GB2112594A - Switching voltage regulator - Google Patents

Switching voltage regulator Download PDF

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Publication number
GB2112594A
GB2112594A GB08138967A GB8138967A GB2112594A GB 2112594 A GB2112594 A GB 2112594A GB 08138967 A GB08138967 A GB 08138967A GB 8138967 A GB8138967 A GB 8138967A GB 2112594 A GB2112594 A GB 2112594A
Authority
GB
United Kingdom
Prior art keywords
diode
switch
inductor
voltage regulator
output terminals
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Withdrawn
Application number
GB08138967A
Inventor
Ian Francis Brown
Donald William Semple
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.)
Ferranti International PLC
Original Assignee
Ferranti PLC
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 Ferranti PLC filed Critical Ferranti PLC
Priority to GB08138967A priority Critical patent/GB2112594A/en
Priority to DE19823246288 priority patent/DE3246288A1/en
Priority to JP22648682A priority patent/JPS58119017A/en
Publication of GB2112594A publication Critical patent/GB2112594A/en
Withdrawn legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/02Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145Conversion of dc power input into dc power output without intermediate conversion into ac 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
    • H02M3/155Conversion of dc power input into dc power output without intermediate conversion into ac 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

A switching voltage regulator includes a series-connected switch TR, and a smoothing circuit connected between the switch and a pair of output terminals 11. The smoothing circuit includes a pair of inductors L1 and L2 connected in series between the switch TR and one of the output terminals 11. A first diode D1 is connected between the junction of the two inductors and the other output terminal, and a capacitor C is connected between the two output terminals. A second diode D2 is connected so as to dissipate any energy stored in the inductor L2 when the switch TR is open. <IMAGE>

Description

SPECIFICATION Switching voltage regulator This invention relates to switching voltage regulators, that is to direct current regulator in which the output voltage is determined by the on-off ratio of a series-connected switch.
Many types of such regulator are known, normally using a semiconductor switching device. The circuits may be more or less complicated, depending upon the arrangements used to control the switching device and to maintain the output voltage at a required value despite changes in the current supplied to a load. Switching voltage regulators require some form of smoothing to reduce the ripple to an acceptable level, and one commonlyused arrangement uses a series-connected inductor having a diode connected between the switch side of the inductor and common, and a capacitor connected between the load side of the inductor and common. In operation, this arangement allows energy to be stored in the inductor whilst the series switch is closed, during which time the diode is non-conducting.When the switch opens, load current is maintained through the diode which becomes conducting and allows the energy stored in the inductor to be passed to the load.
In order to reduce the switching losses, the switch must operate quickly. However, it is frequently found that the diode is still conducting when the switch closes, due to the hole storage effect of the diode. This causes a short duration large amplitude current pulse to flow through the diode until the diode stops conducting. Such a current pulse is wasteful, and may also cause considerable radio-frequency interference.
It is an object of the invention to provide a switching voltage regulator having a seriesconnected switch in which the above problem is eliminated.
According to the present invention there is provided a switching voltage regulator having a series-connected switch and an output voltage smoothing circuit connected between the series-connected switch and a pair of output terminals, the smoothing circuit comprising a first and a second inductor connected in series with one another between the switch and one of said output terminals, a first diode connected between the junction of the two inductors and the other of said output terminals, a capacitor connected between said pair of output terminals, and a second diode connected so as to dissipate any energy stored in that inductor nearest to the switch when said switch is open.
The invention will now be described with reference to the accompanying drawings, in which Figure 1 is a circuit diagram of a known switching voltage regulator; Figure 2 is a circuit diagram of a first embodiment of the invention, and Figure 3 illustrates a further embodiment.
In all the drawings the control circuitry for the switching device has been omitted for the sake of clarity. Many control arrangements are known for series-connected switches in this type of voltage regulator.
Referring now to Fig. 1, a known form of switching voltage regulator an input d.c. voltage is applied to a pair of input terminals 10.
The common side of the input is connected to one of a pair of output terminals 11. The other input terminal is connected to the collector of a switching transistor TR, the emitter of which is connected through an inductor L1 to the other output terminal. A diode D1 is connected between the common line and the junction of the inductor L1 and the transistor TR, and a capacitor C is connected between the common line and the other end of the inductor. A load LD is shown connected to the output terminals.
In operation, the transistor TR switches on and off at a rate determined by the control circuitry. When the transistor is turned on, current flows to the load, charging the capacitor C and storing energy in the inductor L1 at the same time. The diode D1 is reverse biased and hence non-conducting. When the transistor switches off, inductor L1 dissipates its energy through the diode into the load, and the load current is maintained. Ideally, when the transistor again becomes conducting, the diode D1 should immediately become nonconducting, to avoid a large amplitude short duration current pulse which causes the problems referred to earlier. The diode also has to pass the full load current when the transistor is switched off.It is this combination of high current capacity and high switching speed which is difficult to achieve, due to hold storage effects, particularly at load current values in excess of five amps or so. High switching speed at low current is easily achieved, as is high current capacity at low switching speeds.
Figure 2 shows one way in which the problem may be overcome. The circuit shown has all the features of Fig. 1, but a second inductor L2 is connected in series with the first inductor, and between it and the transistor TR. A diode D2 is connected across this inductor L2 in such a way as to be able to dissipate the energy stored in the inductor when the transistor TR is switched off. The inductor L2 will usually have a lower inductance than that of L1.
When the transistor TR conducts, current flows in the inductor L2, and builds up to the required load value whilst the previously-conducting diode D1 recovers and stops conducting. Current then flows through inductor L1 to the load as before. When the transistor switches off, the load current previously flowing through inductor L2 is allowed to decay in a controlled manner through the diode D2. At the same time diode D1 starts conducting as previously described, to maintain the load current.
Diode D1 is not required to switch between its conducting and non-conducting states particularly fast, but is required to carry the load current. Diode D2, on the other hand, has to change state quickly, but carries a relatively low current. Diode D2 is what is called, in the manufacturers literature, a "high-speed" diode. This means, generally, that no more than 10% of the time spent in one state (i.e.
conducting or non-conducting) is spent in changing to that state from the other state.
Ideally the time should be 2-3%. Diodes of the two types specified above are readily available.
Figure 3 is an alternative embodiment, showing diode D2 connected between the switch end of inductor L2 and the common line. The effect of this connection is similar to that already described. Other arrangements of the diode D2 are also possible.

Claims (5)

1. A switching voltage regulator having a series-connected switch and an output voltage smoothing circuit connected between the series-connected switch and a pair of output terminals, the smoothing circuit comprising a first and a second inductor connected in series with one another between the switch and one of said output terminals, a first diode connected between the junction of the two inductors and the other of said output terminals, a capacitor connected between said pair of output terminals, and a second diode connected so as to dissipate any energy stored in that inductor nearest to the switch when said switch is open.
2. A voltage regulator as claimed in Claim 1 in which the second diode is connected in parallel with said second inductor.
3. A voltage regulator as claimed in Claim 1 in which the second diode is connected between the junction of the switch and the second inductor and the said other output terminal.
4. A voltage regulator as claimed in any one of Claims 1 to 3 in which the said second diode is a high-speed diode as hereinbefore defined.
5. A switching voltage regulator substantially as herein described with reference to Figs. 2 and 3 of the accompanying drawings.
GB08138967A 1981-12-24 1981-12-24 Switching voltage regulator Withdrawn GB2112594A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
GB08138967A GB2112594A (en) 1981-12-24 1981-12-24 Switching voltage regulator
DE19823246288 DE3246288A1 (en) 1981-12-24 1982-12-14 SWITCHING VOLTAGE REGULATOR
JP22648682A JPS58119017A (en) 1981-12-24 1982-12-24 Switching voltage regulator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08138967A GB2112594A (en) 1981-12-24 1981-12-24 Switching voltage regulator

Publications (1)

Publication Number Publication Date
GB2112594A true GB2112594A (en) 1983-07-20

Family

ID=10526852

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08138967A Withdrawn GB2112594A (en) 1981-12-24 1981-12-24 Switching voltage regulator

Country Status (3)

Country Link
JP (1) JPS58119017A (en)
DE (1) DE3246288A1 (en)
GB (1) GB2112594A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0388069A2 (en) * 1989-03-16 1990-09-19 Nokia Mobile Phones Ltd. DC-DC converter circuit
EP0992811A3 (en) * 1998-10-06 2003-04-23 Hitachi, Ltd. Battery apparatus and control system therefor
EP1441574A1 (en) * 2001-11-01 2004-07-28 Harison Toshiba Lighting Corporation Discharging lamp apparatus

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0388069A2 (en) * 1989-03-16 1990-09-19 Nokia Mobile Phones Ltd. DC-DC converter circuit
EP0388069A3 (en) * 1989-03-16 1990-10-17 Nokia Mobile Phones Ltd. Dc-dc converter circuit
EP0992811A3 (en) * 1998-10-06 2003-04-23 Hitachi, Ltd. Battery apparatus and control system therefor
EP1441574A1 (en) * 2001-11-01 2004-07-28 Harison Toshiba Lighting Corporation Discharging lamp apparatus
EP1441574A4 (en) * 2001-11-01 2007-05-09 Harison Toshiba Lighting Corp Discharging lamp apparatus

Also Published As

Publication number Publication date
JPS58119017A (en) 1983-07-15
DE3246288A1 (en) 1983-07-07

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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)