Discharge-lamp lighting apparatus
First Claim
Patent Images
1. A discharge-lamp lighting apparatus comprising:
- a first series circuit connected to each end of a DC power source and including a high-side first p-type FET and a low-side first n-type FET that are connected in series;
a second series circuit connected to each end of the DC power source and including a high-side second p-type FET and a low-side second n-type FET that are connected in series;
a transformer having a primary winding and a secondary winding, a series circuit of the primary winding and a capacitor being connected between a connection point of the first p- and n-type FETs and a connection point of the second p- and n-type FETs, and the secondary winding being connected to a discharge lamp;
a control circuit configured to alternately turn on/off the first p-type FET and second n-type FET and the first n-type FET and second p-type FET by providing the FETs with control signals according to a lamp current passed through the discharge lamp; and
a first drive circuit configured to drive the first p-type FET and a second drive circuit configured to drive the second p-type FET, each of the first and second drive circuits including;
a first switch element configured to discharge a gate-source capacitance of the corresponding p-type FET as being turned on and thereby turn off the p-type FET;
a resistance element having one end connected to the DC power source, configured to determine the potential of a control terminal of the first switch element as the first switch element is turned on;
a second switch element configured to charge the gate-source capacitance of the corresponding p-type FET as being turned on and thereby turn on said corresponding p-type FET;
a constant current circuit connected in series with the resistance element; and
a switch connected in series with the series circuit of the constant current circuit and resistance element, configured to turn on/off the constant current circuit under the control of the control circuit.
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Abstract
A discharge-lamp lighting apparatus includes series circuits connected to each end of a DC power source, a transformer, FETs Qp1, Qn1, Qp2, and Qn2, and a drive circuit. The drive circuit includes transistors Q1 and Q3 to discharge gate-source capacitances of the Qp1 and Qp2, resistance elements to determine gate potentials of the transistors Q1 and Q3 when the transistors Q1 and Q3 are turned on, transistors Q2 and Q4 to charge the gate-source capacitances of the Qp1 and Qp2, constant current circuits, and switches connected in series with the series circuits of the constant current circuits and resistance elements, respectively, to turn on/off the constant current circuits.
6 Citations
4 Claims
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1. A discharge-lamp lighting apparatus comprising:
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a first series circuit connected to each end of a DC power source and including a high-side first p-type FET and a low-side first n-type FET that are connected in series; a second series circuit connected to each end of the DC power source and including a high-side second p-type FET and a low-side second n-type FET that are connected in series; a transformer having a primary winding and a secondary winding, a series circuit of the primary winding and a capacitor being connected between a connection point of the first p- and n-type FETs and a connection point of the second p- and n-type FETs, and the secondary winding being connected to a discharge lamp; a control circuit configured to alternately turn on/off the first p-type FET and second n-type FET and the first n-type FET and second p-type FET by providing the FETs with control signals according to a lamp current passed through the discharge lamp; and a first drive circuit configured to drive the first p-type FET and a second drive circuit configured to drive the second p-type FET, each of the first and second drive circuits including; a first switch element configured to discharge a gate-source capacitance of the corresponding p-type FET as being turned on and thereby turn off the p-type FET; a resistance element having one end connected to the DC power source, configured to determine the potential of a control terminal of the first switch element as the first switch element is turned on; a second switch element configured to charge the gate-source capacitance of the corresponding p-type FET as being turned on and thereby turn on said corresponding p-type FET; a constant current circuit connected in series with the resistance element; and a switch connected in series with the series circuit of the constant current circuit and resistance element, configured to turn on/off the constant current circuit under the control of the control circuit. - View Dependent Claims (2)
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3. A discharge-lamp lighting apparatus comprising:
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a first series circuit connected to each end of a DC power source (Vin) and including a high-side p-type FET and a low-side n-type FET that are connected in series; a transformer having a primary winding and a secondary winding, the primary winding being connected to a connection point of the p- and n-type FETs and to a connection point that is connected through a capacitor to at least one end of the DC power source, and the secondary winding being connected to a discharge lamp; a control circuit configured to alternately turn on/off the p- and n-type FETs according to a lamp current passed through the discharge lamp; and a drive circuit configured to drive the p-type FET, the drive circuit including; a first switch element configured to, when turned on, discharge a gate-source capacitance of the p-type FET and thereby turn off said p-type FET; a resistance element having one end connected to the DC power source, configured to determine the potential of a control terminal of the first switch element when the first switch element is turned on; a second switch element configured to charge the gate-source capacitance of the p-type FET as being turned on and thereby turn on said p-type FET; a constant current circuit connected in series with the resistance element; and a switch connected in series with the series circuit of the constant current circuit and resistance element, configured to turn on/off the constant current circuit under the control of the control circuit. - View Dependent Claims (4)
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Specification