Patent EP0075176A2 successfully refreshed from Google Patents.
EP0075176A2
Expired / Lapsed
EP
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Electronic ballast for a discharge lamp
Assignee: Helvar Oy AB
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Filing: 1982-09-07
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Granted: —
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Expires: 2002-09-07
Abstract
Abstract An electronic ballast for a discharge lamp (8) for restricting and stabilizing a current, said ballast comprising a high frequency oscillator connected to a source of direct current, said oscillator consisting of two series connected transistors (1, 2), a base drive transformer (3) connected there between and bringing transistors (1, 2) into alternating phase operation, an inductor (7) connected in series with the primary winding (4) of a transformer (3), and a resonance capacitor (10, 11) in the latter series circuit between a lamp (8) and a source of current, as well as a filtering capacitor connected between the terminals of a source of direct current and having high charging ability. An object is to reduce the radio interference level produced by a ballast and on the other hand to reduce RMS value of the ripple current of a filtering capacitor as well as the switching losses of transistors. This is achieved by connecting one (8a) of the electrodes of lamp (8) by way of resonance capacitors (10 and 11) to each opposite terminal of said source of current. The circuit solution further includes diodes (23, 24) connected parallel to capacitors (10, 11) for stable circuit operation despite the negative resistance on the part of a lamp.
Inventors
- 👤 Martti Sairanen
- 👤 Matti Virta
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 06:51
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/26; H05B41/28; H05B41/282; H05B41/2825; H05B41/2827; H05B41/36; H05B41/38; H05B41/39; H05B41/392; H05B41/3921; H05B41/3925; Y; Y10; Y10S; Y10S315/00; Y10S315/01
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
199 words
An electronic ballast for a discharge lamp (8) for the restriction and stabilization of the current, comprising a highfrequency oscillator connected to a D. C. supply, the said oscillator being made up of two transistors (1, 2) connected in series, with a base drive transformer (3) coupled in between to bring the transistors (1, 2) into alternating phase operation, as well as a resonance circuit connected in series with the primary winding (4) of the transformer, comprising in turn an inductor (7) and resonance capacitors (10 and 11) together with a capacitor (9) coupled parallel to the lamp (8), and which lamp (8) in turn is connected in series with the resonance circuit, in addition to which a filter capacitor (C) having a high charging ability is coupled between the terminals of the D. C. supply, characterized in that the resonance capacitors (10 and 11) are connected in series between the terminals of the D. C. supply, and diodes (23, 24) are connected parallel to them, and that the last part of the resonance circuit is connecting to a point common for the capacitors and the diodes, e. g. by means of the electrode (8a) of the lamp (8).
Claim 2
Dependent Claim
199 words
An electronic ballast for a discharge lamp (8) for the restriction and stabilization of the current, comprising a highfrequency oscillator connected to a D. C. supply, the said oscillator being made up of two transistors (1, 2) connected in series, with a base drive transformer (3) coupled in between to bring the transistors (1, 2) into alternating phase operation, as well as a resonance circuit connected in series with the primary winding (4) of the transformer, comprising in turn an inductor (7) and resonance capacitors (10 and 11) together with a capacitor (9) coupled parallel to the lamp (8), and which lamp (8) in turn is connected in series with the resonance circuit, in addition to which a filter capacitor (C) having a high charging ability is coupled between the terminals of the D. C. supply, characterized in that the resonance capacitors (10 and 11) are connected in series between the terminals of the D. C. supply, and diodes (23, 24) are connected parallel to them, and that the last part of the resonance circuit is connecting to a point common for the capacitors and the diodes, e. g. by means of the electrode (8a) of the lamp (8).
Claim 3
Dependent Claim
50 words
Electronic ballast according to patent claim 1, characterized in that a switching capacitor (9) is coupled parallel to the lamp (8) between the opposite ends of the electrode filaments, having a capacitance about 1/2 - 1/4 of the sum of the capacitances of the mentioned resonance capacitors (10 and 11).
Claim 4
Dependent Claim
30 words
Electronic ballast according to patent claim 1 or 2, characterized in that the diode (23 or 24) is connected parallel only to one of the resonance capacitors (10 or 11).
Claim 5
Dependent Claim
38 words
Electronic ballast according to patent claim 1, characterized in that diodes (12, 13) are connected in series with the switching transistors (1, 2), by means of which the time is reduced, during which both transistors are on simultaneously.
Claim 6
Dependent Claim
156 words
5: A method for the regulation of the light level of a discharge lamp by means of an electronic ballast controlling the current of the discharge lamp, comprising a high frequency oscillator made up of two transistors (1, 2) connected in series, a base drive transformer (3) connected in between, an inductor (7) connected in series with the primary winding (4) of the transformer, and in the latter circuit, a capacitor (10, 11) between the lamp (8) and the current supply, characterized in that in the series resonance circuit of the primary winding (4) of the base drive transformer, the inductor (7), and the capacitor (10, 11), the current of the transistor switches (1, 2) is controlled by short-circuiting the secondary winding (17) of the base drive transformer (3) at one half-period, at which the current is turning off at the other half-period on account of the core (16) of the base drive transformer becoming saturated.
Claim 7
Dependent Claim
156 words
5: A method for the regulation of the light level of a discharge lamp by means of an electronic ballast controlling the current of the discharge lamp, comprising a high frequency oscillator made up of two transistors (1, 2) connected in series, a base drive transformer (3) connected in between, an inductor (7) connected in series with the primary winding (4) of the transformer, and in the latter circuit, a capacitor (10, 11) between the lamp (8) and the current supply, characterized in that in the series resonance circuit of the primary winding (4) of the base drive transformer, the inductor (7), and the capacitor (10, 11), the current of the transistor switches (1, 2) is controlled by short-circuiting the secondary winding (17) of the base drive transformer (3) at one half-period, at which the current is turning off at the other half-period on account of the core (16) of the base drive transformer becoming saturated.
Claim 8
Dependent Claim
130 words
Electronic ballast for a discharge lamp for the restriction and control of the current by the method according to patent claim 5, comprising a high frequency oscillator made up of two transistors (1, 2) coupled in series, a base drive transformer (3) connected in between, an inductor (7) connected in series with the primary winding (4) of the transformer, and in the latter circuit, a capacitor (10, 11) between the lamp (8) and the current supply, characterized in that an electronic switch (19) is coupled between the terminals of the secondary winding (17) of the base drive transformer (3), while a control circuit (20, 22) being connected to the control electrode of said switch (19) to bring it to the state of conduction at every other half-period in desired phase.
Claim 9
Dependent Claim
180 words
7: A method for the regulation of the light level of a discharge lamp by means of an electronic ballast controlling the current of the discharge lamp, comprising a high frequency oscillator made up of two transistors (1, 2) connected in series, base drive transformers (3a, 3b) connected in between an inductor (7) connected in series with the primary windings (4a, 4b) of the transformers, and in the latter circuit, a capacitor (10, 11) between the lamp (8) and the current supply, characterized in that in the series resonance circuit of the primary windings (4a, 4b) of the base drive transformers, the inductor (7), and the capacitors (10, 11), the current of one transistor switch (1) is controlled by short-circuiting the secondary winding (17) of the base drive transformer (3a) at every other half-period, when the corresponding transistor switch has been on a desired length of time, and that the base drive transformer (3b) of the other transistor switch (2) discharges a resonance impulse through the respective transistor switch (2) to oscillate in accordance with normal operation until the end.
Claim 10
Dependent Claim
180 words
7: A method for the regulation of the light level of a discharge lamp by means of an electronic ballast controlling the current of the discharge lamp, comprising a high frequency oscillator made up of two transistors (1, 2) connected in series, base drive transformers (3a, 3b) connected in between an inductor (7) connected in series with the primary windings (4a, 4b) of the transformers, and in the latter circuit, a capacitor (10, 11) between the lamp (8) and the current supply, characterized in that in the series resonance circuit of the primary windings (4a, 4b) of the base drive transformers, the inductor (7), and the capacitors (10, 11), the current of one transistor switch (1) is controlled by short-circuiting the secondary winding (17) of the base drive transformer (3a) at every other half-period, when the corresponding transistor switch has been on a desired length of time, and that the base drive transformer (3b) of the other transistor switch (2) discharges a resonance impulse through the respective transistor switch (2) to oscillate in accordance with normal operation until the end.
Claim 11
Dependent Claim
128 words
Electronic ballast for a discharge lamp for the restriction and control of the current by the method according to patent claim 7, said ballast comprising a high frequency oscillator made up of two transistors (1, 2), base drive transformers (3a, 3b) connected in between, an inductor (7) coupled in series with the primary windings (4a, 4b) of the transformers, and in latter circuit, a capacitor (10, 11) between the lamp (8) and the current supply, characterized in that an electronic switch (19) is connected between the terminals of the secondary winding (17) of one base drive transformer (3a), while a control circuit (20, 22) being connected to the control electrode of said switch (19) to bring it the state of conduction at every other half-period in desired phase.
Claim 12
Dependent Claim
43 words
Electronic ballast according to patent claims 6 and 8, characterized in that the said electronic switch is a tyristor (19), and the said control circuit is a potentiometer (20), connected to the grid of the tyristor by way of the unijunction transistor (22).
Claim 13
Dependent Claim
53 words
Filtering inductor of an electronic ballast for a gas discharge lamp, said inductor being connected between the high frequency oscillator (O) to form a line current filtering circuit together with the filter capacitor (C), characterized in that the inductor is made up of two separate inductor circuits (25), connected to different line wires.
Claim 14
Dependent Claim
53 words
Filtering inductor of an electronic ballast for a gas discharge lamp, said inductor being connected between the high frequency oscillator (O) to form a line current filtering circuit together with the filter capacitor (C), characterized in that the inductor is made up of two separate inductor circuits (25), connected to different line wires.
References Cited (Backward Citations)
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