GB2112594A - Switching voltage regulator - Google Patents
Switching voltage regulator Download PDFInfo
- 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- Withdrawn
Links
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
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion 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
- H02M3/145—Conversion 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
- H02M3/155—Conversion 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
Landscapes
- 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.
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)
| 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 |
-
1981
- 1981-12-24 GB GB08138967A patent/GB2112594A/en not_active Withdrawn
-
1982
- 1982-12-14 DE DE19823246288 patent/DE3246288A1/en not_active Withdrawn
- 1982-12-24 JP JP22648682A patent/JPS58119017A/en active Pending
Cited By (5)
| 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) |