| 摘要 |
PURPOSE:To ensure the high degree of freedom in the arrangement and design of each element, and allow brightness adjustment and temperature correction with a simple circuit configuration. CONSTITUTION:This device is equipped with a stepup transformer 25 having one end of primary winding applied with source voltage Vcc and both ends of secondary winding connected to both electrodes of a flat fluorescent tube 26 as a drive object, a differentiating circuit 21 having a fixed time constant for differentiating a reference pulse (d) reversible at every constant time, and a resistance dividing circuit 23 for dividing DC voltage Vcc through resistance division. Furthermore, the device is equipped with a comparator 22 for outputting a switching pulse (f) by making a comparison between output (e) from the circuit 21 and output (g) from the circuit 23, and a field effect transistor 24 as a switching element connected to the other end of the primary winding of the transformer 25, and intermittently applying the source voltage Vcc to the primary winding of the tube 26 in reaction to the switching pulse (f) from the comparator 22. |
