SA828 Family
Three-Phase PWM Waveform Generator
DS4226 - 2.0 November 1996
The SA828 PWM generator has been designed to provide
waveforms for the control of variable speed AC machines,
uninterruptible power supplies and other forms of power
electronic devices which require pulse width modulation as a
means of efficient power control.
The six TTL level PWM outputs (Fig. 2) control the six
switches in a three-phase inverter bridge. This is usually via an
external isolation and amplification stage.
AD
AD
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28
27
26
25
24
23
22
21
20
19
18
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16
15
1
3
4
5
6
7
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2
1
0
2
3
4
VDD
5
ZPPB
WR* (R/W†)
RD* (DS†)
ALE* (AS†)
RST
6
ZPPY
The SA828 is fabricated in CMOS for low power
consumption.
7
ZPPR
WSS
SA828
Information contained within the pulse width modulated
sequences controls the shape, power frequency, amplitude,
and rotational direction (as defined by the red-yellow-blue
phase sequence) of the output waveform. Parameters such as
the carrier frequency, minimum pulse width, and pulse delay
time may be defined during the initialisation of the device. The
pulse delay time (underlap) controls the delay between turning
on and off the two power switches in each output phase of the
inverter bridge, in order to accommodate variations in the turn-
on and turn-off times of families of power devices.
The SA828 is easily controlled by a microprocessor and its
fully-digitalgenerationofPWMwaveformsgivesunprecedented
accuracy and temperature stability. Precision pulse shaping
capability allows optimum efficiency with any power circuitry.
The device operates as a stand-alone microprocessor
peripheral, reading the power waveform directly from an
internal ROM and requiring microprocessor intervention only
when operating parameters need to be changed.
An8-bitmultiplexeddatabusisusedtoreceiveaddressesand
data from the microprocessor/controller. This is a standard
MOTELTMbus,compatiblewithmostmicroprocessors/controllers.
Rotational frequency is defined to 12 bits for high accuracy
and a zero setting is included in order to implement DC
injection braking with no software overhead.
This family is pin and functionally compatible with the
MA828 PWM generator . Two standard wave shapes are
available to cover most applications. In addition, any
symmetrical wave shape can be integrated on-chip to order.
8
9
RPHT
SET TRIP
YPHT
BPHT
CLK
10
11
12
13
14
CS
TRIP
RPHB
V
SS
YPHB
BPHB
DP28
* = Intel bus format
† = Motorola bus format
1
28
27
26
25
24
23
22
21
20
19
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16
15
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AD
3
4
5
6
7
2
1
0
2
3
4
VDD
5
ZPPB
6
WR* (R/W†)
RD* (DS†)
ALE* (AS†)
RST
ZPPY
7
ZPPR
WSS
SA828
8
9
RPHT
SET TRIP
YPHT
BPHT
CLK
10
11
12
13
14
CS
TRIP
RPHB
V
SS
YPHB
BPHB
MP28
Fig. 1 Pin connections – top view (not to scale)
FEATURES
■ Fully Digital Operation
ORDERING INFORMATION
SA8281/IG/DP1S (28-lead DIL, sine + third harmonic
waveform)
■ Interfaces with Most Microprocessors
■ Wide Power-Frequency Range
■ 12-Bit Speed Control Accuracy
■ Carrier Frequency Selectable up to 24kHz
■ Waveform Stored in Internal ROM
■ Double Edged Regular Sampling
■ Selectable Minimum Pulse Width and Underlap Time
■ DC Injection Braking
SA8282/IG/DP1S (28-lead DIL, sine waveform)
SA8281/IG/MP1S (28-lead SOIC, Sine + third
harmonic waveform)
SA8382/IG/MP1S (28-lead SOIC, sine waveform)
MOTEL is a registered Trademark of Intel Corp. and Motorola Corp.