The TLC555 device is used to generate the PWM for the open-loop flyback power supply. The TLC555 is a monolithic timing circuit fabricated using the TI LinCMOS™ technology. The timer is fully compatible with CMOS, TTL, and MOS logic and operates at frequencies up to 2 MHz. Because of its high-input impedance, this device supports smaller timing capacitors than those supported by the NE555 or LM555. As a result, more accurate time delays and oscillations are possible. Power consumption is low across the full range of power-supply voltage.