July 1996
Product Highlights
Low Cost Replacement for Discrete Switchers
20 to 50 fewer components - cuts cost, increases reliability
Source-connected tab and Controlled MOSFET turn-on
reduce EMI and EMI filter costs
Allows for a 50% smaller and lighter solution
Cost competitive with linears above 5 W
Up to 90% Efficiency in Flyback Topology
Built-in start-up and current limit reduce DC losses
Low capacitance 350 V MOSFET cuts AC losses
CMOS controller/gate driver consumes only 6 mW
70% maximum duty cycle minimizes conduction losses
Simplifies Design - Reduces Time to Market
Supported by many reference designs
Integrated PWM Controller and 350 V MOSFET in a
industry standard three pin TO-220 package
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 pins, all
functions necessary for an off-line switched mode control
system: high voltage N-channel power MOSFET with controlled
turn-on gate driver, voltage mode PWM controller with
integrated 100 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. These
PI-1704112995
AC
IN
DRAIN
SOURCE
CONTROL
TOPSwitch
Figure 1. Typical Application.
TOP100-4
TOPSwitch
Family
Three-terminal Off-line PWM Switch
ORDER
PART
NUMBER
OUTPUT POWER RANGE
TOPSwitch SELECTION GUIDE
FLYBACK
TOP100YAI* 0-20 W
0-30 W
TOP101YAI* 15-35 W
25-50 W
TOP102YAI* 20-45 W
35-70 W
TOP103YAI* 25-55 W
45-90 W
TOP104YAI* 30-60 W
55-110 W
12-25 W
* Package Outline: Y03A
devices are intended for 100/110 VAC off-line Power Supply
applications in the 0 to 60 W range and power factor correction
(PFC) applications in the 0 to 110 W range. They are also well
suited for Telecom, Cablecom and other DC to DC converter
applications in the 0-25 W range (see Design Note DN-16).
100/110 V
VAC
0-6.8 W
6-12 W
8.5-17 W
11-22 W
PFC/
BOOST
100/110
VAC
48 V
DC