June 4, 2008

Development of SSC2001 Control IC
for PFC Circuits Mounted in Flat-Screen TVs

Sanken Electric Co., Ltd. today announced the successful development of the SSC2001, a control IC for the PFC (power factor correction) circuits mounted in AV devices such as flat-screen televisions. Sample shipments of the new IC will commence in mid-July at a pre-tax price of 300 yen per unit. Mass production is scheduled to start in November this year, on an initial scale of 100,000 units per month, to be ramped up to 500,000 units per month by the end of 2009.
   
1. Development history and product overview
  The implementation of the U.S. Energy Star Program (*) and other regulations controlling the energy consumption of products has driven up demand for products that can deliver a better power performance in terms of power efficiency and energy savings.
At the same time, efforts to comply with international harmonic current regulations have led to increased use of PFC circuits in electronic devices worldwide, such as flat-screen TVs and personal computers, to suppress harmonic current and reduce reactive power.
While suppressing the harmonic current, however, PFC circuits themselves tend to consume a lot of power, which raises the overall power consumption of the electronic devices in which they are mounted. For this reason, chip manufacturers are now being asked to improve the power efficiency of their PFC circuits.
There are two types of PFC circuit: a high-noise, low-loss continuous current CCM type; and a low-noise, high-loss critical current DCM type. In general, applications with a power specification of 250 W or higher use a CCM type PFC circuit, and those with a power specification of lower than 250 W use a DCM type.

The SSC2001 recently developed by Sanken is a power IC for the high-power CCM-type PFC circuits used in today’s popular large, flat-screen televisions.
By changing the IC control method from voltage detection to current detection, Sanken has eliminated the conventional voltage detection resistors, streamlining the circuit design. The power dissipation characteristics have also been improved to enable a power efficiency of close to 97% (in the case of 230 VAC input, 200 W output).
Two package types—through hole and surface mount—are also provided, facilitating printed circuit board design.
The SSC2001 also features an extensive range of protection functions, including output overvoltage protection, overcurrent protection, output open detection, and, newly added this time, a Brown-in/Brown-out protection function that stops circuit operation upon the detection of a drop in input voltage.

(*) Energy Star: An energy-saving program promoted by the Environmental Protection Agency in the United States. The program covers a wide range of electronic devices, from household appliances to industrial machines and computers.
 
2. Features
 
(1) The SSC2001 uses an average current control method, eliminating the voltage waveform detector on the input AC line. This has led to circuit streamlining (reduction in components) and a higher power efficiency (lower power consumption) of close to 97% (in the case of 230 VAC input, 200 W output).
(2) Maximum duty cycle of 97% (typ.) enables wide-range control.
(3) Oscillation frequency: 65 kHz (internally fixed)
(4)

A frequency jitter (3 to 6 kHz) function is used to reduce EMI noise and enable a simplified EMI protection filter.

(5) Built-in protection functions:
  • Overcurrent protection
  • UVLO (operation stops when Vcc drops)
  • High-speed overvoltage protection
  • Output open detection
  • Brown-in/Brown-out protection
  • (6) High-speed response function ideal for devices with large load variations.
    (7) Small package (through-hole and surface mount types available)
  • Through-hole type: DIP8 (case dimensions: 9.4 mm × 6.5 mm × 3.4 mm)
  • Surface-mount type: SOP8 (case dimensions: 5.1 mm × 4.2 mm × 1.5 mm)
  •    
    3. Applications
     
  • LCD-TVs, PDP-TVs, personal computers, servers, monitors, and more
  •    
    4. Specifications
     
    Parameter Symbol Rating Unit
    Power Supply Voltage Vcc 30 max V
    Switching Frequency fsw 65 kHz
    Jittering Frequency ΔFsw 3 to 6 kHz
    Feedback Detection Voltage VFB 3.5 V
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