AP3984
PRIMARY SIDE POWER SWITCHER FOR OFF-LINE SMPS
Description Pin Assignments
The AP3984 is a power switcher for power supplies with better
conversion efficiency, better voltage & current accuracy, and improved
protection functions. Typical applications include charger, adapter for
(Top View)
ADSL, home appliance power supply and PC auxiliary power supplies.
The AP3984 with built in BJT, regulates the output voltage and current
in the primary side by piece-wise pulse frequency modulation (p-PFM)
1
FB 7 GND
and primary current peak amplitude modulation (AM) in discontinuous
conduction mode (DCM). The system operating frequency reduces CBC 2
linearly from heavy load to light load in each interval of the p-PFM, and
VCC 3 6 C
operating frequency is fixed at medium load by varying primary current
peak amplitude.
5
4 C
CS
The AP3984 has good transient characteristics in combination with
the secondary side IC like AP4341/AP43410. Typically, minimal SO-7
voltage of 4.3V at PCB side can be achieved for dynamic test of 5V
application system.
Applications
The AP3984 provides operating frequency dithering function to
improve EMC performance of power supply. The AP3984 also has
Adapters
programmable cable voltage drop compensation function by external
Set Top Boxes
resistor.
Auxiliary Supplies
Appliances
The AP3984 is packaged in SO-7.
Features
Primary Side Control for Eliminating Opto-coupler
Built-in 700V BJT
Excellent Transient Characteristics
High Voltage and Super-speed Start up
External Adjustable Output Cable Voltage Drop Compensation
Ultra-low No-load Power Consumption(<10mW)
Multiple PWM/PFM Mode to Improve Audio Noise and Efficiency
Valley-on for Higher Efficiency and Better EMI
Multiple Protections:
Over Voltage Protection (OVP)
Output Short Circuit Protection (SCP)
Over Temperature Protection (OTP)
Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. Green Device (Note 3)
Note: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See
AP3984
Typical Applications Circuit
T1
F1
L2
C5 C6
Ns
V
O+
C4 R2
Np
D4 + +
J1
BD1
R12 R11
R3
AC 90-264V
C2
C1
+ +
AP4341
D2 OUT
VCC
N
AUX
U2
V
O-
GND
D1
R4
+
C3
L1
U1 3
5,6 R7
VCC
C
R1 2
7
CBC GND
1
FB
CS
4
R5
R6
R9 R8
For AP3984+AP4341 (5V/1A)
T1
F1
L2
C23 R21
Ns
R22
V
O+
C4 R2
Np
J1
BD1
C21 C22
R3
A A OUTGND
AC 90-264V
C2 + +
C1
+ +
AP43410
D2
N
AUX
R24
VCC K
D1
R4
V
O-
+ GND
C3
L1
U1 3
5,6
R7
VCC
C
R1 2
7
CBC GND
1
FB
CS
4
R5
R6
R9 R8
For AP3984+AP43410 (5V/1A)
2 of 15
AP3984 December 2016
Diodes Incorporated
www.diodes.com
Document number: DS37655 Rev. 3 - 2
NEW PRODUCT