Abstract: An integrated circuit with both ballast control and driver circuitry and power factor correction (PFC) control circuitry. At the beginning of preheating, power is provided to the load circuit at a voltage below a voltage at which the lamp can ignite, and the PFC control circuitry can then bring the DC bus voltage up to its running value. For this purpose, the PFC circuitry is enabled depending on the mode of the ballast control and driver circuitry. The DC bus voltage is regulated at a lower loop speed when the lamp is running than when the lamp is ramping to ignition, to alleviate DC bus droop. A criterion is applied to determine whether over-current detect signals indicate an actual fault. For this purpose, detect signals during ignition ramping can be counted and compared with a fault number. A lamp end-of-life condition can be detected by comparing sensed voltage with upper and lower window voltages. When a lamp is off for only a short time, it can be quickly restarted without full preheating.

Abstract: An integrated circuit with both ballast control and driver circuitry and power factor correction (PFC) control circuitry. At the beginning of preheating, power is provided to the load circuit at a voltage below a voltage at which the lamp can ignite, and the PFC control circuitry can then bring the DC bus voltage up to its running value. For this purpose, the PFC circuitry is enabled depending on the mode of the ballast control and driver circuitry. The DC bus voltage is regulated at a lower loop speed when the lamp is running than when the lamp is ramping to ignition, to alleviate DC bus droop. A criterion is applied to determine whether over-current detect signals indicate an actual fault. For this purpose, detect signals during ignition ramping can be counted and compared with a fault number. A lamp end-of-life condition can be detected by comparing sensed voltage with upper and lower window voltages. When a lamp is off for only a short time, it can be quickly restarted without full preheating.

Abstract: A power factor control circuit for an AC to DC power converter includes an inductor receiving AC rectified power. The charging time of the inductor is controlled by a switching circuit based on a comparison between a DC bus voltage and a fixed reference voltage. The circuit operates without an AC rectified line sensing network, and without a current-sensing resistor connected to the source of the MOSFET switch.

Abstract: A ballast controller integrated circuit which executes a specific set of instructions via an integrated state diagram architecture to control the fluorescent lamp and protect the ballast. The state diagram architecture controls powering up and down of the IC and the half-bridge circuit driven by the IC, preheating and striking of the lamp, running of the lamp, sensing for numerous possible fault conditions, and recovering from these fault conditions based on the normal maintenance of a lamp.

Abstract: A power factor control circuit for an AC to DC power converter includes an inductor receiving AC rectified power. The charging time of the inductor is controlled by a switching circuit based on a comparison between a DC bus voltage and a fixed reference voltage. The circuit operates without an AC rectified line sensing network, and without a current-sensing resistor connected to the source of the MOSFET switch.