top412

Manufacturer Part Numbertop412
DescriptionThree-terminal Dc To Dc Pwm Switch
ManufacturerPower Integrations, Inc.
top412 datasheet
 


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TOP412/414
TOPSwitch Family
Three-terminal DC to DC PWM Switch
Product Highlights
Low Cost Replacement for Discrete Switchers
• Up to 15 fewer components - cuts cost, increases reliability
• Allows for a smaller and lighter solution under 12 mm
height, all surface mount components
Over 80% Efficiency in Flyback Topology
• Built-in start-up and current limit reduce DC losses
• Low capacitance MOSFET cuts switching losses
• CMOS controller/gate driver consumes only 7 mW
• 70% maximum duty cycle minimizes conduction losses
Simplifies Design - Reduces Time to Market
• Integrated PWM Controller and high power MOSFET
• Only one external capacitor needed for compensation,
bypass and start-up/auto-restart functions
System Level Fault Protection Features
• Auto-restart and cycle by cycle current limiting functions
handle both primary and secondary faults
• On-chip latching thermal shutdown protects the entire
system against overload
Highly Versatile
• Implements Buck, Boost, Flyback or Forward topology
• Easily interfaces with both opto and primary feedback
• Supports continuous or discontinuous mode of operation
• Specified for operation down to 16 V DC input
Description
The TOPSwitch family implements, with only three terminals,
all functions necessary for a DC to DC, converter: high voltage
N-channel power MOSFET with controlled turn-on gate driver,
voltage mode PWM controller with integrated 120 kHz oscillator,
high voltage start-up bias circuit, bandgap derived reference,
bias shunt regulator/error amplifier for loop compensation and
fault protection circuitry. Compared to discrete MOSFET and
controller or self oscillating (RCC) switching converter solutions,
a TOPSwitch integrated circuit can reduce total cost, component
count, size, weight and at the same time increase efficiency and
system reliability.
This device is well suited for Telecom,
Cablecom and other DC to DC converter applications up to
®
V IN
Figure 1. Typical Application.
Table 1. TOP412/414 Output Power.
Notes: 1. Assumes maximum junction temperature of 100 °C
2. Assumes output of 5 V and K
(645 mm
power capability in a given application depends on thermal
environment, transformer design, efficiency required, input storage
capacity, etc.
21 W of output power. Internally, the lead frame of the
SMD-8 package uses six of its pins to transfer heat from the chip
directly to the board, eliminating the cost of a heat sink.
D
CONTROL
C
TOP414
S
Output Power Capability
MINIMUM
ORDER PART NUMBER
INPUT
TOP412G
VOLTAGE
18 VDC
3 W
24 VDC
5 W
36 VDC
7 W
48 VDC
9 W
60 VDC
12 W
72 VDC
15 W
90 VDC
18 W
of 0.4 3. Soldered to 1 sq. inch
RP
2
), 2 oz. copper clad (610 gm/mm
®
V O
PI-2371-120198
1-4
TOP414G
4 W
6 W
9 W
12 W
15 W
18 W
21 W
2
) 4. The continuous
April 1999

top412 Summary of contents

  • Page 1

    ... This device is well suited for Telecom, Cablecom and other converter applications up to ® Figure 1. Typical Application. Table 1. TOP412/414 Output Power. Notes: 1. Assumes maximum junction temperature of 100 °C 2. Assumes output and K (645 mm power capability in a given application depends on thermal environment, transformer design, efficiency required, input storage capacity, etc ...

  • Page 2

    ... TOP412/414 V C CONTROL Z C SHUNT REGULATOR/ ERROR AMPLIFIER - + 5 OSCILLATOR D MAX CLOCK SAW R E Figure 2. Functional Block Diagram. Pin Functional Description DRAIN Pin: Output MOSFET drain connection. Provides internal bias current during start-up operation via an internal switched high- voltage current source. Internal current sense point. ...

  • Page 3

    ... V IN DRAIN 0 is regulated in C 5.7 V current is supplied C 4 DRAIN 0 Figure 5. Start-up Waveforms for (a) Normal Operation and (b) Auto-restart. TOP412/414 I B Slope = PWM Gain -16%/mA I CD1 2.5 6 (mA Charging C T Off Switching (a) I CD2 Discharging CD1 Charging C T Discharging C T ...

  • Page 4

    ... TOP412/414 TOPSwitch Family Functional Description (cont.) The first time V reaches the upper threshold, the high-voltage C current source is turned off and the PWM modulator and output transistor are activated, as shown in Figure 5(a). During normal operation (when the output voltage is regulated) feedback control current supplies the V supply current ...

  • Page 5

    ... C approximately 35%. This duty cycle is determined by the ratio of CONTROL pin charge ( This current source is turned off during normal operation CD2 when the output MOSFET is switching. TOP412/414 V C(reset PI-1119-110194 is regulated in hysteretic mode when the power ...

  • Page 6

    ... TOP412/414 General Circuit Operation Figure 7 shows a typical DC-DC converter application using the TOP414G. This supply delivers and works over a wide input range from 36-72 VDC. The power supply operates at an ambient temperature of 0-50 °C. In order to achieve the highest possible efficiency and smallest ...

  • Page 7

    ... Use single point grounding techniques at the SOURCE pin as shown in Figure 8. Use a ceramic high frequency decoupling capacitor to bypass noise transients which might appear on the CONTROL pin. The TOP412 and TOP414 have an over current latching shutdown feature. Failure to use a high frequency decoupling capacitor may allow incidental noise to accidentally trigger this feature ...

  • Page 8

    ... Conditions (Unless Otherwise Specified) See Figure 11 SOURCE = -40 to 125 ° mA ° 0.5 mA, See Figure 9 C CD1 TOP412 mA, C See Figure 9 TOP414 mA ° See Figure 4 See Note A See Figure mA °C ...

  • Page 9

    ... See Note A S1 open S1 open S1 open S1 open S1 open TOP412 di/dt = 400 mA/µ °C J TOP414 di/dt = 600 mA/µ ° See Figure 10 S2 open TOP412/414 Min Typ Max Units -2.4 -1.9 -1.2 mA -2.0 -1.5 -0.8 0.4 %/°C V 5.7 4.7 V 0.6 1 1.2 Hz 2.00 2.90 A 2.95 4 ...

  • Page 10

    ... Device in Latched Shutdown mA 500 µ ° Measured With Figure 7 Schematic Measured With Figure 7 Schematic See Note TOP412 Output MOSFET Enabled TOP414 Output MOSFET Disabled Min Typ Max Units 2.6 3.0 4.2 5.0 Ω 1.7 2.0 2.8 3.3 500 µA V 350 ...

  • Page 11

    ... See Figure 11 VS2 = Ω SOURCE = -40 to 125 °C J See Note ° S1/Open S1/Open ) 100 °C and the energizing voltage across the transformer DS(ON) TOP412/414 Min Typ Max Units Volts 16 -2.30 -1.65 -1.00 mA -1.20 -0.64 -0. 0.85 ...

  • Page 12

    ... TOP412/414 90% DRAIN VOLTAGE 10 Figure 9. TOPSwitch Duty Cycle Measurement. D CONTROL TOPSwitch S NOTES: 1. This test circuit is not applicable for current limit or output characteristic measurements. 2. For P package, short all SOURCE and SOURCE (HV RTN) pins together. Figure 11. TOPSwitch General Test Circuit. ...

  • Page 13

    ... The 12.5% chance of being in the correct state is due to the 8:1 counter. FREQUENCY vs. TEMPERATURE 1.2 1.0 0.8 0.6 0.4 0.2 0 -50 - 100 125 150 Junction Temperature (°C) I vs. DRAIN VOLTAGE 1.6 1.2 0.8 0 Drain Voltage (V) TOP412/414 power supply 100 A 13 4/99 ...

  • Page 14

    ... Drain Voltage ( 4/99 Scaling Factors: TOP414 1.00 TOP412 0. DRAIN CAPACITANCE POWER 100 Scaling Factors: TOP414 1.00 TOP412 0. 160 240 DRAIN Voltage (V) C OSS vs. DRAIN VOLTAGE 1000 Scaling Factors: TOP414 1.00 TOP412 0.67 100 160 240 DRAIN Voltage (V) 320 320 ...

  • Page 15

    ... G08A J2 .010 (.25 SMD-8 Heat Sink is 2 oz. Copper As Big As Possible .046 .060 .060 .046 Pin 1 .086 .186 -D- .286 Solder Pad Dimensions -F- .004 (.10 TOP412/414 DIM inches mm A 0.370-0.385 9.40-9.78 B 0.245-0.255 6.22-6.48 C 0.125-0.135 3.18-3.43 G 0.004-0.012 0.10-0.30 .420 H 0.036-0.044 0.91-1.12 J1 0.060 (NOM) 1 ...

  • Page 16

    ... TOP412/414 For the latest updates, visit our Web site: www.powerint.com Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it convey any license under its patent rights or the rights of others ...