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(R)
VIPER22ADIP VIPER22AS
LOW POWER OFF LINE SMPS PRIMARY SWITCHER
TYPICAL POWER CAPABILITY
Mains type European (195 - 265 Vac) US / Wide range (85 - 265 Vac) SO-8 12 W 7W DIP-8 20 W 12 W SO-8 DIP-8
ORDER CODES
n n n n
FIXED 60 KHZ SWITCHING FREQUENCY 9V TO 38V WIDE RANGE VDD VOLTAGE CURRENT MODE CONTROL AUXILIARY UNDERVOLTAGE LOCKOUT WITH HYSTERESIS SOURCE
PACKAGE
SO-8 DIP-8
TUBE T&R VIPER22AS VIPER22AS13TR VIPER22ADIP -
n HIGH VOLTAGE START UP CURRENT n OVERTEMPERATURE, OVERCURRENT AND
OVERVOLTAGE PROTECTION WITH AUTORESTART DESCRIPTION The VIPER22A combines a dedicated current mode PWM controller with a high voltage Power BLOCK DIAGRAM
MOSFET on the same silicon chip. Typical applications cover off line power supplies for battery charger adapters, standby power supplies for TV or monitors, auxiliary supplies for motor control, etc. The internal control circuit offers the following benefits: - Large input voltage range on the VDD pin accommodates changes in auxiliary supply voltage. This feature is well adapted to battery charger adapter configurations. - Automatic burst mode in low load condition. - Overvoltage protection in hiccup mode.
DRAIN
ON/OFF REGULATOR 60kHz OSCILLATOR
INTERNAL SUPPLY
OVERTEMP. DETECTOR
R1
S FF
PWM LATCH Q
R2 R3 R4
VDD 8/14.5V
_ BLANKING + OVERVOLTAGE LATCH Q
+ _ 0.23 V
+ 42V _ S
R FF
230
1 k FB
SOURCE
September 2002
1/15
VIPER22ADIP / VIPER22AS
PIN FUNCTION
Name Function Power supply of the control circuits. Also provides a charging current during start up thanks to a high voltage current source connected to the drain. For this purpose, an hysteresis comparator monitors the VDD voltage and provides two thresholds: - VDDon: Voltage value (typically 14.5V) at which the device starts switching and turns off the start up current source. - VDDoff: Voltage value (typically 8V) at which the device stops switching and turns on the start up current source. Power MOSFET source and circuit ground reference. Power MOSFET drain. Also used by the internal high voltage current source during start up phase for charging the external VDD capacitor. Feedback input. The useful voltage range extends from 0V to 1V, and defines the peak drain MOSFET current. The current limitation, which corresponds to the maximum drain current, is obtained for a FB pin shorted to the SOURCE pin.
VDD
SOURCE DRAIN
FB
CURRENT AND VOLTAGE CONVENTIONS
I DD
ID
I FB
FB
VDD
CONTROL
DRAIN
VDD VFB
VIPER22A
VD
SOURCE
CONNECTION DIAGRAM
SOURCE SOURCE FB VDD
1 2 3 4
8 7 6 5
DRAIN DRAIN DRAIN DRAIN
SOURCE SOURCE FB VDD
1 2 3 4
8 7 6 5
DRAIN DRAIN DRAIN DRAIN
SO-8
DIP8
2/15
VIPER22ADIP / VIPER22AS
ABSOLUTE MAXIMUM RATINGS
Symbol VDS(sw) VDS(st) ID VDD IFB VESD Tj Tc Tstg Parameter Switching Drain Source Voltage (Tj=25 ... 125C) Start Up Drain Source Voltage (Tj=25 ... 125C) Continuous Drain Current Supply Voltage Feedback Current Electrostatic Discharge: Machine Model (R=0; C=200pF) Charged Device Model Junction Operating Temperature Case Operating Temperature Storage Temperature (See note 1) (See note 2) Value -0.3 ... 730 -0.3 ... 400 Internally limited 0 ... 50 3 200 1.5 Internally limited -40 to 150 -55 to 150 Unit V V A V mA V kV C C C
Note: 1. This parameter applies when the start up current source is off. This is the case when the VDD voltage has reached VDDon and remains above VDDoff. 2. This parameter applies when the start up current source is on. This is the case when the VDD voltage has not yet reached VDDon or has fallen below V DDoff.
THERMAL DATA
Symbol Rthj-case Parameter Thermal Resistance Junction-Pins for : SO-8 DIP-8 Thermal Resistance Junction-Ambient for : SO-8 DIP-8 (See note 1) (See note 1) Max Value 25 15 55 45 Unit C/W
Rthj-amb
C/W
Note: 1. When mounted on a standard single-sided FR4 board with 200 mm of Cu (at least 35 m thick) connected to all DRAIN pins.
ELECTRICAL CHARACTERISTICS (Tj=25C, VDD=18V, unless otherwise specified) POWER SECTION
Symbol BVDSS IDSS RDSon tf tr Coss Parameter Drain-Source Voltage Off State Drain Current Static Drain-Source On State Resistance Fall Time Rise Time Drain Capacitance Test Conditions ID=1mA; VFB=2V VDS=500V; VFB=2V; Tj=125C ID=0.4A ID=0.4A; Tj=100C ID=0.2A; VIN=300V ID=0.4A; VIN=300V VDS=25V (See fig.1) (See note 1) (See fig.1) (See note 1) 15 Min. 730 0.1 17 31 Typ. Max. Unit V mA ns ns pF
100 50 40
Note: 1. On clamped inductive load
3/15
VIPER22ADIP / VIPER22AS
ELECTRICAL CHARACTERISTICS (Tj=25C, VDD=18V, unless otherwise specified) SUPPLY SECTION
Symbol IDDch IDDoff IDD0 IDD1 DRST VDDoff VDDon VDDhyst VDDovp Parameter Start Up Charging Current Start Up Charging Current in Thermal Shutdown Test Conditions VDS=100V; VDD=0V ...VDDon (See fig. 2) VDD=5V; VDS=100V Tj > TSD - THYST 0 3 (Note 1) (See fig. 3) (See fig. 2 & 3) (See fig. 2 & 3) (See fig. 2) 7 13 5.8 38 4.5 16 8 14.5 6.5 42 9 16 7.2 46 5 Min. Typ. -1 Max. Unit mA mA mA mA % V V V V
Operating Supply Current I =2mA FB Not Switching Operating Supply Current I =0.5mA; I =50mA FB D Switching Restart Duty Cycle VDD Undervoltage Shutdown Threshold VDD Start Up Threshold VDD Threshold Hysteresis VDD Overvoltage Threshold
Note: 1. These test conditions obtained with a resistive load are leading to the maximum conduction time of the device.
OSCILLATOR SECTION
Symbol FOSC Parameter Oscillator Frequency Total Variation Test Conditions VDD=VDDoff ... 35V; Tj=0 ... 100C Min. 54 Typ. 60 Max. 66 Unit kHz
PWM COMPARATOR SECTION
Symbol GID IDlim IFBsd RFB td tb tONmin Parameter IFB to ID Current Gain Peak Current Limitation IFB Shutdown Current FB Pin Input Impedance Current Sense Delay to Turn-Off Blanking Time Minimum Turn On Time ID=0mA ID=0.4A VFB=0V Test Conditions (See fig. 4) (See fig. 4) (See fig. 4) (See fig. 4) 0.56 Min. Typ. 560 0.7 0.9 1.2 200 500 700 0.84 A mA k ns ns ns Max. Unit
OVERTEMPERATURE SECTION
Symbol TSD THYST Parameter Thermal Shutdown Temperature Thermal Shutdown Hysteresis Test Conditions (See fig. 5) (See fig. 5) Min. 140 Typ. 170 40 Max. Unit C C
4/15
VIPER22ADIP / VIPER22AS
Figure 1 : Rise and Fall Time
ID
C C << Coss
L
D
t VDS
90% tfv trv
FB VDD
CONTROL
DRAIN
300V
SOURCE
VIPER22A
10%
t
Figure 2 : Start Up VDD Current
IDD
IDD0
VDDhyst
VDDoff IDDch
VDDon
VDD
VDS = 100 V Fsw = 0 kHz
Figure 3 : Restart Duty Cycle
VDD
VDDon
VDD DRAIN
VDDoff tCH tST
10F
FB
CONTROL
100V
SOURCE
t
2V
VIPER22A
tST D RST = ------------------------t ST + tCH
5/15
VIPER22ADIP / VIPER22AS
Figure 4 : Peak Drain Current vs. Feedback Current
100V
ID
IDpeak
4mH
1/FOSC
VDD
DRAIN
t
18V
FB
CONTROL
100V
SOURCE
IFB
47nF
VIPER22A
VFB
I R FBsd FB
The drain current limitation is obtained for VFB = 0 V, and a negative current is drawn from the FB pin. See the Application section for further details.
IFB
IDpeak
IDlim
I Dpea k GID = - ---------------------I FB
IFB
0 IFBsd
Figure 5 : Thermal Shutdown
Tj
TSD THYST
t VDD
VDDon
Automatic start up
t
6/15
VIPER22ADIP / VIPER22AS
Figure 6 : Switching Frequency vs Temperature
1.01
Vdd = 10V ... 35V
Normalized Frequency
1
0.99
0.98
0.97 -20 0 20 40 60 80 100 120 Temperature (C)
Figure 7 : Current Limitation vs Temperature
1.04 1.03 Normalized Current Limitation 1.02 1.01 1 0.99 0.98 0.97 0.96 0.95 0.94 -20 0 20 40 60 80 100 120 Temperature (C)
Vin = 100V Vdd = 20V
7/15
VIPER22ADIP / VIPER22AS
Figure 8 : Rectangular U-I output characteristics for battery charger
DCOUT R1 C2 D1 T1 D2 C1
F1 AC IN C3
T2 + D4 C4 ISO1 U1
VDD
D3
DRAIN
C5 C6
FB
CONTROL
SOURCE
VIPerX2A C7
R2
D5
U2 R3
Vcc Vref
R4
R5 C10
C8
+ GND + -
C9
R6
R7 R10
R8
TSM101
R9
GND
RECTANGULAR U-I OUTPUT CHARACTERISTIC A complete regulation scheme can achieve combined and accurate output characteristics. Figure 8 presents a secondary feedback through an optocoupler driven by a TSM101. This device offers two operational amplifiers and a voltage reference, thus allowing the regulation of both output voltage and current. An integrated OR function performs the combination of the two resulting error signals, leading to a dual voltage and current limitation, known as a rectangular output characteristic. This type of power supply is especially useful for battery chargers where the output is mainly used in current mode, in order to deliver a defined charging rate. The accurate voltage regulation is also convenient for Li-ion batteries which require both modes of operation.
WIDE RANGE OF VDD VOLTAGE The VDD pin voltage range extends from 9V to 38V. This feature offers a great flexibility in design to achieve various behaviors. In figure 8 a forward configuration has been chosen to supply the device with two benefits: - as soon as the device starts switching, it immediately receives some energy from the auxiliary winding. C5 can be therefore reduced and a small ceramic chip (100 nF) is sufficient to insure the filtering function. The total start up time from the switch on of input voltage to output voltage presence is dramatically decreased. - the output current characteristic can be maintained even with very low or zero output voltage. Since the TSM101 is also supplied in forward mode, it keeps the current regulation up whatever the output voltage is.The VDD pin voltage may vary as much as the input voltage, that is to say with a ratio of about 4 for a wide range application.
8/15
VIPER22ADIP / VIPER22AS
FEEDBACK PIN PRINCIPLE OF OPERATION A feedback pin controls the operation of the device. Unlike conventional PWM control circuits which use a voltage input (the inverted input of an operational amplifier), the FB pin is sensitive to current. Figure 9 presents the internal current mode structure. The Power MOSFET delivers a sense current Is which is proportional to the main current Id. R2 receives this current and the current coming from the FB pin. The voltage across R2 is then compared to a fixed reference voltage of about 0.23 V. The MOSFET is switched off when the following equation is reached: In a real application, the FB pin is driven with an optocoupler as shown on figure 9 which acts as a pull up. So, it is not possible to really short this pin to ground and the above drain current value is not achievable. Nevertheless, the capacitor C is averaging the voltage on the FB pin, and when the optocoupler is off (start up or short circuit), it can be assumed that the corresponding voltage is very close to 0 V. For low drain currents, the formula (1) is valid as long as IFB satisfies IFB< IFBsd, where IFBsd is an internal threshold of the VIPER22A. If IFB exceeds this threshold the device will stop switching. This is represented on figure 4, and IFBsd value is specified in the PWM COMPARATOR SECTION. Actually, as soon as the drain current is about 12% of Idlim, that is to say 85 mA, the device will enter a burst mode operation by missing switching cycles. This is especially important when the converter is lightly loaded. It is then possible to build the total DC transfer function between ID and IFB as shown on figure 10. This figure also takes into account the internal blanking time and its associated minimum turn on time. This imposes a minimum drain current under which the device is no more able to control it in a linear way. This drain current depends on the primary inductance value of the transformer and the input voltage. Two cases may occur, depending on the value of this current versus the fixed 85 mA value, as described above. START UP SEQUENCE This device includes a high voltage start up current source connected on the drain of the device. As soon as a voltage is applied on the input of the converter, this start up current source is activated as long as VDD is lower than VDDon. When reaching VDDon, the start up current source is switched off and the device begins to operate by turning on and off its main power MOSFET. As the FB pin does not receive any current from the optocoupler, the device operates at full current capacity and the output voltage rises until reaching Figure 10 : IFB Transfer function
IDpeak
IFB FB R1
0.23V
R 2 ( IS + IFB ) = 0.23V
By extracting IS:
0.23V I S = ------------- - I FB R2
Using the current sense ratio of the MOSFET GID :
0.23V I D = G ID IS = G ID ------------- - IFB R2
The current limitation is obtained with the FB pin shorted to ground (VFB = 0 V). This leads to a negative current sourced by this pin, and expressed by:
0.23V IFB = - ------------R1
By reporting this expression in the previous one, it is possible to obtain the drain current limitation IDlim:
1 1 IDlim = G ID 0.23V ----- + ----- R 2 R 1
Figure 9 : Internal Current Control Structure
DRAIN
60kHz OSCILLATOR
Id
+Vdd
S PWM LATCH R
Q
Secondary feedback
Is
IDlim
1 k
C
230
R2
SOURCE
1 t V ONmin IN -------------------------------------L 2 t V ONmin IN -------------------------------------L
Part masked by the IFBsd threshold
85mA
IFB
IFBsd
0
9/15
VIPER22ADIP / VIPER22AS
Figure 11 : Start Up Sequence
VDD
VDDon
Figure 12 : Overvoltage Sequence
VDD
VDDovp
VDDoff tss
VDDon VDDoff
t IFB
t
VDS
t VOUT
t
t
OVERVOLTAGE THRESHOLD An overvoltage detector on the VDD pin allows the VIPER22A to reset itself when VDD exceeds VDDovp. This is illustrated in figure 12, which shows the whole sequence of an overvoltage event. Note that this event is only latched for the time needed by VDD to reach VDDoff, and then the device resumes normal operation automatically.
the regulation point where the secondary loop begins to send a current in the optocoupler. At this point, the converter enters a regulated operation where the FB pin receives the amount of current needed to deliver the right power on secondary side. This sequence is shown in figure 11. Note that during the real starting phase tss, the device consumes some energy from the VDD capacitor, waiting for the auxiliary winding to provide a continuous supply. If the value of this capacitor is too low, the start up phase is terminated before receiving any energy from the auxiliary winding and the converter never starts up. This is illustrated also in the same figure in dashed lines.
10/15
VIPER22ADIP / VIPER22AS
SO-8 MECHANICAL DATA
mm. MIN. 0.1 0.65 0.35 0.19 0.25 4.8 5.8 1.27 3.81 3.8 0.4 4 1.27 0.6 8 (max.) 0.8 1.2 0.031 0.047 0.14 0.015 TYP MAX. 1.75 0.25 1.65 0.85 0.48 0.25 0.5 45 (typ.) 5 6.2 0.188 0.228 0.050 0.150 0.157 0.050 0.023 0.196 0.244 0.025 0.013 0.007 0.010 0.003 MIN. inch TYP. MAX. 0.068 0.009 0.064 0.033 0.018 0.010 0.019
DIM. A a1 a2 a3 b b1 C c1 D E e e3 F L M S L1
11/15
1
VIPER22ADIP / VIPER22AS
Plastic DIP-8 MECHANICAL DATA
DIM. A A1 A2 b b2 c D E E1 e eA eB L Package Weight 2.92 3.30 Gr. 470 0.38 2.92 0.36 1.14 0.20 9.02 7.62 6.10 3.30 0.46 1.52 0.25 9.27 7.87 6.35 2.54 7.62 10.92 3.81 4.95 0.56 1.78 0.36 10.16 8.26 7.11 mm. MIN. TYP MAX. 5.33
P001
12/15
VIPER22ADIP / VIPER22AS
SO-8 TUBE SHIPMENT (no suffix)
B
C
A
Base Q.ty Bulk Q.ty Tube length ( 0.5) A B C ( 0.1)
All dimensions are in mm.
100 2000 532 3.2 6 0.6
TAPE AND REEL SHIPMENT (suffix "13TR") REEL DIMENSIONS
Base Q.ty Bulk Q.ty A (max) B (min) C ( 0.2) F G (+ 2 / -0) N (min) T (max) 2500 2500 330 1.5 13 20.2 12.4 60 18.4
All dimensions are in mm.
TAPE DIMENSIONS
According to Electronic Industries Association (EIA) Standard 481 rev. A, Feb 1986 Tape width Tape Hole Spacing Component Spacing Hole Diameter Hole Diameter Hole Position Compartment Depth Hole Spacing W P0 ( 0.1) P D ( 0.1/-0) D1 (min) F ( 0.05) K (max) P1 ( 0.1) 12 4 8 1.5 1.5 5.5 4.5 2
End
All dimensions are in mm.
Start Top cover tape 500mm min Empty components pockets saled with cover tape. User direction of feed 500mm min No components Components No components
13/15
1
VIPER22ADIP / VIPER22AS
DIP-8 TUBE SHIPMENT (no suffix)
A
C
B
Base Q.ty Bulk Q.ty Tube length ( 0.5) A B C ( 0.1)
All dimensions are in mm.
20 1000 532 8.4 11.2 0.8
14/15
1
VIPER22ADIP / VIPER22AS
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may results from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a trademark of STMicroelectronics (c) 2002 STMicroelectronics - Printed in ITALY- All Rights Reserved. STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com
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