US5705898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lighting circuit for discharge lamp which restricts inversion of output voltage polarity
Assignee: Koito Manufacturing Co Ltd
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Filing: 1996-05-13
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Granted: 1998-01-06
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Expires: 2016-05-13
Abstract
Abstract In a lighting circuit, a battery voltage is supplied via a DC booster circuit to a DC-AC converter where the voltage is converted to an AC voltage with a rectangular waveform. This AC voltage is supplied to a discharge lamp. At this time, the DC-AC converter controls the frequency of the rectangular wave output from the DC-AC converter in accordance with a signal sent to a bridge type driver from a frequency controller. A lighting detector is provided to detect if the discharge lamp has been lighted. Upon reception of a signal from the lighting detector, the frequency controller sets the frequency of the output voltage of the DC-AC converter in the pre-lighting period of the discharge lamp higher than the frequency of the output voltage of the DC-AC converter after the lighting of the discharge lamp and restricts the inversion of the polarity of the output voltage of the DC-AC converter until a predetermined time passes sfrom the point of the activation of the discharge lamp.
Inventors
- 👤 Masayasu Yamashita
- 👤 Atsushi Toda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:03
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/26; H05B41/28; H05B41/288; H05B41/2885; H05B41/2887; H05B41/2888; H05B41/2881; H05B41/2882; H05B41/2883; H05B41/36; H05B41/38; H05B41/382; H05B41/388; H05B41/39; H05B41/392; H05B41/3921; H05B41/3922; Y; Y02; Y02B; Y02B20/00; Y10; Y10S; Y10S315/00; Y10S315/05; Y10S315/07
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
130 words
A lighting circuit for a discharge lamp having DC-AC converting means for converting a DC voltage to an AC voltage which is to be supplied to said discharge lamp via an inductive load, said lighting circuit comprising: lighting detection means for detecting if said discharge lamp is lighted; and frequency control means for, upon reception of a signal from said lighting detector, setting a frequency of an output voltage of said DC-AC converting means after activation of said discharge lamp higher than a frequency of said output voltage of said DC-AC converting means in a non-lighting period of said discharge lamp, and restricting inversion of a polarity of said output voltage of said DC-AC converting means until a predetermined time passes after a point of activation of said discharge lamp.
Claim 2
Dependent Claim
130 words
A lighting circuit for a discharge lamp having DC-AC converting means for converting a DC voltage to an AC voltage which is to be supplied to said discharge lamp via an inductive load, said lighting circuit comprising: lighting detection means for detecting if said discharge lamp is lighted; and frequency control means for, upon reception of a signal from said lighting detector, setting a frequency of an output voltage of said DC-AC converting means after activation of said discharge lamp higher than a frequency of said output voltage of said DC-AC converting means in a non-lighting period of said discharge lamp, and restricting inversion of a polarity of said output voltage of said DC-AC converting means until a predetermined time passes after a point of activation of said discharge lamp.
Claim 3
Dependent Claim
57 words
The lighting circuit according to claim 1, wherein said frequency control means executes polarity inversion at a lower frequency than said frequency of said output voltage of said DC-AC converting means in said non-lighting period of said discharge lamp during a period from a point of activation of said discharge lamp to passage of said predetermined time.
Claim 4
Dependent Claim
65 words
The lighting circuit according to claim 1, wherein said frequency control means generates different control signals in a first period in which said discharge lamp is lighted from beginning of activation of said discharge lamp, a second period from a point of lighting of said discharge lamp to a point of passage of a predetermined time and a third period subsequent to said second period.
Claim 5
Dependent Claim
65 words
The lighting circuit according to claim 2, wherein said frequency control means generates different control signals in a first period in which said discharge lamp is lighted from beginning of activation of said discharge lamp, a second period from a point of lighting of said discharge lamp to a point of passage of a predetermined time and a third period subsequent to said second period.
Claim 6
Dependent Claim
51 words
The lighting circuit according to claim 3, wherein said frequency control means generates a rectangular-wave signal with a low frequency in said first period, then generates a DC signal with a predetermined polarity in said second period, and generates and a rectangular-wave signal with a high frequency in said third period.
Claim 7
Dependent Claim
51 words
The lighting circuit according to claim 4, wherein said frequency control means generates a rectangular-wave signal with a low frequency in said first period, then generates a DC signal with a predetermined polarity in said second period, and generates and a rectangular-wave signal with a high frequency in said third period.
Claim 8
Dependent Claim
36 words
The lighting circuit according to claim 1, wherein said frequency control means comprises an oscillator for generating a clock signal with a basic frequency, and a frequency divider for frequency-dividing said clock signal from said oscillator.
Claim 9
Dependent Claim
36 words
The lighting circuit according to claim 2, wherein said frequency control means comprises an oscillator for generating a clock signal with a basic frequency, and a frequency divider for frequency-dividing said clock signal from said oscillator.
Claim 10
Dependent Claim
36 words
The lighting circuit according to claim 3, wherein said frequency control means comprises an oscillator for generating a clock signal with a basic frequency, and a frequency divider for frequency-dividing said clock signal from said oscillator.
Claim 11
Dependent Claim
36 words
The lighting circuit according to claim 4, wherein said frequency control means comprises an oscillator for generating a clock signal with a basic frequency, and a frequency divider for frequency-dividing said clock signal from said oscillator.
Claim 12
Dependent Claim
17 words
The lighting circuit according to claim 7, wherein said oscillator has a structure of an astable multivibrator.
Claim 13
Dependent Claim
17 words
The lighting circuit according to claim 8, wherein said oscillator has a structure of an astable multivibrator.
Claim 14
Dependent Claim
17 words
The lighting circuit according to claim 9, wherein said oscillator has a structure of an astable multivibrator.
Claim 15
Dependent Claim
17 words
The lighting circuit according to claim 10, wherein said oscillator has a structure of an astable multivibrator.
Claim 16
Dependent Claim
24 words
The lighting circuit according to claim 7, wherein said frequency divider has a counter, two D type flip-flops and a plurality of logic gates.
Claim 17
Dependent Claim
24 words
The lighting circuit according to claim 8, wherein said frequency divider has a counter, two D type flip-flops and a plurality of logic gates.
Claim 18
Dependent Claim
24 words
The lighting circuit according to claim 9, wherein said frequency divider has a counter, two D type flip-flops and a plurality of logic gates.
Claim 19
Dependent Claim
24 words
The lighting circuit according to claim 10, wherein said frequency divider has a counter, two D type flip-flops and a plurality of logic gates.
Claim 20
Dependent Claim
36 words
The lighting circuit as set forth in claim 1 wherein said detection means comprises a photo sensor for directly detecting the lighting of said lamp and a circuit responsive to the output of said photo sensor.
Claim 21
Dependent Claim
137 words
A lighting circuit for a discharge lamp having DC-AC converting means for converting a DC voltage to an AC voltage which is to be supplied to said discharge lamp via an inductive load, said lighting circuit comprising: a lighting detector circuit for detecting whether said discharge lamp is lighted; and a frequency control circuit operative upon reception of a signal from said lighting detector to set a frequency of an output voltage of said DC-AC converting means after activation of said discharge lamp higher than a frequency of said output voltage of said DC-AC converting means in a non-lighting period of said discharge lamp, and causing inversion of a polarity of said output voltage of said DC-AC converting means a predetermined number of times during a predetermined period after a point of activation of said discharge lamp.
Claim 22
Dependent Claim
137 words
A lighting circuit for a discharge lamp having DC-AC converting means for converting a DC voltage to an AC voltage which is to be supplied to said discharge lamp via an inductive load, said lighting circuit comprising: a lighting detector circuit for detecting whether said discharge lamp is lighted; and a frequency control circuit operative upon reception of a signal from said lighting detector to set a frequency of an output voltage of said DC-AC converting means after activation of said discharge lamp higher than a frequency of said output voltage of said DC-AC converting means in a non-lighting period of said discharge lamp, and causing inversion of a polarity of said output voltage of said DC-AC converting means a predetermined number of times during a predetermined period after a point of activation of said discharge lamp.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-01-05 | 2001-07-07 | 2002-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-01-05 | 2005-07-07 | 2006-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-01-05 | 2009-07-07 | 2010-01-06 | $7700.00 | Window Closed / Lapsed |