SiFirst SF1530DP, SF1530LGT Schematic [ru]

High Performance Current Mode PWM Controller
Proprietary “Zero OCP/OPP Recovery Gap”
Control
Built-in Soft Start Function
All Pins Floating Protection
Very Low Startup Current
High Voltage CMOS Process with Excellent
ESD Protection
Frequency Reduction and Burst Mode Control
for Energy Saving
Current Mode Control
Built-in Frequency Shuffling
Programmable Switching Frequency
Built-in Synchronous Slope Compensation
Cycle-by-Cycle Current Limiting
Built-in Leading Edge Blanking (LEB)
Constant Power Limiting
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
SF1530
GENERAL DESCRIPTION
SF1530 is a high performance, low cost, highly integrated current mode PWM controller for offline flyback converter applications. PWM switching frequency with shuffling is externally programmable, which can reduce conduction EMI emission of a power supply. When the output power demands decrease, the IC automatically decreases switching frequency for high power conversion efficiency. When the current set-point falls below a given value, e.g. the output power demand diminishes, 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. SF1530 integrates functions and protections of Under Voltage Lockout (UVLO), VCC Over Voltage Protection (OVP), Cycle-by-cycle Current Limiting (OCP), All Pins Floating Protection, Over Load Protection (OLP), RT Pin Short-to-GND Protection, Gate Clamping, VCC Clamping, Leading Edge Blanking (LEB). SF1530 is available in SOT23-6, SOP-8 and DIP-8 packages.
TYPICAL APPLICATION
AC IN
GATE
GND
5 46
VDD
SF1530
FB
2
DC Out
CS
RT
31
TL431
©SiFirst Technology www.sifirsttech.com
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SF1530_DS_V1.0
SF1530
Pin Configuration
GND
FB
NC
RT
GND
FB
RT
1
SOT23-6
2
3
6
GATE
GATE
1
8
DIP8
VDD
5
VDD
NC
4
CS
2
3
4
7
6
5CS
Ordering Information
Part Number Top Mark Package Tape & Reel
SF1530LGT .30YWW SOT26 Green Yes
SF1530DP SF1530DP DIP8 RoHS
Marking Information
YWW: Year&Week code
©SiFirst Technology www.sifirsttech.com
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SF1530_DS_V1.0
Block Diagram
RT
Zero OCP Recovery
RT short/floating
protection
Trimmed Voltage &
Current Reference
VDD
9V/14V
33V
Gap Control
POR
27.5V
Internal
blocks
VDD OVP
GND
Oscillator with
Frequency Shuffling
OLP
Reduction Control
OCP
Burst Mode
Control
43ms Delay
S
R
Frequency
Q
CS floating
protection
Soft start
Slope
compensation
Soft Gate
Driver
3.7V
SF1530
GATE
LEB
CS
5.3V
FB
Pin Description
Pin Num Pin Name I/O Description
1 GND P Ground 2 FB I Voltage feedback pin. The loop regulation is achieved by connecting a
photo-coupler to this pin. PWM duty cycle is determined by this pin voltage and the current sense signal at Pin 3.
3 RT I Set the switching frequency by connecting a resistor between RT and
GND. This pin has floating/short-to-GND protection.
4 CS I Current sense input pin. 5 VDD P IC power supply pin. 6 GATE O Totem-pole gate driver output to drive the external MOSFET.
Absolute Maximum Ratings (Note 1)
Parameter Value Unit
VDD DC Supply Voltage 33 V VCC DC Clamp Current 10 mA GATE pin 20 V FB, RT, CS voltage range -0.3 to 7 V Package Thermal Resistance (SOT-26) 250 Package Thermal Resistance (DIP-8) 90 Package Thermal Resistance (SOP-8) 150 Maximum Junction Temperature 150 Operating Temperature Range -40 to 85
o
C/W
o
C/W
o
C/W
o
C
o
C
©SiFirst Technology www.sifirsttech.com
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SF1530_DS_V1.0
Storage Temperature Range -65 to 150 Lead Temperature (Soldering, 10sec.) 260
SF1530
o
C
o
C ESD Capability, HBM (Human Body Model) 3 kV ESD Capability, MM (Machine Model) 250 V
Recommended Operation Conditions (Note 2)
Parameter Value Unit
Supply Voltage, VDD 11 to 25 V Operating Frequency 50 to 130 kHz Operating Ambient Temperature -40 to 85
o
C
ELECTRICAL CHARACTERISTICS
(TA = 25
O
C, RT=100K ohm, VDD=18V, if not otherwise noted)
Symbol Parameter Test Conditions Min Typ Max Unit Supply Voltage Section (VDD Pin)
UVLO(ON) VDD Under Voltage
Lockout Exit (Startup)
UVLO(OFF) VDD Under Voltage
Lockout Enter
I_Startup VDD Start up Current VDD =12.5V, Measure
I_VDD_Op Operation Current VFB=3V,CL=1nF 2.5 3.5 mA VDD_OVP
VDD Over Voltage Protection trigger
VDD_Clamp VDD Zener Clamp
Voltage
T_Softstart Soft Start Time 3 mSec
13 14 15 V
8 9 10 V
5 20 uA
current into VDD
25 27.5 30 V
I(V
) = 15 mA 33 V
DD
Feedback Input Section(FB Pin)
V
Open FB Open Voltage 5.3
FB_
V
IFB_Short FB short circuit
current
A
VCS
PWM Input Gain ΔV
VFB_min_duty FB under voltage gate
Short FB pin to GND,
1.1 mA
measure current
/ΔVcs 2.0 V/V
FB
1.0 V
clock is off.
VTH_PL Power Limiting FB
3.7 V
Threshold Voltage
TD_PL Power limiting
Note 3 43 mSec
Debounce Time
ZFB_IN Input Impedance 5 Kohm
Current Sense Input Section (CS Pin)
Vth_OC_min Internal current
limiting threshold
T_blanking SENSE Input Leading
Edge Blanking Time
TD_OC Over Current
Detection and Control Delay
Zero duty cycle 0.70 0.75 0.80 V
250 nSec
CL=1nF at GATE, 70 nSec
Oscillator Section (RT Pin)
F
Normal Oscillation
OSC
Frequency RT_range Operating RT Range 50 100 150 Kohm V_RT_open RT open voltage 2.0 V F(shuffle)/Fosc Frequency shuffling
range f_Temp Frequency
Temperature Stability ∆f_VDD Frequency Voltage VDD = 12-25V, 5 %
60 65 70 KHZ
Note 4 -4 4 %
-20oC to 100oC (Note 4) 5 %
©SiFirst Technology www.sifirsttech.com
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SF1530_DS_V1.0
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