Document
NEW PRODUCT
Description
A Product Line of Diodes Incorporated
AP31261
GREEN MODE PWM CONTROLLER
Pin Assignments
The AP31261 is a current mode PWM controller which is optimized for high performance, low standby power and cost effective offline flyback converters.
The PWM switching frequency at normal operation is internally fixed (about 65kHz). In middle load, the IC will enter green mode to improve system efficiency with the help of frequency foldback. A minimum switching frequency (about 20kHz) is set to avoid the audible noise. In no load or light load, the IC will enter the burst mode to minimize standby power. Furthermore, the frequency dithering function is built-in to reduce EMI emission.
Internal slope compensation allows more stable Peak-Current Mode control over wide range of input voltage and load conditions. Internal line compensation ensures constant output power limit over entire universal line voltage range.
Comprehensive protection features are included, such as cycle-bycycle current limit (OCP), VCC Over Voltage Protection (VOVP), internal OTP, Over Load Protection (OLP) and pins’ fault protection.
Features
(Top View) Pin 1 Mark
GND 1 FB 2 CTRL 3
6 GATE 5 VCC 4 SENSE
SOT26
Very Low Start-up Current Current Mode Control Non-audible-noise Green-mode Control Internal Slope Compensation Soft Start During Startup Process Frequency Fold Back for High Average Efficiency Secondary Winding Short Protection with FOCP Soft Switching for Reducing EMI VCC Maintain Mode Useful Pin Fault Protection:
SENSE Pin Floating CTRL Pin Short to Ground FB/Opto-coupler Open/Short Comprehensive System Protection Feature: VCC Over Voltage Protection (VOVP) Over Load Protection (OLP) Mini Size Package of SOT26 Pin to Pin Compatible with AP3125A/V/R/L Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. “Green” Device (Note 3)
Applications
Switching AC-DC Adapter/Charger ATX/BTX Auxiliary Power Set-top Box (STB) Power Supply Open Frame Switching Power Supply
Notes:
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"
and Lead-free. 3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
AP31261
Document number: DS37514 Rev. 2 - 2
1 of 13 www.diodes.com
May 2015
© Diodes Incorporated
NEW PRODUCT
F1
+
~
-~ ~
Typical Applications Circuit
C2 R4 R5
C4
R2 R3
NTC
C1
R7 VR1
NTC
U1
VCC
C3
GATE
CTRL SENSE
AP31261
FB GND
R8
R9 C11
A Product Line of Diodes Incorporated
AP31261
R6 C5 R19
T1 C6
R13 C7
L2 C8
R14
R10 R11 R12
R15 C10
R16
AZ431 C9
R17 R18
Pin Descriptions
Pin Number 1 2
3
4 5 6
Pin Name GND FB
CTRL
SENSE VCC GATE
Function
Signal ground. Current return for driver and control circuits
Feedback. Directly connected to the opto-coupler Latch trigger if this pin voltage drops below a threshold or over another threshold, leave CTRL pin open if this function is not needed. Connecting a NTC thermistor to GND can achieve OTP protection Current Sense
Supply voltage of driver and control circuits
Gate driver output
AP31261
Document number: DS37514 Rev. 2 - 2
2 of 13 www.diodes.com
May 2015
© Diodes Incorporated
NEW PRODUCT
Functional Block Diagram
A Product Line of Diodes Incorporated
AP31261
VCC
5
32V
2
FB
16V 7.6V
28V
UVLO
VDD
Internal Bias
VCC_OVP
VCC_OVP OLP
FOCP CTRL_H CTRL_L
OTP
Auto Recovery Protection
Latch-off Protection
Soft Start SS OSC with
Frequency Jitter
0.3V
VDD
D DFF
CLK RB
Q
VCC
Driver 13V
6
GATE
GND
2R
1
R
SENSE
4
1.3V
90ms OLP Debounce
250ns LEB
SS PWM
1.80V FOCP
0.95V
Line Compensation
OCP
OTP +150oC /+125oC
CTRL_H CTRL_L
VDD 3V 100mA
3
10k 1V
0.6V 4.5V
CTRL
AP31261
AP31261
Document number: DS37514 Rev. 2 - 2
3 of 13 www.diodes.com
May 2015
© Diodes Incorporated
NEW PRODUCT
Absolute Maximum Ratings (Note 4)
A Product Line of Diodes Incorporated
AP31261
Symbol VCC IO
VFB, VSENSE, VCTRL θJA PD TJ TSTG – –
Parameter Power Supply Voltage Gate Output Current Input Voltage to FB, SENSE, CTRL Thermal Resistance (Junction to Ambient) Power Dissipation at TA < +25°C Operating Junction Temperature Storage Temperature Range ESD (Human Body Model) ESD (Machine Model)
Rating 30 350
-0.3 to 7 250 500
-40 to +150 +150 3000 300
Unit V mA V
°C/W mW °C °C
V V
Note 4: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability.
Recommended Operating Co.