AP3988 Datasheet, PDF (1/12 Pages) Diodes Incorporated – PRIMARY SIDE POWER SWITCHER FOR OFF-LINE SMPS

A Product Line of
Diodes Incorporated
AP3988
PRIMARY SIDE POWER SWITCHER FOR OFF-LINE SMPS
Description
The AP3988 is a performance enhanced power switcher for power
supplies with better conversion efficiency, better voltage & current
accuracy, and improved protection functions. Typical applications
include charger, adapter for ADSL, home appliance power supply,
LED lighting power supply and PC auxiliary power supplies. The
controller regulates the output voltage and current in the primary
side by piece-wise Pulse Frequency Modulation (p-PFM) in
discontinuous conduction mode (DCM). The system operating
frequency reduces linearly from heavy load to light load in each
interval of the p-PFM, and enters constant current mode when the
load current equals to the maximum system output current.
The AP3988 provides operating frequency dithering function to
improve EMC performance of power supply. It also has built-in
fixed cable voltage drop compensation (5% of nominal system
output voltage) and adjustable line voltage compensation.
Pin Assignments
(Top View)
CPC 1
FB 2
VCC 3
CS 4
SO-7
The AP3988 solution has fewer component number, smaller size,
and lower total cost.
The AP3988 is packaged in SO-7.
Features
 Primary Side Control for Eliminating Opto-coupler and
Secondary CV/CC Control Circuitry
 Built-in NPN Transistor with 700VCBO
 Low Start-up Current: 0.2A (Typ.)
 Internal Output Cable Voltage Drop Compensation
 Hiccup Function to Improve Short Circuit Protection
 Better Over Voltage Protection
 Better Over Temperature Protection
 Low Total Cost Solution
 Output Power Range (Note 1): for 5.5W Adapter
 Totally Lead-free & Fully RoHS Compliant (Note 2 & 3)
 Halogen and Antimony Free. “Green” Device (Note 4)
Applications
 Adapters
 Set Top Boxes
 Appliances
7 GND
6C
5C
Notes:
1. Typical continuous power in a non-ventilated enclosed adapter measured at +50°C ambient.
2. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
3. 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.
4. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
AP3988
Document number: DS36722 Rev. 4 - 2
1 of 12
www.diodes.com
June 2014
© Diodes Incorporated