Richtek R7730GE Schematic [ru]
Preliminary
Burst Triple-Mode PWM Flyback Controller
R7730
General Description
The R7730 is a high-performance, low cost, low startup
current, current mode PWM controller with burst triplemode to support green mode power saving operation. The
R7730 integrates functions of soft-start, Under VoItage
Lockout (UVLO), Leading Edge Blanking (LEB), Over
Temperature Protection (OTP), internal slope
compensation. It provides the users a superior AC/DC
power application of higher efficiency, low external
component counts and lower cost solution.
To protect the external power MOSFET from being
da maged by supply over voltage, the R7730 output driver
is clamped at 12V. Furthermore, R7730 features fruitful
protections like OLP (Over Load Protection) ,OVP (Over
Voltage Protection) to eliminate the external protection
circuits and provide relia ble operation. R7730 is available
in SOT-23-6 pa ckage.
Applications
Features
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z Very Low Start-Up Current (<30uA)
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z 10/14V UVLO
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z Soft Start Function
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z Current Mode Control
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z Internal Leading-Edge Blanking
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z Built-in Slope Compensation
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z Burst Triple-Mode PWM for Green-Mode
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z Cycle-by-Cycle Current Limiting
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z Feedback Open Protection
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z Output Over Voltage Protection
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z Over Temperature Protection
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z Over Load Protection
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z Soft Driving for Reducing EMI
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z High Noise Immunity
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z Opto Coupler Short Protection
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z RoHS Compliant and Halogne Free
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z Ada ptor and Battery Charger
z A TX Standby Power
z Set Top Boxes (STB)
z D VD and CD(R)
z TV/Monitor Standby Power
z PC Peripherals
Typical Application Circuit
AC Mains
(90V to 265V)
RT
COMP
GND
VDD
R7730
GATE
CS
VO+
VO-
DS7730-00 May 2008 www.richtek.com
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R7730
Preliminary
Ordering Information
R7730
Package Type
E : SOT-23-6
Operating Temperature Range
G : Green (Halogen Free with Commer cial Standard)
Note :
Richtek Green 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.
`100% matte tin (Sn) plating.
Marking Information
For marking information, contact our sales re presentative directly or through a Richtek distributor located in your area,
otherwise visit our website for detail.
Pin Configurations
(TOP VIEW)
CSVDDGATE
4
56
23
1
COMP RT
GND
SOT-23-6
Note : There is no pin1 indicator on top mark for SOT-23-6 type, and pin 1 will be lower left pin when reading top mark from left
to right.
DS7730-00 May 2008www.richtek.com
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Function Block Diagram
Preliminary
R7730
COMP
CS
Brown out
sensing
COMP open
sensing
OLP
Constant
Power
LEB
X3
SS
Slope
Ramp
Shutdown
Logic
Counter
-
+
PWM
comparator
OTP
Dmax
Oscillator
POR
UVLO
Burst
Triple Mode
OVP
S
R
+
-
+
-
Bias &
Bandgap
Q
COMP
V
V
V
VDD
27V
14V/10V
RT
Soft
Driver
GATE
BURL
BURH
DD
GND
Functional Pin Description
Pin No. Pin Name Pin Function
1 GND Ground.
2 COMP
3 RT Set the switching frequency by connecting a resistor to GND.
4 CS Primary Current Sense Pin.
5 VDD IC Power Suppl y P in.
6 GATE Gate driver output to drive the external MOSFET.
DS7730-00 May 2008 www.richtek.com
Comparator Input Pin. By connecting a photo-coupler to this pin, the peak
current set point is adjusted accordingly to the output power requirement.
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R7730
Preliminary
Absolute Maximum Ratings (Note 1)
z Supply Input V oltage, V
z GA TE Pin---------------------------------------------------------------------------------------------------------------- 20V
z FB, RT, COMP, CS Pin ---------------------------------------------------------------------------------------------- 6.5V
z I
------------------------------------------------------------------------------------------------------------------------- 10mA
DD
z Power Dissipation, P
------------------------------------------------------------------------------------------- 30V
DD
@ TA = 25°C
D
SOT-23-6 ---------------------------------------------------------------------------------------------------------------- 0.4W
z Package Thermal Re sistance (Note 4)
z SOT-23-6, θ
z Junction T emperature------------------------------------------------------------------------------------------------- 150°C
z Lead Temperature (Soldering, 10 sec.)--------------------------------------------------------------------------- 260°C
z Storage T emperature Range ---------------------------------------------------------------------------------------- −65°C to 150°C
z ESD Susceptibility (Note 2)
----------------------------------------------------------------------------------------------------------- 250°C/W
JA
HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 4kV
MM (Ma chine Mode)-------------------------------------------------------------------------------------------------- 250V
Recommended Operating Conditions (Note 3)
z Supply Input V oltage, V
z Operating Frequency ------------------------------------------------------------------------------------------------- 50k to 130kHz
z Junction T emperature Range---------------------------------------------------------------------------------------- −40°C to 125°C
z Ambient T emperature Range---------------------------------------------------------------------------------------- −40°C to 85°C
------------------------------------------------------------------------------------------- 12V to 25V
DD
Electrical Characteristics
(V
= 15V, RT = 100kΩ, T
DD
Parameter Symbol Conditions Min Typ Max Unit
VDD Section
VDD Over Voltage Protection Level V
On Threshold Voltage V
VDD On/Off Hysteresis V
Start-up Current I
Operating Current I
VDD Hold-up Mode Hysteresis
E nding Lev el
VDD Hold-up Mode Entry Level V
VDD Clamp Voltage V
Oscillator Section (RT pin)
Normal PWM Frequency f
Maximum Duty Cycle D
Frequency Variation Versus VDD
Deviation
= 25°C, unless otherwise specified)
A
V
f
25.5 27 28.5 V
OVP
13 14 15 V
TH_ON
3 4 5 V
DD_hys
VDD = V
DD-ST
V
= 15V, RT = 100kΩ,
DD-OP
DD_hys
DD_Low
DD_Clamp
R
OS C
70 75 80 %
MAX
V
DV
DD
GATE = Open, V
V
V
< 1.6V -- 11.5 -- V
COMP
< 1.6V -- 11 -- V
COMP
-- 29 -- V
= 100kΩ 60 65 70 kHz
T
= 12V to 25V -- -- 2 %
VDD
– 0.1V -- 20 30 uA
TH_ON
COMP
= 2.5V
-- 1.1 2.2 mA
To be continued
DS7730-00 May 2008www.richtek.com
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