AN1625 STMicroelectronics, AN1625 Datasheet - Page 23

• Manufacturer Part Number: AN1625
• Description: L6235 THREE PHASE BRUSHLESS DC MOTOR DRIVER
• Manufacturer: STMicroelectronics

Figure 24. Power Dissipation formulae and results.
Electrical frequency
Average Current
Commutation Time
Total Dissipat-
Dissipating Pw
Dissipating Pw
Current Ripple
r.m.s. Current
Commutation
during Load
during Load
Diss. Power
PowerDMOS
Dissipating
Dissipating
Duty Cycle
Frequency
Load Time
Load Time
ing Power
Rise Time
Rise Time
Quiescent
Switching
Fall Time
Fall Time
Period
power
power
Time
Time
Pload = 1.91E-00
Pcom = 2.86E-01
Tcom = 9.60E-08
Tload = 5.66E-03
Prise = 1.58E-02
Trise =
Irms = 1.34E+00
fSW = 4.90E+04 [Hz]
Pfall = 3.00E-02
Tfall = 5.13E-05
Fel = 1.67E+02 [Hz]
Pq = 1.32E-01
D = 6.08E-01
P = 2.37E+00
T = 6.00E-03
I = 3.19E-01
I = 1.34E+00
5.65E-5
Result
[W]
[W]
[W]
[W]
[W]
[W]
[A]
[A]
[A]
[s]
[s]
[s]
[s]
[s]
-
Lm
–
ln
Ipk Rm
------------------------------------------------------------------------------------------------------------------ -
–
Ipk Rm 2 2Ipk Ron Ipk R s
–
ln
----------------------------------------------------------------------------------------------- -
Ipk Rm
+
Ipk Rs
–
Pq + Pcom + Pload + Pfall + Prise
2
-- - 2 V d Tfall
T
2.1*((2Ron+Rm)*Ipk+Vb)*toff/Lm
(2Vs · I · Tcom · Tload · fSW) / T
Vb+I(2*Ron+Rm))/(Vs -I*Rs)
+


(2Ron · Irms
2Ron Ipk
Ipk
+
Vs 2 Vd
Vs
Ipk
Vs 2 Vd
Vs / (250V/ s)
–
Rs
–
(1-D) / tOFF
Ipk
n*sp/60
T-6Trise
Ipk
Vs · Iq
AN1625 APPLICATION NOTE
1 / fel
+
–
Vs
2
–
2
--------------------------------------
–
–
-----
· Tload) / T
2
Trise
-------------- -
Vs
Rm
–
I
I
3
-------------------------------------------------------------------------------- -
2 Vd
+
1
+
+
------- -
–


2 Vd
+
3
I
Rs
2
exp
V s
-- -
T
2
– fall
--------------- -
Rm
+
T
Lm
----------------------------
--------------------------------------------- -
Rm
Rm
+
Lm
+
+
Rs
Rs
Rs
Lm
Rm
2
+
+
2Ron
Rs
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