Discharge-lamp lighting apparatus

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.