Richtek R7730GE Schematic [ru]
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Preliminary |
R7730 |
Burst Triple-Mode PWM Flyback Controller
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 damaged 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 reliable operation. R7730 is available in SOT-23-6 package.
Features
zVery Low Start-Up Current (<30uA)
z10/14V UVLO
zSoft Start Function
zCurrent Mode Control
zInternal Leading-Edge Blanking
zBuilt-in Slope Compensation
zBurst Triple-Mode PWM for Green-Mode
zCycle-by-Cycle Current Limiting
zFeedback Open Protection
zOutput Over Voltage Protection
zOver Temperature Protection
zOver Load Protection
zSoft Driving for Reducing EMI
zHigh Noise Immunity
zOpto Coupler Short Protection
zRoHS Compliant and Halogne Free
Applications
zAdaptor and Battery Charger
zATX Standby Power
zSet Top Boxes (STB)
zDVDand CD(R)
zTV/Monitor Standby Power
zPC Peripherals
Typical Application Circuit
AC Mains |
VO+ |
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(90V to 265V) |
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VO- |
RT |
VDD |
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R7730 |
COMP |
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GATE |
GND |
CS |
DS7730-00 May 2008 |
www.richtek.com |
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R7730 |
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Preliminary |
Ordering Information |
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R7730 |
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Package Type |
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E : SOT-23-6 |
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Operating Temperature Range |
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G : Green (Halogen Free with Commer- |
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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 representative directly or through a Richtek distributor located in your area, otherwise visit our website for detail.
Pin Configurations
(TOP VIEW)
GATE VDD CS
6 5 4
1 2 3
GND COMP RT
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.
www.richtek.com |
DS7730-00 May 2008 |
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Preliminary |
R7730 |
Function Block Diagram
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OVP + |
VDD |
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POR |
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27V |
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Shutdown |
OTP |
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Logic |
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+ |
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Brown out |
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UVLO |
- |
14V/10V |
sensing |
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COMP open |
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Counter |
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Bias & |
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sensing |
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Bandgap |
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OLP |
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Oscillator |
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Constant |
SS |
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RT |
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Dmax |
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Power |
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Soft |
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S |
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Driver |
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- |
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Q |
GATE |
COMP |
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- |
R |
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+ |
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PWM |
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CS |
Slope |
comparator |
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Ramp |
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COMP |
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Burst |
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VBURL |
LEB |
X3 |
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Triple Mode |
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VBURH |
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VDD |
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GND |
Functional Pin Description
Pin No. |
Pin Name |
Pin Function |
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1 |
GND |
Ground. |
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2 |
COMP |
Comparator Input Pin. By connecting a photo-coupler to this pin, the peak |
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current set point is adjusted accordingly to the output power requirement. |
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3 |
RT |
Set the switching frequency by connecting a resistor to GND. |
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4 |
CS |
Primary Current Sense Pin. |
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5 |
VDD |
IC Power Supply Pin. |
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6 |
GATE |
Gate driver output to drive the external MOSFET. |
DS7730-00 May 2008 |
www.richtek.com |
3
R7730 |
Preliminary |
Absolute Maximum Ratings |
(Note 1) |
z Supply Input Voltage, VDD ------------------------------------------------------------------------------------------- |
30V |
z GATE Pin ---------------------------------------------------------------------------------------------------------------- |
20V |
z FB, RT, COMP, CS Pin ---------------------------------------------------------------------------------------------- |
6.5V |
z IDD ------------------------------------------------------------------------------------------------------------------------- |
10mA |
z Power Dissipation, PD @ TA = 25°C |
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SOT-23-6 ---------------------------------------------------------------------------------------------------------------- |
0.4W |
z Package Thermal Resistance (Note 4) |
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z SOT-23-6, θJA ----------------------------------------------------------------------------------------------------------- |
250°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 2) |
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HBM (Human Body Mode) ------------------------------------------------------------------------------------------ |
4kV |
MM (Machine Mode) -------------------------------------------------------------------------------------------------- |
250V |
Recommended Operating Conditions (Note 3) |
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z Supply Input Voltage, VDD ------------------------------------------------------------------------------------------- |
12V to 25V |
z Operating Frequency ------------------------------------------------------------------------------------------------- |
50k to 130kHz |
z Junction Temperature Range ---------------------------------------------------------------------------------------- |
−40°C to 125°C |
z Ambient Temperature Range ---------------------------------------------------------------------------------------- |
−40°C to 85°C |
Electrical Characteristics
(VDD = 15V, RT = 100kΩ, TA = 25°C, unless otherwise specified)
Parameter |
Symbol |
Conditions |
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Min |
Typ |
Max |
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Unit |
VDD Section |
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VDD Over Voltage Protection Level |
VOVP |
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25.5 |
27 |
28.5 |
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On Threshold Voltage |
VTH_ON |
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13 |
14 |
15 |
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V |
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VDD On/Off Hysteresis |
VDD_hys |
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3 |
4 |
5 |
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V |
Start-up Current |
IDD-ST |
VDD = VTH_ON – 0.1V |
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20 |
30 |
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uA |
Operating Current |
IDD-OP |
VDD = 15V, RT = 100kΩ, |
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1.1 |
2.2 |
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mA |
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GATE = Open, VCOMP |
= 2.5V |
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VDD Hold-up Mode Hysteresis |
VDD_hys |
VCOMP < 1.6V |
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11.5 |
-- |
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Ending Level |
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VDD Hold-up Mode Entry Level |
VDD_Low |
VCOMP < 1.6V |
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11 |
-- |
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V |
VDD Clamp Voltage |
VDD_Clamp |
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-- |
29 |
-- |
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V |
Oscillator Section (RT pin) |
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Normal PWM Frequency |
fOSC |
RT = 100kΩ |
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60 |
65 |
70 |
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kHz |
Maximum Duty Cycle |
DMAX |
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70 |
75 |
80 |
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% |
Frequency Variation Versus VDD |
fDV |
VVDD = 12V to 25V |
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2 |
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% |
Deviation |
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To be continued |
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www.richtek.com |
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DS7730-00 |
May 2008 |
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