Fairchild Semiconductor introduces critical conduction mode (CRM) power factor correction (PFC) controller ICs specially designed to meet stringent stand-by power and harmonic regulations affecting ballast, notebook adaptors, LCD TVs and LCD monitors. The FAN7529 and FAN7530 utilize a variable on-time control method to achieve industry-leading Total Harmonic Distortion (THD) performance (<10 percent at 25 percent load, 265Vac). They also meet stand-by power regulations by reducing input-voltage sensing loss to approximately 100 milliwatts. These integrated PFC controllers utilize an internal voltage-mode PWM method compared with conventional current-mode controllers requiring rectified AC-line voltage information even when the PFC IC does not operate. As a result, the controllers reduce overall power loss by approximately 200 milliwatts.
Moreover, the controllers offer a disable function to further reduce power consumption during stand-by mode, and their current-type error amplifiers enable these devices to use a higher Rfb (output-voltage-sensing resistor) over 1 megaohm, resulting in reduced power loss (80 milliwatts, 2 megaohms). To increase system reliability, the devices feature open-feedback protection and a disable function (65 microamps), making Vcc shut-down circuitry unnecessary. They also offer adjustable-output over-voltage protection (OVP) of plus/minus 2 percent. This type of voltage-sensing OVP is immune to noise. The devices also offer a 150 microsecond internal start-up timer, MOSFET over-current protection and under-voltage lockout with 3.5V hysteresis. Fairchild also offers the FAN7528, a dual-output CRM PFC controller IC. The FAN7529 and FAN7530 are offered separately as pin-out options for meeting specific requirements and design preferences.
Both are available in DIP-8 and SOP-8 packages. These lead-free products meet or exceed the requirements of the joint IPC/JEDEC standard J-STD-020C and are compliant with the European Union requirements which are now in effect. Samples and demo board available now.
