said controlled safety switch 9, so as to short-circuit to ground said power supply network 6 by means of the grounded shunt line 7, actuating said breaking device 5 and thus provoking the disconnection of said solid state relay and its corresponding set of associated loads, with respect to a power source.
In a preferred embodiment of the invention, said solid state relays are constituted on the basis of an PET switch controlled by said microcontroller 4.
For its part, said breaking device 5 will generally be a fuse (duly sized such that the passage of an overcurrent (exceeding a pre-fixed threshold) through it causes it to blow).
e: e: Ace: ::. .:e e' ce.e:: ee. À : If controlled, said safety switch 9 could be an electronic power switch, particularly of the FET type or a power relay.
Claims (9)
1. An active safety circuit with loads protected by solid state relays, of the type wherein a load or a group of loads is fed through at least one solid state relay controlled in turn from a unit such as a microcontroller prepared for provoking the opening of said relay, which is at least one, in case an anomaly occurs in said loads, comprising a current breaking device inserted in the power supply network of said solid state relay, which is at least one, a grounded shunt line from one point of said supply network, placed between said fuse and said solid state relay, and a safety switch controlled by said microcontroller and inserted in said grounded shunt line, characterized by comprising a set of at least one temperature detector associated to said solid state relay, which is at least one, and connected to said microcontroller such that the latter sequentially checks the state of said temperature detector to open, if an anomaly in temperature is produced, the corresponding solid state relay and, if the problem persists, to close said controlled safety switch so as to short-circuit to ground said power supply through said grounded shunt line, actuating said breaking device, thereby provoking the disconnection of said solid state relay and its corresponding set of associated loads, with respect to a power source.
2. A safety circuit according to claim 1, characterized in that said solid state relay is an FET switch controlled by said microcontroller.
3. A safety circuit according to claim 1 or claim 2, characterized in that said breaking device is a fuse, so that the passage of an overcurrent through it causes it to I:. t:t d. blow.
4. A safety circuit according to any one of claims 1 to 3, characterized in that each load has an FET protection switch associated to it, and each one of these switches has a dedicated temperature detector.
5. A safety circuit according to any one of claims 1 to 3, characterized in that various loads have a single associated FET protection switch, and the latter has a dedicated temperature detector.
6. A safety circuit according to any one of the proceeding claims, characterized in that said controlled safety switch is an electronic power switch.
7. A safety circuit according to any one of the proceeding claims, characterized in that said controlled safety switch is of the FET type.
8. A safety circuit according to any one of the preceding claims, characterized in that said controlled safety switch is a relay.
9. A safety circuit substantially as herein described with reference to the accompanying drawings.
9. A safety circuit substantially as herein described with reference to the accompanying drawings.
Amendments to the claims have been filed as follows
1. An active safety circuit with loads protected by solid state relays, of the type wherein a load On a group of loads is fed from a power source via a power supply network through at least one solid state relay controlled in turn from a unit such as a microcontroller prepared for provoking the opening of said solid state relay in case an anomaly occurs in said loads; the circuit comprising a current breaking device inserted in the power supply network of said solid state relay, a grounded shunt line from one point of said power supply network placed between said current breaking device and said solid state relay, and a safety switch controlled by said microcontroller and inserted in said grounded shunt line; characterized by the circuit further comprising a set of at least one temperature detector associated with said solid state relay and connected to said microcontroller such that the latter sequentially checks the state of said temperature detector and if an anomaly in temperature is produced opens the corresponding solid state relay, and if the anomaly persists, closes said controlled safety switch so as to short- circuit to ground said power source through said grounded shunt line, thereby actuating said breaking device and provoking the disconnection of said solid state relay and its corresponding set of associated loads from the power source.
2. A safety circuit according to claim 1, characterized in that said solid state relay is an PET switch controlled by said microcontroller.
3. A safety circuit according to claim 1 or claim 2, characterized in that said breaking device is a fuse, so that the passage of an overcurrent through it causes it to
- - blow.
4. A safety circuit according to any one of claims 1 to 3, characterized in that each load has an FET protection switch associated to it, and each one of these switches has a dedicated temperature detector.
5. A safety circuit according to any one of claims 1 to 3, characterized in that various loads have a single lO associated FET protection switch, and the latter has a dedicated temperature detects'.
6. A safety circuit according to any one of the proceeding claims, characterized in that said controlled safety switch is an electronic power switch.
7. A safety circuit according to any one of the proceeding claims, characterized in that said controlled safety switch is of the FET type.
8. A safety circuit according to any one of the preceding claims, characterized in that said controlled safety switch is a relay.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ES200203038A ES2211352B1 (en) | 2002-12-30 | 2002-12-30 | ACTIVE SECURITY CIRCUIT OF PROTECTED LOADS BY SOLID STATE RELAYS. |
Publications (3)
Publication Number | Publication Date |
---|---|
GB0330093D0 GB0330093D0 (en) | 2004-02-04 |
GB2396982A true GB2396982A (en) | 2004-07-07 |
GB2396982B GB2396982B (en) | 2004-12-15 |
Family
ID=31502902
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB0330093A Expired - Fee Related GB2396982B (en) | 2002-12-30 | 2003-12-29 | Active safety circuit with loads protected by solid state relays |
Country Status (3)
Country | Link |
---|---|
DE (1) | DE10361641A1 (en) |
ES (1) | ES2211352B1 (en) |
GB (1) | GB2396982B (en) |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1630923A1 (en) * | 2004-08-31 | 2006-03-01 | Catem GmbH & Co. KG | Control circuit for a plurality of electrical loads with a safeguard for the semiconductor switches |
EP1630013A1 (en) * | 2004-08-31 | 2006-03-01 | Catem GmbH & Co. KG | Electric supplementary heating for vehicles with current safety |
EP1932698A1 (en) * | 2006-12-12 | 2008-06-18 | Behr France Rouffach SAS | Method to test the operation of an electrical heater, in particular for a motor vehicle |
EP1932699A1 (en) * | 2006-12-12 | 2008-06-18 | Behr France Rouffach SAS | Method for testing the operation of an electric heating device, in particular for a motor vehicle |
US20140035359A1 (en) * | 2012-08-02 | 2014-02-06 | Infineon Technologies Ag | Vehicle voltage supply |
GB2556081A (en) * | 2016-11-18 | 2018-05-23 | Ge Aviat Systems Ltd | System and method for protecting a solid state power controller |
EP3691127A1 (en) * | 2019-01-31 | 2020-08-05 | Siemens Aktiengesellschaft | Secure electronic switch |
US11121538B2 (en) | 2014-12-22 | 2021-09-14 | Ecom Instruments Gmbh | Electronic circuit arrangement for use in an area exposed to explosion hazards |
EP4088125A4 (en) * | 2020-01-21 | 2024-03-06 | Amber Semiconductor, Inc. | Intelligent circuit interruption |
US12015261B2 (en) | 2019-05-18 | 2024-06-18 | Amber Semiconductor, Inc. | Intelligent circuit breakers with solid-state bidirectional switches |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2173016A1 (en) | 2008-10-02 | 2010-04-07 | DBK David + Baader GmbH | Switch for an electric consumer with a voltage switching device |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0956153A (en) * | 1995-08-18 | 1997-02-25 | Toyo Electric Mfg Co Ltd | Protection circuit of switching regulator |
US6373671B1 (en) * | 1998-10-16 | 2002-04-16 | Hitachi, Ltd. | Apparatus with an over-current shutdown means and an over-temperature shutdown means |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1583140A (en) * | 1976-05-06 | 1981-01-21 | Ranco Gmbh | Automatic temperature control devices |
JPS60131026A (en) * | 1983-12-16 | 1985-07-12 | 日産自動車株式会社 | Automotive electronic circuit device |
US5995347A (en) * | 1997-05-09 | 1999-11-30 | Texas Instruments Incorporated | Method and apparatus for multi-function electronic motor protection |
-
2002
- 2002-12-30 ES ES200203038A patent/ES2211352B1/en not_active Withdrawn - After Issue
-
2003
- 2003-12-29 GB GB0330093A patent/GB2396982B/en not_active Expired - Fee Related
- 2003-12-30 DE DE10361641A patent/DE10361641A1/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0956153A (en) * | 1995-08-18 | 1997-02-25 | Toyo Electric Mfg Co Ltd | Protection circuit of switching regulator |
US6373671B1 (en) * | 1998-10-16 | 2002-04-16 | Hitachi, Ltd. | Apparatus with an over-current shutdown means and an over-temperature shutdown means |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1630013A1 (en) * | 2004-08-31 | 2006-03-01 | Catem GmbH & Co. KG | Electric supplementary heating for vehicles with current safety |
EP1630923A1 (en) * | 2004-08-31 | 2006-03-01 | Catem GmbH & Co. KG | Control circuit for a plurality of electrical loads with a safeguard for the semiconductor switches |
EP1932698A1 (en) * | 2006-12-12 | 2008-06-18 | Behr France Rouffach SAS | Method to test the operation of an electrical heater, in particular for a motor vehicle |
EP1932699A1 (en) * | 2006-12-12 | 2008-06-18 | Behr France Rouffach SAS | Method for testing the operation of an electric heating device, in particular for a motor vehicle |
US20140035359A1 (en) * | 2012-08-02 | 2014-02-06 | Infineon Technologies Ag | Vehicle voltage supply |
US9302637B2 (en) * | 2012-08-02 | 2016-04-05 | Infineon Technologies Ag | Vehicle voltage supply |
US11121538B2 (en) | 2014-12-22 | 2021-09-14 | Ecom Instruments Gmbh | Electronic circuit arrangement for use in an area exposed to explosion hazards |
GB2556081A (en) * | 2016-11-18 | 2018-05-23 | Ge Aviat Systems Ltd | System and method for protecting a solid state power controller |
US11005254B2 (en) | 2016-11-18 | 2021-05-11 | Ge Aviation Systems Limited | System and method for protecting a solid-state power controller |
GB2556081B (en) * | 2016-11-18 | 2019-12-18 | Ge Aviat Systems Ltd | System and method for protecting a solid state power controller |
EP3691127A1 (en) * | 2019-01-31 | 2020-08-05 | Siemens Aktiengesellschaft | Secure electronic switch |
WO2020156905A1 (en) * | 2019-01-31 | 2020-08-06 | Siemens Aktiengesellschaft | Safe electronic switch |
US11437987B2 (en) | 2019-01-31 | 2022-09-06 | Siemens Aktiengesellschaft | Safe electronic switch |
US12015261B2 (en) | 2019-05-18 | 2024-06-18 | Amber Semiconductor, Inc. | Intelligent circuit breakers with solid-state bidirectional switches |
EP4088125A4 (en) * | 2020-01-21 | 2024-03-06 | Amber Semiconductor, Inc. | Intelligent circuit interruption |
Also Published As
Publication number | Publication date |
---|---|
DE10361641A1 (en) | 2004-10-14 |
GB2396982B (en) | 2004-12-15 |
ES2211352B1 (en) | 2005-09-16 |
ES2211352A1 (en) | 2004-07-01 |
GB0330093D0 (en) | 2004-02-04 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20091229 |