GSD200 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
GSD200 Datasheet PDF : 17 Pages
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GS-D200/GS-D200S
Ppw = 1.1 • [2•1.8•1•0.25+2•1•1•0.75 + 0.5 • 1]
Ppw = 1.1 • [0.9 + 1.5 + 0.5] = 3.19 W
The factor 1.1 takes into account the power dissi-
pation during the switching transient.
SLOW DECAY. The power dissipation during the
ON period is the same. The RECIRCULATION is
made internally through a power transistor
(Vsatsink) and a diode. The power dissipation is,
therefore:
Ppw = 1.1•[2 Vsat •Iph •D.C.+(Vsat+Vd)•Iph •(1-D.C.)]
Ppw = 1.1•[2•1.8 •1•0.25 + (1.8 + 1) • 1 • 0.75]
Ppw = 1.1 • [0.9 + 2.1] = 3.3 W
WAVE MODE. When operating in this mode the
power dissipation is given by values of FAST and
SLOW DECAY mode, because one phase is ener-
gized at any given time.
NORMAL MODE. At any given time, two windings
are always energized. The power dissipation of the
power output stage is therefore multiplied by a
factor 2.
HALF STEP. The power sequence, one-phase-on,
two-phase-on forces the power dissipation to be
1.5 times higher than in WAVE MODE when the
motor is running. In stall condition the worst case
for power dissipation is with two-phase-on i.e. a
power dissipation as in NORMAL MODE.
The following table summarizes the power dissipa-
tions of the output power stage of the GS-D200
when running for this example:
Fast Decay
Slow Decay
Wave
3.19 W
3.30 W
Normal
6.38 W
6.60 W
Half Step
6.38 W
6.60 W
q Calculate the total power dissipation for the GS-
D200 :
Ptot = Plogic + Ppw
In this example, for slow decay and normal mode
Ptot = 1.1 + 6.6 = 7.7 W
q The case temperature can now be calculated:
Tcase = Tamb + (Ptot•Rth) = 55 + (7.7 • 5) = 93.5 °C
q If the calculated case temperature exceeds the
maximum allowed case temperature, as in this
example, an external heat-sink is required and the
thermal resistance can be calculated according to:
Rthtot
=
Tcmax − Tamb
Ptot
=
85 − 55
7.7
=
3.9
°C
and then
Rthhs
=
Rth ⋅
Rth −
Rthtot
Rthtot
=
5 ⋅ 3.9
5 − 3.9
=
17.7°C
The following table gives the thermal resistance of
some commercially available heath-sinks that fit on
the GS-D200 module.
Manufacturer Part Number Rth (°C/W)
Thermalloy
6177
3
Thermalloy
6152
4
Thermalloy
6111
10
Fischer
SK18
3
Assman
V5440
4
Assman
V5382
4
Mounting
Horizontal
Vertical
Vertical
Vertical
Vertical
Horizontal
15/17
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