STK672-080 View Datasheet(PDF) - SANYO -> Panasonic
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STK672-080
SANYO -> Panasonic
STK672-080 Datasheet PDF : 17 Pages
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STK672-080
Thermal Design
<Hybrid IC Average Internal Power Loss Pd>
The main elements internal to this hybrid IC with large average power losses are the current control devices, the
regenerative current diodes, and the current detection resistor. Since sine wave drive is used, the average power loss
during microstepping drive can be approximated by applying a waveform factor of 0.64 to the square wave loss during 2
phase excitation.
The losses in the various excitation modes are as follows.
2 phase excitation
fclock
Pd2EX
=
(Vsat
+
Vdf)
·
———
2
·
IOH
·
t2
+
—IO—H ·—fc—loc—k
2
· (Vsat · t1 + Vdf · t3)
1-2 phase excitation
fclock
Pd1-2EX
=
0.64
·
{(Vsat
+
Vdf)
·
———
4
· IOH · t2 +
—IO—H ·—fc—loc—k
4
· (Vsat · t1 + Vdf · t3)}
W1-2 phase excitation
PdW1-2EX = 0.64 · {(Vsat + Vdf) ·
fclock
———
8
· IOH · t2 +
—IO—H ·—fc—loc—k
8
· (Vsat · t1 + Vdf · t3)}
2W1-2 phase excitation
Pd2W1-2EX
=
0.64
·
{(Vsat
+
Vdf)
·
fclock
———
16
·
IOH
·
t2
+
—IO—H ·—fc—loc—k
16
·
(Vsat
·
t1
+
Vdf
·
t3)}
4W1-2 phase excitation
Pd4W1-2EX
=
0.64
·
{(Vsat
+
Vdf)
·
fclock
———
16
·
IOH
·
t2
+
—IO—H ·—fc—loc—k
16
·
(Vsat
·
t1
+
Vdf
·
t3)}
Here, t1 and t3 can be determined from the same formulas for all excitation methods.
–L
R + 0.35
t1 = ———— · n (1 – ————— · IOH)
R + 0.35
VCC1
–L
t3 = —— ·
n (———V—CC—1 +—0—.3—5 ——)
R
IOH · R + VCC1 + 0.35
However, the formula for t2 differs with the excitation method.
2
2 phase excitation t2 = ——— – (t1 +t3)
fclock
3
1-2 phase excitation t2 = ——— – t1
fclock
7
W1-2 phase excitation t2 = ——— – t1
fclock
2W1-2 phase excitation
15
t2 = ——— – t1
4W1-2 phase excitation
fclock
IOH
t3 t1
t2
Motor Phase Current Model Figure (2 Phase Excitation)
A13270
fclock: CLK input frequency (Hz)
Vsat: The voltage drop of the power MOSFET and the current detection resistor (V)
Vdf: The voltage drop of the body diode and the current detection resistor (V)
IOH: Phase current peak value (A)
t1: Phase current rise time (s)
t2: Constant-current operating time (s)
VCC1: Supply voltage applied to the motor (V)
L: Motor inductance (H)
t3: Phase switching current regeneration time (s) R: Motor winding resistance (W)
No. 6507-14/17
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