Circuit for converting an AC voltage to a DC voltage

• US 20050237771A1
• Filed: 04/22/2005
• Published: 10/27/2005
• Est. Priority Date: 04/22/2004
• Status: Abandoned Application

• Current Assignee: Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen mbH (Ams-Osram AG)
• Original Assignee: Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen mbH (Ams-Osram AG)
• Inventors: Niedermeier, Peter, Franck, Felix
• Application Number:
  US11/111,702
• Publication Number:
  US 20050237771A1
• Time in Patent Office: Days
• US Class Current: 363/84
• CPC Class Codes: H02M 1/4233 using a bridge converter comprising active switches
• CPC Class Codes: H02M 7/219 in a bridge configuration
• CPC Class Codes: H05B 41/28 using static converters
• CPC Class Codes: Y02B 70/10 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

Abstract

Circuit for converting an AC voltage to a DC voltage in which a full-bridge rectifier is replaced by two controlled switches. An inductor is connected upstream such that power factor correction is also made possible for the rectifying function. The circuit has a mid-voltage at the output. As a result, a square-wave load current can be generated with the aid of two further switches.

Claims

1. A circuit for converting an AC voltage to a DC voltage having the following features:

a first (J1) and a second (J2) input terminal to which a source can be connected which can emit an AC input voltage (UN) and an alternating input current (IN), and

a first (J3) and a second (J4) output terminal to which a load can be connected,

characterized by the following features;

a first (S1) and a second (S2) controlled switch which are connected in series between the output terminals (J3, J4) and form a switch connecting node (N1),

a first (C1) and a second (C2) storage capacitor which are connected in series between the output terminals (J3, J4) and form a capacitor connecting node (N2),

the first input terminal (J1) is connected to the switch connecting node (N1) via an inductor (L1), and

the second input terminal (J2) is connected to the capacitor connecting node (N2).

2. The circuit as claimed in claim 1, characterized

in that a first freewheeling diode (D1) is connected in parallel with the first switch (S1), and a second freewheeling diode (D2) is connected in parallel with the second switch (S2).

3. The circuit as claimed in claim 1, characterized

in that the second input terminal (J2) is connected to the capacitor connecting node (N2) via a second inductor.

4. The circuit as claimed in claim 1, characterized in that the circuit comprises a control device which provides control signals for the switches (S1, S2),

the control signals causing the two switches (S1, S2) to switch on and off alternately,

and a duty cycle being selected between the switch-on duration and switch-off duration of the switches (S1, S2) such that the waveform of the alternating input current (IN) essentially follows the waveform of the AC input voltage (UN).

5. The circuit as claimed in claim 1, characterized by the following features:

a third switch (S3) is connected in series with the first switch (S1) and forms with it a third connecting node (N3),

a fourth switch (S4) is connected in series with the second switch (S2) and forms with it a fourth connecting node (N4),

a first clamping diode (D3) is connected between the capacitor connecting node (N2) and the third connecting node (N3), and

a second clamping diode (D4) is connected between the capacitor connecting node (N2) and the fourth connecting node (N4).

6. The circuit as claimed in claim 5, characterized

in that a third freewheeling diode (D5) is connected in parallel with the third switch (S3), and a fourth freewheeling diode (D6) is connected in parallel with the fourth switch (S4).

7. The circuit as claimed in claim 1, characterized by the following features:

a fifth (S5) and a sixth (S6) switch are connected in series between the output terminals (J3, J4) and form a fifth connecting node (N5), and

a series circuit comprising a gas discharge lamp (Lp) and a lamp inductor (L2) is connected between the capacitor connecting node (N2) and the fifth connecting node (N5).

8. The circuit as claimed in claim 7, characterized

in that a fifth freewheeling diode (D7) is connected in parallel with the fifth switch (S5), and a sixth freewheeling diode (D8) is connected in parallel with the sixth switch (S6).

9. The circuit as claimed in claim 7, characterized by the following features:

a seventh switch (S7) is connected in series with the fifth switch (S5) and forms with it a sixth connecting node (N6),

an eighth switch (S8) is connected in series with the sixth switch (S6) and forms with it a seventh connecting node (N7),

a third clamping diode (D9) is connected between the capacitor connecting node (N2) and the sixth connecting node (N6), and

a fourth clamping diode (D10) is connected between the capacitor connecting node (N2) and the seventh connecting node (N7).

10. The circuit as claimed in claim 9, characterized

in that a seventh freewheeling diode (D11) is connected in parallel with the seventh switch (S7), and an eighth freewheeling diode (D12) is connected in parallel with the eighth switch (S8).