GB2531415A - An alarm device drive circuit - Google Patents
An alarm device drive circuit Download PDFInfo
- Publication number
- GB2531415A GB2531415A GB1515197.0A GB201515197A GB2531415A GB 2531415 A GB2531415 A GB 2531415A GB 201515197 A GB201515197 A GB 201515197A GB 2531415 A GB2531415 A GB 2531415A
- Authority
- GB
- United Kingdom
- Prior art keywords
- power supply
- negative
- rail
- inductor
- controller
- 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
- 239000000779 smoke Substances 0.000 claims abstract description 7
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 claims abstract description 4
- 230000005855 radiation Effects 0.000 claims abstract description 3
- 239000003990 capacitor Substances 0.000 claims description 10
- 230000007935 neutral effect Effects 0.000 claims description 5
- 238000009499 grossing Methods 0.000 claims description 4
- 230000011664 signaling Effects 0.000 claims description 4
- 239000004020 conductor Substances 0.000 claims description 2
- SGPGESCZOCHFCL-UHFFFAOYSA-N Tilisolol hydrochloride Chemical compound [Cl-].C1=CC=C2C(=O)N(C)C=C(OCC(O)C[NH2+]C(C)(C)C)C2=C1 SGPGESCZOCHFCL-UHFFFAOYSA-N 0.000 claims 1
- 230000005540 biological transmission Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
- H02M7/066—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode particular circuits having a special characteristic
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
- G08B21/02—Alarms for ensuring the safety of persons
- G08B21/12—Alarms for ensuring the safety of persons responsive to undesired emission of substances, e.g. pollution alarms
- G08B21/14—Toxic gas alarms
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/05—Capacitor coupled rectifiers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fire Alarms (AREA)
- Rectifiers (AREA)
Abstract
An electronic device drive circuit has a power supply 1 with mains terminals 11, 12, a first rectifier CR2 feeding a positive rail 5 and a second rectifier CR18 feeding a negative rail 4. A controller uses an inductor L2 to drive negative current from the mains onto the positive rail. The controller is arranged to cause negative current to flow through the inductor from the negative rail when additional power is required for activities such as RF transmission. The controller may comprise control switches QP19a, QP19b arranged to receive a square wave for starting and stopping negative current flow. The electronic device may be an alarm device such as a smoke, heat fire or carbon monoxide alarm. The controller may be adapted to not drive said negative current during device standby, and cause said negative current if the device is in alarm mode and/or communicating with a radiation transmitter.
Description
"An Alarm Device Drive Circuit"
INTRODUCTION
Field of the Invention
The invention relates to drive circuits in devices which receive mains power and convert it to DC. Examples are mains-powered smoke alarm devices, heat alarm devices, carbon monoxide alarm devices, and thermostats.
RefelTing to Fig. 1. a conventional power supply for such a device is shown. There is a full-wave rectifier of diodes Dl. D2, D3. and D4 receiving AC power via a capacitor Cl for reducing the voltage. While such a circuit is compact, reliable, and does not excessively heat up. it provides a ow level of current and it requires four leads namely Live (L). Neutral (N), Circuit Ground (CG), and Interconnect (I/C). Regarding the current it makes available, for example, a circuit using a 0.68 jiF capacitor as the mains dropping element can at most supply a current of 49 mA (hf its impedance is 4680 0 and 230/4680 = 49mA).
If the number of leads is kept to three (L. N, and TIC) to comply with legacy networks then only half-wave rectification is possible. This is because the rectifier does not have a CO at its output.
it being possible to use only the N lead. hi this case the current available to power the device is even lower because offly half of the input power is utilized.
Having such low currents poses a major problem for devices, such as those having RF circuits, a sound emitter, andlor LEDs. An example is a smoke alarm device having an RE transceiver for sending alarm messages and "housekeeping" messages. Having offly a very low level of available current limits the extent of features which can be included.
EP2377 109 (Sprue) describes an alarm device power supply which supplies current at a level lower than that required to energise an audible alarm.
0B2508033 (Sprue) describes a power supply having a half wave rectifier and a charge pump.
and capacitors holding different levels.
The invention addresses this problem.
SUMMARY OF THE INVENTION
According to the invention, there is provided a power supply for an electronic device drive circuit, (he power supply comprising: mains termina's, a rectifier feeding a positive rail and a rectifier feeding a negative rail, an inductor and a controller arranged to use the inductor to drive negative current onto the positive rail.
In one embodiment, the positive rail rectifier is a half-bridge and the negative rail rectifier is a half-bridge.
Tn one embodiment, the rectifiers comprise diodes arranged to provide a negative pulse on the negative rail on every negative voltage cycle of a mains supply.
Tn one embodiment, the controller is arranged to cause negative current to flow through the inductor from the negative rail.
In one embodiment, the controller is arranged to change frequency of starting and stopping the negative current according to conditions.
lii one embodiment, the controller comprises control switches arranged to receive a square wave for starting and stopping negative current flow.
In one embodiment, the control switches comprise a primary switch which closes to short the inductor to (lie negative rail while the current is flowing in the inductor.
Tn one embodiment, the power supply comprises a reverse biased diode between the primary switch and the positive rail.
In one embodiment, the square wave drive has a frequency in the range of 0.01 MHz to 10 MHz.
In one embodiment., the power supply further comprises at least one smoothing capacitor between the negative and positive rails.
In one embodiment, the power supply further comprises at least one smoothing capacitor connected between the negative rail and a 0 Volts conductor.
In one embodiment, the inductor has a value in the range of lOpi-1 to l000p I-I.
In one embodiment., the power supply comprises only three external connections for connecting to a mains supply and also for signalling to other alarms, said connections comprising a live connection, a neutral connection, and a signalling connection.
In another aspect. the invention provides an electronic device drive circuit comprising a power supp'y as defined above in any embodiment.
In another aspect, the invention provides an electronic device comprising a drive circuit as defined above in any embodiment.
In one embodiment, the device is an alarm device.
In one embodiment, the controller is adapted to: not drive said negative current during device standby, cause said negative currcnt if the dcvicc is in alarm mode and/or communicating with a radiation transmitter.
In various embodiments, the alarm device is a smoke, heat, fire or carbon monoxide alarm device.
DETAILED DESCRIPTION OF THE INVENTION
Brief Description of the Drawings
The invention will be more clearly understood from the following descnption of some embodiments thereof, given by way of examp'e only with reference to the accompanying drawings in which:-Fig. 1 is a circuit diagram of a conventional full-wave rectifier power supply as described above; and Fig. 2 is a circuit diagram of a power supply of the invention.
Description of the Embodiments
Referring to Fig. 2 a power supply 1 of the invention has only three leads, live, neutral and interconnect. It can therefore be used in legacy three-wire networks. There is a negative rail 4 and a positive rail 5, the latter providing power to the main circuit 10 of a smoke alarm device.
A capacitor Cl is in series with the live terminal 11 and peitorms mains voltage dropping. There is also a mains neutral terminal 12. A diode CR2 half wave rectifies the positive voltage cycle of the mains and a capacitor C2 acts as a ballast and smoothes the voltage. A 16V Zener CRIa regulates this half-wave rectified voltage to 16.OV. A voltage regulator U2 further reduces this voltage to 9.9V onto the positive railS, this voltage being set by resistors R27 and R3.
The regulator U2 has a precision output which is required to charge lithium rechargeable cells (not shown).
A diode CRI8a and a ISV Zener diode CRI7a produce a negative rectangular voltage pulse on every negative voltage cycle of the mains, at the cathode of CR1 Sa in conjunction with the rectifier diode CR18.
A microcontroller. (not shown) puts a 100kHz rectangular +2.5 V to 0 V voltage wave train on the gate of a P-channel PET QPI9a (this is designated "NEG_ POWER') to turn it on and off This PET in turn connects resistors R8 and R9 in series between a +2.5 V rail 6 arid the -15 V rail (4). The R8/R9 common node therefore applies a 100KHz voltage wave train going from -ISV to -6.25V to the gate of an N-channel FET. QPI9h. turning it on and off When QPI9h is on, a current flows from the DV rail to the -15V rail through a 100pM inductor L2. When QPI9h switches off the magnetic energy stored in the L2 inductance causes a positive voltage "spike" on the anode of lhe diode CR1 Sb, injecting current into the +9.9V rail 5.
There is quite a large voltage swing on the L2/CR1Sb node -when QP19b is on, it is at -iSV and S when QP19U is off it rises to +9.9V (plus the voltage drop across the diode CR18b). This approximately doubles the current available for (he + 9.9V rail 5 (assuming 100% efficiency -typically this circuit will he over 90% efficient). Capacitors C7, CS and C9 are used to store and smooth the current pulses. The voltage on the +9.9V rail is monitored by the microcontroller (not shown) and if the voltage is tending to go over 9.9V, then the output of the charge pump is reduced, by lowering the frequency, or even stopping the 100kHz voltage pulses. This can occur if the current required by the circuit is reduced. With alarm devices in standby (such as smoke or heat alarm devices) the current required is very low, so the charge pump action is normally left oh However, when it is in the alarm mode and needs current to power the horn and the RF transceiver the charge pump is turned on.
It is envisaged that the change pump action may alternatively be achieved by using bipolar transistors or other solid state switching devices instead of FETs.
The invention is not limited to the embodiments described but may be varied in construction and detail.
Claims (18)
- Claims 1. A power supply for an electronic devicc drive circuit, the power supply comprising: mains terminals (11).a rectifier (CR2, CR1a) feeding a positive rail (5), and a rectifier (CR18, CR18a, CR17a) feeding a negative rail (4), an inductor (L2), and a controller arranged to use the inductor to drive negative current onto the positive rail (5).
- 2. A power supply as claimed in claim 1, wherein the positive rail rectifier is a half-bridge (CR2) and the negative rail rectifier is a half-bridge (CR18).
- 3. A power supply as claimed in claim 2, wherein the rectiliers comprise diodes arranged to provide a negative pulse on the negative rail on every negative voltage cycle of a mains supply.
- 4. A power supply as claimed in claims I or 2 or 3, wherein the controller is arranged to cause negative culTent to flow through the inductor (L2) from the negative rail 4).
- 5. A power supply as claimed in claim 4. wherein the controller is arranged to change frequency of starting and stopping the negative current according to conditions.
- 6. A power supply as claimed in any preceding claim, wherein the controller comprises control switches (QPI9a and QPI9h) arranged to receive a square wave for starting and stopping negative current flow.
- 7. A power supply as claimed in claim 6. wherein (lie control switches comprise a primary switch (QP19a) which closes to short the inductor (L2) to the negative rail (4, QP19b) while the current is flowing in the inductor.
- 8. A power supply as claimed in claim 7, wherein the power supply comprises a reverse biased diode (CR1 Sb) between the primary switch and the positive rail (5).
- 9. A power supply as claimed in claims 7 or 8, wherein the square wave drive has a frequency in the range of 0.01 MHz to 10 MHz.
- 10. A power supply as claimed in any preceding claim, further comprising at least one smoothing capacitor (C7, C8, C9) between the negative and positive rails.
- 11. A power supply as claimed in any of claims 7 to 10, further comprising at least one smoothing capacitor (C?, CS) connected between the negative rail (4) and a 0 Volts conductor.
- 12. A power supply as claimed in any preceding claim, wherein the inductor L2) has a value in the range of 1OMH to l000pH.
- 13. A power supply as claimed in any preceding claim, wherein the power supply comprises only three external connections (11. 12, TIC) for connecting to a mains supply and also for signalling to other alarms, said connections comprising a live connection (11), a neutral connection (12), and a signalling connection (I/C).
- 14. An electronic device drive circuit (10) comprising a power supply (1) of any preceding claim.
- 15. An electronic device comprising a drivc circuit as claimed in daim 14.
- 16. An electronic dcvicc as claimed in claim 15. wherein the device is an alarm device.
- 17. An electronic device as claimed in claim 16, wherein the controller is adapted to: not drive said ncgative current during device standby, cause said negative current if the device is in alarm mode and/or communicating with a radiation transmitter.
- 18. An electronic device as claimed in claims 16 or 17, wherein the alarm device is a smoke, heat, fire or carbon monoxide alarm device.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP14182627 | 2014-08-28 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB201515197D0 GB201515197D0 (en) | 2015-10-14 |
| GB2531415A true GB2531415A (en) | 2016-04-20 |
| GB2531415B GB2531415B (en) | 2021-03-03 |
Family
ID=51429090
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1515197.0A Active GB2531415B (en) | 2014-08-28 | 2015-08-27 | An alarm device drive circuit |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2531415B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108806217A (en) * | 2018-08-01 | 2018-11-13 | 合肥阅辞科技有限公司 | Intelligent wireless safety-protection system |
| WO2020063869A1 (en) * | 2018-09-29 | 2020-04-02 | 深圳市合元科技有限公司 | Output control circuit |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106597952A (en) * | 2016-12-27 | 2017-04-26 | 东莞市狮王安防科技有限公司 | Communication base station active tear controller |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2421643A (en) * | 2004-12-22 | 2006-06-28 | Landis & Gyr Ag | AC-DC converter with improved effciency |
-
2015
- 2015-08-27 GB GB1515197.0A patent/GB2531415B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2421643A (en) * | 2004-12-22 | 2006-06-28 | Landis & Gyr Ag | AC-DC converter with improved effciency |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108806217A (en) * | 2018-08-01 | 2018-11-13 | 合肥阅辞科技有限公司 | Intelligent wireless safety-protection system |
| WO2020063869A1 (en) * | 2018-09-29 | 2020-04-02 | 深圳市合元科技有限公司 | Output control circuit |
| US11925213B2 (en) | 2018-09-29 | 2024-03-12 | Shenzhen First Union Technology Co., Ltd. | Output control circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2531415B (en) | 2021-03-03 |
| GB201515197D0 (en) | 2015-10-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10193437B1 (en) | Bridgeless AC-DC converter with power factor correction and method therefor | |
| US20130077364A1 (en) | Power converter and the method thereof | |
| CN105610315A (en) | System and method for startup cell circuit | |
| JP6563729B2 (en) | Insulation synchronous rectification type DC / DC converter, power supply device using the same, power supply adapter, and electronic device | |
| US11611282B2 (en) | Switching power circuit for charging a battery | |
| CN109217697B (en) | Synchronous bridge rectifier, method of operating a synchronous bridge rectifier and components thereof | |
| WO2017049900A1 (en) | Igbt short-circuit detection and protection circuit and igbt-based controllable rectifier circuit | |
| US10236879B2 (en) | Thyristor driving apparatus | |
| KR20190037093A (en) | Synchronous rectifier controller for offline power converter, and offline power converter and method therefor | |
| US20070002592A1 (en) | Switching power device | |
| GB2531415A (en) | An alarm device drive circuit | |
| US9780690B2 (en) | Resonant decoupled auxiliary supply for a switched-mode power supply controller | |
| US7817445B2 (en) | Computer power supply | |
| US10418906B2 (en) | High efficiency primary and secondary bias flyback converter with dual outputs | |
| US9660544B1 (en) | Self-driven synchronous rectifier circuit | |
| US9883902B2 (en) | Surgical device with improved mains module | |
| US8456872B2 (en) | Switching power supply | |
| JP3154706U (en) | AC / DC power supply circuit | |
| JP6563648B2 (en) | Insulated DC / DC converter, primary side controller, synchronous rectification controller, power supply device using the same, power supply adapter, and electronic device | |
| US10333424B2 (en) | Offline power supply | |
| US9755502B2 (en) | Start-up circuit and power device using the same | |
| US10749444B1 (en) | Power supply circuit capable of setting turn-off point | |
| CN107947776B (en) | Isolated switching tube driving circuit | |
| KR101228425B1 (en) | Power supply circuit for light sources, such as lighting led systems | |
| JP4465713B2 (en) | Switching power supply device and synchronous rectifier circuit |