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Series STR-F6600
INTERIM DATA SHEET
(Subject to change without notice) February 22, 2000
OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
The Series STR-F6600 is specifically designed to satisfy the requirements for increased integration and reliability in off-line quasi-resonant flyback converters. The series incorporates a primary control and drive circuit with discrete avalanche-rated power MOSFETs.
Data Sheet 28102.8
FDBK
OSC.
LATCH
OCP
UVLO OVP TSD
Covering the power range from below 25 watts up to 300 watts for 100/115/230 VAC inputs, and up to 150 watts for 85 to 265 VAC universal input, these devices can be used in a range of applications, from battery chargers and set top boxes, to televisions, monitors, and industrial power supply units. Cycle-by-cycle current limiting, under-voltage lockout with hysteresis, over-voltage protection, and thermal shutdown protects the power supply during the normal overload and fault conditions. Over-voltage protection and thermal shutdown are latched after a short delay. The latch may be reset by cycling the input supply. Low-current startup and a low-power standby mode selected from the secondary circuit completes a comprehensive suite of features. The series is provided in a five-pin overmolded TO-3P style package, affording dielectric isolation without compromising thermal characteristics.
2
3
VIN
1
OVER-CURRENT & FEEDBACK
4
Dwg. PK-011-1
ABSOLUTE MAXIMUM RATINGS at TA = +25C
Control Supply Voltage, VIN . . . . . . . . 35 V Drain-Source Voltage, VDS Series STR-F6620 . . . . . . . . . . . . 450 V Series STR-F6630 . . . . . . . . . . . . 500 V Series STR-F6650 . . . . . . . . . . . . 650 V Series STR-F6670 . . . . . . . . . . . . 900 V Drain Switching Current, ID . . . See Table Peak Drain Current, IDM . . . . . . See Table Avalanche Energy, EAS . . . . . . . See Table OCP/FB Voltage Range, VOCP . . . . . . . . . . . . . . . -0.3 V to +6 V Package Power Dissipation, PD control (VIN x IIN(ON)) . . . . . . . . . 0.8 W total . . . . . . . . . . . . . . . . . . . See Graph FET Channel Temperature, TJ . . . +150C Internal Frame Temperature, TF . . +125C Operating Temperature Range, TA . . . . . . . . . . . . . . . -20C to +125C Storage Temperature Range, TS . . . . . . . . . . . . . . . . -40C to +125C
GROUND
SOURCE
SUPPLY
DRAIN
5
FEATURES
s Flyback Operation with Quasi-Resonant Soft Switching for Low Power Dissipation and EMI s Rugged Avalanche-Rated MOSFET s Choice of MOSFET Voltage and rDS(on) s Full Over-Current Protection (no blanking) s Under-Voltage Lockout with Hysteresis s Over-Voltage Protection s Direct Voltage Feedback s Low Start-up Current (<400 A) s Low-Frequency, Low-Power Standby Operation s Overmolded 5-Pin Package
Always order by complete part number, e.g., STR-F6652 .
TM
TM
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
FUNCTIONAL BLOCK DIAGRAM
V IN 4 DRIVE REG. UVLO OVER-VOLT. PROTECT S REF. R FAULT LATCH Q 3 2 DRAIN SOURCE
TSD OSC
-
r SS
+
1.45 V FEEDBACK & OVER-CURRENT PROTECTION
c SS
- + 0.73 V 1
GROUND
Dwg. FK-002-6
1.0
NORMALIZED ALLOWABLE AVALANCHE ENERGY in mJ
0.8
0.6
Allowable package power dissipation curves are shown on page 10.
0.4
0.2
0 25 50 75 100 125
Dwg.
STARTING CHANNEL TEMPERATURE in C
2
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright (c) 2000 Allegro MicroSystems, Inc.
TM TM
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
OUTPUT MAXIMUM RATINGS at TA = +25C
Part Number STR-F6624 STR-F6626 STR-F6628 STR-F6632 STR-F6652 STR-F6653 STR-F6654 STR-F6656 STR-F6672 STR-F6674 STR-F6676 VDSS (V) 450 450 450 500 650 650 650 650 900 900 900 rDS(on) () 0.92 0.58 0.35 2.54 2.8 1.95 1.15 0.71 7.7 4.49 2.81 EAS (mJ)* 204 327 647 7.4 126 260 399 521 163 242 275 ID (A) 16 16 22 9.0 7.9 5.6 9.7 16 4.6 6.0 7.8 IDM (A) 19 26 36 11.2 10 14 18 25 6.4 9.2 12 POUT (W) at VIN (V rms) 100 120 100 120 100 120 100 120 85-265 220 85-265 220 85-265 220 85-265 220 220 220 85-265 220 85-265 220
98 130 145 190 225 290 36 50 40 86 58 120 92 190 150 300 25 (no heatsink) 50 (with heat sink) 28 76 44 115
* Derate per graph, page 2 Derate per graph, page 12
3
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
ELECTRICAL CHARACTERISTICS at TA = +25C, VIN = 18 V (unless otherwise specified).
Limits Characteristic On-State Voltage Under-Voltage Lockout Over-Voltage Threshold Drain-Source Breakdown Voltage Drain Leakage Current On-State Resistance Maximum Off Time Minimum Pulse Duration for Input of Quasi-Resonant Signals Minimum Off Time Feedback Threshold Voltage Symbol VINT VINQ VOVP(th) VBR(DSS) IDSS Test Conditions Turn-on, increasing VIN Turn-off, decreasing VIN Turn-off, increasing VIN ID = 300 A At VDS max VS = 10 V, ID = 0.9 A, TJ = +25C Drain waveform high Drain waveform high1 Drain waveform high1 Drain waveform low to high1 Oscillation synchronized2 Over-Current Protection/Feedback Sink Current Latch Holding Current Latch Release Voltage Switching Time Supply Current IOCP/FB IIN(OVP) VIN tf IIN(ON) IIN(OFF) Insulation RMS Voltage VWM(RMS) VOCP/FB = 1.0 V VIN reduced from 24.5 V to 8.5 V IIN 20 A, VIN reduced from 24.5 V VDD = 200 V, ID = 0.9 A Operating3 Increasing VIN prior to oscillation All terminals simultaneous reference to a metal plate against the backside Output channel to mounting frame Min. 14.4 9.0 20.5 VDS max - - 45 - - 0.68 1.3 1.2 - 6.6 - - - 2000 Typ. 16 10 22.5 - - - - - - 0.73 1.45 1.35 - - - - - - Max. 17.6 11 24.5 - 300 see table 55 1.0 1.5 0.78 1.6 1.5 400 8.4 250 30 100 - Units V V V V A s s s V V mA A V ns mA A V
rDS(ON)
toff tw(th) toff VFDBK
Thermal Resistance Thermal Shutdown
RJM TJ
- 140
- -
1.75 -
C/W C
Notes: Typical Data is for design information only. 1. Feedback is square wave, VIM = 2.2 V, th = 1 s, tl = 35 s. 2. For quasi-resonant operation, the input signal must be longer than tw(th) and greater than VFDBK. 3. Feedback is square wave, VIM = 2.2 V, th = 4 s, tl = 1 s.
4
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
TM TM
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Functional Description and Operation
The voltage on the VIN terminal (pin 4) controls startup and shutdown of the Series STR-F6600 devices. Figure 1 shows a typical start up circuit. The VIN terminal voltage during startup is shown in figure 2. At startup, C2 is charged through the startup resistor RS. When the VIN terminal voltage reaches 16 V (typ.), the control circuit enables regulator operation. Once the regulator starts, it draws up to 30 mA from C2 causing the voltage on C2 to fall momentarily. Once the regulator output voltage is established, the drive winding D starts to charge C2 via D2. The voltage on C2 thus recovers to the nominal drive voltage (18 V). As shown in figure 3, the input current is below 100 A (at TM = 25C) prior to control circuit turn on. The latch circuit holding current is 400 A (max.). To ensure latch operation, the current in RS at the lowest ac input voltage should be at least 500 A.
IIN
VINQ
30 mA (MAX.)
IIN(ON)
Figure 1 - Start-Up Circuit
VIN
16 V ON-STATE VOLTAGE (VINT) (TYP.)
100 A (MAX.)
IIN(OFF) 11 V (MAX.)
VINT
14.4 V (MIN.)
VIN
Figure 3 - Supply Terminal Current, IIN
11 V (MAX.) UNDER-VOLTAGE LOCKOUT (VINQ)
OPERATION START
DRIVE WINDING VOLTAGE
The value of RS thus determines the charge time of C2 and thus the startup delay. RS is typicaly 68 k for wide operation (90 V ac to 265 V ac) and 100 k for 220 volt ac operation. The choice of C2 is a compromise between an acceptable startup delay (in conjunction with RS) and a hold-up time sufficient to keep pin 4 above its under-voltage shutdown threshold of 11 V. Typically C2 is in the range of 47 F to 100 F.
continued, next page...
STARTUP DELAY
TIME
Figure 2 - Waveform of VIN Terminal Voltage at Startup
5
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Functional Description and Operation (cont'd)
The drive winding voltage is set such that in normal operation the C2 voltage is above the specified maximum shutdown voltage (11 V) and below the specified minimum over-voltage threshold (20.5 V). In applications where there is a significant variation in load current, the VIN terminal voltage may vary, as shown in figure 4. This is due to peak charging of C2. In this case, adding a resistor in the range of a few ohms to tens of ohms in series with the rectifier diode D2 will bring the voltage variation within limits.
VIN
comparator output pre-terminates the oscillator, which turns off the MOSFET drive signal. The MOSFET is turned on again when either cSS discharges or a quasi-resonance signal is detected on pin 1. Fixed 50 s Off-Time: Soft-Start Mode This is the mode of operation in the absence of a quasiresonance signal on pin 1 (see figure 5), and occurs at
IOUT
Figure 5 - Soft-Start Operation
Figure 4 - Output Current IOUT - Terminal Voltage VIN
Soft Start, Quasi Resonant and Voltage Regulation Refer to the Functional Block Diagram and the Typical Application Diagram (figure 6). The internal oscillator uses the charge/discharge of an internal 4700 pF capacitor (cSS) to generate the MOSFET drive signals. The regulator has two modes of operation: 1. fixed 50 s off time (soft start) and 2. demagnetization sensing quasi-resonant mode -- normal operation. In both cases, voltage regulation is achieved by taking the composite optocoupled voltage error and superimposed drain current ramp (current-mode control) and comparing this to an internal 0.73 V reference. The FBK/OCP
startup and in overload. It also can be commanded externally to provide low-power standby operation. In the absence of a feedback signal (such as at startup, or a short circuit) the drain current ramp, sensed across R5 and noise filtered by R4/C5 appears on pin 1. When the ramp voltage on C5 exceeds the 0.73 V reference signal, the FBK/OCP comparator changes state, shutting down the oscillator and turning off the MOSFET. Thus the voltage on cSS is held high (6.5 V) by the comparator. When the comparator changes state, cSS discharges via rSS; the voltage on cSS ramps down until it reaches 3.7 V. The oscillator turns on the MOSFET. This ramp-down time is internally trimmed to 50 s. The comparator changes state again and the cycle repeats. Thus in the absence of feedback, the current-sense resistor R5 accurately controls the MOSFET maximum current.
6
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
TM TM
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Functional Description and Operation (cont'd)
+ OUTPUT
4 DRIVE REG. UVLO OVER-VOLT. PROTECT S R FAULT LATCH Q 3 2
+
VOLTAGE SENSE
FULL-BRIDGE RECTIFIER
REF.
AC INPUT
+
TSD OSC
+
- OUTPUT
- + 1.45 V
- + 0.73 V
1
5
Dwg. EK-003-5A
Figure 6 - Series STR-F6600 Typical Application
WARNING -- These devices are designed to be operated at lethal voltages and energy levels. Circuit
designs that embody these components must conform with applicable safety requirements. Precautions must be taken to prevent accidental contact with power-line potentials. Do not connect grounded test equipment. The use of an isolation transformer is recommended during circuit development and breadboarding.
Soft Start with Voltage Feedback (refer to figure 7) Output voltage control is achieved by sensing the optocoupled feedback current (proportional to the output voltage error signal) across resistor R4 and summing this with the drain current ramp on R5. The signal on pin 1 is therefore the opposite of the output voltage error signal and the drain current ramp. The dc bias signal across R4 is thus a function of the load. Consequently at light load, the bias signal on R4 is closer to the threshold voltage of the comparator. To eliminate the possibility of false shutdown at MOSFET turn on (when there is a current spike due to the discharge of primary capacitance), a constant-current sink of 1.35 mA is turned on, effectively lowering the input impedance on pin 1, and momentarily increasing the shutdown threshold.
7
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Functional Description and Operation (cont'd)
t = LpC4 VP f R = 1/2LpC4
VDS
VP
VIN
VDS (min) VD
Figure 7 - Voltage Regulation Waveforms
Normal Operation (Quasi-Resonant) Mode Refer to the Functional Block Diagram, Typical Application diagram (figure 6), and Quasi-Resonance Waveforms (figure 8). Regulation is achieved as in fixed off-time mode but instead of having a fixed off-time, the demagnetization of the transformer is sensed by a second comparator. This comparator threshold, Vth(2) is nominally 1.45 V. Quasiresonance sensing makes use of the natural magnetizing and leakage inductances and self-capacitances of the power circuit. Figure 8 shows the drain voltage waveform, (VDS), on pin 3 of the STR-F66xx, as well as VP, the voltage on the primary of the transformer. Once the current in the output diode stops flowing, the primary stored energy `rings' as shown by VP and VDS. The resonant frequency (fr) is determined by the magnetizing inductance of the transformer and the capacitor C4.
VFDBK
VOCP 2.8 V Vth(2) 1.45 V Vth(1) 0.73 V
ID
Dwg. GK-021
Figure 8 - Quasi-Resonance Waveforms
The addition of this capacitor sets the ringing frequency and reduces the harmonic content in the VDS waveform, lowering EMI. Also since VDS falls to a minimum during the first half-cycle of the ring this point can be sensed and used to turn on the MOSFET with minimum voltage across it. Thus the MOSFET is low voltage and zero current switched (LVS/ZCS).
8
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
TM TM
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Functional Description and Operation (cont'd)
The voltage VOCP (pin 1) has the same form as the VDS waveform. The condition for quasi-resonant operation is given by: 2.0 V < VOCP > 5.5 V for >1 s Transformer design is exactly as for any other discontinuous-mode type flyback. For optimum EMI/efficiency performance, quasiresonance turn off is achieved when the MOSFET is at zero voltage and zero current; that is, at one half cycle of the quasi-resonance frequency, fr. Over-Current Protection (OCP) Functions Refer to the Functional Block diagram and Typical Application diagram (figure 6). The regulator implements pulse-by-pulse over-current protection, which limits the maximum drain current in the MOSFET on every pulse by switching off the internal drive to the MOSFET, and the MOSFET drain current is detected across R5. Drive Circuit Refer to the Functional Block Diagram. This circuit is driven from the oscillator and provides the current drive to charge and discharge the MOSFET gate-source capacitance, thereby switching the device on and off. The basic circuit configuration is totem-pole type with an additional limiting resistor in the gate circuit at turn on. This limits the turn on speed of the MOSFET, thereby reducing EMI due to the discharge of primary capacitance. This is possible because of the low-voltage switching, zero-current switching nature of the turn on. The value of the turn-off resistance is lower, allowing the device turn-off current to be increased. This reduces the turn-off loss in the MOSFET. The gate drive voltage (8.3 V) is such that even with 0.73 V across R5 (drain current sense resistor), the MOSFET is fully enhanced, allowing full use to be made of its high current handling capacity. Latch Circuit The latch circuit keeps the oscillator output low to inhibit operation of the regulator when over-voltage protection (OVP) and thermal shutdown (TSD) circuits are in operation. As long as the latch hold-in current is 400 A (max., supplied via RS) with VIN at 8.5 V (pin 4), the regulator will stay in the off state. An internal noise filter provides 10 s of noise immunity to prevent spurious operation of the over-voltage protection or thermal shutdown. With the latch `on', the voltage on pin 4 cycles between 16 V and 10 V as shown in figure 9. This is due to the higher current drawn when the pin 4 is at 16 V compared to that drawn close to shutdown (10 V). Pulling VIN (pin 4) below 6.5 V will reset the latch circuit, re-enabling the regulator. Thermal Shutdown This internal feature triggers the latch if the internal frame temperature exceeds 140C (typ.). The temperature is sensed on the control IC, but also protects against overheating of the MOSFET as the MOSFET and the control IC are mounted on the same lead frame. Additionally, protection is provided for other onboard components.
VIN
16 V (TYP.)
10 V (TYP.)
TIME
Figure 9 - Example of VIN Terminal Voltage Waveform at Latch Circuit On
9
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Functional Description and Operation (cont'd)
Over-Voltage Protection Circuit This feature of the STR-F66xx triggers the latch circuit when the VIN voltage (pin 4) exceeds 22.5 V (typ.). Because the voltage on pin 4 is proportional to the output voltage (they are linked by the transformer turns ratio), the regulator protects the output against over-voltage. This function is entirely independant of the output-voltage regulation loop and indeed will protect against output over-voltage should the voltage error signal be lost. The measure of over-voltage is given by: VOUT(OVP) = VOUT(NOM) x VIN(OVP)/VIN(NOM) where VIN(OVP) is the drive voltage on pin 4. In an over-voltage sensitive application, the drive voltage can be set to close to 20 V and thus will protect the output, if it rises more than 10% above nominal.
VOUT
AC LOW
AC HIGH
IOUT
Figure 10 - Power Supply Output Overload Characteristics
ALLOWABLE PACKAGE POWER DISSIPATION
STR-F665x
60
ALLOWABLE PACKAGE POWER DISSIPATION in WATTS
STR-F667x
60
40
ALLOWABLE PACKAGE POWER DISSIPATION in WATTS
MOUNTING SURFACE TEMPERATURE STR-F6656, 56 W MAX. STR-F6654, 55 W MAX. STR-F6653, 48 W MAX. STR-F6652, 43 W MAX.
MOUNTING SURFACE TEMPERATURE STR-F6676, 53 W MAX. STR-F6672, 45 W MAX.
40
RECOMMENDED MAX. FRAME TEMP. = +115C
RECOMMENDED MAX. FRAME TEMP. = +115C 20 CONTROLLER 0.8 W MAX. FREE AIR ALL DEVICES 2.8 W MAX. LIMITED BY FRAME TEMP. = +125C MAX.
20 CONTROLLER 0.8 W MAX. FREE AIR ALL DEVICES 2.8 W MAX.
LIMITED BY FRAME TEMP. = +125C MAX.
0 20 60 100 TEMPERATURE in C 140
Dwg. GK-0
0 20 60 100 TEMPERATURE in C 140
Dwg. GK-0
10
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
TM TM
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
MOSFET Safe Operating Areas (single pulse at TA = +25C)
STR-F6652
50
50
STR-F6653
15
15
tw
=
DRAIN CURRENT in AMPERES
5 LIMITED BY rDS(on)
1.5
=0 tw .1 =1 ms ms SI NG SIN LE GL EP PU LS UL E SE
DRAIN CURRENT in AMPERES
tw
5
LIMITED BY rDS(on)
tw
=1
0.1 ms SI NG LE
ms SI NG LE
PU LS E
1.5
PU LS E
LIMITED BY VDS max
0.5 TA = +25C 0.15
0.5 TA = +25C 0.15
0.05 3.0 10 30 100 300
Dwg. GK
0.05 3.0 10 30 100 300
Dwg. GK
DRAIN-SOURCE VOLTAGE in VOLTS
DRAIN-SOURCE VOLTAGE in VOLTS
STR-F6654
50 50
STR-F6656
tw
15 LIMITED BY rDS(on) 5
tw =1
tw
DRAIN CURRENT in AMPERES
PU LS E
PU LS E
DRAIN CURRENT in AMPERES
ms SI NG LE
=0 .1 ms SI NG LE
15 LIMITED BY rDS(on) 5
tw =1
ms SI NG LE
=0 .1 ms SI NG LE PU LS E
PU LS E
1.5
1.5
LIMITED BY VDS max
0.5 TA = +25C 0.15
0.5 TA = +25C 0.15
0.05 3.0 10 30 100 300
Dwg. GK
0.05 3.0 10 30 100 300
Dwg. GK
DRAIN-SOURCE VOLTAGE in VOLTS
DRAIN-SOURCE VOLTAGE in VOLTS
LIMITED BY VDS max
LIMITED BY VDS max
11
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
MOSFET Safe Operating Areas (cont) (single pulse at TA = +25C)
STR-F6672
50
50
STR-F6676
15
15
tw =0 .1 ms SI NG LE PU LS E
DRAIN CURRENT in AMPERES
5 LIMITED BY rDS(on) 1.5
=0 .1 ms SIN tw GL =1 EP ms UL SI SE NG LE PU LS E
tw
DRAIN CURRENT in AMPERES
5 LIMITED BY rDS(on)
tw
=1
ms SI NG LE
PU LS E
1.5
0.5 TA = +25C
0.5 TA = +25C
0.15
0.15
0.05 3.0 10 30 100 300
Dwg. GK
0.05 3.0 10 30 100 300
Dwg. GK
DRAIN-SOURCE VOLTAGE in VOLTS
DRAIN-SOURCE VOLTAGE in VOLTS
S.O.A. Derating
1.0
20
Drain Switching Current (ID) Derating
TA = -20C to +125C
0.8
NORMALIZED SAFE OPERATING AREA
MAXIMUM SWITCHING CURRENT (ID) in AMPERES
16 STR-F6656
0.6
12
STR-F6654 8.0 STR-F6652 & STR-F6672 STR-F6653 4.0 STR-F6672
0.4
0.2
0 25 50 75 100 125
Dwg. G
0 0.8 0.9 1.0 1.1
Dwg
FRAME TEMPERATURE in C
SOURCE-TO-GROUND VOLTAGE (V2-V5) in VOLTS
12
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
TM TM
LIMITED BY V
LIMITED BY
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Transient Thermal Impedance
STR-F665x
10
10
STR-F667x
1.0
THERMAL IMPEDANCE (ZJC) in C/W
THERMAL IMPEDANCE (ZJC) in C/W
1.0
STR-F6652 STR-F6653 0.1
0.1 STR-F6672 STR-F6676 0.01
0.01
STR-F6654 STR-F6656
0.001
0.001
0.0001 10 n 100 n
1
10
100
0.0001
1m
10 m
100 m
10 n
100 n
1
10
100
1m
10 m
100 m
POWER PULSE DURATION in SECONDS
POWER PULSE DURATION in SECONDS
13
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Applications Information
Capacitors Electrolytic capacitors carrying large switching frequency ripple currents (C1 and the output capacitors) should be capable of handling the high rms currents involved. Capacitors with low ESR are suitable. The quasi-resonance capacitor C4 should be a high-voltage ceramic type suitable for pulsed current operation. The safety critical nature of the off-line application must be considered when selecting both X and Y capacitors for common- and differential-mode noise filtering. Use of the low-noise quasi-resonant Series STR-F6600 will allow optimization of these capacitor values. C5, the 470 pF filtering capacitor should be a 50 V temperature-stable (COG) ceramic type. Resistors Resistor R5 carries high-frequency current, and so a low internal inductance type of 1 W rating should be used. Resistor R9 (RS) should be 2 W metal oxide. All other resistors can be 1/4 watt or 1/2 watt metal film. Diodes Diodes carrying the high-frequency flyback currents (such as the transformer rectifier diodes) should have a fast or ultrafast reverse-recovery characteristic, adequate current handing and peak reverse-voltage rating. Allegro/ Sanken supplies a range of suitable diodes, and these are described in the Allegro/Sanken short-form catalogue (AMS-127) or latest issue of Bulletin D01EC0. Optocoupler Both Toshiba TLP 621 and Siemens SFH 610A2 or 615A2 are suitable. A current-transfer ratio of 50% to 200% is acceptable. Error Amplifier A standard TL431 transconductance amplifier or an Allegro/Sanken Series SE error-amplifier IC can be used. The Series SE is particularly well-suited to high-voltage (70 V to 140 V) power outputs. If a Series SE error-amplifier IC is used, normally phase compensation is not required. Should additional highfrequency attenuation be required, a capacitor (0.022 F or less) can be connected across the primary side (collectoremitter) of the optocoupler, a diode to maintain quasiresonant operation should be added in series with the phototransistor emitter.
The products described here are manufactured in Japan by Sanken Electric Co., Ltd. for sale by Allegro MicroSystems, Inc. Sanken Electric Co., Ltd. and Allegro MicroSystems, Inc. reserve the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of their products. Therefore, the user is cautioned to verify that the information in this publication is current before placing any order. These products are not authorized for use as critical components in life-support appliances, devices, or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Sanken Electric Co., Ltd. and Allegro MicroSystems, Inc. assume no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
14
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
TM TM
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Dimensions in Inches
(for reference only)
0.614
0.008
T M REF. 0.126 o
0.008
0.216
0.008
0.136
0.004
0.216 0.008
0.906 0.012
0.132
0.004
0.276
0.016
0.216 0.033
+0.008 -0.004
0.026 1 5
+0.008 -0.004
0.177
0.028
0.100
0.004 AT ROOT
Dwg. MK-003-50 in
Recommended mounting hardware torque: 4.34 - 5.79 lbf*ft. Recommended silicone grease: Dow Corning SC102, Toshiba YG6260, Shin-Etsu G746., or equivalent
15
Series STR-F6600 OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS
Dimensions in Millimeters
(controlling dimensions)
15.6
0.2
T 3.2 o
0.2
M
REF. 5.5
0.2
3.45
0.1
5.5 0.2
23.0 0.3
3.35
0.1
7.0
0.5
5.5 0.85
+0.2 -0.1
0.65 1 5
+0.2 -0.1
4.5
0.7
2.54
0.1 AT ROOT
Dwg. MK-003-50 mm
Recommended mounting hardware torque: 6 - 8 kg*cm or 0.588 - 0.784 Nm. Recommended silicone grease: Dow Corning SC102, Toshiba YG6260, Shin-Etsu G746., or equivalent
16
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
TM TM

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