PRIMARY SIDE REGULATED SWITCHING MODE POWER SUPPLY CONTROLLER
The AP3785T is a high performance AC/DC power supply controller
for battery charger and adapter applications. It can meet less than
10mW standby power for “Super Star” charger criteria. The device
uses Pulse Frequency Modulation (PFM) method to build
discontinuous conduction mode (DCM) flyback power supplies.
The AP3785T provides accurate constant voltage (CV), constant
current (CC) and outstanding dynamic performance without requiring
an opto-coupler. It also eliminates the need of loop compensation
circuitry while maintaining stability.
The AP3785T is equipped with both cable drop compensation
function to meet various cables with different lengths and gauges and
adjustable line voltage compensation function.
When AP3785T is used with AP4341 or synchronous rectifier series
(for example APR343 + MOSFET, APR3415, APR34330), better
under-shoot performance and higher conversion efficiency can be
The AP3785T has internal over temperature protection for itself, and
also provides dedicated pin for external over temperature protection.
This IC is available in SO-8 package.
Adapter/Chargers for Shaver, Cell/Cordless Phones, PDAs, MP3
and Other Portable Apparatus
Standby and Auxiliary Power Supplies
Primary Side Control for Eliminating Opto-coupler
10mW No-load Input Power
Flyback Topology in DCM Operation
External Adjustable Line Compensation for CC
External Adjustable Cable Compensation for CV
Multiple PWM/PFM Control Mode to Improve Audio Noise and
VCS Jitter to Reduce System EMI
Valley-on for the Higher Efficiency and Better EMI
Over Voltage Protection (OVP)
Output Short Circuit Protection (SCP)
Transformer Saturation Protection (TSP) via Primary Peak
OTP and External Over Temperature Protection (OTP)
Matching AP4341 with Schottky or APR343/APR3415
Synchronous Rectifier Solution
Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
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"
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.
Document number: DS37552 Rev. 4 - 2
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