Richtek R7735AGE, R7735AGN, R7735GGE, R7735GGN, R7735HGE Schematics

...

High Performance Enhanced Quadruple Mode PWM Flyback Controller

R7735

General Description

R7735 series is the successor of R7732/3 and fully

compatible with most of SOT-23-6 / DIP-8 product so far

in the market. It has enhanced quadruple mode PWM

controller and owns excellent green power performance,

especially under light load and no load conditions. It

focuses on "easy to design" in different applications and

it will save both design effort and external components.

Besides the general features shown in the Features

section, R7735 covers wide protection options, such as

internal Over Load Protection (OLP) and Over Voltage

Protection (OVP) to eliminate the external protection

circuits. Moreover, it also features Secondary Rectifier

Short Protection (SRSP) and CS pin open protection. This

protection will make the PSU design for reliability and

safety easier.

R7735 is designed for power supply such as NB adaptor

which is a very cost effective and compact design. The

precise external OVP and Over Temperature Protection

(OTP) can be implemented by very simple circuit. The

start-up resistors can also be replaced by bleeding

resistors to save power loss and component count.

Features

z No Load Input Power Under 100mW

z Accurate Over Load Protection

z UVLO 9V/14V

z Soft Start Function

z Current Mode Control

z Built-in Slope Compensation

z Internal Leading Edge Blanking

z PWM Quadruple Mode for Green-Mode

z Excellent Green Power Performance

z Cycle-by-Cycle Current Limit

z Internal Over Voltage Protection

z Secondary Rectifier Short Protection

z Opto-Coupler Short Protection

z Feedback Open-Loop Protection

z CS Pin Open Protection

z Built-in Jittering Frequency

z Built-in PRO Pin for External Arbitrary OVP/OTP

z Soft Driving for EMI Noise

z High Noise Immunity

z RoHS Compliant and Halogen Free

Application

z Switching AC/DC Adaptor

Ordering Information

R7735

(B)* (* : See Version Table)

Package Type E : SOT-23-6 N : DIP-8 (R7735G Only)

Lead Plating System

z DVD Open Frame Power Supply

z Set-T op Box (STB)

z ATX Standby Power

z TV/Monitor Standby Power

z PC Peripherals

z NB Adaptor

G : Green (Halogen Free and Pb Free)

R7735 Version (Refer to Version Table)

Note :

Richtek products are :

` RoHS compliant and compatible with the current

requirements of IPC/JEDEC J-STD-020.

` Suitable for use in SnPb or Pb-free soldering processes.

R7735-03 September 2012 www.richtek.com

Marking Information

For marking information, contact our sales representative

directly or through a Richtek distributor located in your

area.

R7735

Pin Configurations

(TOP VIEW)

GND

COMP

GATE

VDD CS

GND

SOT-23-6

COMP

PRO

GATE

DIP-8

R7735 Version Table

Version R7735G R7735R R7735L R7735A R7735H

Frequency 65kHz 65kHz 65kHz 65kHz 100kHz

OLP Delay Time 56ms 56ms 56ms 28ms 36ms

Internal OVP(27V) Auto Recovery Auto Recovery Latch Latch Auto Recovery

OLP & SRSP Auto Recovery Auto Recovery Auto Recovery Latc h Auto Recovery

PRO Pin High Latch Auto Recovery Latc h Latch Auto Recover y

PRO Pin Low Auto Recovery Latch Latch Latch Latch

* : V

R7735XGE : V

R7735HGE(B) : V

: Secondary Rectifier Short Protection (SRSP) triggered threshold.

SRSP_TH

= 1.7V, X = G/R/L/A

SRSP_TH

= 2.6V

SRSP_TH

NCVDD

PRO

678

Typical Application Circuit

AC Mains (90V to 265V)

PRO

COMP

NTC

VDD

R7735

GND

GATE

# : See Application Information

Vo+

Vo-

www.richtek.com

R7735-03 September 2012

Functional Pin Description

R7735

Pin No.

Pin Name Pin Function

SOT-23-6 DIP-8

1 8 GND Ground.

2 7 COMP

Voltage Feedback. By connecting an opto-coupler to close control loop and achieve the regulation.

3 5 PRO For External Arbitrary OVP or OTP.

4 4 CS Primary Current Sense.

5 2 VDD Power Supply.

6 1 GATE Gate Drive Output to Drive the External MOSFET.

-- 3, 6 NC No Internal Connection.

Function Block Diagram

L_TH

PRO

BIAS

SRSP_TH

H_TH

Secondary Rectifier Short & CS Open Protection

Brownout

Sensing

COMP Open

Sensing

OLP

Auto

Recovery

Latch

Auto

Recovery

Latch

POR

Shutdown

Logic

Counter

Oscillator

OVP

UVLO

Bias &

Bandgap

VDD

27V

9V/14V

PWM

Dmax

Quadruple Mode

Soft Driver

COMP

BURL

BURH

www.richtek.com

Constant

Power

COMP

LEB

Slope Ramp

Comparator

R7735-03 September 2012

GATE

GND

R7735

Absolute Maximum Ratings (Note 1)

z Supply Input Voltage, VDD ----------------------------------------------------------------------------------------------- −0.3V to 30V

z GATE Pin--------------------------------------------------------------------------------------------------------------------- −0.3V to 16.5V

z PRO, COMP, CS Pin ------------------------------------------------------------------------------------------------------ −0.3V to 6.5V

z I

------------------------------------------------------------------------------------------------------------------------------ 10mA

z Power Dissipation, P

SOT-23-6 -------------------------------------------------------------------------------------------------------------------- 0.400W

DIP-8-------------------------------------------------------------------------------------------------------------------------- 0.714W

z Package Thermal Resistance (Note 2)

SOT-23-6, θJA--------------------------------------------------------------------------------------------------------------- 250°C/W

DIP-8, θJA-------------------------------------------------------------------------------------------------------------------- 140°C/W

z Junction Temperature ------------------------------------------------------------------------------------------------------ 150°C

z Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------- 260°C

z Storage Temperature Range --------------------------------------------------------------------------------------------- −65°C to 150°C

z ESD Susceptibility (Note 3)

HBM (Human Body Model)----------------------------------------------------------------------------------------------- 3kV

MM (Machine Model) ------------------------------------------------------------------------------------------------------ 250V

@ TA = 25°C

Recommended Operating Conditions (Note 4)

z Supply Input Voltage, VDD ----------------------------------------------------------------------------------------------- 12V to 25V

z Junction Temperature Range --------------------------------------------------------------------------------------------- −40°C to 125°C

z Ambient Temperature Range --------------------------------------------------------------------------------------------- −40°C to 85°C

Electrical Characteristics

= 15V, T

VDD Section

VDD Over Voltage Protection Level V

VDD Zener Clamp VZ 29 -- -- V

On Threshold Voltage V

Off Threshold Voltage V

VDD Holdup Mode Entry Point V

VDD Holdup Mode Ending Point V

Latch-off Voltage VLH 4.5 5.5 6.5 V

Latched Reset Voltage V

Start-up Current I

Oper ating Supply Current I

= 25°C, unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Unit

26 27 28 V

OVP

13 14 15 V

TH_ON

TH_OFF

DD_LOW

DD_HIGH

LH_RST

DD_ST

DD_OP

8.5 9 9.5 V

< 1.6V 9.5 10 10.5 V

COMP

< 1.6V 10 10.5 11 V

COMP

4 5 6 V

= −40ºC to 100ºC (Note 5)

GATE pin open

= V

TH_ON –

= 15V, V

COMP

0.2V,

= 2.5V,

1 5 10 μA

0.55 0.9 1.6 mA

Latch-off Operating Current I

TA= −40ºC to 100ºC (Note 5) 2 -- 8 μA

DD_LH

www.richtek.com 4

R7735-03 September 2012

Parameter Symbol Test Conditions Min Typ Max Unit

Oscillator Section

R7735

Normal PWM Frequency f

Frequency Reduction Mode

Minimum Frequency

Maximum Duty Cycle DCY

OSC

FR_MIN

R7735H 92 100 108

R7735G/R/L/A 18 22 -R7735H -- 25 --

70 75 80 %

MAX

kHz

PWM Frequency Jitter Range Δf -- ±6 -- %

R7735G/R/L/A 60 65 70

PWM Frequency Jitter Period T

Frequency Variation Versus V

Deviation

Frequency Variation Versus Temperature Deviation

For 65kHz -- 4 -- ms

JIT

= 12V to 25V -- -- 2 %

= −30°C to 105°C

(Note 5)

-- -- 5 %

COMP In put Section

Open-Loop Voltage V

COMP_OP

COMP pin Open 5.5 5.75 6 V

R7735G/R/L 45 56 65 COMP Open-Loop Protection Delay Time

OLP

R7735A 22 28 34

R7735H 30 36 42

Short Circuit Current I

Frequency Reduction Mode Entry Voltage

Frequency Reduction Mode Ending Voltage

ZERO

2.85 3 3.15 V

FR_ET

FR_ED

= 0V 0.15 0.29 0.45 mA

COMP

R7735G/R/L/A 2.75 2.9 3.05

R7735H 2.65 2.8 2.95

Current Sense Section

Initial Peak Current Limitation Offset

Maximum Clamping Current Limit V

Leading Edge Blanking Time t

0.68 0.7 0.72 V

CS_TH

CS(MAX)

LEB

1.05 1.1 1.15 V

(Note 6) 150 250 350 ns

Internal Propagation Delay Time tPD (Note 6) -- 100 -- ns

Minimum On Time t

ON(MIN)

250 350 450 ns

GATE Section

Rising Time tR V

Falling Time tF V

GATE Output Clamping Voltage V

VDD= 25V 12.1 14 15.9 V

CLAMP

= 15V, CL= 1nF 60 125 140 ns

= 15V, CL= 1nF 25 40 65 ns

PRO Interface Section

Pull Low Threshold V

Pull High Threshold V

Internal Bias Current I

Pull High Sinking Current I

R7735-03 September 2012

0.47 0.5 0.53 V

L_TH

3.5 3.8 4.1 V

H_TH

90 100 110 μA

BIAS

(Note 7) 0.7 -- 1.4 mA

SINK

www.richtek.com

R7735

Note 1. Stresses beyond those listed “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 in the

operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect

device reliability.

Note 2. θ

is measured at T

Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. Guaranteed by design. Note 6. Leading edge blanking time and internal propagation delay time are guaranteed by design. Note 7. The sourcing current of PRO pin must be limited below 5mA. Otherwise it may cause permanent damage to the

device.

= 25°C on a low effective thermal conductivity single-layer test board per JEDEC 51-3.

www.richtek.com

R7735-03 September 2012

+ 13 hidden pages