FSEZ2016_10 Datasheet, PDF (1/14 Pages) Fairchild Semiconductor – Low-Power Green-Mode EZSWITCH without Secondary Side Feedback Circuitry

January 2010
FSEZ2016 — Low-Power Green-Mode EZSWITCH without
Secondary Side Feedback Circuitry
Features
ƒ Linearly Decreasing PWM Frequency
ƒ Green Mode Under Light-load and Zero-Load
Conditions
ƒ Constant Voltage (CV) and Constant Current (CC)
around ±25% without Secondary Side Feedback
Circuitry
ƒ Precise Constant Voltage (CV) at ±5% by Secondary
Side Feedback Circuitry
ƒ Low Startup Current: 8μA
ƒ Low Operating Current: 3.6mA
ƒ Leading-Edge Blanking (LEB)
ƒ Constant Power Limit
ƒ Universal AC Input Range
ƒ Synchronized Slope Compensation
ƒ 140°C OTP Sensor with Hysteresis
ƒ VDD Over-Voltage Clamping
ƒ Cycle-by-Cycle Current Limiting
ƒ Under-Voltage Lockout (UVLO)
ƒ Fixed PWM Frequency with Hopping
ƒ Gate Output Maximum Voltage Clamped at 17V
Applications
General-purpose switching-mode power supplies and
flyback power converters, such as:
ƒ Battery Chargers for Cellular Phones, Cordless
Phones, PDAs, Digital Cameras, Power Tools
ƒ Power Adapters for Ink Jet Printers, Video Game
Consoles, Portable Audio Players
ƒ Open-Frame SMPS for TV/DVD Standby and
Auxiliary Supplies, Home Appliances, Consumer
Electronics
ƒ Replacement for Linear Transformers and RCC SMPS
ƒ PC 5V Standby Power
Description
This highly integrated PWM controller provides several
features to enhance the performance of low-power
flyback converters. To minimize standby power
consumption, a proprietary green-mode function provides
off-time modulation to linearly decrease the switching
frequency under light-load and zero-load conditions. This
green mode enables the power supply to meet
international power conservation requirements. The
supply voltage VDD is also used for feedback
compensation, to regulate the output voltage without
requiring a conventional TL431 and a photo-coupler. A
typical output CV/CC characteristic is shown in Figure 1.
Another advantage of the FSEZ2016 is that the typical
startup current is only 8μA, while the typical operating
current can be as low as 3.6mA. A large startup
resistance can be used to achieve even higher power
conversion efficiency.
FSEZ2016 integrates frequency hopping function
internally to reduce EMI emissions with minimum line
filters. Also, built-in synchronized slope compensation
maintains the stability of peak current-mode control.
Proprietary internal compensation ensures constant
output power limiting over a universal range of AC input
voltages, from 90VAC to 264VAC.
The FSEZ2016 provides many protection functions.
Pulse-by-pulse current limiting ensures constant output
current, even if a short circuit occurs. The internal
protection circuit disables PWM output if VDD exceeds
22.7V. The gate output is clamped at 17V to protect the
power MOS from over-voltage damage. The built-in
over-temperature protection (OTP) function shuts down
the controller at 140°C with a 30°C hysteresis.
Maximum
Vo
With Secondary Feedback
8
Minimum
Without Secondary Feedback
7
6
5
4
3
2
1
0
Io
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Figure 1. Typical Output V-I Characteristic
© 2008 Fairchild Semiconductor Corporation
FSEZ2016 • Rev. 1.0.1
www.fairchildsemi.com