GB2246648A - A regulated step-down switching circuit for the DC converter of a power supply - Google Patents
A regulated step-down switching circuit for the DC converter of a power supply Download PDFInfo
- Publication number
- GB2246648A GB2246648A GB9017142A GB9017142A GB2246648A GB 2246648 A GB2246648 A GB 2246648A GB 9017142 A GB9017142 A GB 9017142A GB 9017142 A GB9017142 A GB 9017142A GB 2246648 A GB2246648 A GB 2246648A
- Authority
- GB
- United Kingdom
- Prior art keywords
- diode
- power supply
- capacitor
- mos
- converter
- 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.)
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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
- H02M3/02—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
- H02M3/156—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 with automatic control of output voltage or current, e.g. switching regulators
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
A regulated step-down switching circuit for the DC converter of a power supply consists of a pulse width modulator IC, a MOS-FET, a zener diode (Z1), a number of diodes (D1-D4), capacitors (C1-C3), resistor (R1), and an inductor (L1); wherein the drain of the MOS-FET is connected to a power supply, with its source being connected to the output lead. The gate of the MOSFET is connected to one of the transistors (Q1) within the pulse width modulation IC. Between the source and the drain of the MOS-FET, a diode (D2) and a capacitor (2) are connected in series, and at the junction point (e) of this diode and the capacitor. a diode (D3) and resistor R1 are serially connected. The other end of the resistor (RI) is connected to the transistor (Q1) within the pulse width modulator IC, as well as being connected to the zener diode (Z1), capacitor (C1) and diode (D1) in parallel branches. The other ends of these parallel branches are connected to the power input lead and the pulse width modulator IC. <IMAGE>
Description
A REGULATED STEP-DOWN SWITCHING CIRCUIT FOR
THE DC CONVERTER OF A POWER SUPPLY
The present invention relates to a regulated step-down switching circuit for the DC converter of a power supply, in particular, including a pulse width modulation IC and a MOS-FET to regulate the step-down output from the DC converter of a power supply.
A power supply is an indispensable major part in computers, electronic devices and communication equipment, its main function being to provide a single or several regulated voltage sources for the said equipment.
A conventional regulated step-down switching circuit for the DC converter of a power supply can be represented by the circuit as shown within the solid line rectangular enclosure (A) in Fig. 1, which was developd by a U.S. firm "Linear Technology
Corporation". This circuit comprises two metal-oxidesemiconductor field effect transistors (MOS-FETli and
MOS-FET12) a transistor (ill), a voltage regulator (ICI), two diodes (D12 & D14), two capacitors (cull and
C12) and resistors (roll, R12, R13, R14 etc.). In this circuit, MOS-FETli will become conductive when the voltage on the gate of MOS-FETil is greater than the input voltage.
But this circuit possesses defects as follows:
(1) It requires two MOSFETS, a voltage regulator IC, a transistor, and a number of passive components such as capacitors, resistors etc.. Because of its complex in circuitry, more parts are required to construct such circuit, and consequently, not only its product costs are therefore increased but also its reliability is reduced;
(2) The voltage regulator IC of this circuit is always maintained in a working state, therefore, it always consumes power.
In view of the defects of such a conventional regulated step-down switching circuit for the DC converter of a power supply, the purpose of the present invention is to provide an innovative regulated stepdown switching circuit, which is simple in structure, precise in action, more reliable and more efficient in performance compared with conventional arrangements for the converter of a power supply.
Since the present invention has a simple circuit structure as compared with the conventional arrangements, the product costs can be reduced, which is one of the advantages of the present invention, and because it als uses less active and passive components, it is more efficient as compared with the conventional arrangements, and better reliability can be expected.
Furthermore, compared with the conventional circuits, which consume power constantly, the present invention operates only when the voltage increases, so it is energy-saving. This is another advantage of the present invention.
The present invention will be described further by way of example, with reference to the accompanying drawings, in which:
Fig. 1 referred to above shows a conventional regulated step-down switching circuit (enclosed by a solid line rectangle A) for the DC converter of a power supply; and
Fig. 2 is the regulated step-down switching circuit of the present invention.
Referring to the Fig. 2, the present invention comprises a MOS-FET, a pulse width modulation (PWM) IC, a zener diode (Z1), diodes (D1, D2, D3 and
D4), capacitors (C1, C2 and C3), a resistor (R1), an inductor (L1) and etc.; wherein, the drain 'd' of the
MOS-FET is connected to the power input, the source 's' is connected to the power output terminal via an inductor L1, and the gate 'g' is connected to one of the
PNP or NPN transistors Q1 inside the PWM IC. Between the drain 'd' and the source 's', a diode D2 and a capacitor C2 are connected in series, and at the junction point of D2 and C2 a diode D3 and a resistor R1 are connected in series.The free end of the resistor Ri is connected to the transistor Q1 inside the PWM IC.
A lead wire 12 is provided to connect the power input terminal and the P: IC for furnishing power to the same, and between lead wires 11 and 12, are connected a zener diode Z1, a capacitor C1, and a diode D1 in parallel. A ground lead wire 13 is furnished to connect the input power ground terminal and the output power ground terminal and also the two terminals of L1 are connected via respective diode D4 and capacitor C3 parallel branches to ground lead wire 13.
The operating principles of the present invention are described as follows:
In general, a MOS-FET goes into conductive state only when its gate voltage (Vg) becomes greater than the input power voltage (Vin) for 6 to 15 volts.
In the present invention, when input power is just switched on, the potential at point 'b' is Vb=O, therefore, capacitor C2 starts charging to a potential
VC2, which equals the potential difference between input power voltage Vin and diode D2's voltage drop VD2, i.e.
VC2=Vin-VD2. At this time, transistor Q1, inside the
PWM IC, starts to operate, which causes the MOS-FET to go into a conductive state and the potential Vb at the point b' therefore rises. The potential Ve at the junction point 'd' of capacitor C2 and diode D2 can be represented by: Ve=VD4+VC2; therefore, when the voltage is rising, potential Ve will become greater than potential Vin, which makes a part of the circuit of the present invention operate. In the meantime, the diode
D3 conducts, the capacitor C1 charges, and when the potential VC1 rises to a level which is greater than
Vin, the whole circuit will then go into operation.
From the above statement, it can be understood that the circuit of the present invention utilizes a zener diode Z1, a MOS-FET, a PWM IC as its major parts. In comparison with the typical conventional step-down regulated circuit developed by "Linear Technology Corporation" U.S.A., a lot of parts as well as the product costs can be saved. Furthermore, since the present invention operates only when the voltage is rising, it will not consume the power constantly, so it is energy-saving, precise in action and reliable in its performance.
Although the present invention has been described with a certain degree of particularity, the present disclosure has been made by way of example and changed in details of structure may be made without departing from the scope thereof.
Claims (2)
1. A regulated step-down switching circuit for the DC converter of a power supply, comprising a PWM IC, a MOS-FET, a zener diode, diodes, capacitors, resistors and an inductor; wherein a first diode and a first capacitor are connected in series between the source and the drain of the MOS-FET, and a second diode and resistor are connected in series between the first diode and first capacitor and a transistor of the PWM IC, the input power supply being connected as the power source to the PWM IC and at the junction point between said resistor and said transistor, a zener diode, a capacitor and a diode are connected in parallel to the power input.
2. A regulated step-down switching circuit for the DC converter of a power supply, substantially as herein described with reference to the accompanying drawings.
Published 1992 at The Patent Office. Concept House. Cardiff Road. Nevpon. Gwent NPS IRH. Funher coples may be obtained from
Sales Branch. Unit 6. Nine Mile Point. Cwmfelinfach. Cross Keys. h'eport. NPt 7HZ. Printed by Multiplex techmques Itd. St Mart Crazy. I
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9017142A GB2246648A (en) | 1990-08-04 | 1990-08-04 | A regulated step-down switching circuit for the DC converter of a power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9017142A GB2246648A (en) | 1990-08-04 | 1990-08-04 | A regulated step-down switching circuit for the DC converter of a power supply |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9017142D0 GB9017142D0 (en) | 1990-09-19 |
| GB2246648A true GB2246648A (en) | 1992-02-05 |
Family
ID=10680183
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9017142A Withdrawn GB2246648A (en) | 1990-08-04 | 1990-08-04 | A regulated step-down switching circuit for the DC converter of a power supply |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2246648A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2284283B (en) * | 1993-11-12 | 1997-12-24 | Bosch Gmbh Robert | Circuit arrangement for current measurement via a switching transistor |
| GB2372842A (en) * | 2000-11-01 | 2002-09-04 | Edinburgh Comm Ltd | Voltage regulator using a field effect transistor |
| FR2834143A1 (en) * | 2001-12-20 | 2003-06-27 | Thales Sa | Series chopper with synchronous communication, uses switched capacitive ladder with pairs of switches bridged by capacitors and connected to the next pair via their mid-points |
| EP1641109A1 (en) * | 2004-09-28 | 2006-03-29 | Delphi Technologies, Inc. | A switched mode power supply |
| US7342326B2 (en) * | 2002-01-18 | 2008-03-11 | Robert Bosch Gmbh | Circuit arrangement for momentarily maintaining an internal operating direct current voltage in the event of an interruption in the vehicle electrical system power supply voltage |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1547320A (en) * | 1976-07-02 | 1979-06-06 | Raytheon Co | Regulated power supply circuit |
-
1990
- 1990-08-04 GB GB9017142A patent/GB2246648A/en not_active Withdrawn
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1547320A (en) * | 1976-07-02 | 1979-06-06 | Raytheon Co | Regulated power supply circuit |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2284283B (en) * | 1993-11-12 | 1997-12-24 | Bosch Gmbh Robert | Circuit arrangement for current measurement via a switching transistor |
| GB2372842A (en) * | 2000-11-01 | 2002-09-04 | Edinburgh Comm Ltd | Voltage regulator using a field effect transistor |
| FR2834143A1 (en) * | 2001-12-20 | 2003-06-27 | Thales Sa | Series chopper with synchronous communication, uses switched capacitive ladder with pairs of switches bridged by capacitors and connected to the next pair via their mid-points |
| WO2003055048A1 (en) * | 2001-12-20 | 2003-07-03 | Thales | Series chopper with synchronous communication |
| US6987680B2 (en) | 2001-12-20 | 2006-01-17 | Thales | Series chopper with synchronous switching |
| US7342326B2 (en) * | 2002-01-18 | 2008-03-11 | Robert Bosch Gmbh | Circuit arrangement for momentarily maintaining an internal operating direct current voltage in the event of an interruption in the vehicle electrical system power supply voltage |
| EP1641109A1 (en) * | 2004-09-28 | 2006-03-29 | Delphi Technologies, Inc. | A switched mode power supply |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9017142D0 (en) | 1990-09-19 |
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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) |