APR34309CA [DIODES]
SECONDARY SIDE SYNCHRONOUS RECTIFICATION SWITCHER;型号: | APR34309CA |
厂家: | DIODES INCORPORATED |
描述: | SECONDARY SIDE SYNCHRONOUS RECTIFICATION SWITCHER |
文件: | 总11页 (文件大小:481K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
APR34309CA
SECONDARY SIDE SYNCHRONOUS RECTIFICATION SWITCHER
Description
Pin Assignments
APR34309CA is a secondary side Combo IC, which combines an N-
Channel MOSFET and a driver circuit designed for synchronous
rectification (SR) in DCM operation. It also integrates output voltage
detect function for primary side control system.
(Top View)
DRISR
GND
GND
8
1
2
3
4
The N-Channel MOSFET has been optimized for low gate charge,
low RDS(ON), fast switching speed and body diode reverse recovery
performance.
VDET
AREF
VCC
7
6
5
GND
The synchronous rectification can effectively reduce the secondary
side rectifier power dissipation and provide high performance solution.
By sensing MOSFET drain-to-source voltage, APR34309CA can
output ideal drive signal with less external components. It can provide
high performance solution for 5V output voltage application.
DRAIN
Note: The DRAIN pin of internal MOSFET is exposed PAD, which is at the bottom
of IC (the dashed box). The secondary current should flow from GND(pin 6,7,8) to
this exposed PAD.
Same as AP4341, APR34309CA detects the output voltage and
provides a periodical signal when the output voltage is lower than a
certain threshold. By fast response to secondary side voltage,
APR34309CA can effectively improve the transient performance of
primary side control system.
SO-8EP
The APR34309CA is available in SO-8EP package.
Applications
•
•
Adapters/Chargers for Cell/Cordless Phones, ADSL Modems, MP3
and Other Portable Apparatus
Standby and Auxiliary Power Supplies
Features
•
•
•
•
Synchronous Rectification for DCM Operation Flyback
Eliminate Resonant Ring Interference
Fast Detector of Supply Voltages
Fewest External Components
Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Notes:
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"
and Lead-free.
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.
Typical Applications Circuit
C21 C22
+
+
C23
R21
APR34309CA
DRAIN
GND
GND
DRAIN
R23
R24
DRISR
VDET
GND
VCC
C24
AREF
CAREF
RAREF
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
Pin Descriptions
Pin Number
Pin Name
Function
1
DRISR
Synchronous rectification MOSFET drive.
Synchronous rectification sense input and dynamic function output, connected to DRAIN
through a resistor.
2
3
VDET
AREF
Program a voltage reference with a resistor from AREF to GND, to enable synchronous
rectification MOSFET drive signal.
4
VCC
DRAIN
GND
Power supply, connected with system output.
5
Drain pin of internal MOSFET. The Drain voltage signal can obtain from this pin.
Source pin of internal MOSFET, connected to Ground.
6,7,8
Drain pin of internal MOSFET. The secondary current should flow from GND (pin 6.7.8)
to this DRAIN pad.
Exposed PAD
DRAIN
Functional Block Diagram
VCC
4
VREF
IOVP
Dynamic
Integrator
(VDET-VCC)*tONP
OVP
IAREF
Counter
tONPDET
3
AREF
OSC
1
SRDRIVER
DRISR
6,7,8
GND
5, EP
DRAIN
2
VDET
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
Absolute Maximum Ratings (Note 4)
Symbol
Parameter
Value
-0.3 to 7.5
-2 to 50
-0.3 to 6
20
Unit
V
VCC
Supply Voltage
VDET, VDRAIN
Voltage at VDET, DRAIN Pin
Voltage at AREF, DRISR Pin
Continuous Drain Current
Pulsed Drain Current
V
VAREF, VDRISR
V
ID
A
IDM
PD
80
A
Power Dissipation at TA=+25ºC
2.2
W
Thermal Resistance (Junction to Ambient)
(Note 5)
θJA
θJC
56
12
ºC /W
ºC /W
Thermal Resistance (Junction to Case)
(Note 5)
TJ
Operating Junction Temperature
Storage Temperature
+150
-65 to +150
+300
ºC
ºC
ºC
V
TSTG
TLEAD
ESD
Lead Temperature (Soldering, 10 sec)
Charge Device Model
1000
Notes: 4. Stresses greater than those listed under “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 under “Recommended Operating Conditions” is not implied.
Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability.
5. FR-4 substrate PC board, 2oz copper, with 1 inch2 pad layout.
Recommended Operating Conditions
Symbol
VCC
Parameter
Min
3.3
-40
Max
6
Unit
V
Supply Voltage
Ambient Temperature
TA
+85
ºC
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
Electrical Characteristics (@TA = +25°C, VCC=5V, unless otherwise specified.)
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
Supply Voltage ( VCC Pin )
ISTARTUP
IOP
Startup Current
Operating Current
VCC=VSTARTUP-0.1V
–
100
100
150
150
μA
μA
VDET pin floating
VCC=VTRIGGER+20mV
40
VSTARTUP
Startup Voltage
UVLO
–
–
2.6
2.3
3.1
2.8
3.4
3.1
V
V
–
Dynamic Output Section/Oscillator Section
VTRIGGER
–
Internal Trigger Voltage
Duty Cycle
–
5.1
4
5.15
15
5.2
18
V
%
μs
–
tOSC
Oscillation Period
VCC=5V
18
30
37.5
VCC=VTRIGGER, VCC/VDET pin is
separately connected to a 20Ω
resistor
ITRIGGER
Internal Trigger Current
30
60
80
mA
tDIS
VDIS
Minimum Period
–
18
5.13
1.5
30
5.3
3
37.5
5.38
4.5
ms
V
Discharge Voltage
–
IDIS
Discharge Current
VCC=VDIS+0.1V
mA
mV
V
VDIS-VTRIGGER
VOVP
Trigger Discharger Gap
Overshoot Voltage for Discharge
–
–
30
110
5.74
–
5.64
5.84
VCC=VOVP+0.1V, VCC pin is
connected to a 20Ω resistor
IOVP
Overshoot Current for Discharge
40
–
100
mA
Synchronous Voltage Detect
VTHON
VTHOFF
tDON
Gate Turn-on Threshold
–
0
-17
–
–
-10
70
100
50
50
1.8
–
1
V
mV
ns
ns
ns
ns
Gate Turn-off Threshold
Turn-on Delay Time
–
-3
From VTHON to VDRISR=1V
From VTHOFF to VDRISR=3V
From 1V to 3V, CL=4.7nF
From 3V to 1V, CL=4.7nF
(VDET-VCC)*tONP = 25Vµs
(VDET-VCC)*tONP = 50Vµs
VCC=5V
130
150
100
100
2.7
6.5
–
tDOFF
Turn-off Propagation Delay Time
Gate Turn-on Rising Time
Gate Turn-off Falling Time
–
tRG
–
tFG
–
tLEB_S
tLEB_L
VDRISR_HIGH
0.9
–
Minimum On Time
μs
Drive Output Voltage
3.7
–
V
V
SR Minimum Operating Voltage
(Note 6)
VS_MIN
–
–
–
4.5
tOVP_LAST
Kqs
Added OVP Discharge Time
(Note 7)
–
–
2.0
–
ms
0.325
–
0.515
mA*μs
(VDET-VCC)*tONP = 25Vµs
Notes: 6. This item specifies the minimum SR operating voltage of VIN_DC, VIN_DC≥NPS*VS_MIN.
7. This item is used to specify the value of RAREF
.
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
Electrical Characteristics (@TA =+25°C, unless otherwise specified. Cont.)
MOSFET Static Characteristics
Parameters
Symbol
VDSS(BR)
VGS(TH)
IDSS
Conditions
VGS=0V, ID=0.25mA
VDS=VGS, ID=0.25mA
VDS=50V, VGS=0V
Min
50
0.7
–
Typ
–
Max
100
2
Unit
V
Drain to Source Breakdown
Voltage
Gate Threshold Voltage
1.3
–
V
Zero Gate Voltage Drain
Current
1
µA
Gate to Source Leakage
Current
IGSS
VGS=10V, VDS=0V
VGS=4.5V, ID=3A
–
–
–
±100
nA
Drain to Source On-state
Resistance
RDS(ON)
8
–
mΩ
MOSFET Dynamic Characteristics
Parameters
Input Capacitance
Symbol
Ciss
Conditions
Min
–
Typ
4149
206
Max
Unit
–
–
–
–
Output Capacitance
Coss
VGS=0V, VDS=25V, f=1MHz
–
pF
Reverse Transfer Capacitance
Gate to Source Charge
Crss
–
159
Qgs
–
10.3
VGS=0V to 10V, VDD=25V,
ID=15A
Gate to Drain Charge (Miller
Charger)
Qgd
–
8.4
–
nC
Total Gate Charge
Gate Resistance
Qg
Rg
VGS=4.5V
–
–
39
–
–
–
1.8
Ω
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
Output Voltage Detect Function Description
tOSC
tOSC
tDIS
tDIS
tDIS
tDIS
tDIS
tDIS
VDET
VCC
VOVP
VDIS
VDIS
VTRIGGER
VTRIGGER
VOFF
VON
UVLO
tOVP_LAST
IOVP
IDIS
IVCC
Figure 1. Typical Waveforms of APR34309CA
When VCC is beyond power-on voltage (VON), the APR34309CA starts up. The VDET pin asserts a periodical pulse and the oscillation period is
tOSC. When VCC is beyond the trigger voltage (VTRIGGER), the periodical pulse at VDET pin is discontinued. When VCC is beyond the discharge
voltage (VDIS), the discharge circuit will be enabled, and a 3mA current (IDIS) will flow into VCC pin. When VCC is higher than the overshoot voltage
(VOVP), the APR34309CA will enable a discharge circuit, the discharge current (IOVP) will last tOVP_LAST time. After the tOVP_LAST time, APR34309CA
will stop the discharge current and detect VCC voltage again. If VCC is still higher than VOVP, the tOVP_LAST time discharge current will be enabled
again. Once the OVP discharge current is asserted, the periodical pulse at VDET pin will be disabled.
When the VCC falls below the power-off voltage (VOFF), the APR34309CA will shut down.
Operation Description
MOSFET Driver
The operation of the SR is described with timing diagram shown in Figure 2. APR34309CA monitors the MOSFET drain-source voltage. When the
drain voltage is lower than the turn-on threshold voltage VTHON, the IC outputs a positive drive voltage after a turn-on delay time (tDON). The
MOSFET will turn on and the current will transfer from the body diode into the MOSFET’s channel.
In the process of drain current decreasing linearly toward zero, the drain-source voltage rises synchronically. When it rises over the turn off
threshold voltage VTHOFF, APR34309CA pulls the drive signal down after a turn-off delay (tDOFF).
I,V
VDET
IS
VTHON
0
t
VTHOFF
VDRISR
0.9VDRISR
0.9VDRISR
0.1VDRISR
tRG
0.1VDRISR
0
t
tFG
tDON
tDOFF
Figure 2. Typical Waveforms of APR34309CA
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
Operation Description (Cont.)
Minimum On Time
When the controlled MOSFET gate is turned on, some ringing noise is generated. The minimum on-time timer blanks the VTHOFF comparator,
keeping the controlled MOSFET on for at least the minimum on time. If VTHOFF falls below the threshold before minimum on time expires, the
MOSFET will keep on until the end of the minimum on time.
The minimum on time is in direct proportion to the (VDET-VCC)*tONP. When (VDET-VCC)*tONP=5V*5μs, the minimum on time is about 1.8μs.
The Value and Meaning of AREF Resistor
As to DCM operation Flyback converter, after secondary rectifier stops conduction the primary MOSFET Drain-to-source ringing waveform is
resulted from the resonant of primary inductance and equivalent switch device output capacitance. This ringing waveform probably leads to
Synchronous Rectifier error conduction. To avoid this fault happening, APR34309CA has a special function design by means of volt-second
product detecting. From the sensed voltage of VDET pin to see, the volt-second product of voltage above VCC at primary switch on time is much
higher than the volt-second product of each cycle ringing voltage above VCC. Therefore, before every time Synchronous Rectifier turning on,
APR34309CA judges if the detected volt-second product of VDET voltage above VCC is higher than a threshold and then turn on synchronous
Rectifier. The purpose of AREF resistor is to determine the volt-second product threshold. APR34309CA has a parameter, Kqs, which converts
RAREF value to volt-second product,
Area2 RAREF *Kqs
In general, Area1 and Area3, the value of which should be test on system, depend on system design and are always fixed after system design
frozen. As to BCD PSR design, the Area1 value changes with primary peak current value and Area3 value generally keeps constant at all of
conditions. So the AREF resistor design should consider the worst case, the minimum primary peak current condition. Since of system design
parameter distribution, Area1 and Area3 have moderate tolerance. So Area2 should be designed between the middle of Area1 and Area3 to keep
enough design margin.
Area3 RAREF *Kqs Area1
Area1=(VDET-VCC)*tONP
Area3
VDET
VCC
Area2=Kqs*RAREF
Figure 3. AREF Function
SR Minimum Operating Voltage
APR34309CA sets a minimum SR operating voltage by comparing the difference between VDET and output voltage (VCC). The value of VDET–VCC
must be higher than its internal reference, then APR34309CA will begin to integrate the area of (VDET–VCC)*tONP. If not, the area integrating will not
begin and the SR driver will be disabled.
SR Turning Off Timing Impact on PSR CV Sampling
As to synchronous rectification on Flyback power system, SR MOSFET need to turn off in advance of secondary side current decreasing to zero to
avoid current flowing reversely. When SR turns off in advance, the secondary current will flow through the body diode. The SR turning off time is
determined by the VTHOFF at a fixed system. When VTHOFF is more close to zero, the SR turning on time gets longer and body diode conduction time
gets shorter. Since of the different voltage drop between SR MOSFET and body diode, the PSR feedback signal VFB appears a voltage jump at the
time of SR MOSFET turning off. If the PSR CV sampling time tSAMPLE is close to even behind this voltage jump time, there will be system unstable
operation issue or the lower output voltage issue.
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
Operation Description (Cont.)
To ensure stable operating of system, it must be met:
tBODYDIODE<tONS*(1- tSAMPLE
)
tSAMPLE
SR Turnoff,
Bodydiode operating
SR Operating
tBODYDIODE
VFB
tONS
Figure 4. SR Turning Off Timing Impact on PSR CV Sampling
Recommended Application Circuit Parameters
The two resistors R23 and R24 are used to pass ESD test. The value of R23 and R24 should be over 20Ω and below 47Ω respectively because of
the undershoot performance. The package of R23 and R24 should be at least 0805 and there isn’t any trace under these two resistors.
CAREF is suggested to parallel with AREF resistor to keep the volt-second product threshold stable. And the recommended value of CAREF is 100nF.
The recommended value of C24 is 100nF.
Ordering Information
APR34309CA XX XX - XX
Product Name
RoHS/Green
G1 : Green
Package
Packing
MP: SO-8EP
TR : Tape & Reel
Package
Temperature Range
-40 to +85C
Part Number
Marking ID
34309CAMP-G1
Packing
SO-8EP
APR34309CAMPTR-G1
4000/Tape & Reel
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
Marking Information
(Top View)
First and Second Lines: Logo and Marking ID
Third Line: Date Code
Y: Year
WW: Work Week of Molding
A: Assembly House Code
XX: 7th and 8th Digits of Batch No.
34309C
AMP-G1
YWWAXX
Package Outline Dimensions (All dimensions in mm(inch).)
(1) Package Type: SO-8EP
3.800(0.150)
4.000(0.157)
2.110(0.083)
2.710(0.107)
4.700(0.185)
1.270(0.050)
TYP
5.100(0.201)
0.300(0.012)
0.510(0.020)
0.050(0.002)
0.150(0.006)
5.800(0.228)
6.200(0.244)
1.350(0.053)
1.550(0.061)
0.400(0.016)
1.270(0.050)
0.150(0.006)
0.250(0.010)
Note: Eject hole, oriented hole and mold mark is optional.
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
Suggested Pad Layout
(1) Package Type: SO-8EP
Y1
G
Z
X1
Y
E
X
Z
G
X
Y
X1
Y1
E
Dimensions
(mm)/(inch) (mm)/(inch) (mm)/(inch) (mm)/(inch)
(mm)/(inch)
(mm)/(inch)
(mm)/(inch)
Value
6.900/0.272 3.900/0.154 0.650/0.026 1.500/0.059
3.600/0.142
2.700/0.106
1.270/0.050
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APR34309CA
Document number: DS37672 Rev. 5 - 2
APR34309CA
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes
without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume
all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated
website, harmless against all damages.
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indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings
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This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any
use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its
representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2015, Diodes Incorporated
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