International Rectifier (IR) introduced the IR1150 family of µPFC for AC-DC power-factor-correction (PFC) circuits. The company says that the SO-8 packaged device will cut PFC control board space in half while enabling a flexible high-density solution for computing, consumer electronics, and home appliances from 75W to 4kW.

IR's One Cycle Control (OCC) approach in the IR1150 delivers the performance of continuous-conduction-mode (CCM) PFC with the low component count of a discontinuous-current-mode (DCM) circuit for PFC applications.

Power factor (PF) is the relationship between AC voltage and current waveforms, and is a measure of "power quality" that affects the efficiency of electrical transmission networks. With unity PF as the ultimate goal, the IR1150 enables 0.999 PF with only 4% total harmonic distortion, enabling AC-DC applications to conform to international legislative requirements, says the company. The One Cycle Control method used in the IR1150 controller does not have an analog multiplier, input voltage sensing, or fixed oscillator ramp. Instead, IR's OCC uses a proprietary integrator with a reset circuit: The output of the error amplifier is integrated over each clock cycle to generate a variable-slope ramp. This variable ramp is compared with the error voltage and subtracted from the current-sense signal to generate the PWM gate drive. The IR1150 provides a solution to PFC legislation, such as IEC 1000-3-2 in Europe, JIC C 61000-3-2 in Japan, and the China Compulsory Certificate (CCC) for products using more than 75W.