Power supply device and method for limiting an output current of a power supply device

Patent metadata

Field	Value
Publication number	US-2016285356-A1
Application number	US-201415033041-A
Country	US
Kind code	A1
Filing date	Nov 18, 2014
Priority date	Dec 6, 2013
Publication date	Sep 29, 2016
Grant date	—

Abstract

The invention relates to a power supply device for converting an input voltage (U E ) into an output voltage (U A ), comprising at least one switching stage ( 4 ) controlled by a pulse-width modulation circuit ( 9 ) in a clocked manner, wherein a control circuit ( 8 ) is provided, which influences the pulse-width modulation circuit ( 9 ) so as to change the level of the output voltage (U A ), wherein a current limiting circuit is provided which, after a threshold has been exceeded, limits an output current (I A ) of the power supply device first to an elevated maximum current (I′ max ) for a period of time and thereafter to a regular maximum current (I max ). According to the invention, the control circuit ( 8 ) is configured such that the period of time for which the output current (I A ) is limited to the elevated maximum current (I′ max ) is dependent on the level of the output current (I A ). The invention further relates to a method for limiting the output current (I A ) of a power supply device.

First claim

1 . (canceled)

2 . (canceled)

3 . (canceled)

4 . (canceled)

5 . (canceled)

6 . (canceled)

7 . (canceled)

8 . (canceled)

9 . (canceled)

10 . (canceled)

11 . (canceled)

12 . (canceled)

13 . (canceled)

14 . (canceled)

15 . A switched-mode power supply arrangement for converting an input voltage (U E ) to an output voltage (U A ), comprising:
(a) a transformer ( 5 ) having primary (I) and secondary (II) windings; (b) at least one switching stage circuit ( 4 ) for supplying said input voltage (U E ) to said transformer primary winding, thereby causing said secondary winding to produce an output current (I A ) and an output voltage (U A ), said switching stage circuit including a switching element ( 41 ); (c) a pulse-width modulation circuit ( 9 ) connected with said switching stage switching element for controlling in a clocked manner the operation of said switching stage circuit; and (d) a control circuit ( 8 ) controlling the operation of said pulse-width modulation circuit to vary the level of the output voltage (U A ), said control circuit including:
(1) means for establishing a threshold level; and
(2) a current limiting circuit operable when said threshold level has been exceeded by a voltage signal that is a function of the output current (I A ) to limit for a first period of time the output current to an elevated maximum current (I′ max ), and thereafter to limit the output current to a regular maximum current (I max ), said first period of time being dependent on the level of said output current (I A ).

16 . A switched-mode power supply arrangement as defined in claim 15 , wherein the longer said first period of time exists, the smaller is the difference between said first voltage signal (V 1 ) and said first threshold value during said first period of time.

17 . A switched-mode power supply arrangement as defined in claim 16 , wherein said current limiting circuit includes:
(a) a first comparison circuit ( 83 ) for comparing said first voltage signal (V 1 ) with said first reference voltage (V ref1 ), thereby to produce an output voltage signal (V 4 ) that controls the operation of said pulse-width modulation circuit, and thereby control the level of said output voltage (U A ).

18 . A switched-mode power supply arrangement as defined in claim 17 , wherein said current limiting circuit further includes:
(b) an integrator circuit ( 85 ) for filtering said first voltage signal (V 1 ) to produce a second voltage signal (V 2 ); (c) a second comparison circuit ( 84 ) for comparing said second voltage signal (V 2 ) with a second reference voltage (V ref2 ) corresponding with said regular maximum current (I max ), thereby to produce a third voltage signal (V 3 ) that is supplied as an input to said first comparison circuit ( 83 ), thereby to influence the operation of said first comparison circuit.

19 . A switched-mode power supply arrangement as defined in claim 18 , wherein said integrator circuit comprises a low-pass filter arrangement including at least one charging/discharging resistor ( 856 ) and a capacitor ( 855 ).

20 . A switched-mode power supply arrangement as defined in claim 18 , wherein said integrator circuit ( 85 ) includes a first branch including a charging resistor ( 851 ) connected in series with a first diode ( 852 ) having a first polarity, and a second branch connected in parallel with said first branch, said second branch including a discharging resistor ( 853 ) connected in series with a second diode ( 854 ) of the opposite polarity.

21 . A switched-mode power supply arrangement as defined in claim 20 , and further including a temperature-dependent resistor ( 857 ) connect in series in said second branch.

22 . A switched-mode power supply arrangement as defined in claim 15 , wherein said input voltage (U E ) has a range of from between about 10 volts to about 800 volts.

23 . A switched-mode power supply arrangement as defined in claim 15 , wherein said input voltage (U E ) has a range of from about 15 volts to about 265 volts.

24 . A switched-mode power supply arrangement as defined in claim 15 , wherein said input voltage (U E ) is an alternating-current voltage, and said output voltage (UA) is a direct-current voltage.

25 . A switched-mode power supply arrangement as defined in claim 15 , wherein said output current normally has a nominal current value (I nom ), and further wherein said elevated maximum current (I′ max ) is between 5 to 10 times said nominal current value, and said regular maximum current (I max ) is between 1.1 and 1.5 times said nominal current (I nom ).

26 . A switched-mode power supply arrangement for converting an input voltage to an output voltage, comprising:
(a) a transformer ( 5 ) having primary (I) and secondary (II) windings; (b) at least one switching stage circuit ( 4 ) for supplying said input voltage (U E ) to said transformer primary winding, thereby causing said transformer secondary winding to produce an output current (I A ) and an output voltage (U A ), said switching stage circuit containing a switching element ( 41 ); (c) a pulse-width modulation circuit ( 9 ) connected with said switching stage switching element for controlling in a clocked manner the operation of said switching stage circuit; and (d) a control circuit ( 8 ) controlling the operation of said pulse-width modulation circuit to vary the level of the output voltage (U A ), said control circuit including:
(1) a first comparison stage ( 83 ) including:
(a) a first operational amplifier ( 831 ) having an output terminal connected with said pulse-width modulation circuit, and a pair of input terminals; and
(b) a first reference voltage (V ref1 ) connected with a first one of said first operational amplifier input terminals;

(2) means ( 81 , 82 ) for applying to a second input terminal of said first operational amplifier a first voltage signal (V 1 ) that is a function of the output current (I A ), whereby upon the occurrence of an overload, an elevated maximum current (I′ max ) is permitted;
(3) an integrator circuit ( 85 ) for generating from said first voltage signal (V 1 ) a time-integrated second voltage signal (V 2 );
(4) a second comparison stage ( 84 ) including:
(a) a second operational amplifier ( 841 ) having an output terminal connected with said first operational amplifier first input terminal, and a pair of input terminals; and
(b) a second reference voltage (V ref2 ) connected with a first input terminal of said second operational amplifier, the second input of said second operational amplifier being connected with said integrator circuit to receive said time-integrated second voltage signal (V 2 ), thereby to produce a third voltage signal (V 3 ) at the output terminal of said second operational amplifier that influences the operation of said first operational amplifier;

(5) said control circuit being operable when the threshold level established by said second reference voltage has been exceeded to limit for a first period of time the output current at the elevated maximum current (I′ max ), and thereafter to limit the output current to a regular maximum current (I max ), said first period of time being dependent on the level of said output current (I A ).

27 . A method for limiting the output current (I A ) of a switched-mode power supply system ( 1 ) having a transformer with primary an

Assignees

• Weidmueller Interface Gmbh & Co Kg
• Weidmueller Interface Gmbh & Co Kg

Inventors

• Schuermann Klaus
• Buschkamp Michael

Classifications

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H02H9/02

  responsive to excess current {(current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025)} · CPC title

• H02M3/33507

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title