as v c decreases the operating frequency of the vco undergoes a corresponding decrease as shown in fig8 coupled to the vco 46 is a parallel grounded arrangement of resistor 48 and capacitor 50 which establishes the operating frequency range of the vco thus a pulsed output having a given frequency is provided from the vco 46 to the t input pin of a toggle type flip flop 52 the q and q outputs from the toggle type flip flop 52 are alternately rendered active in response to the pulsed timed output from the vco 46 with a high q enable output from r s flip flop 34 provided to and gates 40 and 42 a high q output from flip flop 52 will result in a high output from and gate 40 to one power switch mosfet within the inverter bridge 17 similarly a high q output from flip flop 52 will cause and gate 42 to provide a high output to the other power switch in this manner and gates 40 and 42 alternately provide drive signals to the power switches for controlling the operation of the inverter bridge 17 and initiating start up and controlling the steady state operation of the fluorescent lamp the start pulse generator circuit 27 is coupled to line 23 by means of which the ev l 39 voltage is provided to or gate 30 within the error amplifier 101 the start pulse generator circuit 27 operates in the following manner to provide a high voltage.