Basic Info.
Product Description
General Description
SF1539HT is a high performance, high efficiency, highly integrated current mode PWM power switch for offline flyback converter applications.
In SF1539HT, PWM switching frequency with shuffling is fixed to 65KHz and is trimmed to tight range. When the output power demands decrease, he IC decreases switching frequency based on the proprietaryη -BalanceTM control to boost power conversion efficiency at the light load. When output power falls below a given value, the IC enters into burst mode and provides excellent efficiency without audio noise.
The IC can achieve "Zero OCP/OPP Recovery Gap" using SiFirst's proprietary control algorithm. Meanwhile, the OCP/OPP variation versus universal line input is compensated.
The IC has built-in synchronized slope compensation to prevent sub-harmonic oscillation at high PWM duty output. The IC also has built-in soft start function to soften the stress on the MOSFET during power on period.
SF1539HT integrates functions and protections of Under Voltage Lockout (UVLO), Over Temperature Protection (OTP), VCC Over Voltage Protection (OVP), Cycle-by-cycle Current Limiting (OCP), Pins Floating Protection, Over Load Protection (OLP), VCC Clamping, Leading Edge Blanking (LEB), etc.SF1539HT is available in DIP8 packages.
Features
Built-in 600V Power MOSFET
Over Temperature Protection (OTP)
Proprietary η -BalanceTM Control to Boost Light Load Efficiency
Proprietary "Zero OCP/OPP Recovery Gap Control
Fixed 65KHz Switching Frequency
Built-in Soft Start Function
Very Low Startup Current
Frequency Reduction and Burst Mode Control for Energy Saving
Current Mode Control
Built-in Frequency Shuffling
Built-in Synchronous Slope Compensation
Cycle-by-Cycle Current Limiting
Built-in Leading Edge Blanking (LEB)
Constant Power Limiting
Pins Floating Protection
Audio Noise Free Operation
VDD OVP & Clamp
VDD Under Voltage Lockout (UVLO)
Applications
Offline AC/DC Flyback Converter for
AC/DC Adaptors
Open-frame SMPS
Set-Top Box Power Supplies
ATX Standby Power
Typical Circuit
Why choose us?
* Specilaze in IC for around 14 years
* 100% Tested before sale
* Cooperate with over 35 famous brands from domestic and international market
* Competitive and reasonable price
* Abundant inventory and short lead time
* 24hrs supports from our sales and R&D team
| Warranty | 1 Year |
| Lead time | 3-7 Days |
Notes
1.The pictures are taken by camera.
2.You can contact us for a better price.
3.Feel free to contact us if you would like to see other models.
Our company
