September 11, 2009

Sanken Develops STR-Y6700 Series of Quasi-Resonant Power Supply ICs
Realizing the world's Lowest Power Consumption,30mW (100VAC), 50mW (230VAC) or less, for Standby Power Saving in LCD TVs.

Sanken Electric Co., Ltd. has developed the STR-Y6700 Series of quasi-resonant power supply ICs for switching power supplies that realize the world's lowest power consumption*; 30mW or less (100VAC), 50mW or less (230VAC), for the standby power saving in LCD TVs. The ICs are encapsulated in a TO-220F package. In the lineup, totally 10 types are provided according to input voltage and output power. Sample shipment has just started with the price range of 700 to 1,200 yen/unit. Mass production shipment is planned to start with 200,000 units a month in November and ramp up to 1 million units a month in the first half of 2010.
* As of August 2009, based on Sanken survey on quasi-resonant mode ICs for 100 W class power supplies.
   
1. Development Background and Product Overview
  The energy saving for digital consumer electronics products and home appliances (white goods) is strongly required not only in normal operation but also in standby.

Power saving is progressing steadily, in the LCD TV applications, where 32-inch models with power consumption around 100 W are being released. In addition, the more standby power saving in the applications is required. However, for the conventional power supply ICs, the standby power reduction is difficult, and the additional power supply only for standby power is generally needed besides the main power supply.

For the above requirement, Sanken has developed the STR-Y6700 Series of quasi-resonant power supply ICs.
The ICs enable to eliminate a dedicated standby power supply, because the input power at no load achieves 30mW or less for 100VAC input and 50mW or less for 230VAC (about one third compared with conventional quasi-resonant ICs of Sanken product), the world's lowest level, by selecting IC functions for main power supply considering the market requirements, and reducing internal circuit current with reviewing internal circuit resulted in circuit elimination.

To improve the efficiency of power with the quasi-resonant, the switching mode is changed to the bottom-skip mode according to load conditions in case an IC has this function, but the phenomenon that the switching change may cause the audible noise from transformer has been a disadvantage.

For solving it, the STR-Y6700 adopts Sanken proprietary circuit to reduce the audible noise.

In addition to various protection functions, such as Overcurrent Protection, Overload Protection, Overvoltage Protection, Thermal Shutdown Protection, and Short Circuit Protection between both windings of transformer, the STR-Y6700 Series also incorporate Bias Assist Function. This function stabilizes the standby mode operation even when the input voltage drops lower, contributing to the enhanced power supply system reliabilities.
 
2. Applications
 
Switching power supplies for:
(1) AV equipment, digital consumer electronics products, such as LCD TVs, Blu-ray recorders/players, DVD recorders/players, audio equipment, etc.
(2) Home appliances (white goods), such as auxiliary power supplies of air conditioners (indoor & outdoor units), refrigerators, and laundry machines, power supplies of toilet seats with warm water bidet, etc.
   
3. Features
 
(1) World's lowest power consumption (*) for standby power
Input power at no load; 30mW or less for 100VAC, 50mW or less for 230VAC
* As of August 2009, based on Sanken survey on quasi-resonant mode ICs for 100 W class power supplies.
(2) Quasi-resonant mode
It enables low noise and high efficiency.
(3) Built-in bottom-skip mode
It reduces the switching loss and enables high efficiency under medium to light load range.
(4) Automatic standby mode
It automatically switches the operation mode to the standby mode according to load conditions, eliminating dedicated external elements usually needed.
(5) Reduction of audible noise from transformer
(6) arious protection functions
Overcurrent Protection, Overload Protection, Overvoltage Protection, Thermal Shutdown Protection, Short Circuit Protection between both windings of transformer, Bias Assist Function
   
4.  Lineup
 
Product No. Sample
Price
(Yen)
MOSFET Output Power (W)
VDSS(MIN)
(V)
RDS(ON)
(MAX)
(Ω)
Input Voltage
100VAC
Input Voltage
230VAC
Input Voltage
85 to 264VAC
nput Voltage
380VDC
STR-Y6734 800 500 1.3 60 - - -
STR-Y6735 900 0.8 120 - - -
STR-Y6752 700 650 2.8 - 70 50 80
STR-Y6753 800 1.9 - 90 60 100
STR-Y6754 900 1.4 - 100 67 120
STR-Y6755 1,000 1.1 - 110 75 135
STR-Y6756 1,200 0.6 - 130 100 150
STR-Y6763 800 800 3.5 - 60 50 80
STR-Y6765 900 2.1 - 100 70 120
STR-Y6766 1,000 1.7 - 120 80 140
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