GB2057168A - Power supplies - Google Patents
Power supplies Download PDFInfo
- Publication number
- GB2057168A GB2057168A GB8023893A GB8023893A GB2057168A GB 2057168 A GB2057168 A GB 2057168A GB 8023893 A GB8023893 A GB 8023893A GB 8023893 A GB8023893 A GB 8023893A GB 2057168 A GB2057168 A GB 2057168A
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- Prior art keywords
- series
- voltage
- direct current
- output
- transistors
- Prior art date
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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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
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- 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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/337—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only in push-pull configuration
- H02M3/3376—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only in push-pull configuration with automatic control of output voltage or current
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- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
In a power supply, an unregulated DC, rectified from AC 2, is periodically applied via switches S1, S2 to a resonant circuit. The desired DC output voltage across capacitor 32 is derived by rectifying means 26, 28 coupled to the resonant circuit. Regulation is achieved by determining the error between the output voltage and a reference voltage 44', and using this to control the relationship between the periodicity of the switches and the resonant frequency of the resonant circuit. Control of the switches may be attained by varying the inductance of one of the inductors in an inductive oscillator O so as to vary its frequency and coupling another inductor in the oscillator to transformers that activate the switches. <IMAGE>
Description
SPECIFICATION
Power supplies
This invention is concerned with improvements in or relating to power supplies.
Power supplies that produce regulated direct current voltage from a source of AC voltage generally operate by rectifying the AC voltage to derive an unregulated DC voltage, applying this unregulated DC voltage to the primary winding of a transformer at a fixed frequency with the aid of switches so as to produce an AC voltage across its secondary and rectifying this latter AC voltage to produce the desired DC output voltage. Regulation is achieved by varying the duration of the periods during which the switches apply the unregulated DC voltage to the primary of the transformer, a technique known as "pulse width modulation",
PWM. A distinct disadvantage of this type of power supply is that it produces a high level of radio frequency interference that can impair the operation of associated apparatus and may involve complex control circuitry.A pulse width modulation system is also vulnerable to short circuits.
The present invention provides a regulated direct current voltage power supply, comprising a source of a direct current voltage, a resonant circuit, switching means for coupling said source of direct current voltage to said resonant circuit, control means for causing said switching means to periodically apply said direct current voltage to said resonant circuit so as to cause said circuit to produce an alternating current voltage, rectifying means coupled to said resonant circuit for deriving an output direct current voltage from said alternating current voltage, a source of reference voltage, means for deriving an error signal related to the difference between said output direct current voltage and said reference voltage, and means for bringing the resonant frequency of said resonant circuit and the periodicity of said means for controlling said switching means closer together when said difference signal indicates that said output direct current voltage is less than said reference voltage and for making the resonant frequency of said circuit and the periodicity of said coupling means lie farther apart when said difference signal indicates that said output direct current voltage is greater than said reference voltage.
In a power supply as set forth in the last preceding paragraph, it is preferred that said latter means includes means for changing the periodicity of said control means.
In a power supply as set forth in either one of the last two immediately preceding paragraphs, it is preferred that said latter means includes means for changing the resonant frequency of said resonant circuit.
In a power supply as set forth in any one of the last three immediately preceding paragraphs, it is preferred that said resonant circuit comprises an inductor and a primary winding of a transformer connected in series, a secondary winding of said transformer and a capacitor connected in parallel with said secondary winding.
In a power supply as set forth in any one of the last four immediately preceding paragraphs, it is preferred that said means for controlling said switching means includes an oscillator.
The present invention further provides a power supply for deriving a regulated direct current output voltage from an alternating current voltage source, comprising a rectifier having an input and an output, an impedance connected across said output, a pair of switches connected in series across said output, an inductor and a primary winding of a first transformer connected in series between the junction of said series switches and a central point on said impendance, a secondary winding of said transformer, a capacitor connected across said secondary winding, rectifying means coupled to said secondary winding for producing a direct current output voltage, control means for alternately closing said switches, means for deriving an error signal related to the difference between said output direct current voltage and a reference voltage, and means for controlling the frequency at which said control means alternately closes and opens said switches in accordance with the value of said error signal.
In a power supply as set forth in the last preceding paragraph it is preferred that said switches are field effect transistors having their source-to-drain paths connected in series and having gate electrodes, and wherein said control means comprises an oscillator having a pair of capacitors connected in series, a pair of transistors of different conductivity types having their emitter-to-collector paths connected in series parallel with said pair of capacitors in such manner that current can flow through said emitter-to-collector paths in one direction, a primary winding of a second transformer connected between the junction of said capacitors and the like electrodes of said transistors that are connected together, first and second control windings magnetically coupled to said primary winding, each of said control windings being respectively coupled between the gate electrodes of said field effect transistors and one of the source and drain electrodes thereof, the said first and second control windings being oppositely poled with respect to said primary winding, a secondary winding of said second transformer and a resistor connected in series between the junction of the emitter-to-collector paths of said transistors and their base electrodes, another inductor connected between the base electrodes of said transistors and the junction of said capacitors, means for applying a direct current potential across the series circuit formed by said capacitors as well as across said series transistors; and means is provided for varying the inductance of said another inductor in accordance with said error signal, thereby changing the frequency of said oscillator.
The present invention further provides a power supply for deriving a regulated direct current output voltage from an alternating current voltage source, comprising a rectifier having an input and an output, an impedance connected across said output, a pair of switches connected in series across said output, an inductor and a primary winding of a transformer connected in series between the junction of said series switches and a central point on said impedance, a secondary winding of said transformer, a capacitor connected across said secondary winding, rectifying means coupled to said secondary winding for producing a direct current output voltage, control means for alternately closing said switches, means for deriving an error signal related to the difference between said output direct current voltage and a reference voltage, and means for varying the inductance of said inductor in accordance with the value of said error signal.
The present invention further provides an oscillator, comprising a pair of capacitors connected in series, means for applying a direct current operation potential across the series circuit formed by said capacitors, a pair of transistors of different conductivity types having their emitter-to-collector paths connected in series parallel with said pair of capacitors in such manner that current can flow through said emitter-to-collector paths in one direction, a primary winding of a transformer connected between the junction of said transistors and the like electrodes of said transistors that are connected together, a secondary winding of said transformer and a resistor connected in series between the junction of the emitter-to-collector paths of said transistors and their base electrodes, and an inductor connected between the base electrodes of said transistors and the junction of said capacitors.
In accordance with this invention, the amount of radio frequency interference (rfi) is substantially reduced by applying the unregulated DC voltage to a resonant circuit and rectifying the voltage produced across it.
Regulation is achieved by a relatively simple circuit that utilizes an oscillator to control the frequency with which the switches apply the unregulated voltage to the resonant circuit or by varying the resonant frequency of that circuit. A combination of these methods could also be employed. Whichever method is used, the DC output voltage may be increased by bringing the frequency of the switching action and the resonant frequency of the resonant circuit closer together, and it may be decreased by increasing the separation between these frequencies. The resonant circuit referred to can be formed with the principle inductance thereof being supplied by an inductor in series with the primary of a transformer and the capacitance thereof in shunt with the secondary and the load.The leakage inductance of the transformer adds to the inductance of the series inductor, and the combined inductance provides protection in the presence of a sudden short circuit.
Although oscillators other than the particular one illustrated may be used, it has the advantage of providing maximum current at the beginning of each half-cycle so as to achieve a hard turn-on that is desirable for capacitive loads. The particular oscillator illustrated has the further advantage that its frequency is independent of the supply voltage.
There now follows a detailed description, which is to be read with reference to the accompanying drawings, of a power supply incorporating two embodiments of the present invention; it is to be clearly understood that this power supply has been selected for description to illustrate the present invention by way of example and not by way of limitation.
In the accompanying drawings:
Figure lisa schematic diagram of a power supply incorporating the two different embodiments of this invention;
Figure 7A illustrates the response of the resonant circuit involved in this invention; and
Figure 2 is a series of graphs illustrating the operation of Figure 1.
In Figure 1, a source 2 of alternating current voltage, which may be a power line, is coupled to a rectifier 4 that produces an unregulated direct current voltage between its output leads 6 and 8. A smoothing filter is formed by capacitors 10 and 12 connected in series between the leads 6 and 8 and resistors 14 and 16 that are connected in series between these leads. Switches si and 52 are also connected in series between the leads 6 and 8. As herein illustrated, the switches are field effect transistors with their source-drain paths respectively connected between the leads 6 and 8 and an input 18 of a resonant circuit to be described.
An inductor L, a primary winding 20 of a transformer T and a DC blocking capacitor 21 are respectively connected in series between the input 18 and the junctions J1 and J2 of the capacitors 10 and 12 and of the resistors 14 and 16 respectively. A removable link 19 is connected between the junction J1 and a mutual point, not shown, in the rectifier 4 so as to permit operation on either 11 0V or 220V AC. The secondary winding of the the transformer T has two halves 22 and 24, and a capacitor C is connected in parallel with them. The principal components of the resonant circuit are the inductor Land the capacitor C as the impedance of the transformer has very little effect. Its purpose is to provide any required step in a voltage.
Diodes 26 and 28 are respectively connected between the outer ends of the halves 22 and 24 of the secondary winding and one input of a filter 30, and the junction of the windings is connected to the other input. The desired regulated DC output voltage appears across an output capacitor 32 that is connected across the output of the filter 30.
Regulation of the value of the DC out ut voltage produced across the output capacitor 32 can be achieved by controlling the relationship between the frequency with which the switches sl and s2 are alternately closed and the resonant frequency of the circuit LC in response to an error signal representing the difference between the DC output voltage and a reference voltage. If the output voltage is too low, the frequencies are brought closer together; and if it is too high, the frequencies are made to be farther apart. The relationship between the frequencies can be affected by changing either or both.
Assume, for example, that the response of the resonant circuit LC with frequency is as illustrated by the solid curve 34 of Figure 1 A and that the frequency at which the switches sl and s2 are normally operated is at a frequency fO that is above the resonant peak F. If the DC output voltage is to be increased, the switching frequency is decreased and vice-versa. Instead of changing the frequency at which the switches are operated, the value of either L or C can be varied so as to shift the response curve up or down in frequency.If the switches si and s2 are operated at the frequency fO and the DC output voltage is to be decreased, the response of the resonant circuit LC is shifted down in frequency as indicated by the dashed curve 34'; and if the DC output voltage is to be increased, the resonse is shifted up in frequency as indicated by the dotted curve 34".
In the circuit represented by the solid lines of Figure 1, regulation is achieved by controlling the operating frequency of the switches Si and s2 with an oscillator 0 and controlling its frequency with an error signal related to the difference between the actual DC output signal and a reference signal that corresponds to the desired value of the DC output signal. A resistor 36, a potentiometer 38 and a resistor 40 are connected in series between the ungrounded side of the output capacitor 32 and ground. The tap of the potentiometer 38
Is connected to the non-inverting input of an operational amplifier 42 and its inverting input is connected to a source 44 of DC reference potential.Connection of a capacitor 46 and a resistor 48 in series between the output of the amplifier 42 and its non-inverting input produces an error signal at the output that is the integral of the differences between the voltage at the tap of the potentiometer 38 and the reference potential supplied by the source 44.
The error signal is applied via a resistor 50 to the base of an NPN transistor Q having its collector connected to a point of positive operating potential via a control winding 52 and its emitter connected to ground via a resistor 54. The control winding 52 is magnetically coupled by means of a common core 53 to an inductor,' so as to vary its inductance as well as the frequency of the oscillator 0 of which it is a part. A source 56 of bias potential is connected to the base of the transistor Q via a resistor 58.When the error voltage is at a minimum value, the bias voltage is such that the current flowing in the transistor Q and the control winding 52 is such as to set the magnetic core 53 at an intermediate point of its BH curve and thereby make the inductance of the inductor ( such as to set the frequency of the oscillator 0 at some value such as fO of Figure 1A. As the error voltage varies about its minimum value, the current through the transistor Ovaries so as to change the inductance of the inductor ( and the frequency of the oscillator O as required.
As will be explained, the current through a primary winding P of a transformer incuded in the oscillator circuit changes direction at the oscillator frequency. Coupling between the primary winding P and oppositely poled switch control windings cw1 and cw2 that are respectively connected between the gate and source electrodes of the field effect transistor switches sl and s2 causes one switch to be closed and the other to be opened when current flows in one direction through the primary winding P and to reverse the switch conductivities when current passes through the primary winding Pin the other direction. Thus, the frequency at which the unregulated DC voltage at the output of the rectifier 4 is applied to the resonant circuit
LC is determined by the error signal at the output of the amplifier 42.
The Oscillator O
The oscillator 0 is shown as comprising a pair of capacitors C1 and C2 connected in series between ground and a point of positive operating potential, herein shown as being the output lead 6 of the rectifier 4. The emitter of an NPN transistor Q1 and the emitter of a PNP transistor Q2 are connected to a junction J3, and their collectors are respectively connected to the outer sides of the capacitors C1 and C2. The primary 'winding P of a transformer, previously referred to, is connected between the junction J3 of the emitters of Q1 and Q2 and a junction J4 between the capacitors C1 and C2.A secondary winding S is connected in series with a variable resistor R between the junction Js and the bases of Q1 and Q7. As will be explained below, the frequency of the oscillator 0 is related to the inductance of the inductor,' and, as has been explained, this in turn depends on the flux in the magnetic core 53 that is common to the inductor,' and the coil 52.
In order to start the oscillator 0, a resistor 60 and a capacitor 62 are connected in series between a point oi positive DC potential and the emitters of the transistors Q1 and 02, and a diac 64 is connected between ground ro u nd a and the ju junction of the resistor 60 and the capacitor 62.
Operation of the Oscillator O Before the diac 64 fires so as to trigger the oscillator 0 into operation, the junction J3, where the emitters of 0i and Q2 meet, is at the same potential as the junction J4 which is at half the positive operating potential derived from the lead 6 owing to the voltage division of the equal valued capacitors C1 and C2. When the diac 64 fires, the junction J3 iS momentarily grounded so as to cause a current to flow through the primary P in the direction of the dotted arrow.Because of the indicated polarities of the primary winding P and the secondary winding S, a voltage, kVCe, that is proportional to the voltage across each of C1 and C2, is induced across the secondary winding S with such polarity as to cause a current to flow from the base of 02, through the resistor
R and the secondary S, and back to the emitter of Q2 as indicated by the dotted arrows. The maximum value,
I, of this current is equal to (kVCc - VIE ) R, where VBE iS the base-to-emitter voltage of Q2. Under these conditions, Q2 conducts so as to maintain current flow through the primary winding P. After the first instant, the induced voltage causes an increasing current to flow in the inductor,' in the direction of the solid arrow,
As the latter current increases, the base current from Q2 decreases. When the current reaches zero, the current in i is I, Q7 is cut off and the flo N of current in the primary P ceases. The collapse of the magnetic field of the primary P now induces a voltage kVCC of the opposite polarity in the secondary S so as to cause current
I = (kVcc - VBE,)lR to flow into the base of Qa as indicated by the solid arrow and start Q1 conducting. This maintains current flow in the primary Pin the direction of the solid arrow.
A point in time when a2 iS cut off and Q1 starts to conduct is the time to in the graphs of Figure 2. At to the current in ( is I and is added to the current I that flows into the base of Q1 as a result of the induced voltage in the secondary S. As VBE, = VBF,, the two current I are equal. Thus, the current initially flowing into the base of Qi at time to is 21 as indicated in the graph A.The reduction in the current I initially flowing from the inductor ( into the base of 01 due to collapse of the magnetic field of t and the diversion of a greater portion of the current I that initially flowed into the base of QQ due to the induced voltage in the secondary S cause the current flowing into the base of Q1 to reduce. When a reduction equal to I occurs, the current in the inductor 6 is zero as indicated at 66 in the graph B, which illustrates the current in 6, and the current flowing into the base of QQ as indicated at 72 of graph A.Reduction of the base current of QA to zero in this manner cuts off QA and the resulting collapse in the magnetic field of the primary P causes the induced voltage in the secondary
S to reverse polarity and turn on Q2 once more. However, unlike the start-up situation previously described, there is now a current I flowing in 6 in the direction of the dotted arrow that adds to the current I initially drawn from the base of Q2 by the induced voltage in the secondary Sso as to make the current initially flowing into the base of Q2 equal to -21 as indicated at 74 of graph C.
Thus, whenever Q1 or 02 iS turned on, a large current of 21 is applied to their respective bases so as to turn them on quickly even when they are coupled to the capacitive load of the gates of the FETs that are the switches si and s2.
Graph D illustrates the current flowing in the secondary S and the resistor R. Owing to the fact that the base currents of whichever of Q, or 02 iS conducting are linearly reducing, the collector-to-emitter current and the current in the primary P is also linearly reducing so as to produce a constant induced voltage in the secondary S and consequently a constant current in the secondary S and the resistor R. The voltage across P is therefore a square wave so that the voltages across the control windings cw, and cw2 are also square waves. The slope m of the decrease in base current of Q2 iS equal to (Vcc + VBEl',' as indicated in the graph C, and the slope of the decrease in base current of 01 its the same.
The relationship of the frequency of the oscillator 0 to the values of the,parameters may be derived as follows:
(1) If V equals the voltage across(,
(2) V = Vac + VBE (from ground across C2 and the base-to-emitter junction of 02)
(4) Substituting (2) and (3) in (1) and transposing
(5) Since T equals one-half the period of the wave of graph B,
From equation (5), it can be seen that if KV5 " VBE, then (6)
Overall Operation
Assume that the frequency of the oscillator 0 due to the bias current in Q is above the resonant peak F of the resonant circuit LC as indicated atf0 in Figure 1A.If the DC output voltage across the output capacitor 32 becomes too large, the error signal becomes positive and increases the voltage applied to the base of Q as well as the current through it and the coil 52. This decreases the incremental inductance of the inductor ( and increases the frequency of the oscillator O so as to drive it farther away from the resonant peak frequency F and reduce the amplitude of the alternating current voltage across the capacitor C and hence the DC output voltage. If the DC output voltage becomes too small, the frequency of the oscillator O is decreased so as to bring it closerto the resonant peak frequency F and increase the amplitude of the alternating voltage across the capacitor C and the DC output voltage.
Instead of achieving regulation by varying the frequency of the oscillator 0 in the manner just described, regulation can be attained by keeping the frequency of the oscillator 0 constant and varying the resonant frequency of the tuned circuit LC. To do this, it is only necessary to insert an inverter, indicated by the dashed rectangle 66, between the transistor Q and the junction of the resistors 50 and 58 and magnetically couple the coil 52 to the inductor L, as indicated by the coil 52' drawn with a dashed line. In this arrangement, an output voltage that is too low causes the error signal to be negative but because of the inverter 66, the voltage applied to the base of the transistor Q is positive so as to reduce the inductance of L.This raises the peak frequency F to a point such as F" that is closer to the frequency fO of the oscillator 0 and increases the amplitude of the alternating current voltage across the capacitor C and hence the value of the DC output voltage.
It would also be possible to form the resonant circuit by turning the primary winding 20, the secondary windings 22 and 24, or both, by placing a capacitor in parallel with each.
In the previous pulse width modulation power supplies, the switches apply the unregulated DC directly to the transformer. and even though its output is coupled via a low pass filter to the load a high pulse of current flows through the ground lead because of the capacitive coupling between the primary and secondary windings. In the circuit of Figure 1, however, the inductor L greatly attenuates the high frequency components of the pulses before they reach the primary winding so that little high frequency energy is coupled to the ground lead to the load by the capacitance between windings.
Claims (9)
1. A regulated direct current voltage power supply, comprising:
a source of a direct current voltage,
a resonant circuit,
switching means for coupling said source of direct current voltage to said resonant circuit,
control means for causing said switching means to periodically apply said direct current voltage to said resonant circuit,
control means for causing said switching means to periodically apply said direct current voltage to said resonant circuit so as to cause said circuit to produce an alternating current voltage.
rectifying means coupled to said resonant circuit for deriving an output direct current voltage from said alternating current voltage,
a source of reference voltage,
means for deriving an error signal related to the difference between said output direct current voltage and said reference voltage, and
means for bringing the resonant frequency of said resonant circuit and the periodicity of said means for controlling said switching means closer together when said difference signal indicates that said output direct current voltage is less than said reference voltage and for making the resonant frequency of said resonant circuit and the periodicity of said coupling means lie farther apart when said difference signal indicates that said output direct current voltage is greater than said reference voltage.
2. A power supply according to claim 1 wherein said latter means includes means for changing the periodicity of said control means.
3. A power supply according to either one of claims 1 and 2 wherein said latter means includes means for changing the resonant frequency of said resonant circuit.
4. A power supply according to any one of the preceding claims wherein said resonant circuit comprises an inductor and a primary winding of a transformer connected in series, a secondary winding of said transformer and a capacitor connected in parallel with said secondary winding.
5. A power supply according to any one of the preceding claims wherein said means for controlling said switching means includes an oscillator.
6. A power supply for deriving a regulated direct current output voltage from an alternating current voltage source, comprising:
a rectifier having an input and an output,
an impedance connected across said output,
a pair of switches connected in series across said output,
an inductor and a primary winding of a first transformer connected in series between the junction of said series switches and a central poi lt on said impedance,
a secondary winding of said transformer,
a capacitor connected across said secondary winding,
rectifying means coupled to said secondary winding for producing a direct current output voltage,
control means for alternately closing said switches,
means for deriving an error signal related to the difference between said output direct current voltage and a reference voltage, and
means for controlling the frequency at which said control means alternately closes and opens said .witches in accordance with the value of said error signal.
7. A power supply according to claim 6 wherein said switches are field effect transistors having their .ource-to-drain paths connected In series and having gate electrodes, and wherein said control means comprises an oscillator having:
a pair of capacitors connected in series,
a pair of transistors of different conductivity types having their emitter-to-collector paths connected in series parallel with said pair of capacitors in such manner that current can flow through said emitter-to-collector paths in one direction,
a primary winding of a second transfomer connected between the junction of said capacitors and the like electrodes of said transistors that are connected together,
first and second control windings magnetically coupled to said primary winding, each of said control windings being respectively coupled between the gate electrodes of said field effect transistors and one of the source and drain electrodes thereof, the said first and second control windings being oppositely poled with respect to said primary winding,
a secondary winding of said second transformer and a resistor connected in series between the junction of the emitter-to-collector paths of said transistors and their base electrodes,
another inductor connected between the base electrodes of said transistors and the junction of said capacitors,
means for applying a direct current potential across the series circuit formed by said capacitors as well as across said series transistors; and
means is provided for varying the inductance of said another inductor in accordance with said error signal, thereby changing the frequency of said oscillator.
8. A power supply for deriving a regulated direct current output voltage from an alternating current voltage source, comprising:
A rectifier having an input and an output,
an impedance connected across said output,
a pair of switches connected in series across said output,
an inductor and a primary winding of a transformer connected in series between the junction of said series switches and a central point on said impedance,
a secondary winding of said transformer,
a capacitor connected across said secondary winding,
rectifying means coupled to said secondary winding for producing a direct current output voltage,
control means for alternately closing said switches,
means for deriving an error signal related to the difference between said output direct current voltage and
a reference voltage, and
means for varying the inductance of said inductor in accordance with the value of said error signal.
9. An oscillator, comprising:
a pair of capacitors connected in series,
means for applying a direct current operating potential across the series circuit formed by said capacitors,
a pair of transistors of different conductivity types having their emitter-to-collector paths connected in
series parallel with said pair of capacitors in such manner that current can flow through said
emitter-to-collector paths in one direction,
a primary winding of a transformer connected between the junction of said transistors and the like
electrodes of said transistors that are connected together,
a secondary winding of said transformer and a resistor connected in series between the junction of the
emitter-to-collector paths of said transistors and their base electrodes, and
an inductor connected between the base electrodes of said transistors and the junction of said capacitors.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US7047979A | 1979-08-28 | 1979-08-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2057168A true GB2057168A (en) | 1981-03-25 |
Family
ID=22095543
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8023893A Withdrawn GB2057168A (en) | 1979-08-28 | 1980-07-22 | Power supplies |
Country Status (3)
| Country | Link |
|---|---|
| JP (2) | JPS5635679A (en) |
| DE (1) | DE3031901A1 (en) |
| GB (1) | GB2057168A (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0081302A1 (en) * | 1981-11-17 | 1983-06-15 | Hughes Aircraft Company | Series resonant inverter with integrating feedback control loop |
| EP0107313A1 (en) * | 1982-09-13 | 1984-05-02 | Ferranti plc | Resonant current-driven power source |
| EP0108336A2 (en) | 1982-11-03 | 1984-05-16 | General Electric Company | High frequency x-ray generator power supply |
| GB2131209A (en) * | 1982-11-02 | 1984-06-13 | Newton Derby Ltd | Switch mode power supply |
| GB2137780A (en) * | 1983-02-10 | 1984-10-10 | Newton Derby Ltd | Current regulated power supply circuit |
| GB2170663A (en) * | 1985-02-02 | 1986-08-06 | Brian Ernest Attwood | Harmonic-resonant power supply |
| EP0232915A2 (en) * | 1986-02-13 | 1987-08-19 | Salora Oy | Circuit arrangement of a DC voltage source based on resonance |
| US4757432A (en) * | 1981-11-17 | 1988-07-12 | Hughes Aircraft Company | Series resonant inverter with integrating feedback control loop |
| EP0293874A2 (en) * | 1987-06-05 | 1988-12-07 | Siemens Nixdorf Informationssysteme Aktiengesellschaft | Method and circuit arrangement to control the state of a resonant converter |
| WO2003049270A2 (en) * | 2001-12-06 | 2003-06-12 | Koninklijke Philips Electronics N.V. | Power supply for an x-ray generator |
| CN116722737A (en) * | 2023-08-09 | 2023-09-08 | 东莞市奥源电子科技有限公司 | Control method, system and storage medium for LLC power supply self-adaptive adjustment output |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5889075A (en) * | 1981-11-24 | 1983-05-27 | Hitachi Ltd | Resonance type switching power source |
| US4481654A (en) * | 1982-09-09 | 1984-11-06 | General Electric Company | X-Ray tube bias supply |
| US4477868A (en) * | 1982-09-30 | 1984-10-16 | General Electric Company | High frequency series resonant dc-dc converter |
| JPH0710168B2 (en) * | 1984-10-15 | 1995-02-01 | ソニー株式会社 | Magnetic flux control type isolated power supply circuit |
| US4814962A (en) * | 1988-05-27 | 1989-03-21 | American Telephone And Telegraph Company, At&T Bell Laboratories | Zero voltage switching half bridge resonant converter |
| JPH06101930B2 (en) * | 1988-09-16 | 1994-12-12 | 九州大学長 | Switching power supply |
| US5027263A (en) * | 1988-09-16 | 1991-06-25 | Kyushu University | Switching power source means |
| JPH0287969A (en) * | 1988-09-21 | 1990-03-28 | Origin Electric Co Ltd | Resonant converter |
| JPH0687656B2 (en) * | 1988-10-12 | 1994-11-02 | 耕介 原田 | converter |
| JPH0326283U (en) * | 1989-07-21 | 1991-03-18 | ||
| JPH03109615A (en) * | 1989-09-22 | 1991-05-09 | Yokogawa Electric Corp | Voltage resonance type switching power supply |
| DE4212189A1 (en) * | 1992-04-10 | 1993-10-14 | Lambda Physik Forschung | Pulsed charging of capacitor for laser operation - has inverter driving transformer with output stage including resonator circuit capacitor for low loss operation. |
-
1980
- 1980-07-22 GB GB8023893A patent/GB2057168A/en not_active Withdrawn
- 1980-08-23 DE DE19803031901 patent/DE3031901A1/en not_active Withdrawn
- 1980-08-28 JP JP11858480A patent/JPS5635679A/en active Pending
-
1985
- 1985-11-28 JP JP1985183909U patent/JPS6196784U/ja active Pending
Cited By (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0081302A1 (en) * | 1981-11-17 | 1983-06-15 | Hughes Aircraft Company | Series resonant inverter with integrating feedback control loop |
| US4757432A (en) * | 1981-11-17 | 1988-07-12 | Hughes Aircraft Company | Series resonant inverter with integrating feedback control loop |
| EP0107313A1 (en) * | 1982-09-13 | 1984-05-02 | Ferranti plc | Resonant current-driven power source |
| US4475149A (en) * | 1982-09-13 | 1984-10-02 | Venus Scientific Inc. | Resonant current-driven power source |
| GB2131209A (en) * | 1982-11-02 | 1984-06-13 | Newton Derby Ltd | Switch mode power supply |
| EP0108336A2 (en) | 1982-11-03 | 1984-05-16 | General Electric Company | High frequency x-ray generator power supply |
| EP0108336A3 (en) * | 1982-11-03 | 1986-06-11 | General Electric Company | High frequency x-ray generator power supply |
| GB2137780A (en) * | 1983-02-10 | 1984-10-10 | Newton Derby Ltd | Current regulated power supply circuit |
| US4692851A (en) * | 1985-02-02 | 1987-09-08 | Attwood Brian E | Harmonic-resonant power supply |
| WO1986004750A1 (en) * | 1985-02-02 | 1986-08-14 | Brian Ernest Attwood | Harmonic-resonant power supply |
| GB2170663A (en) * | 1985-02-02 | 1986-08-06 | Brian Ernest Attwood | Harmonic-resonant power supply |
| GB2170663B (en) * | 1985-02-02 | 1989-06-14 | Brian Ernest Attwood | Harmonic-resonant power supply |
| EP0232915A2 (en) * | 1986-02-13 | 1987-08-19 | Salora Oy | Circuit arrangement of a DC voltage source based on resonance |
| EP0232915A3 (en) * | 1986-02-13 | 1988-10-12 | Salora Oy | Circuit arrangement of a dc voltage source based on resonance |
| EP0293874A2 (en) * | 1987-06-05 | 1988-12-07 | Siemens Nixdorf Informationssysteme Aktiengesellschaft | Method and circuit arrangement to control the state of a resonant converter |
| EP0293874A3 (en) * | 1987-06-05 | 1989-11-29 | Siemens Aktiengesellschaft | Method and circuit arrangement to control the state of a resonant converter |
| WO2003049270A2 (en) * | 2001-12-06 | 2003-06-12 | Koninklijke Philips Electronics N.V. | Power supply for an x-ray generator |
| WO2003049270A3 (en) * | 2001-12-06 | 2003-11-06 | Koninkl Philips Electronics Nv | Power supply for an x-ray generator |
| US7050539B2 (en) | 2001-12-06 | 2006-05-23 | Koninklijke Philips Electronics N.V. | Power supply for an X-ray generator |
| CN116722737A (en) * | 2023-08-09 | 2023-09-08 | 东莞市奥源电子科技有限公司 | Control method, system and storage medium for LLC power supply self-adaptive adjustment output |
| CN116722737B (en) * | 2023-08-09 | 2024-03-19 | 东莞市奥源电子科技有限公司 | Control method, system and storage medium for LLC power supply self-adaptive adjustment output |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5635679A (en) | 1981-04-08 |
| DE3031901A1 (en) | 1981-03-19 |
| JPS6196784U (en) | 1986-06-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |