EP0756222A2 - Circuit de verrouillage pour tension détectée à distance - Google Patents
Circuit de verrouillage pour tension détectée à distance Download PDFInfo
- Publication number
- EP0756222A2 EP0756222A2 EP96110932A EP96110932A EP0756222A2 EP 0756222 A2 EP0756222 A2 EP 0756222A2 EP 96110932 A EP96110932 A EP 96110932A EP 96110932 A EP96110932 A EP 96110932A EP 0756222 A2 EP0756222 A2 EP 0756222A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- load
- coupled
- source
- voltage potential
- voltage
- 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.)
- Withdrawn
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Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
- G05F1/569—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for protection
Definitions
- This invention relates generally to the field of power supplies, and, in particular, to power supplies which use a feedback path to remotely sense an output voltage at a load.
- the remaining printed circuit boards may comprise a load, which may include, for example, a plurality of digital integrated circuits.
- a prior-art power supply 20 is shown in FIGURE 2.
- Power can be routed from an output of power supply 20 to a load R LOAD , which may comprise the plurality of digital loads, through a connector P1, which may be mounted on a periphery of the power supply's printed circuit board.
- Power supply 20 can be tested under simulated load conditions.
- power supply 20 may include, as shown in FIGURE 2, a resistance R2 coupled between an output of the power supply and the remote sensing feedback path FB. Resistance R2 provides a feedback path for the output voltage V OUT to error amplifier EA, thereby allowing error amplifier EA to sense and regulate output voltage V OUT in the event of a no-load condition at the output of power supply 20.
- resistor R2 is sufficiently large that it does not interfere with the remote sensing function provided by remote sensing feedback path FB when power supply 20 is assembled within the electronic device.
- load voltage V LOAD may be interrupted by a fault condition, for example, an intermittent connection at connector P1, transients or spikes on remote sensing feedback path FB or a short circuit load condition.
- load voltage V LOAD at remote sensing feedback path FB may drop to a low level because output voltage V OUT is isolated from remote sensing feedback path FB by resistor R2.
- error amplifier EA causes power supply 20 to compensate for the decrease in load voltage V LOAD by increasing output voltage V OUT to a potentially unacceptably high level, thereby possibly damaging the load that is coupled to the output of power supply 20.
- the output voltage potential of a power supply is held below a predetermined voltage potential in the event that the apparatus attempts to increase its output voltage potential in response to a fault condition.
- such an apparatus comprises: a source of voltage potential; means for sensing the voltage potential at a load; means for isolating the sensing means from the source; means for adjusting the voltage potential having an input coupled to the sensing means; and, clamping means coupled to the source and to the sensing means.
- the clamping means may comprise a diode having an anode coupled to the source of voltage potential and a cathode coupled to the sensing means.
- the isolating means may comprise a resistance.
- the adjusting means may comprise an amplifier having a non-inverting input coupled to an amplifier reference voltage potential and an inverting input, and a switch device coupled to an output of the amplifier.
- the sensing means may comprise a feedback path coupled from the load to the inverting input of the amplifier.
- such an apparatus comprises: a source of voltage potential; means for sensing the voltage potential at a load; means for isolating the sensing means from the source; and, a switch device coupled to the source and to the sensing means.
- the switch device may comprise a diode having an anode coupled to the source of voltage potential and a cathode coupled to the sensing means.
- the switch device may conduct a current after a difference in the voltage potential between the source and the load exceeds a predetermined value. While the switch device conducts the current, it may render the isolating means inoperative.
- the isolating means may comprise a resistance.
- the use of a diode as a clamping means or as a switch device has been found to be particularly advantageous for at least two reasons.
- the diode provides a low-resistance path for a current to flow from the apparatus to the load without affecting a remote sensing function provided by the sensing means during normal operation of the apparatus.
- the diode consumes relatively little space on the apparatus's printed circuit board in relation to the amount of power that the diode is required to dissipate.
- FIGURE 1 is a schematic diagram of a power supply circuit according to an inventive arrangement.
- FIGURE 2 is a schematic diagram of a prior-art buck-topology power supply circuit.
- a buck-topology power supply 10 shown in FIGURE 1, derives an input voltage V IN of 15.5 V from a secondary winding of a flyback power transformer (not shown).
- Power supply 10 provides a substantially regulated output voltage V OUT of 5 V to a load comprising a plurality of digital integrated circuits, represented in FIGURE 1 by a resistor R LOAD , through a connector P1.
- a power switching regulator U1 includes an error amplifier EA, a switch device Q1, a reference voltage V REF for a non-inverting input of error amplifier EA and a control circuit 21 for switch device Q1.
- Power switching regulator U1 is represented in FIGURE 1 by an integrated circuit which has the industry part number MC34167TV and which is manufactured by Motorola.
- Power switching regulator U1 can, however, comprise any integrated circuit that is functionally compatible with the MC34167TV, such as, for example, the integrated circuit which has the industry part number L4960 and which is manufactured by SGS Thomson Electronics.
- a power stage 11 of power supply 10 comprises diode D1, inductor L1, and capacitors C11, C12 and C13, which correspond in function to capacitor C1 of FIGURE 2.
- a first terminal of inductor L1 is coupled to pin 2 of power switching regulator U1.
- Diode D1 has a cathode coupled to the first terminal of inductor L1 and an anode coupled to a reference voltage potential of power supply 10.
- Capacitor C2 is coupled in parallel with diode D1.
- First terminals of capacitors C11, C12 and C13 are coupled to a second terminal of inductor L1, and second terminals of capacitors C11, C12 and C13 are coupled to the reference voltage potential of power supply 10.
- Resistor R2 has a first terminal coupled to the first terminals of capacitors C11, C12 and C13, and a second terminal coupled to a first terminal of resistor R3.
- Diode D2 has an anode coupled to the first terminal of resistor R2 and a cathode coupled to the second terminal of resistor R2.
- Resistor R3 has a second terminal coupled to a first terminal of resistor R4.
- the first terminal of resistor R4 is also coupled to pin 1 of power switching regulator U1.
- a second terminal of resistor R4 is coupled to the reference voltage potential of power supply 10.
- the first terminal of resistor R2 is coupled to a first plurality of pins of connector P1.
- the second terminal of resistor R2 is coupled to a second plurality of pins of connector P1.
- a first terminal of digital loads R LOAD is coupled to the first and second pluralities of pins of connector P1.
- a second terminal of digital loads R LOAD is coupled to the reference voltage potential of power supply 10.
- the effective load resistance of digital loads R LOAD may be approximately 5 ⁇ , as shown in FIGURE 1.
- a compensation network 22 for error amplifier EA is formed by capacitor C5 and resistor R5.
- Capacitor C5 has a first terminal coupled to a second terminal of resistor R3 and a second terminal coupled a first terminal of resistor R5.
- a second terminal of resistor R5 is coupled to pin 5 of power switching regulator U1.
- Power switching regulator U1 and power stage 11 convert input voltage V IN into output voltage V OUT in a manner that is well known in the art.
- the load voltage V LOAD can be measured at a point near the digital loads R LOAD to ensure that load voltage V LOAD is within its allotted tolerance.
- Load voltage V LOAD is fed back through the second plurality of pins of connector P1 and along remote sensing feedback path FB.
- Voltage V LOAD is then divided by the voltage divider network formed by resistors R3 and R4, before being applied to pin 1 of power switching regulator U1. No load current flows back to power supply 10 through the remote sensing feedback path FB.
- error amplifier EA and control circuit 21 adjust the conduction time of switch device Q1, thereby adjusting output voltage V OUT such that load voltage V LOAD returns to a level that is within its allotted tolerance.
- Resistor R2 is included in power supply 10 to facilitate testing of power supply 10 prior to final assembly. During testing of power supply 10, resistor R2 provides a feedback path from output voltage V OUT to pin 1 of power switching regulator U1, thereby allowing power switching regulator U1 to sense and regulate output voltage V OUT in the event of a no-load condition at the output of power supply 10. Resistor R2 is sufficiently large that it does not interfere with the remote sensing function provided by remote sensing feedback path FB when power supply 10 is assembled within an electronic device.
- Diode D2 protects digital loads R LOAD from a situation wherein output voltage V OUT rises to the level of input voltage V IN . Such a situation might arise if load voltage V LOAD on the remote sensing feedback path FB drops to a value which is too low. This may occur, for example, because of an intermittent connection at the first plurality of pins of connector P1. Regardless of the particular mechanism whereby load voltage V LOAD is caused to drop, such a condition can result in resistor R2 undesirably forming a voltage divider network with the digital loads R LOAD .
- the load voltage V LOAD at the first terminal of digital loads R LOAD thus becomes 5V ⁇ ( 5 ⁇ 10k ⁇ +5 ⁇ ), or approximately 2.5 mV.
- Load voltage V LOAD can drop to an unacceptably low level because the effective load resistance of digital loads R LOAD is small in relation to the value of resistor R2.
- the effective load resistance of digital loads R LOAD can be significantly greater than the 5 ⁇ value shown in FIGURE 1, so long as the effective load resistance of digital loads R LOAD remains small in relation to resistor R2.
- power switching regulator U1 attempts to compensate by raising output voltage V OUT to a level that can become as high as input voltage V IN . Such a rise in output voltage V OUT may damage the plurality of digital integrated circuits that comprises digital loads R LOAD .
- diode D2 As output voltage V OUT begins to rise, diode D2 becomes forward biased, thereby clamping output voltage V OUT to the load voltage V LOAD plus the forward voltage drop of diode D2. Once diode D2 is forward biased, it also provides a low-resistance path for an output current I OUT to flow to digital loads R LOAD .
- diode D2 in such a manner is advantageous for at least two reasons. First, during normal operation of power supply 10, diode D2 is non-conducting and thus has no deleterious effect on the remote sensing function provided by remote sensing feedback path FB. Second, diode D2 also consumes relatively little space on the power supply's printed circuit board in relation to the amount of power that the diode is required to dissipate.
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Automation & Control Theory (AREA)
- Dc-Dc Converters (AREA)
- Control Of Voltage And Current In General (AREA)
- Tests Of Electronic Circuits (AREA)
- Measurement Of Current Or Voltage (AREA)
- Logic Circuits (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US50769095A | 1995-07-25 | 1995-07-25 | |
US507690 | 1995-07-25 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0756222A2 true EP0756222A2 (fr) | 1997-01-29 |
EP0756222A3 EP0756222A3 (fr) | 1998-01-07 |
Family
ID=24019727
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96110932A Withdrawn EP0756222A3 (fr) | 1995-07-25 | 1996-07-06 | Circuit de verrouillage pour tension détectée à distance |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP0756222A3 (fr) |
JP (1) | JPH09200027A (fr) |
KR (1) | KR970008873A (fr) |
CN (1) | CN1166639A (fr) |
BR (1) | BR9603137A (fr) |
SG (1) | SG67358A1 (fr) |
TW (1) | TW296506B (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1113352A1 (fr) * | 1999-12-29 | 2001-07-04 | STMicroelectronics SA | Dispositif de régulation |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100559141B1 (ko) * | 2004-01-26 | 2006-03-10 | 주식회사 효성 | 자기신장성이 우수한 폴리에스테르 필라멘트사 및 이의 제조방법 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3098192A (en) * | 1961-02-06 | 1963-07-16 | Raytheon Co | Protective circuit for direct current voltage regulators |
US3532936A (en) * | 1969-01-14 | 1970-10-06 | Automatic Elect Lab | Protective circuit for direct current voltage regulators |
DE3211989A1 (de) * | 1982-03-31 | 1983-10-13 | Siemens AG, 1000 Berlin und 8000 München | Stromversorgungsgeraet |
US4779037A (en) * | 1987-11-17 | 1988-10-18 | National Semiconductor Corporation | Dual input low dropout voltage regulator |
JPH01303055A (ja) * | 1988-05-30 | 1989-12-06 | Omron Tateisi Electron Co | リモートセンシング端子付スイツチング電源装置 |
-
1996
- 1996-01-12 TW TW085100351A patent/TW296506B/zh not_active IP Right Cessation
- 1996-07-06 EP EP96110932A patent/EP0756222A3/fr not_active Withdrawn
- 1996-07-10 KR KR1019960027697A patent/KR970008873A/ko not_active Application Discontinuation
- 1996-07-11 JP JP8182210A patent/JPH09200027A/ja active Pending
- 1996-07-22 BR BR9603137A patent/BR9603137A/pt not_active Application Discontinuation
- 1996-07-23 SG SG1996010306A patent/SG67358A1/en unknown
- 1996-07-24 CN CN96108537A patent/CN1166639A/zh active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3098192A (en) * | 1961-02-06 | 1963-07-16 | Raytheon Co | Protective circuit for direct current voltage regulators |
US3532936A (en) * | 1969-01-14 | 1970-10-06 | Automatic Elect Lab | Protective circuit for direct current voltage regulators |
DE3211989A1 (de) * | 1982-03-31 | 1983-10-13 | Siemens AG, 1000 Berlin und 8000 München | Stromversorgungsgeraet |
US4779037A (en) * | 1987-11-17 | 1988-10-18 | National Semiconductor Corporation | Dual input low dropout voltage regulator |
JPH01303055A (ja) * | 1988-05-30 | 1989-12-06 | Omron Tateisi Electron Co | リモートセンシング端子付スイツチング電源装置 |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 014, no. 099 (E-0893), 22 February 1990 & JP 01 303055 A (OMRON TATEISI ELECTRON CO), 6 December 1989, * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1113352A1 (fr) * | 1999-12-29 | 2001-07-04 | STMicroelectronics SA | Dispositif de régulation |
FR2803400A1 (fr) * | 1999-12-29 | 2001-07-06 | St Microelectronics Sa | Dispositif de regulation |
US6433526B2 (en) | 1999-12-29 | 2002-08-13 | Stmicroelectronics S.A. | Regulating device for receiving a variable voltage and delivering a constant voltage and related methods |
Also Published As
Publication number | Publication date |
---|---|
SG67358A1 (en) | 1999-09-21 |
EP0756222A3 (fr) | 1998-01-07 |
TW296506B (fr) | 1997-01-21 |
CN1166639A (zh) | 1997-12-03 |
JPH09200027A (ja) | 1997-07-31 |
KR970008873A (ko) | 1997-02-24 |
BR9603137A (pt) | 1998-05-05 |
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Withdrawal date: 19980728 |