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GB2149984A - Backup power source circuit for control circuit - Google Patents

Backup power source circuit for control circuit Download PDF

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Publication number
GB2149984A
GB2149984A GB08428114A GB8428114A GB2149984A GB 2149984 A GB2149984 A GB 2149984A GB 08428114 A GB08428114 A GB 08428114A GB 8428114 A GB8428114 A GB 8428114A GB 2149984 A GB2149984 A GB 2149984A
Authority
GB
United Kingdom
Prior art keywords
voltage
circuit
control circuit
power source
battery
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
Application number
GB08428114A
Other versions
GB2149984B (en
GB8428114D0 (en
Inventor
Yoshiki Kan
Takashi Noda
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pioneer Corp
Original Assignee
Pioneer Electronic Corp
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 Pioneer Electronic Corp filed Critical Pioneer Electronic Corp
Publication of GB8428114D0 publication Critical patent/GB8428114D0/en
Publication of GB2149984A publication Critical patent/GB2149984A/en
Application granted granted Critical
Publication of GB2149984B publication Critical patent/GB2149984B/en
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems

Landscapes

  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Stand-By Power Supply Arrangements (AREA)
  • Power Sources (AREA)
  • Safety Devices In Control Systems (AREA)
  • Direct Current Feeding And Distribution (AREA)

Abstract

When application of a main supply voltage 2 to a control circuit 1 is suspended, a backup voltage 7 is supplied via a diode 8 to the circuit 1 to maintain predetermined operating conditions in the circuit 1. If, during supply of the voltage 2 to the circuit 1, the backup voltage 7 is lower than a predetermined level, a reset signal is applied to the circuit 1 by means of a reset circuit comprising a comparator 6 and a differentiator 9, 10, 11. Comparator 6 compares the voltage 7 with the voltage normally applied to circuit 1 from supply 2 via a constant voltage circuit 4 and a diode 5. If, during supply of voltage 2 to circuit 1, the voltage 7 is higher than the predetermined level, no current flows from supply 7 to circuit 1 because the forward voltage of diode 8 is much higher than that of diode 5. The circuit 1 may be an audio device for a vehicle, supply 2 being the vehicle battery and supply 7 being a battery built into the audio device. The reset signal may erase the contents of a memory or counter. <IMAGE>

Description

SPECIFICATION Backup power source circuit for control circuit The present invention relates to a backup power source circuit for a control circuit.
Recently, there has been proposed a variety of devices which are operated by control circuits implemented with microcomputers, etc.
Some of these devices are provided with a backup power source circuit used to continue operations necessary for the control operation of the control circuit, such as maintaining the contents of memories and a time measuring operation, when the main power source fails or is disconnected.
In the case when the backup power source is a battery, the output voltage of the battery will eventually drop due to normal battery discharge. When the output voltage of the battery falls below a certain level, abnormal conditions occur within the control circuit, for instance, the contents of the memories may be lost. When such abnormal conditions occur, the control circuit will no longer operate correctly when the main supply voltage is applied thereto again.
Accordingly, an object of the invention is to provide a backup power source circuit which prevents the occurrence of the difficulty of the control circuit operating erroneously after the main supply voltage is applied thereto again due to a drop of the output voltage of a backup power source.
A specific feature of the backup power source circuit according to the invention is the provision of means for generating a reset signal if, during application of the main supply voltage, the backup voltage is lower than a predetermined value, to thereby reset the control circuit.
The single figure is a circuit diagram of a preferred embodiment of a backup power source circuit of the invention.
A preferred embodiment of the invention will now be described in detail with reference to the accompanying drawing.
The single figure of the accompanying drawing shows a backup power source circuit for a control circuit 1 which forms a part of a so-called quick release type audio device intended for vehicular use. As shown in the figure, the output voltage of a vehicle battery 2, which forms a main power source, is supplied through a connector 3 to a voltage regulator circuit 4. The positive output terminal of the voltage regulator circuit 4 is connected through a diode 5 to one power input terminal VDD of the control circuit 1 and to one input terminal of a comparator 6.
A backup power source, namely, a battery 7, is built into the audio device. The positive output terminal of the batterty 7 is connected to the other input terminal of the comparator 6, and it is further connected through a diode 8 to the power input terminal VDD. The output terminal of the comparator 6 is connected to the reset terminal RST of the control circuit 1 through a differentiator circuit 1 2 composed of a capacitor 9, a resistor 10 and a diode 11.
The negative output terminals of the batteries 2 and 7 and the other power input terminal V55 of the control circuit are grounded. The output voltage of the constant voltage circuit 4 is applied to the comparator 6.
In the backup power souce circuit thus constructed, when the audio device is not set in the vehicle or when the battery 2 is not connected to the voltage regulator circuit 4, the output voltage of the battery 7 is supplied through the diode 8 to the control circuit. In this case, since no voltage is applied to the comparator 6 from the voltage regulator circuit 4, the comparator 6 is not in operation.
When the audio device has been installed and connected to the battery via the voltage regulator circuit 4, the volrage regulator circuit 4 applies a predetermined voltage through the diode 5 to the one input terminal of the comparator 6 and to the control circuit 1. The predetermined voltage is further applied to the comparator 6 where it is compared with the output voltage of the battery 7. When the output voltage of the battery 7 is higher than the predetermined voltage, the output of the comparator is set to a low level.
When the output voltage of the battery 7 is lower than the predetermined voltage, the output of the comparator is raised to a high level. This high level output of the comparator is applied as a reset signal to the control circuit 1 through the differentiator circuit 1 2.
The control circuit 1 is reset by the reset signal, in which case the contents of the memory, the counter etc., are erased.
When the output voltage of the battery 7 is higher than the predetermined voltage, no current flows to the control circuit 1 from the battery 7 because the forward voltage of the diode 8 is much higher than that of the diode 5.
As is apparent from the above description, in the control circuit backup power source circuit according to the invention, when the voltage of the backup battery becomes lower than the predetermined voltage, the control circuit is reset. Therefore, even if, during the use of the backup battery, its voltage is decreased resulting in the occurance of abnormal conditions such as the loss of the content of the memory, it is possible to readily provide to the user an indication of this condition.
1. A backup power source circuit for applying, a backup voltage to a control circuit to maintain predetermined operating conditions of the control circuit when application of a main supply voltage to the control circuit is
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Backup power source circuit for control circuit The present invention relates to a backup power source circuit for a control circuit. Recently, there has been proposed a variety of devices which are operated by control circuits implemented with microcomputers, etc. Some of these devices are provided with a backup power source circuit used to continue operations necessary for the control operation of the control circuit, such as maintaining the contents of memories and a time measuring operation, when the main power source fails or is disconnected. In the case when the backup power source is a battery, the output voltage of the battery will eventually drop due to normal battery discharge. When the output voltage of the battery falls below a certain level, abnormal conditions occur within the control circuit, for instance, the contents of the memories may be lost. When such abnormal conditions occur, the control circuit will no longer operate correctly when the main supply voltage is applied thereto again. Accordingly, an object of the invention is to provide a backup power source circuit which prevents the occurrence of the difficulty of the control circuit operating erroneously after the main supply voltage is applied thereto again due to a drop of the output voltage of a backup power source. A specific feature of the backup power source circuit according to the invention is the provision of means for generating a reset signal if, during application of the main supply voltage, the backup voltage is lower than a predetermined value, to thereby reset the control circuit. The single figure is a circuit diagram of a preferred embodiment of a backup power source circuit of the invention. A preferred embodiment of the invention will now be described in detail with reference to the accompanying drawing. The single figure of the accompanying drawing shows a backup power source circuit for a control circuit 1 which forms a part of a so-called quick release type audio device intended for vehicular use. As shown in the figure, the output voltage of a vehicle battery 2, which forms a main power source, is supplied through a connector 3 to a voltage regulator circuit 4. The positive output terminal of the voltage regulator circuit 4 is connected through a diode 5 to one power input terminal VDD of the control circuit 1 and to one input terminal of a comparator 6. A backup power source, namely, a battery 7, is built into the audio device. The positive output terminal of the batterty 7 is connected to the other input terminal of the comparator 6, and it is further connected through a diode 8 to the power input terminal VDD. The output terminal of the comparator 6 is connected to the reset terminal RST of the control circuit 1 through a differentiator circuit 1 2 composed of a capacitor 9, a resistor 10 and a diode 11. The negative output terminals of the batteries 2 and 7 and the other power input terminal V55 of the control circuit are grounded. The output voltage of the constant voltage circuit 4 is applied to the comparator 6. In the backup power souce circuit thus constructed, when the audio device is not set in the vehicle or when the battery 2 is not connected to the voltage regulator circuit 4, the output voltage of the battery 7 is supplied through the diode 8 to the control circuit. In this case, since no voltage is applied to the comparator 6 from the voltage regulator circuit 4, the comparator 6 is not in operation. When the audio device has been installed and connected to the battery via the voltage regulator circuit 4, the volrage regulator circuit 4 applies a predetermined voltage through the diode 5 to the one input terminal of the comparator 6 and to the control circuit 1. The predetermined voltage is further applied to the comparator 6 where it is compared with the output voltage of the battery 7. When the output voltage of the battery 7 is higher than the predetermined voltage, the output of the comparator is set to a low level. When the output voltage of the battery 7 is lower than the predetermined voltage, the output of the comparator is raised to a high level. This high level output of the comparator is applied as a reset signal to the control circuit 1 through the differentiator circuit 1 2. The control circuit 1 is reset by the reset signal, in which case the contents of the memory, the counter etc., are erased. When the output voltage of the battery 7 is higher than the predetermined voltage, no current flows to the control circuit 1 from the battery 7 because the forward voltage of the diode 8 is much higher than that of the diode 5. As is apparent from the above description, in the control circuit backup power source circuit according to the invention, when the voltage of the backup battery becomes lower than the predetermined voltage, the control circuit is reset. Therefore, even if, during the use of the backup battery, its voltage is decreased resulting in the occurance of abnormal conditions such as the loss of the content of the memory, it is possible to readily provide to the user an indication of this condition. CLAIMS
1. A backup power source circuit for applying, a backup voltage to a control circuit to maintain predetermined operating conditions of the control circuit when application of a main supply voltage to the control circuit is suspended, the backup circuit including reset signal generating means for generating a reset signal to reset the control circuit if, during application of the main supply voltage to the control circuit, the backup voltage is lower than a predetermined value.
2. A backup power source circuit according to claim 1, wherein the reset signal generatidng means comprises a comparator having a first input terminal for receiving the main supply voltage and a second input terminal for receiving the backup supply voltage, the comparator being powered by the main supply voltage; and a differentiator circuit coupled between an output of the comparator and a reset input terminal of the control circuit.
3. A backup power source circuit according to claim 2, further comprising a diode coupled between the first and second input terminals of the comparator.
4. A backup power source circuit substantially as described with reference to the accompanying drawing.
GB08428114A 1983-11-15 1984-11-07 Backup power source circuit for control circuit Expired GB2149984B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17660583U JPS6087001U (en) 1983-11-15 1983-11-15 Control circuit backup power supply circuit

Publications (3)

Publication Number Publication Date
GB8428114D0 GB8428114D0 (en) 1984-12-12
GB2149984A true GB2149984A (en) 1985-06-19
GB2149984B GB2149984B (en) 1987-03-18

Family

ID=16016486

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08428114A Expired GB2149984B (en) 1983-11-15 1984-11-07 Backup power source circuit for control circuit

Country Status (3)

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JP (1) JPS6087001U (en)
DE (1) DE3441461A1 (en)
GB (1) GB2149984B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3810397A1 (en) * 1988-03-26 1989-10-05 Bernhard Dipl Ing Froelich Power supply for an electrical device
DE3812770A1 (en) * 1988-04-16 1989-10-26 Bosch Gmbh Robert Circuit for increasing current in accumulator-power apparatuses
DE3910039A1 (en) * 1989-03-28 1990-10-04 Legrand Gmbh CIRCUIT DEVICE FOR BRIDGING THE FAILURE OF A PRIMARY ENERGY SOURCE, e.g. AC POWER NETWORK, FOR CONTINUOUSLY REDUNDANTLY UNINTERRUPTIBLE SUPPLY OF ELECTRONIC CONTROL AND CONTROL DEVICES, ESPECIALLY
DE4013996A1 (en) * 1990-05-01 1991-11-14 Karl Kapfer Light with emergency back-up support - provided by battery with reed relay switching
DE4120337A1 (en) * 1991-06-20 1992-12-24 Wabco Westinghouse Fahrzeug TWO-CIRCUIT POWER SUPPLY CIRCUIT FOR VEHICLES
DE19602171A1 (en) * 1996-01-23 1997-07-24 Teves Gmbh Alfred Wiring a voltage regulator in the vehicle electrical system
JP4821139B2 (en) * 2005-03-07 2011-11-24 日本電気株式会社 Power control method for portable device and power control circuit for portable device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1177361A (en) * 1966-02-07 1970-01-14 Kidde Walter Co Ltd Improvements in or relating to electrically operated warning systems.
EP0043222A2 (en) * 1980-06-26 1982-01-06 Texas Instruments Incorporated Data processing memory system
WO1982004345A1 (en) * 1981-05-27 1982-12-09 Aswell Cecil James Power supply control for integrated circuit
EP0071525A1 (en) * 1981-07-30 1983-02-09 AlliedSignal Inc. A power processing reset system for a microprocessor responding to sudden deregulation of a voltage

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55153007A (en) * 1979-05-17 1980-11-28 Omron Tateisi Electronics Co Sequence controller
DE2936675C2 (en) * 1979-09-11 1981-11-19 Wörl-Alarm August Wörl, 8035 Gauting Emergency battery monitoring circuit
DE3044658C2 (en) * 1980-11-27 1983-02-24 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Circuit arrangement for uninterrupted switching of a consumer to a reserve power source

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1177361A (en) * 1966-02-07 1970-01-14 Kidde Walter Co Ltd Improvements in or relating to electrically operated warning systems.
EP0043222A2 (en) * 1980-06-26 1982-01-06 Texas Instruments Incorporated Data processing memory system
WO1982004345A1 (en) * 1981-05-27 1982-12-09 Aswell Cecil James Power supply control for integrated circuit
EP0071525A1 (en) * 1981-07-30 1983-02-09 AlliedSignal Inc. A power processing reset system for a microprocessor responding to sudden deregulation of a voltage

Also Published As

Publication number Publication date
JPS6087001U (en) 1985-06-15
DE3441461A1 (en) 1985-05-23
GB2149984B (en) 1987-03-18
GB8428114D0 (en) 1984-12-12

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Legal Events

Date Code Title Description
746 Register noted 'licences of right' (sect. 46/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19931107