Discharge lamp lighting circuit
First Claim
Patent Images
1. A discharge lamp lighting circuit comprising:
- a direct current-alternating current converting circuit for receiving a direct current input voltage and converting the direct current input voltage to an alternating current voltage,a starting circuit for supplying a starting signal to a discharge lamp, andcontrolling means for controlling a power provided by the direct current-alternating current converting circuit;
wherein the direct current-alternating current converting circuit comprises switching elements driven by the controlling means and a series resonating circuit including a capacitor and at least one of an inductance element or a transformer, the direct current-alternating current converting circuit further including;
a frequency modulating circuit for restraining an acoustic resonance by modulating a frequency of driving the switching elements; and
a limiter circuit for preventing the frequency of driving the switching elements from exceeding an upper limit frequency capable of maintaining a state of lighting the discharge lamp (Fmax).
1 Assignment
0 Petitions
Accused Products
Abstract
A discharge lamp lighting circuit 1 includes a direct current-alternating current converting circuit 3, a starting circuit 4, controlling means 15 for controlling power, switching elements 5H, 5L driven by the controlling means 15 and a series LC resonance circuit (7p, 8, 9). A frequency modulating circuit is provided for restraining acoustic resonance by modulating a frequency of driving the switching element. When a basic frequency related to the drive frequency is equal to or higher than 1 MHz, a modulation width is set to be equal to or higher than 20 kHz.
-
Citations
11 Claims
-
1. A discharge lamp lighting circuit comprising:
-
a direct current-alternating current converting circuit for receiving a direct current input voltage and converting the direct current input voltage to an alternating current voltage, a starting circuit for supplying a starting signal to a discharge lamp, and controlling means for controlling a power provided by the direct current-alternating current converting circuit; wherein the direct current-alternating current converting circuit comprises switching elements driven by the controlling means and a series resonating circuit including a capacitor and at least one of an inductance element or a transformer, the direct current-alternating current converting circuit further including; a frequency modulating circuit for restraining an acoustic resonance by modulating a frequency of driving the switching elements; and a limiter circuit for preventing the frequency of driving the switching elements from exceeding an upper limit frequency capable of maintaining a state of lighting the discharge lamp (Fmax). - View Dependent Claims (2, 3, 4, 5)
-
-
6. A discharge lamp lighting circuit comprising:
-
a direct current-alternating current converting circuit for receiving a direct current input voltage and converting the direct current input voltage to an alternating current voltage, a starting circuit for supplying a starting signal to a discharge lamp, and controlling means for controlling a power provided by the direct current-alternating current converting circuit; wherein the direct current-alternating current converting circuit comprises switching elements driven by the controlling means and a series resonating circuit including a capacitor and at least one of an inductance element or a transformer, the direct current-alternating current converting circuit further including; a frequency modulating circuit for restraining an acoustic resonance by modulating a frequency of driving the switching elements; wherein the controlling means includes a voltage-frequency converting portion for outputting a signal of a frequency changed in accordance with an input voltage; and
the controlling means is configured so that the output signal of the voltage-frequency converting portion is subjected to a frequency modulation by an output signal of the frequency modulating circuit, and a drive signal generated based on the frequency-modulated output signal of the voltage-frequency converting portion is supplied to the switching elements. - View Dependent Claims (7, 8)
-
-
9. A discharge lamp lighting circuit comprising:
-
a direct current-alternating current converting circuit for receiving a direct current input voltage and converting the direct current input voltage to an alternating current voltage, a starting circuit for supplying a starting signal to a discharge lamp, and controlling means for controlling a power provided by the direct current-alternating current converting circuit; wherein the direct current-alternating current converting circuit comprises switching elements driven by the controlling means and a series resonating circuit including a capacitor and at least one of an inductance element or a transformer, the direct current-alternating current converting circuit further including; a frequency modulating circuit for restraining an acoustic resonance by modulating a frequency of driving the switching elements; wherein the controlling means includes a voltage-frequency converting portion for outputting a signal of a frequency changed in accordance with an input voltage; and
the controlling means is configured so that the input voltage modulated by an output signal of the frequency modulating circuit is supplied to the voltage-frequency converting portion, and a drive signal generated based on the output signal of the voltage-frequency converting portion is supplied to the switching elements. - View Dependent Claims (10, 11)
-
Specification