Fairchild RD-310 service manual

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Reference Design RD-310

Primary-Side-Regulation PWM with POWER MOSFET – 3.5W
Design

Featured Device Application

FSEZ1317

Cell Phone

Charger

Input Voltage

Range

90~265V

AC

Output Voltage

(Rated Current)

5V (0.7A) 3.5W

Rated Output

Power

Key Features

 Low Standby Power Under 30mW
 High Voltage Startup
 Constant-Voltage (CV) and Constant-Current (CC) Control without Secondary-Feedback

Circuitry

 Green Mode Function: Frequency Reduction at Light-Load
 Fixed PWM Frequency at 50kHz with Frequency Hopping to Reduce EMI
 Cable Voltage Drop Compensation in CV Mode
 Various Protection Functions: V

(UVLO), and Over-Temperature Protection (OTP)

Over-Voltage Protection (OVP), VDD Under-Voltage Lockout

DD

 7-Lead Small Outline Package (SOP)

1. Schematic

Topology

Primary-Side

Regulated

Flyback

Converter

Figure 1. Schematic

© 2009 Fairchild Semiconductor Corporation 1 RD-310_FSEZ1317 • Rev. 0.0.2

www.fairchildsemi.com

2. Transformer

Figure 2. Transformer Schematic Diagram

Notes:

1. When W4R’s winding is reversed winding, it must wind one layer.

2. When W2 is winding, it must wind three layers and put one layer of tape after winding the first
layer.

2.1. Winding Specification

No.

W1 4 5 2UEW 0.23*1 15 2

W2 3 1 2UEW 0.18*1

W3 1 COPPER SHIELD 1.2 3
W4 7 9 TEX-E 0.55*1 9 3

CORE ROUNDING TAPE 3

Terminal

Wire ts

S F ts Primary Seconds

41 1
39 0
37 2

Insulation Barrier Tape

Core: EE16
Bobbin: EE16

2.2. Electrical Characteristics

Pin Specification Remark

Primary-Side Inductance 1－3 2.25mH ± 5% 100kHz, 1V

Primary-Side Leakage Inductance

1－3

80μH Maximum

Short One of the Secondary Windings

© 2009 Fairchild Semiconductor Corporation 2 RD-310_FSEZ1317 • Rev. 0.0.2