The µPFC family of controller ICs radically alters traditional thinking about PFC solutions. The IR1150 uses a new, patented "One-Cycle Control, integrator with reset" technique to deliver the high performance of Continuous Conduction Mode (CCM) PFC with the simplicity and low component count of Discontinuous Current Mode (DCM).
OCC does not have the traditional analog multiplier, AC line sensing or fixed oscillator ramp. In OCC 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 responds to changes in output voltage in just “one cycle” of the internal clock giving excellent response.
High Power (>200W) Systems
High power applications (>200W) need CCM PFC to have high efficiency and small system sizes. However, traditional CCM multiplier-based solutions are complex, require many design stages and have a high component count, making CCM solutions very expensive.
In a typical 1kW SMPS, the new OCC solution has 40% fewer resistors and capacitors, removes a current transformer and has a 50% smaller PCB area for the PFC control section. In addition, the IR1150 has a dedicated Over Voltage Protection (OVP) pin to give greater protection for high power systems.
Low Power (<250W) Systems
Lower power applications (<250W) traditionally use DCM systems for simplicity and low system cost. However, as system power increases to 100W and above – e.g. for high end laptop or LCD TV adaptors - DCM systems are large due to high peak currents and EMI filter requirements. OCC operates in CCM mode with reduced peak currents and a 43% reduction in EMI filter needs. This translates into a 16% reduction in PCB and an increase in power density of 10% for a typical 120W laptop adaptor.
Governmental & Energy Standards Compliance
The IR1150 includes features such as enable, micro-power start-up and “sleep mode” for compliance with energy efficiency standards such as “1W Standby”, Blue Angel and Energy Star.
IR’s OCC method used in the IR1150 is an attractive solution to PFC (THD) legislation such as IEC 1000-3-2 in Europe, JIS C 61000-3-2 in Japan and the China Compulsory Certificate (CCC) for products using more than 75W. PFC is not yet a requirement in the US, however, specifications are being prepared by the IEEE.
Even without the need to meet governmental legislation, PFC solutions using the IR1150 OCC IC offer two more advantages; a) designers can create one design with universal AC input for worldwide use which streamlines manufacturing, inventory and logistics, and b) PFC eliminates AC-line harmonics, reducing the rms current and so allows higher power motors or pumps to be used without tripping domestic circuit breakers.
DESIGN SUPPORT TOOLS:
PFC Design Software
THE IR ADVANTAGE
|Small, easy, powerful solution|
|Enables high power density|
|Fast time to market|
|Enables compliance with PFC (THD) regulations for Japan, Europe, and China|
|Enables compliance with energy standards (1W, Blue Angel, Energy Star)|
|No AC line voltage sense required|
|0.999 power factor|
|Programmable, fixed switching frequency, 50kHz to 200kHz|
|Fast, powerful 1.5A peak gate drive|
|Peak current mode control|
|Dedicated OVP with soft start, brownout and output undervoltage protection|
|Cycle by cycle peak current limit system protection|
|For high power systems (>200W)|
- 40% fewer resistors and capacitors
- Eliminates a current transformer
- 50% smaller PCB area for the PFC control section
|For lower power systems (<250W)|
- Reduced peak currents
- 40% reduction in EMI filter cost
- >16% smaller PCB
- >10% higher power density
|AC-DC smps >75W
- Server SMPS & Telecom Rectifier
- Notebook computers, LCD TVs, mini-PC power adapters
- Plasma TVs, CRT monitors
- High-end Set Top Boxes / PVRs, home theatre systems
- Office machines such as photocopiers and printers
- PC silver box power supplies
|Motor Drive / Pumps >75W
- Washing machines, dish washers
- Air conditioners
- Pools, spas, well pumps