AN9035 MOTION-SPM IN MINI-DIP APPLICATION NOTE
4
REV. B 7/19/05
Introduction
1.1 Introduction
The terms "energy-saving" and "quiet-running" are
becoming very important in the world of variable speed
motor drives. For low-power motor control, there are
increasing demands for compactness, built-in control, and
lower overall-cost. An important consideration, in justifying
the use of inverters in these applications, is to optimize the
total-cost-performance ratio of the overall drive system. In
other words, the systems have to be less noisy, more
efficient, smaller and lighter, more advanced in function and
more accurate in control with a very low cost.
In order to meet these needs, Fairchild has developed a new
series of compact, high-functionality, and high efficiency
power semiconductor device called "Motion-SPM in Mini-
DIP". This Motion-SPM based inverters are now considered
an excellent alternative to conventional discrete-based
inverters for low-power motor drives, specifically for
appliances such as washing machines, air-conditioners,
refrigerators, water pumps etc.
This Motion-SPM combines optimized circuit protection and
drive matched to the IGBT’s switching characteristics.
System reliability is further enhanced by the integrated
under-voltage protection function and short circuit
protection function. The high speed built-in HVIC provides
an opto-coupler-less IGBT gate driving capability that
further reduces the overall size of the inverter system design.
Additionally, the incorporated HVIC allows the use of a
single-supply drive topology without negative bias.
The objective of this application note is to show the detailed
power circuit design of Motion-SPM in Mini-DIP and its
applications for users. This document provides design
examples which enable motor drive design engineers to
create efficient optimized designs with shortened design
cycles by employing Fairchild Motion-SPM products.
1.2 Design Concept
The key design objective of Motion-SPM in Mini-DIP is to
create a low power module with improved reliability. This is
achieved by applying existing IC and LSI transfer mold
packaging technology. The structure of Motion-SPM is
relatively simple: power chips and IC chips are directly die
bonded on the copper lead frame, the bare ceramic material
is attached to the frame, and then molded into epoxy resin. In
comparison, the typical IPM is made of power chips bonded
on a metal or ceramic substrate with the ICs and the passive
components assembled on a PCB. This is then assembled
into a plastic or epoxy resin case and filled up with silicon
gel. The Motion-SPM in Mini-DIP greatly minimizes the
number of parts and material types, optimizing the assembly
process and overall cost.
The second important design advantage of Motion-SPM in
Mini-DIP is the realization of a product with smaller size and
higher power rating. Of the low power modules released to
date, the Motion-SPM in Mini-DIP has the highest power
density with 3A to 30A rated products built into a single
package outline.
The third design advantage is design flexibility enabling use
in a wide range of applications. This Motion-SPM series has
two major flexibility features. First is the 3-N terminal
structure with the negative rail IGBT emitters terminated
separately. With this structure, shunt resistance can be placed
in series with each 3-N terminal to easily sense individual
inverter phase currents. Second is the high-side IGBT
switching dv/dt control. This is made possible by the
insertion of an appropriate impedance network in the high-
side IGBT gate drive circuits. By properly designing the
impedance network, the high-side switching speed can be
adjusted so that critical EMI problems may be easily dealt
with.
The detailed features and integrated functions are as follows:
• 600V/3A to 30A ratings in one package (with identical
mechanical layouts)
• Low-loss efficient IGBTs and FRDs optimized for motor
drive applications
• High reliability due to fully tested coordination of HVIC
and IGBTs
• 3-phase IGBT Inverter Bridge including control ICs for
gate drive and protection
- High-Side Features: Control circuit under voltage (UV)
protection (without fault signal output)
- Low-Side Features: UV and short-circuit (SC)
protection through external shunt resistor
(with fault signal output)
• Single-grounded power supply and opto-coupler-less
interface due to built-in HVIC
• Active-high input signal logic resolves the startup and
shutdown sequence constraint between the VCC control
supply and control input providing fail-safe operation
with direct connection between the Motion-SPM and a
3.3V CPU or DSP. Additional external sequence logic is
not needed
• Divided negative DC-link terminals for inverter
applications requiring individual phase current sensing
• Isolation voltage rating of 2500Vrms for one minute
• Very low leakage current due to ceramic or DBC
substrate.
1.3 Technology
Power Devices - IGBT and FRD
The improved performance of Motion-SPM in Mini-DIP is
primarily the result of the technological advancement of the
power devices (i.e., IGBTs and FRDs) in the 3-phase inverter
circuit. The fundamental design goal is to reduce the die size
and increase the current density of these power devices. This
Motion-SPM IGBTs represent Fairchild's latest technology.
Through optimized PT planar IGBT design, they maintain a
SOA (Safe Operating Area) suitable for motor control
application while dramatically reducing the on-state