US20010006341A1 - Reset circuit - Google Patents

Reset circuit Download PDF

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Publication number
US20010006341A1
US20010006341A1 US09/738,641 US73864100A US2001006341A1 US 20010006341 A1 US20010006341 A1 US 20010006341A1 US 73864100 A US73864100 A US 73864100A US 2001006341 A1 US2001006341 A1 US 2001006341A1
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Prior art keywords
supply voltage
current source
active switching
switching elements
reset circuit
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Granted
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US09/738,641
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US6459249B2 (en
Inventor
Marten Swart
Ekkehart-Peter Wagner
Christian Zelger
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Continental Automotive GmbH
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Siemens AG
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Assigned to SIEMENS AKTIENGESELLSCHAFT reassignment SIEMENS AKTIENGESELLSCHAFT ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: WAGNER, EKKEHART-PETER, ZELGER, CHRISTIAN, SWART, MARTEN
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Assigned to CONTINENTAL AUTOMOTIVE GMBH reassignment CONTINENTAL AUTOMOTIVE GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SIEMENS AKTIENGESELLSCHAFT
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
    • G06F1/24—Resetting means
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
    • G06F1/26—Power supply means, e.g. regulation thereof
    • G06F1/30—Means for acting in the event of power-supply failure or interruption, e.g. power-supply fluctuations
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S323/00—Electricity: power supply or regulation systems
    • Y10S323/901—Starting circuits

Definitions

  • the invention relates to a reset circuit for deactivating a circuit configuration in the event that the supply voltage drops below a specific level to an undervoltage.
  • a reset circuit of the generic type serves for deactivating an external circuit configuration, e.g. in the form of a microcontroller circuit which is operated by a supply voltage and is intended to be brought to a stable, deactivated state if the supply voltage falls below a specific level, so that logic circuits operated in connection with the microcontroller circuit cannot assume undefined states.
  • the external circuit configuration is deactivated.
  • Reset circuits operate, e.g. with a charge pump, which is fed by the supply voltage of the microcontroller, and with a transistor operating as an actuator, across which a bias voltage is dropped.
  • the bias voltage can be kept very small by means of the charge pump during normal operation.
  • the bias voltage assumes a relatively large value and thus reliably deactivates the microcontroller circuit if the supply voltage drops below a specific value. A hysteresis effect is produced in this case, so that the microcontroller circuit “starts up” again only if the supply voltage rises above a specific threshold value.
  • DE 195 27 603 A1 discloses an electrical circuit configuration for generating a reset signal in the case of undervoltage supply of a microcomputer, which circuit configuration has a series circuit—connected to a voltage to be monitored—formed by an npn transistor and a resistor, at the junction point of which the reset signal can be tapped off.
  • the resistor must have a relatively high resistance in order to keep the thermal loading on the transistor within limits.
  • This resistor together with resistors which are located in the microcomputer and are connected to the positive pole of the voltage to be monitored forms a voltage divider, whereby an unambiguous reset signal (low signal) is not ensured.
  • EP 0 767 416 A1 discloses a circuit for supplying voltage to a microcomputer with generation of a reset signal in the case of undervoltage supply, which circuit has a plurality of capacitors. Undefined states, which should be avoided under all circumstances, can arise in the time between the undershooting of the minimum supply voltage and the appearance of a reset signal.
  • a reset circuit for, in an event of an undervoltage supply, deactivating a circuit configuration that is fed by a supply voltage.
  • the reset circuit includes two active switching elements having forward paths connected together at a junction point and connected in series between a supply voltage and a ground reference potential. Each one of the two active switching elements has a control terminal.
  • the reset circuit also includes a resistor having one terminal connected to the ground reference potential and another terminal connected to the junction point, at least one forward-biased diode; a first current source connected to the supply voltage via the at least one diode; and a second current source connected to the supply voltage.
  • the control terminal of each one of the two active switching elements is driven by a respective one of the first current source and the second current source.
  • the junction point provides a reset signal.
  • the active switching elements are transistors selected from the group consisting of bipolar transistors and field-effect transistors.
  • the reset circuit includes a current mirror circuit which includes one of the two active switching elements.
  • the one of the two active switching elements has a drain-source path connected between the supply voltage and the junction point.
  • the one of the two active switching elements is driven by the first current source.
  • the current mirror circuit also includes another active switching element having a drain-source path connected between the first current source and the ground reference potential, the other active switching element being driven by the first current source.
  • the reset signal is active low.
  • the reset circuit is used with a motor vehicle electronic circuit.
  • the second current source is directly connected to the supply voltage.
  • the reset circuit according to the invention has the advantage that a minimum number of components are required and deactivation of the external circuit configuration is performed reliably.
  • FIG. 1 shows a first circuit diagram of a reset circuit
  • FIG. 2 a shows the profile of the current of the current source 11 plotted against the supply voltage
  • FIG. 2 b shows the profile of the current of the current source 10 plotted against the supply voltage
  • FIG. 3 shows a second exemplary embodiment of a reset circuit
  • FIG. 4 a shows the profile of the current I PD through the transistor 2 ;
  • FIG. 4 b shows the profile of the current I PU through the transistor 3 .
  • FIG. 1 there is shown a first exemplary embodiment of an inventive reset circuit.
  • Two active switching elements 1 and 2 are shown with their forward paths connected in series between supply voltage U V and ground reference potential.
  • the reset signal U RESET is present as an active low signal for deactivating e.g. an external microcontroller circuit 12 .
  • the junction point 5 is connected to ground reference potential via the resistor R DOWN .
  • the resistor R DOWN can also be omitted.
  • the active switching elements 1 and 2 are bipolar npn transistors T UP and T DOWN .
  • the control terminals 6 and 7 of the active switching elements 1 and 2 which are embodied as bases of the bipolar transistors T UP and T DOWN , are directly driven with respective currents I PU and I PD of respective current sources 10 and 11 .
  • the current sources 10 and 11 are fed by the supply voltage U V .
  • the first current source 10 is connected to the supply voltage U V via at least one forward-biased diode D 1 .
  • two or more forward-biased diodes D 1 , D 2 can be provided between current source 10 and supply voltage U V .
  • the supply voltage U V has a sufficiently high level of e.g. 5 V for operating the external circuit configuration 12 e.g. in the form of a microcontroller
  • the currents I PU and I PD flow for the purpose of driving the respective active switching element 1 and 2 in the form of a bipolar npn transistor T UP or T DOWN .
  • a high level is established at the junction point 5 on account of the currents IPU and IPD chosen and on account of the characteristics of the two bipolar transistors T UP and T DOWN , respectively.
  • the external circuit configuration 12 is not deactivated, but rather remains in its operating state.
  • the current source 10 cannot supply a sufficient drive current for the base of the transistor T UP , the potential at the junction point 5 then goes to a low level.
  • the microcontroller circuit 12 is thereby deactivated.
  • Each current source requires a certain drop voltage for operation.
  • the available voltage for the current source I PU driving the transistor TUP is reduced.
  • the current I PU falls first and only subsequently does the current I PD , which drives the transistor T DOWN , drop.
  • the forward path of the transistor T DOWN is kept at a lower resistance than the forward path of the transistor T UP . Therefore, the reset signal U RESET is always pulled to a low level when the supply voltage U V drops. If the supply voltage U V is then so low that the current IPD of the current source 11 also fails, the resistor R DOWN performs the task of keeping the reset signal U RESET at a low level in a defined manner.
  • the second exemplary embodiment—illustrated in FIG. 3—of the reset circuit according to the invention operates, in principle, similarly to that shown in FIG. 1.
  • a current mirror circuit 9 formed from field-effect transistors 3 , 4 and a bipolar transistor 2 are provided as active switching elements.
  • the current mirrored by the field-effect transistor 4 to the field-effect transistor 3 is designated by I PU and the current flowing through the collector-emitter path of the bipolar transistor 2 is designated by I PD .
  • the currents I PU and I PD are the respective current of the current sources 10 and 11 magnified by the current gain factor of the transistors.
  • the gate electrodes 8 of both field-effect transistors 3 and 4 are connected to the current source 10 and to the drain electrode of the field-effect transistor 4 .
  • FIGS. 4 a and 4 b are in principle identical to FIGS. 2 a,b.
  • the threshold voltage of the field-effect transistors as gate-source voltage, which is approximately 2 V in addition, is superposed on the diode forward voltages U D of the two diodes D 1 and D 2 . Therefore, the diodes D 1 and D 2 can also be obviated when using the current mirror circuit with the field-effect transistors.
  • the current mirror circuit 9 is characterized in that the first field-effect transistor 3 is connected with its drain-source path between the supply voltage U V and the junction point 5 , and the second field-effect transistor 4 is connected with its drain-source path between the first current source 10 and ground reference potential.
  • the gate electrodes 8 of both field-effect transistors 3 , 4 are connected together and connected to the first current source 10 .
  • the reset signal U RESET is an active low signal.
  • FIGS. 1 and 3 can also be used as supplementation to a comparator circuit (not illustrated).
  • the accuracy of the reset threshold is distinctly increased by such a comparator circuit.
  • the reset circuit according to the invention is characterized by the use in motor vehicle electronics.

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  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Electronic Switches (AREA)

Abstract

A reset circuit for deactivating a circuit configuration, which is fed by a supply voltage, in the case of an undervoltage supply. In this case, active components 1,2 (FIG. 1); or 3,2 (FIG. 3) are provided and their forward paths are connected in series between the supply voltage Uv and ground reference potential. The active components are fed directly or indirectly by a current mirror circuit 9 from a respective current source 10, 11. A reset signal Ureset (active=low signal) being present at the junction point 5 of the active components, where the junction point 5 is connected to ground reference potential via a resistor Rdown.

Description

    CROSS-REFERENCE TO RELATED APPLICATION
  • This is a continuation of international application PCT/DE99/01720, filed Jun. 11, 1999, which designated the United States. [0001]
    • BACKGROUND OF THE INVENTION
  • 1. Field of the Invention [0002]
  • The invention relates to a reset circuit for deactivating a circuit configuration in the event that the supply voltage drops below a specific level to an undervoltage. [0003]
  • A reset circuit of the generic type serves for deactivating an external circuit configuration, e.g. in the form of a microcontroller circuit which is operated by a supply voltage and is intended to be brought to a stable, deactivated state if the supply voltage falls below a specific level, so that logic circuits operated in connection with the microcontroller circuit cannot assume undefined states. In other words, the external circuit configuration is deactivated. [0004]
  • Reset circuits according to the prior art operate, e.g. with a charge pump, which is fed by the supply voltage of the microcontroller, and with a transistor operating as an actuator, across which a bias voltage is dropped. The bias voltage can be kept very small by means of the charge pump during normal operation. In the case of undervoltage supply, the bias voltage assumes a relatively large value and thus reliably deactivates the microcontroller circuit if the supply voltage drops below a specific value. A hysteresis effect is produced in this case, so that the microcontroller circuit “starts up” again only if the supply voltage rises above a specific threshold value. [0005]
  • Circuits of the aforementioned type are relatively complex and expensive. [0006]
  • DE 195 27 603 A1 discloses an electrical circuit configuration for generating a reset signal in the case of undervoltage supply of a microcomputer, which circuit configuration has a series circuit—connected to a voltage to be monitored—formed by an npn transistor and a resistor, at the junction point of which the reset signal can be tapped off. The resistor must have a relatively high resistance in order to keep the thermal loading on the transistor within limits. This resistor together with resistors which are located in the microcomputer and are connected to the positive pole of the voltage to be monitored forms a voltage divider, whereby an unambiguous reset signal (low signal) is not ensured. [0007]
  • EP 0 767 416 A1 discloses a circuit for supplying voltage to a microcomputer with generation of a reset signal in the case of undervoltage supply, which circuit has a plurality of capacitors. Undefined states, which should be avoided under all circumstances, can arise in the time between the undershooting of the minimum supply voltage and the appearance of a reset signal. [0008]
    • SUMMARY OF THE INVENTION
  • It is accordingly an object of the invention to provide a reset circuit which overcomes the above-mentioned disadvantageous of the prior art circuits of this general type, and which operates reliably over a wide supply voltage range, requires few components and is thus cost-effective and simple to integrate. [0009]
  • With the foregoing and other objects in view there is provided, in accordance with the invention a reset circuit for, in an event of an undervoltage supply, deactivating a circuit configuration that is fed by a supply voltage. The reset circuit includes two active switching elements having forward paths connected together at a junction point and connected in series between a supply voltage and a ground reference potential. Each one of the two active switching elements has a control terminal. The reset circuit also includes a resistor having one terminal connected to the ground reference potential and another terminal connected to the junction point, at least one forward-biased diode; a first current source connected to the supply voltage via the at least one diode; and a second current source connected to the supply voltage. The control terminal of each one of the two active switching elements is driven by a respective one of the first current source and the second current source. The junction point provides a reset signal. [0010]
  • In accordance with an added feature of the invention, the active switching elements are transistors selected from the group consisting of bipolar transistors and field-effect transistors. [0011]
  • In accordance with an additional feature of the invention, the reset circuit includes a current mirror circuit which includes one of the two active switching elements. The one of the two active switching elements has a drain-source path connected between the supply voltage and the junction point. The one of the two active switching elements is driven by the first current source. The current mirror circuit also includes another active switching element having a drain-source path connected between the first current source and the ground reference potential, the other active switching element being driven by the first current source. [0012]
  • In accordance with another feature of the invention, the reset signal is active low. [0013]
  • In accordance with a further feature of the invention, the reset circuit is used with a motor vehicle electronic circuit. [0014]
  • In accordance with a concomitant feature of the invention, the second current source is directly connected to the supply voltage. [0015]
  • The reset circuit according to the invention has the advantage that a minimum number of components are required and deactivation of the external circuit configuration is performed reliably. [0016]
  • Other features which are considered as characteristic for the invention are set forth in the appended claims. [0017]
  • Although the invention is illustrated and described herein as embodied in a reset circuit, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. [0018]
  • The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. [0019]
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1: shows a first circuit diagram of a reset circuit; [0020]
  • FIG. 2[0021] a: shows the profile of the current of the current source 11 plotted against the supply voltage;
  • FIG. 2[0022] b: shows the profile of the current of the current source 10 plotted against the supply voltage;
  • FIG. 3: shows a second exemplary embodiment of a reset circuit; [0023]
  • FIG. 4[0024] a: shows the profile of the current IPD through the transistor 2; and
  • FIG. 4[0025] b: shows the profile of the current IPU through the transistor 3.
    • DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a first exemplary embodiment of an inventive reset circuit. Two [0026] active switching elements 1 and 2 are shown with their forward paths connected in series between supply voltage UV and ground reference potential. At the junction point 5 of the switching elements, the reset signal URESET is present as an active low signal for deactivating e.g. an external microcontroller circuit 12. The junction point 5 is connected to ground reference potential via the resistor RDOWN. The resistor RDOWN can also be omitted. In the exemplary embodiment, the active switching elements 1 and 2 are bipolar npn transistors TUP and TDOWN. The control terminals 6 and 7 of the active switching elements 1 and 2, which are embodied as bases of the bipolar transistors TUP and TDOWN, are directly driven with respective currents IPU and IPD of respective current sources 10 and 11. The current sources 10 and 11 are fed by the supply voltage UV. The first current source 10 is connected to the supply voltage UV via at least one forward-biased diode D1. In the preferred embodiment shown in FIG. 1, two or more forward-biased diodes D1, D2 can be provided between current source 10 and supply voltage UV.
  • The method of operation of the first exemplary embodiment shown in FIG. 1 shall be explained with reference to the diagrams of FIGS. 2[0027] a and 2 b.
  • If the supply voltage U[0028] V has a sufficiently high level of e.g. 5 V for operating the external circuit configuration 12 e.g. in the form of a microcontroller, the currents IPU and IPD flow for the purpose of driving the respective active switching element 1 and 2 in the form of a bipolar npn transistor TUP or TDOWN. A high level is established at the junction point 5 on account of the currents IPU and IPD chosen and on account of the characteristics of the two bipolar transistors TUP and TDOWN, respectively. As a result, the external circuit configuration 12 is not deactivated, but rather remains in its operating state. If the level of the supply voltage UV then falls to an extent such that, on account of the threshold voltage of the two diodes D1 and D2, the current source 10 cannot supply a sufficient drive current for the base of the transistor TUP, the potential at the junction point 5 then goes to a low level. The microcontroller circuit 12 is thereby deactivated.
  • Each current source requires a certain drop voltage for operation. By inserting the two diodes D[0029] 1 and D2, the available voltage for the current source IPU driving the transistor TUP is reduced. In this way, it can be ensured that when the supply voltage UV drops, the current IPU falls first and only subsequently does the current IPD , which drives the transistor TDOWN, drop. Thus, even at a relatively low supply voltage UV, the forward path of the transistor TDOWN is kept at a lower resistance than the forward path of the transistor TUP. Therefore, the reset signal URESET is always pulled to a low level when the supply voltage UV drops. If the supply voltage UV is then so low that the current IPD of the current source 11 also fails, the resistor RDOWN performs the task of keeping the reset signal URESET at a low level in a defined manner.
  • The second exemplary embodiment—illustrated in FIG. 3—of the reset circuit according to the invention operates, in principle, similarly to that shown in FIG. 1. [0030]
  • A [0031] current mirror circuit 9 formed from field- effect transistors 3,4 and a bipolar transistor 2 are provided as active switching elements. The current mirrored by the field-effect transistor 4 to the field-effect transistor 3 is designated by IPU and the current flowing through the collector-emitter path of the bipolar transistor 2 is designated by IPD. The currents IPU and IPD are the respective current of the current sources 10 and 11 magnified by the current gain factor of the transistors. The gate electrodes 8 of both field- effect transistors 3 and 4 are connected to the current source 10 and to the drain electrode of the field-effect transistor 4.
  • The method of operation is apparent from the diagrams of FIGS. 4[0032] a and 4 b, which are in principle identical to FIGS. 2a,b.
  • The only difference to be found in FIGS. 4[0033] a,b is that the threshold voltage of the field-effect transistors as gate-source voltage, which is approximately 2 V in addition, is superposed on the diode forward voltages UD of the two diodes D1 and D2. Therefore, the diodes D1 and D2 can also be obviated when using the current mirror circuit with the field-effect transistors.
  • The [0034] current mirror circuit 9 is characterized in that the first field-effect transistor 3 is connected with its drain-source path between the supply voltage UV and the junction point 5, and the second field-effect transistor 4 is connected with its drain-source path between the first current source 10 and ground reference potential. The gate electrodes 8 of both field- effect transistors 3,4 are connected together and connected to the first current source 10.
  • The reset signal U[0035] RESET is an active low signal.
  • The above-described circuits of FIGS. 1 and 3 can also be used as supplementation to a comparator circuit (not illustrated). The accuracy of the reset threshold is distinctly increased by such a comparator circuit. [0036]
  • The circuits described guarantee a reliable reset signal URESET even when the minimum operating voltage of the comparator is undershot. [0037]
  • The reset circuit according to the invention is characterized by the use in motor vehicle electronics. [0038]

Claims (6)

We claim:
1. A reset circuit for, in an event of an undervoltage supply, deactivating a circuit configuration that is fed by a supply voltage, the reset circuit comprising:
two active switching elements having forward paths connected together at a junction point and connected in series between a supply voltage and a ground reference potential, each one of said two active switching elements having a control terminal;
a resistor having one terminal connected to the ground reference potential and another terminal connected to said junction point, said junction point providing a reset signal;
at least one forward-biased diode;
a first current source connected to the supply voltage via said at least one diode; and
a second current source connected to the supply voltage;
said control terminal of each one of said two active switching elements being driven by a respective one of said first current source and said second current source.
2. The reset circuit according to
claim 1
, wherein said active switching elements are transistors selected from the group consisting of bipolar transistors and field-effect transistors.
3. The reset circuit according to
claim 1
, comprising:
a current mirror circuit including one of said two active switching elements, said one of said two active switching elements having a drain-source path connected between said supply voltage and said junction point, said one of said two active switching elements being driven by said first current source;
said current mirror circuit including another active switching element having a drain-source path connected between said first current source and said ground reference potential, said other active switching element being driven by said first current source.
4. The reset circuit according to
claim 3
, wherein the reset signal is active low.
5. The reset circuit according to
claim 1
, wherein the reset circuit is used with a motor vehicle electronic circuit.
6. The reset circuit according to
claim 1
, wherein said second current source is directly connected to the supply voltage.
US09/738,641 1998-06-22 2000-12-22 Reset circuit Expired - Fee Related US6459249B2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE19827705 1998-06-22
DE19827705A DE19827705C1 (en) 1998-06-22 1998-06-22 Reset circuit i.e. for vehicle electronics circuitry e.g. for airbag
DE19827705.9 1998-06-22
PCT/DE1999/001720 WO1999067881A1 (en) 1998-06-22 1999-06-11 Reset circuit

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1999/001720 Continuation WO1999067881A1 (en) 1998-06-22 1999-06-11 Reset circuit

Publications (2)

Publication Number Publication Date
US20010006341A1 true US20010006341A1 (en) 2001-07-05
US6459249B2 US6459249B2 (en) 2002-10-01

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US (1) US6459249B2 (en)
EP (1) EP1090460B1 (en)
DE (1) DE19827705C1 (en)
WO (1) WO1999067881A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007004794B4 (en) * 2007-01-31 2012-04-19 Leopold Kostal Gmbh & Co. Kg Controller block with monitoring by a watchdog
GB2469264A (en) 2009-04-03 2010-10-13 Nokia Corp Hardware reset circuit for mobile phones with a first state that blocks the reset signal and second state that allows the reset

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4011484A (en) * 1976-02-23 1977-03-08 The United States Of America As Represented By The Secretary Of The Interior Undervoltage release with electrical reset for circuit breaker
JPH02168714A (en) * 1988-12-22 1990-06-28 Omron Tateisi Electron Co Switching circuit
JPH043513A (en) * 1990-04-20 1992-01-08 Nec Corp Power-on reset circuit
US5359233A (en) * 1990-09-28 1994-10-25 Dallas Semiconductor Corporation Reset monitor for detection of power failure and external reset
US5274274A (en) * 1992-03-23 1993-12-28 Power Integrations, Inc. Dual threshold differential discriminator
US5463335A (en) * 1992-10-30 1995-10-31 International Business Machines Corporation Power up detection circuits
US5552725A (en) * 1994-08-05 1996-09-03 Advanced Micro Devices, Inc. Low power, slew rate insensitive power-on reset circuit
DE19527603C2 (en) * 1994-08-10 1997-12-18 Kostal Leopold Gmbh & Co Kg Electrical circuit arrangement
US5760625A (en) * 1995-10-03 1998-06-02 Ford Motor Company Low cost microcomputer power supply with power on reset and low voltage inhibit functionality
US5781051A (en) * 1996-07-26 1998-07-14 Exel Microelectronics, Inc. Power-up detector for low power systems
US6163183A (en) * 1999-07-16 2000-12-19 Lucent Technologies, Inc Multifunction reset for mixed-signal integrated circuits

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US6459249B2 (en) 2002-10-01
WO1999067881A1 (en) 1999-12-29
EP1090460A1 (en) 2001-04-11
DE19827705C1 (en) 1999-10-28
EP1090460B1 (en) 2001-12-12

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